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Baking Problems Solved

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Baking ProblemsSolved

Second Edition

Stanley P. Cauvain

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Contents

Preface to the First Edition xxxiPreface to the Second Edition xxxiiiWoodhead Publishing Series in Food Science, Technology and Nutrition xxxv

1. Introduction to problem solving techniques

1.1 How to problem solve 21.1.1 Low-bread volume 31.1.2 Keyholing 4

1.2 The record 61.3 The analysis 91.4 Modelling techniques 121.5 Matching patterns and visualising changes 141.6 The information sources 16

1.6.1 Personal 171.6.2 Written 171.6.3 Constructing knowledge trees and knowledge fragments 231.6.4 Knowledge (computer)-based systems 261.6.5 The ‘Web’ 27

1.7 New product development 271.7.1 Concept 281.7.2 Product development investigation � prototype product 291.7.3 Scale-up to commercialisation assessment 301.7.4 Prototype trials on the plant 301.7.5 Pre-launch trials 301.7.6 Launch 301.7.7 On-going product maintenance/handover 31

1.8 Conclusions 31References 31

2. Raw materials

2.1 Wheat and grains 332.1.1 Can you explain the functions of the different compo-

nents in the wheat grain and, after milling, theircontributions to the manufacture of baked products? 33

2.1.2 We understand that millers often use a mixture ofdifferent wheats to manufacture the flours that theysupply to us. Can you explain why they do this? 36

v

2.1.3 Why are there so many varieties of wheat and howare they classified? 37

2.1.4 We have heard several experienced bakers talkingabout the ‘new harvest effect’ and the problems thatit can cause. Can you explain what is behind thisphenomena and how we can mitigate its effects? 39

2.1.5 We are a bakery working with a local farmer and millerto produce a range of local breads and want to usesome different varieties and forms of malted grains thatwe are producing. Can you advise us on any specialissues that we should be aware of? 40

2.1.6 Can we mix oats or oat products with our wheat floursto make bakery products? If so, are there any specialissues that we should be aware of? 41

2.1.7 What is micronized wheat? 422.2 Flours 43

2.2.1 Can you explain what the ash content means andshould we ask for it to be determined on our flours? 43

2.2.2 What does the term grade colour figure mean in flourspecifications? How is it measured? What are theimplications for bread quality? 45

2.2.3 We have the water absorption capacity of our flourassessed regularly but find that this is different to theactual water level that we use in the bakery. Whatare the reasons for this difference and is it importantfor breadmaking? 47

2.2.4 What effects will variations in flour protein contenthave on baked product quality? How is the propertymeasured? 50

2.2.5 There are many references to protein and glutenquality in the technical literature, how importantare these properties for bread and other bakedproducts? 52

2.2.6 I have seen that there are several different methodswhich can be used to assess flour protein quality,which one gives the most meaningful results? 53

2.2.7 We have been using a flour ‘fortified’ with dry glutenfor breadmaking. The bread is satisfactory when madeon a high-speed mixer but so less when we use alow-speed mixer. What is ‘dry gluten’ and can youexplain why we get different results when wechange mixers? 55

2.2.8 Why is the protein content of wholemeal bread flourtypically higher than that of white flours but the breadvolume is commonly smaller with the former? 56

2.2.9 We get a significant variation in the quality of ourwholemeal bread and rolls depending on which flour

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we purchase. What characteristics should we look forin a wholemeal flour specification to get moreconsistent results? 57

2.2.10 What is the Falling Number of a flour, how is itmeasured and what values should we specify forour flour miller? 58

2.2.11 What is damaged starch in flour? How is it damagedand how is it measured? What is its importancein baking? 59

2.2.12 What characteristics should we specify for whitebread flour and why? 61

2.2.13 As enzymes such as alpha-amylase are inactivatedby heat during baking, is it possible to use heattreatment of flour to inactivate the enzymes inlow Hagberg Falling Number flours before baking? 63

2.2.14 We are considering making traditional German-typerye breads and have researched the recipes andproduction methods. Do you have any suggestionsas to what characteristics we should have in therye flour? 64

2.2.15 We wish to add non-wheat fibres to some of ourbaked products to increase their healthiness.What fibres can we used, in what products andwhat potential technical problems should we beaware of? 65

2.2.16 Why is flour particle size important in cakemaking? 672.2.17 What is heat-treated flour and how can it be used? 682.2.18 What is chlorinated flour and how is it used? 692.2.19 What characteristics should we specify for cake flour? 712.2.20 We have had some wholemeal flour in stock for a

while and noticed that it has passed its use by date.Can we still use it? And what are there any relatedissues with white flours? 72

2.2.21 What are the active components in self-raising flour? 732.2.22 We have changed suppliers of our self-raising flour

and find that we are not achieving the same productvolume as before. If we adjust the recipe by addingmore baking powder we, find that the products tendtowards collapse. Can you explain why and how dowe overcome the problems? 74

2.2.23 What are ‘organic’ flours, how do they differ fromother flours and what will be the differences to thebaked product? 75

2.2.24 What characteristics should we specify for ourbiscuit and cookie flours? 76

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2.3 Fats 772.3.1 What are the critical properties of fats for making

bread, cakes and pastries? 772.3.2 Can you explain the different terms used to describe

bakery fats? What are the functionalities of thedifferent forms in baking? 79

2.3.3 Our bread doughs prove satisfactorily but they donot rise in the oven. On some occasions, they mayeven collapse and blisters form on the dough surfacein the corners of the pans. What is the cause of theseproblems? 81

2.3.4 What is the role of fat in the manufacture ofpuff pastry? 83

2.3.5 Our puff pastry fails to rise sufficiently even thoughwe believe that we are using the correct level of fat.Are we using the correct type of fat? 84

2.3.6 What is the role of fat in cakemaking? 852.3.7 We are making ‘all-butter’ cakes but find that after

baking they lack volume and have a firm eatingcharacter. Why is this and is there any way toimprove the cake quality? 86

2.3.8 We have been using oil in the production of oursponge cakes but we wish to change to using butter.Can you advise on how to do this? 87

2.3.9 We wish to produce a softer eating sponge cake andhave been trying to add fat or oil but cannot get thequality we are seeking. Is the addition of fat tosponge batters possible and what do we need todo to achieve the quality we are seeking? 88

2.3.10 We want to make a range of bakery products usingbutter as the main or only fat in the recipe. Can youadvise us of any special technical issues that weneed to take into when using butter? 89

2.3.11 We are using butter in several of our bakery productswhich comes in chilled at about 4�C (as cartons onpallets) and are encountering problems with variabilityin its processing. We recognise that is likely to beassociated with the temperature of the butter when weare using it. What is the best way to treat the butterto get a more consistent performance? 90

2.3.12 We are seeking to reduce the level of fat that we usein some of our cake recipes but find that simply takingfat out adversely changes our product quality.What are the possibilities of using ‘fat replacers’to help us with our strategy? 91

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2.4 Sugars and sweeteners 932.4.1 What type of sugar (sucrose) should we use for the

different products that we make in our bakery? 932.4.2 Can you explain some of the main features of

alternative sugars to sucrose, and how they mightbe used in baking? 95

2.4.3 Why are sugars added to some bread recipes butnot others? 97

2.5 Other ingredients 992.5.1 The chocolate fondant on our cream eclairs has

been falling off the top of the casing and gatherson the tray underneath as a sticky syrup. Whatcauses this and how can we prevent it? 99

2.5.2 When we changed our supply of bun spice wewere using in our Hot Cross buns, we experiencedproblems with slow gassing in the prover and flowingof the buns during baking. What can we do to avoidthese problems? 100

2.5.3 We wish to use milk powder in our fermented goodsand have heard that it is advisable to use aheat-treated form. Can you explain why this is so? 101

2.5.4 What are the functions of salt in baking, and howdo set about reducing the levels that we use? 102

2.5.5 We are using walnuts in our gateau buttercreamfilling and find that it turns black. It does not appearto be mould. What is the cause of this discolouration? 104

2.5.6 What is the role of emulsifier in the productionof sponge cake products? 105

2.5.7 What ingredients are commonly used as preservatives?Are there any particular benefits associated withdifferent ones? 107

2.5.8 What effect does vinegar have on bread and why isit added? 109

2.5.9 We have heard that alcohol can be used as apreservative. How is this achieved? 110

2.5.10 What are the possible alternatives to chemicallybased preservatives? 111

2.5.11 What are the differences between diastatic andnon-diastatic malt powders, and how can they beused in baking? 112

2.5.12 We read a lot about the different enzymes whichare now available and how they might be usedin baking. Can you tell us what they are and whatfunctions they have? 113

2.5.13 How do anti-staling enzymes work? Can they beused in cake as well as in bread and fermentedproducts? 116

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2.5.14 What is lecithin and how is it used in baking? 1172.5.15 We have been having some problems with the

quality of our bread, pastries and biscuits and onesolution that has been recommended to us is thatwe should add a reducing agent to our recipes. Can youtell us more about reducing agents, and how theyfunction in baked products? 118

2.6 Aeration 1212.6.1 I have heard that yeast requires oxygen before

it can work correctly, is this true? 1212.6.2 How does baker’s yeast produce carbon dioxide

in breadmaking? 1222.6.3 Are there any particular precautions that we should

take in handling, storing and using bakers’ yeastin the compressed form? 123

2.6.4 What are the causes of the dark brown patches wesometimes see on compressed baker’s yeast, and dothey have any effect on baked product quality? 125

2.6.5 We have been advised to store our compressed yeastin the refrigerator but our dough temperature ismuch higher, is this the correct thing to do? 126

2.6.6 We have seen references to a ‘lag phase’ for bakers’yeast; what does this means and what are theimplications for baking? 127

2.6.7 What different types of bakers’ yeast are available?Would there be any particular advantages for us touse an alternative to Saccromyces cerivisii in themanufacture of our fermented products? 128

2.6.8 What are the correct proportions of acids and alkalito use in baking powders? 130

2.6.9 What is meant by the term ‘double-acting’ bakingpowder, and what is the value of using such products? 131

2.6.10 Why is sodium bicarbonate frequently used aloneor in excess to the normal in baking powder for theproduction of ginger products? 132

2.7 Improvers 1332.7.1 What are bread improvers and why are they used? 1332.7.2 What are the differences between dough conditioners

and bread improvers? What consideration should wetake into account when choosing which one to use? 135

2.7.3 What are the functions of ascorbic acid in breadmaking? 1362.7.4 We have heard that soya flour is added in breadmaking

to make the bread whiter. Is this true, and if so howdoes it work? 138

2.7.5 I understand that an enzyme called alpha-amylase canbe added to flour or dough to improve bread qualitybut that there are several different forms. I have triedseveral and get different effects on bread softness.Which one(s) should I use? 139

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2.7.6 Why are emulsifiers used in bread improvers?And how do I decide which one I should be using? 141

2.7.7 What is L-cysteine hydrochloride, and what is it usedfor in bread improvers? 142

2.7.8 Can we add a reducing agent during doughmakingso that we can reduce the energy input requiredduring the mixing? 143

2.7.9 What is deactivated yeast and how is it used? 144

3. Key relationships between ingredients, recipesand baked product qualities

3.1 Introduction 1453.2 Structure of bread and fermented product recipes 1463.3 Some key relationships in the manufacture of bread

and fermented products 1463.4 Structure of laminated product recipes 1473.5 Some key relationships in the manufacture of laminated

products 1483.6 Structure of shortcrust product recipes 1483.7 Some key relationships in the manufacture of shortcrust

pastries 1493.8 Cakes � high- and low-ratio recipes 1493.9 Cakes and sponges � the role of recipe balance 1503.10 Some key relationships in the manufacture cakes and

sponges 151References 152

4. Bread and other fermented products

4.1 Bread 1534.1.1 We are producing a range of pan breads, some baked

in a rack oven and others in a deck oven, and findthat there are large indents or cavities in the base ofmany of the loaves. What is the cause of this effectand how can it be overcome? 153

4.1.2 We are experiencing a problem with the sides ofsandwich loaves caving in. Sometimes, the lid alsoshows the same problem, though to a lesser degree.Is the problem associated with overbaking? 155

4.1.3 We are producing hearth-style (oven-bottom) breads,baguettes and French sticks and are experiencingproblems with ragged cracks appearing along the sidesof the loaves. What are the likely causes of thisproblem? 156

4.1.4 We have noticed the development of a ‘fruity’ odourin our breads after they have been stored. The problem

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is particularly noticeable with our wholemeal products.What is the cause of this problem and are there anyremedies we can apply to prevent its occurrence? 158

4.1.5 When viewing the crumb appearance of our slicedbread, we notice the appearance of dark streaks andpatches which have a coarser cell structure and firmertexture than the rest of the crumb. Is this a problemwith uneven mixing? 159

4.1.6 Periodically, we observe the formation of large holesin the crumb of our pan breads and suspect that theadjustment to the pressure board on our final moulderis faulty; can you confirm our suspicions? 161

4.1.7 We have been having problems with holes appearingin different places in our pan breads. Can you explainwhere they come from and how to eliminate them?Is there any relationship between the holes that we seeinside dough pieces coming from the divider and theproblems that we are experiencing? 163

4.1.8 We are making open-top pan breads and find that thetop crust of some of our loaves is being lifted off duringthe slicing process. Sometimes, there is a holeunderneath the crust, whereas on other occasionsthere is not. Do you have an explanation for thisproblem? We have tried making the dough strongerby adding more improver but without any reductionin the problem; in fact, it may have beenslightly worse 168

4.1.9 We are using the Chorleywood bread process todevelop our doughs and apply a partial vacuum duringmixing to produce a fine and uniform cell structure inthe baked loaf. Sometimes, we observe that the cellstructure becomes more open even though the vacuumpump is still working. Can you explain the cause ofthis problem? 170

4.1.10 We are seeking to improve the quality of our breadproducts and are getting conflicting advice on whatthe optimum dough temperature ex-mixer should be.Can you advise us as to how to decide what is theoptimum temperature to use? 172

4.1.11 How can I calculate the amount of ice I need toreplace some of the added water when my finaldough temperature is too warm? 173

4.1.12 We are using spiral mixers for our bread doughs.What is the best mixing time to use? 176

4.1.13 Why is it necessary to control the temperatureof bread doughs? 178

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4.1.14 We have been experiencing some variation in crustcolour on our bread products. What causes breadcrust colour and why should it vary? 179

4.1.15 Why is the surface of some bread doughs cutbefore baking? 180

4.1.16 What are the best conditions to use for provingbread dough? 182

4.1.17 Can we freeze our unproved dough pieces and storethem for later use? 184

4.1.18 What happens when dough bakes? 1854.1.19 We make crusty breads in a retail store, and recently,

we have been having complaints about our productsgoing soft quickly. We have not changed our recipeor process. Can you help us understand what hashappened? 187

4.1.20 We have been comparing our bread with that of ourcompetitors and find that the crumb of our bread isfirmer. Can you explain why? 189

4.1.21 We are having problems keeping a uniform shapewith our bloomers. They tend to assume a bent or‘banana’ shape. This happens even though we takegreat care to straighten them when they are placed onthe trays. Can you explain why we get this problem? 191

4.1.22 We have been taught to always place the seam of ourmoulded bloomer dough pieces downwards on the traybefore proof but we do not take the same precautionswith our pan breads. Can you explain the relevance ofplacing the bloomer dough piece ‘seam down? Shouldwe also do this with our pan breads? 193

4.1.23 Can we make bread without using additives? What willbe the key features of the ingredients and process thatwe should use? 194

4.1.24 We make bread and rolls using a bulk fermentationprocess; can we use ascorbic acid (AA) to improveour bread quality? 195

4.1.25 We have had bread returned to us by the retail storethrough which it is sold. They are not satisfied withthe quality. We have some pictures of the productsconcerned. This seems to be a ‘one-off’ and we areat a loss to understand what has lead to the problem.Can you help us understand where the problemcame from? 196

4.1.26 We have noticed that loaves sometimes break onlyon one side of the pan but that the break is not formedconsistently on one side. Can you explain why this is? 198

4.1.27 We are making a range of crusty breads using a smallbread plant. We appreciate the value of having an open

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cell structure to encourage the formation and retentionof the crust. However, from time to time we havedifficulty in achieving the desired degree of opennessin the structure. Can you help us identify why thishappens? 199

4.1.28 During the manufacture of bread and other fermentedproducts, we sometimes have small quantities of‘leftover’ dough from a mixing, can we add theseback to other mixings or reuse it in other ways? 200

4.1.29 Our total time for bread production from flour tobaked loaf is set for about 6 hours. Currently, weuse a bulk fermentation time of 4 hours and a finalproof time of 90 minutes. We find that with increasedbread sales that we do not have enough provingcapacity. If we were to shorten the final proof time whatother changes would we have to make to maintain ourcurrent bread quality? 201

4.1.30 In breadmaking what is the difference between asponge and a ferment and when would they be used?We have also seen references to barms, can you tellus anything about these as well? 202

4.1.31 How would we prepare and use a sponge with theChorleywood Bread Process (CBP)? 203

4.1.32 Our bread and buns prove to a satisfactory height inabout 50 minutes, but we get no additional lift from theproducts in the oven. We have tried increasing itsstrength and using more improver, but whateverwe do we see no oven spring. Do you have any ideasas to why we are getting no oven lift? 204

4.1.33 We are experiencing a problem with loaves bakedin rack ovens since we bought new pans. As theenclosed photograph shows, they are joining togetherabove the pans. The portions of the loaves that touchhave no crust formation which makes them weakwhen they are depanned and handled. How can weprevent this from happening? 205

4.1.34 We wish to create a bolder shape and more open cellstructure with our crusty sticks and have recentlyincreased our dough development by mixing longer.Now, we experience problems with the productsjoining together in the oven. If we under-prove thedough pieces, we have problems with ragged breadand poor shapes. Should we reduce our mixing timeback to its original level? 207

4.1.35 We are finding that the crumb of our bread is too softfor slicing. We also notice a tendency for the sides of theloaves to slightly collapse inwards. We do not think thatconditions in our cooler have changed can youplease advise us of what to investigate? 209

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4.2 Other fermented products 2104.2.1 Can you suggest what steps could be taken to prevent

our round doughnuts shrinking or collapsing withina few minutes of leaving the fryer? 210

4.2.2 The fermented doughnuts we are making tend to bequite greasy to eat. Can you advise on how we canreduce this problem? 212

4.2.3 We have recently been experiencing difficultieswith the production of our bread rolls. The finishedrolls have poor volume with large holes in the crumb.Can you suggest measures we might take to eliminatethese faults? 213

4.2.4 We have been receiving complaints that our smallfermented products, such as rolls, teacakes and baps,are staling too quickly. Can you advise on how wecan improve the product softness? 214

4.2.5 Our fruit breads rise very slowly in the prover and failto rise any further in the oven. We make some unfruitedproducts with the same formulation and they aresatisfactory in all respects. Can you explain why? 216

4.2.6 Our fruited buns frequently collapse when they leavethe oven. We have tried baking them for longer butthis does not cure the problem. Our fruited loavesmade with the same dough do not have the problem.Can you advise? 217

4.2.7 We are making a fruited bun product and from timeto time experience problems with the product flowingout during proof and baking. Can you identify thecause and suggest a remedy? 218

4.2.8 When we cut open bread rolls and hamburger bunswhich have been stored in the deep freeze fora period of time we observe a white ring just insidethe crust which has a hard eating character.Where does this problem come from? 219

4.2.9 We are not a large bakery but are planning topart-bake and freeze bread products for bake-off atsome later time; what points should we be aware of? 221

4.2.10 When we reheat par-baked products we find that theyremain soft for only a short period of time, typicallyan hour or so, but they quickly go hard and becomeinedible. If we do not reheat them we find thatpar-baked products can stay fresh for several days.What causes the change in the rate of firming? Is itthe additional moisture lost on the second bake? 223

4.2.11 While reading about the manufacture of hamburgerbuns, we see references to the pH and TTA of the brew.

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What do these terms mean? When are theyused and what is the purpose of controlling them? 224

4.2.12 We have problems with our retarded teacakes whichhave large holes underneath the top crust. We do notexperience the same problem with scratch-madeproducts. Why is this? 225

4.2.13 When we retard our rolls before proving and bakingwe sometimes see a dark mark on the base immediatelyafter baking and cooling. We see similar problemswith our retarded doughnuts. Is this mould becausewe have left the products to cool on the trays beforewrapping? We use silicon paper to bake on, does thisaggravate the problem? 226

4.2.14 When we retarding our roll and stick doughs overnightbut find that the products made baked from them arecovered with many small, white, almost translucentspots on the surface. We do not get the same problemwith our scratch production using the same recipe.Can you give an explanation for their appearanceand advise on how to get rid of them? 227

4.2.15 We have been experimenting with retarding fruitedrolls and buns. We find that the smaller products arequite satisfactory but loaves made using the sameformulation and baked in pans have ‘stains’ around thefruit pieces and a darker crust colour than we wouldlike. Can you please advise us on how to cure theseproblems? 229

4.2.16 We are retarding rolls in our retarder-prover and findthat they lean to one side and lose weight duringstorage. Can you advise us as to how to cure theseproblems? 230

4.2.17 We are producing a variety of finger rolls using whiteflour. The rolls must be soft eating and retain theirsoftness for several days; to achieve this we are usinga roll concentrate. To help us cope with fluctuations indemand we freeze a proportion of our production, butfind that the defrosted product is very fragile and mayeven fall apart. Can you help us overcome thisproblem? 231

4.2.18 Can you tell us something about Chinese steamedbreads and their production? We make our standardbreads using the Chorleywood bread process, wouldwe be able to make these products using this process? 232

4.2.19 What is cinnamon twist bread and how couldwe make it? 234

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5. Cakes, sponges and muffins

5.1 What is the flour-batter method of cakemaking? 2355.2 What is the sugar-batter method of cakemaking? 2375.3 Why do our cake batters made by the sugar-batter method

sometimes have a curdled appearance? And does thisaffect final cake quality? 238

5.4 We are experiencing some variation in cake quality,especially volume. How important is it to control thetemperature of our cake batters? 239

5.5 How do we calculate the likely temperature of our cakebatter at the end of mixing and what temperature shouldwe aim for? 240

5.6 We use an all-in cakemaking method for the manufactureof our plain cakes. Occasionally, we experience loss ofvolume and the top of the baked product becomes peakedrather than flat. It has been suggested that we areover-mixing the batter and developing the gluten in theflour; is this correct? 242

5.7 When making fruit cakes, we find that the fruit settlesto the bottom of the cake after baking. Why is this? Andwhat can we do about it? 244

5.8 Can we freeze cake batters and what happens to themduring storage? 246

5.9 Why do cakes go mouldy? 2475.10 In the light of the previous question, why do heavily fruited

cakes go mouldy more slowly? And are there any specialconditions we should observe when making Christmaspuddings. 249

5.11 Unexpectedly, we are getting mould between our decoratedcakes and the board on which they sit. Why should thishappen? 250

5.12 We are experiencing mould growth on the surface of ouriced Christmas cakes. This is the first time we have had thisproblem and cannot explain why. Can you? 251

5.13 We are experiencing a ‘musty’, off-odour developing inour cakes, even though we store them in a deep freeze.Can you advise? 252

5.14 We regularly measure the water activity of the individualcomponents in our composite cake products and try toadjust them to reduce the differential between them toreduce moisture migration. Even though we do this we arestill having problems keeping the cake moist duringshelf-life. Can you give us some advice as to what we maybe doing wrong? 253

5.15 When we take our cup cakes from the oven, we find thatthe paper cases they were baked in fall off. How do weavoid this problem? 254

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5.16 Our small cakes often shrink excessively during cooling.How can we avoid this? 255

5.17 Our cake sheets tend to lack volume, are uneven in shapeand have cores in the crumb. Can you advise? 256

5.18 Sometimes, our unit cake has a poor (coarse) texture.How can we improve it? 257

5.19 What are the causes of the small, white speckles wesometimes see on the crust of our cakes? 258

5.20 We are getting an orange discoloration of the crumbof our fruit cakes. Can you offer an explanation? 259

5.21 When we add fresh fruits such as blackcurrants to our cakebatters, we sometimes find that they fail to keep their colourduring baking and often discolour the batter adjacent to thefruit. Can you offer an explanation and a solution to theproblem? 260

5.22 We are baking fruit cakes using sultanas and find that whilethe centre of the crumb is a nice golden yellow around threesides of the cut face of the cake (the bottom and the twosides) the colour is much browner and darker in colour.Can you help us identify the cause of this problem? 261

5.23 We are using natural colours in our slab cake baking andfind that we get variable results, not just from batch tobatch but sometimes within a batch. Can you suggest anyreasons for this problem? 262

5.24 We are getting large holes in the crumb of our fruited slabcake but are not sure why this is happening. Can you offersome advice? 263

5.25 Our sultana cakes are collapsing. What can we do toremedy this problem? 264

5.26 Why do cakes sometimes sink in the middle? 2655.27 We are encountering an intermittent fault with our round

high ratio cakes in that a shiny ring with pitting is seenon the cake surface. What factors are likely to giverise to this fault? 266

5.28 Our fruited cakes are fine to eat soon after production buttend to become drier eating after a few days; why is this? 267

5.29 We have seen that our cake quality varies when we changefrom one type of oven to another, even when they registerthe same temperature. Why is this? 269

5.30 How important is the temperature of cakes at the point ofwrapping? 271

5.31 What precautions should we take when freezing cake andsponge products? 273

5.32 What happens to the batter when cakes enter the oven,and how can you tell when a cake is baked? 274

5.33 What are the advantages of having the oven filled whenbaking slab or other cakes? 276

5.34 Why do we add extra acid to make white cake batters? 277

xviii Contents

5.35 We have been making a range of different cake sizes usingthe same plain batter and get varying quality results in termsof their shape and appearance despite having adjusted thebaking conditions. Do you have any advice? 278

5.36 We would like to change the physical dimensions of someour cake products to make different sizes and shapes do youhave any advice that you can give us as to how to adjustthe batter deposit weights for the different pan sizes? 279

5.37 We have recently changed the acid that we use for ourbaking powder mix and have adjusted the neutralising valueaccordingly. Subsequently, we have been having someproblems achieving the volume and shape that we wantwith our small cakes. Can you explain why we are havingthese problems? 281

5.38 What are the factors which control the shape andappearance of the top of a cake? 282

5.39 Currently, we add alcohol, in the form of spirits or liqueurs,to our celebration cakes after they have been baked andcooled. We leave them for a few days after treating them,but this is taking up a lot of space. What advantages/disadvantages would there be if we added the alcoholto the batter before baking? 284

5.40 Why do some traditional sponge cakemaking methodsspecify a delay in the addition of the sodium bicarbonateand the use of hot water? Would this approach haveany practical applications today? 285

5.41 We have been experiencing problems with collapseof our sponge sandwiches which leaves the product with adepression forming on the top of the cake and an area ofcoarse cell structure in the crumb. What causes thisproblem? 286

5.42 Recently, we have been experiencing problems with oursponge sandwich cakes assume a peaked shape duringbaking. We have not changed ingredients or recipe.Can you suggest why we are having this problem? 288

5.43 We are having problems with the bottom crust of oursponge cake products becoming detached after baking.We also notice that the corners of the product becomerounded and the texture close. Can you offer anyexplanation for these problems? 289

5.44 When making sponge drops, we find that the last ones tobe deposited are not as good as the first ones. Why is this? 291

5.45 From time to time, we experience problems with Swiss rollscracking on rolling. Can you help identify the causes of theproblem? 292

5.46 What are the key elements to consider when makingchocolate cakes with cocoa powder? 293

Contents xix

5.47 We have been making cake muffins and find that whenwe cut them open, they have large vertical holesin the crumb. Why is this and how do we eliminate them? 294

5.48 Why do some of our cake muffins lean to one sideduring baking? 295

5.49 What is Baumkuchen and how is it made? 297

6. Biscuits, cookies, crackers and wafers

6.1 How important are the dough and batter temperaturesin biscuit, cookie, cracker and wafer making? 299

6.2 What is ‘Vol’ and what is its function in biscuits doughs? 3036.3 A batch of our biscuits containing oatmeal has developed a

‘soapy’ after-taste which makes them unpalatable.Why is this? 304

6.4 From time to time, we have noticed a white discolourationon the surface of our all-butter shortbread. Can you explainwhy this occurs? 305

6.5 We produce biscuits-containing powdered fructose whichwe cream with the fat and sucrose before adding the otheringredients. Recently, we have seen the appearance of brownspots on the product. Do you know what causes this effect? 306

6.6 How do biscuits and crackers get broken during storage,even if they are not disturbed? Can we stop this fromhappening? 307

6.7 We are making a ginger crunch cookie, but find that weexperience variations size. Can you advise? 308

6.8 When making ginger nuts, we find that we do not alwaysget the degree of cracking that we would like. Why is this? 309

6.9 We are trying to make soft-eating cookies and are having adegree of success with the recipe that we are using.The products are not expected to have a long shelf-life, butwe find that they are going hard too quickly. Can yousuggest any ways of extending the period of time that the cookieswill stay soft eating? 310

6.10 We assemble a selection pack of biscuits and cookies, oneof which is a rectangular product coated on the top withicing. When the pack is opened after some time this coatedbiscuit has a ‘bowed’ shape, the base is soft eating butthe icing remains hard. Can you suggest reasons forthese changes? 312

6.11 We are experiencing dark brown specks on the surfaceof our plain sheeted biscuits. We have been using the samerecipe for a number of years without a problem. Can youidentify the cause of the specks and suggest a remedy? 313

6.12 We are having some problems with packing our rotarymoulded biscuit lines. When we measure the thicknessof the biscuits, we have noticed that some are thicker

xx Contents

than others. Can you suggest any reasons why we should begetting such variations? 314

6.13 We are having intermittent problems with shrinkage of oursemi-sweet biscuits after they have been cut out from thedough sheet. How can we stop this from happening? 315

6.14 We are experiencing blistering on the surface of oursemi-sweet biscuits and sometimes see cavities underthe top crust and little hollows on the bottom. Can youidentify the possible cause of the problemand suggest a solution? 317

6.15 We are manufacturing short-dough biscuits using a rotarymoulder and have been offered an alternative supply ofsugar. We notice that the new sugar is more granular thanthe material we have been using previously; would thishave any effect on biscuit quality? 319

6.16 Is it possible to reduce the level of sugar in our biscuit andcookie recipes without affecting their quality? What wouldbe the alternatives we could use to sucrose? 320

6.17 We would like to reduce the level of fat in our biscuitrecipes. How can we do this? 322

6.18 What are main issues that we should be aware of in themanufacture of savoury puff biscuits? 323

6.19 Is it important to use a fermentation period in themanufacture of crackers? What effects are we likelyto see from variations in the fermentation time? 324

6.20 We have installed a new cutting and creaming machine forthe preparation of our sandwich wafers and refurbishedthe production area. We have found that we are now gettingintermittent problems with the wafer sheets breaking up oncutting. Can you offer an explanation as to why this mightbe happening? 325

6.21 Our chocolate-coated wafer biscuits are prone to cracking.Can you suggest why this happens and how we can avoidthe problem? 326

6.22 We are experiencing intermittent problems with glutenformation in our wafer batter. What causes this problem? 327

6.23 What are Shrewsbury biscuits and how are they made? 3286.24 We find that our Viennese fingers go soft very quickly after

baking. How can we prevent this from happening? 329

7. Pastries

7.1 Laminated pastries 3317.1.1 What causes puff pastry to rise during baking? 3317.1.2 We are experiencing a problem with our puff pastry

which fails to lift and shows no sign of layeringon baking. Why is this? 333

Contents xxi

7.1.3 Why do we get a less regular lift in our puff pastrywhen we use the Scotch method compared with theEnglish or French? 334

7.1.4 What are the purposes of the resting periods in themanufacture of laminated products? 335

7.1.5 We have been experiencing some problems withexcessive shrinking of our puff pastry products.Can you advise as to what the likely causes might be? 337

7.1.6 Why are acids sometimes added to puff pastry? 3387.1.7 What is the best way to reuse puff pastry trimmings?

At present, we are feeding them back into the sheetingstages 339

7.1.8 We are experiencing problem with the discolourationof unbaked puff paste stored under refrigeratedconditions. Sometimes black spots appear on thesurface. Can you explain why this happens and adviseon how to avoid it? 341

7.1.9 We have been experiencing considerable variability inprocessing our short and puff paste products; sometimes,we have problems with paste shrinkage and on otheroccasions we get stickiness. We have checked ourweighing systems and can find no problems withingredients additions. We have no climatic temperaturecontrol in the factory or ingredient storage facilities,are these likely to significant contributors to theproblems? 342

7.1.10 Why should croissant and Danish pastry doughsbe given less lamination than puff pastry? 344

7.1.11 What is the optimum level of fat to use in theproduction of puff pastry? 345

7.1.12 We would like to reduce the level of fat that weuse to make our puff pastry but would like to retainpastry lift. Can you provide us with some guidance asto how we might achieve our objectives? 346

7.1.13 We are experiencing distortion of our pastry shapes.We have measured the shrinkage but find that it is not even.We have also noticed that the laminatedproducts are experiencing some variation inproduct lift. What might be the causes ofthese problems? 348

7.1.14 We are looking to start production of croissant.In my travels, I have seen many variations on productswhich are called croissant. Why are there so manydifferent forms and how are they made? 350

7.1.15 We wish to make croissant with the moulded endsjoining to form a circle but find that they open upduring baking. Can you suggest how we canovercome this problem? 353

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7.1.16 We have been trying to freeze fully proved croissantfor later bake-off. Can you identify the importantcriteria for their successful production? 355

7.1.17 We are making puff pastry, Danish pastries andcroissant using all butter and often have problemswith the processing of the pastes and feel that we donot get the best of quality from the final products.What are the best processing temperatures andconditions when using butter with such products? 356

7.2 Short pastry 3577.2.1 What characteristics should we specify for the flour

that we should use for making savoury and sweet shortpastes for unbaked chilled and frozen shells andscratch-baked products? 357

7.2.2 Why is the hot water method preferred for theproduction of savoury pastry but not forsweetened pastry? 358

7.2.3 What method should we use to calculate the watertemperature to deliver a consistent final savouryshort paste temperature at the end of mixing? 359

7.2.4 We are manufacturing savoury short pastry productswhich are blocked out to shape and lids by sheeting apaste with the same formulation. We wish to increaseour production rate and are considering reducing oreliminating the rest periods in the productionsequence. Can you advise us on their functionand any consequences that we may face if wechange them? 360

7.2.5 From time to time, we experience problems with thesheeting of our short paste, in particular it cracks orfails to remain cohesive. Can you suggest why thishappens? 361

7.2.6 We are producing unbaked meat pies but find that theshort pastry lid cracks on freezing. The cracks becomelarger when the product thaws out and during bakingthe filling may boil out leaving an unsightly blemishon the surface. Why is this and what can we doabout it? 362

7.2.7 Some of the short pastry cases that we make forrestaurants to fill and serve have been returned tous as being ‘mouldy’ on the base. We were surprisedas we thought that the water activity of the shells wastoo low to support mould growth, and when weexamined the bottom of the pastries, we can see thatthere is a discolouration but we do not think that it ismould. Can you identify what has caused thediscolouration and how to eliminate it? 363

Contents xxiii

7.2.8 We are having problems with the custard tarts that wemake. The pastry shell is very pale coloured, but if weincrease the baking time, we find that the custard fillingis not very stable and shrinks away from the case duringstorage. If we raise the baking temperature, the custardfilling boils and breaks down during storage. Can yougive us any advice on how to get a better pastry colourwithout causing problems with the filling? Sometimesthe baked custard has a watery appearance. 364

7.2.9 We have been receiving complaints from customersthat that our short pastry which we use for meat pieproducts has an unpleasant eating character which theydescribe as ‘waxy’. The comments are most oftenrelated to the base pastry in the pies. Why is this? 366

7.2.10 Why does our pork pie pastry go soft during storageand what can we do to make our pastry crisper? 367

7.2.11 We are having difficulty in blocking out savoury piepaste in foils, there is a tendency for the dough to stickto the die block causing the base of the foil case tobecome misshapen. We do not have the same problemswith our sweetened paste, can you explain why? 369

7.2.12 Why do our baked pastries and quiches have smallindents in the base which project upwards and arepale in colour? They are baked in individual foils. 370

7.2.13 How can we make the sweet pastry that we use withour apple pies crisper eating? 371

7.2.14 How do we avoid ‘boil-out’ of our pie fillings? 3737.2.15 We wish to reuse pastry trimmings but find that

sometimes we experience a ‘soapy’ taste in the finalproduct. Can you suggest a cause for the flavour andhow best to reuse the trimmings to avoid this and anyother potential problems? 374

8. Other bakery products

8.1 What are the most important factors which control thevolume of choux paste products? 375

8.2 Why are cream buns baked under covers and eclairsare not? 377

8.3 Our choux buns collapse during baking. Can you suggestwhy this happens? 378

8.4 We are getting a grey�green colouration to ourchoux buns. Can you explain why this should happen? 379

8.5 Why is powdered ammonium carbonate or ‘vol’ added tochoux paste? 380

8.6 We wish to make a large batch of eclair cases and storethem for a few days before filling and icing them.Can you advise on the best way to keep them topreserve their quality? 381

xxiv Contents

8.7 We stand our finished choux buns on U-shaped cardboardand wrap them in a cellulose-based film. Recently, we haveobserved the growth of mould colonies on the products.Why is this? 382

8.8 Our scones are made from frozen dough but frequently lackvolume. We also find that the crumb colour is rather brown.Can you offer suggestions to improve our product quality? 383

8.9 Some of our scones have a coarse break at the side and anopen crumb cell structure but the results are not consistent.Can you please suggest steps we might take to obtaina better and more consistent product quality? 384

8.10 We wish to extend the shelf-life of our scones. How canwe do this? 385

8.11 The surface of our scones is covered with speckles of ayellowish-brown colour. We are using GDL as the acidcomponent in the baking powder. Can you suggest whywe have this problem? 386

8.12 Why should particular care be taken when washing sconeswith egg wash to ensure that none runs down the sidesof the pieces of dough? 387

8.13 We are freezing a range of unbaked, chemically aeratedproducts including scones and cake batters and now want toinclude some variations using fresh fruits. We have carriedout a number of trials and have a range of issues which aremostly related to the fragility of the fruit. Can you providesome advice? 388

8.14 We have been asked to improve the sensory qualities ofour scones and have been able to do this by a number ofrecipe changes. Although these changes have been largelysatisfactory for our plain scones the fruited varieties,we make still tend to be too dry eating. Do you have anysuggestions as to how we can make them moremoist eating? 390

8.15 We make and bake scones on a daily basis. Recently, weplaced them unbaked in a refrigerator but the baked qualitywas poor. We used a retarder instead but we still find thatthe products were small in volume. Is it possible to retardunbaked scones and still produce an acceptable product? 391

8.16 I am having difficulty with royal icing which will not hardenadequately. Can you advise? 392

8.17 I have heard that off-odours can be caused by the icingused for cake decorations. Is this true? 393

8.18 After 2 days our royal icing tends to turn yellow.Can this discolouration be prevented? 394

8.19 We are receiving complaints of opaque spots on our fudgeicing. Can you suggest a remedy? 395

Contents xxv

8.20 After storing our coated products overnight, we find thatcracks form in fondant coating. Can you suggest ways toovercome this problem? 396

8.21 We make sugar paste shapes and store them in plasticcontainers for later use. In a few days, the shapes softenand are inclined to droop. Can you suggest how we mightovercome this problem? 397

8.22 We would like to store our heavily fruited wedding cakesafter coating with marzipan for some time before we icethem but find that the marzipan hardens. Why is this andhow can we achieve our aims? 398

8.23 We are not getting the quality of finish that we would likefrom the fondant we are using, often the finished productslack gloss. Can you give us some tips on how to improveour use of the fondant? 399

8.24 We bake our meringues on aluminium sheets and are havingproblems with the meringues becoming discoloured. Canyou offer any advice on how to eliminate this problem? 400

8.25 When making Italian meringues why is the boiling sugarwater added slowly? 401

8.26 We are experiencing cracking of our meringue shells duringbaking. Why is this? 402

8.27 We are having problems with softening of coffee meringuesin which we use coffee powder as the flavouring. Is this thecause of the problem? 403

8.28 On some occasions, our almond macaroons exhibit verycoarse cracks on the surface instead of the fine cracks weare seeking. We have not been able to trace the cause,can you help? 404

8.29 What are stotty cakes and how are they produced? 4058.30 Why does our whipped cream collapse on standing? 4068.31 Recently, we experienced a problem with a fishy taint in a

batch of buttercream. Can you suggest why? 4088.32 We are experiencing seepage of our jam in our frozen fresh

cream gateau when they are thawed; can we avoid this? 4098.33 We have recently been experiencing ‘weeping’ from our

non-dairy cream formulation. This shows itself as a ‘soggy’layer where the cream is in contact with the cake. Can youplease advise on how to cure the problem? 410

8.34 How can we prevent our apple pie filling going mouldywithin a few days without changing the filling recipe? 412

8.35 In some of our apple pies, we find that the filling has turnedblue. Why should this happen? 413

8.36 Can you suggest a solution to the problem of shrinkagein our apple pie filling? 414

8.37 Why have our crumpets lost their characteristic surfaceholes? 415

xxvi Contents

8.38 Why is a small amount of bicarbonate of soda addedto pikelet batters just before baking? 416

8.39 The chocolate coating on our marshmallow teacakes cracksduring storage. Can you offer an explanation and solutionto the problem? 417

8.40 What causes the white bloom which sometimes occurs onchocolate coatings? 418

8.41 The bakers’ chocolate coating we use has recently tendedto flake off our eclairs. Can you identify a likely causeof the problem? 419

8.42 What is ganache? 4208.43 What are staffordshire oatcakes and how are they made? 4218.44 What are farls and how are they made? 4228.45 The edges of our soda farls become gummy a couple of

days after baking. What is the cause of this quality defect? 4238.46 We want to add freshly baked deep-pan pizza to the

product range that we sell through our bakery shop.We do not want to make small quantities of doughthroughout the day for their manufacture, but when wetry to work with a larger bulk of dough, we find that thevariation in quality is too great, even when we refrigeratethe dough in our retarder. What would be a suitableway for us to make the bases? 424

8.47 We freeze our unbaked pizza bases in a nitrogen tunnel.On defrosting and baking, we get bubbles forming on thetop of the base accompanied with an open crumb cellstructure. Can you suggest ways of overcoming theseproblems? 425

8.48 What are the key characteristics of cake doughnuts andhow do they differ from other types of doughnut? 426

8.49 We have been producing a range of cake doughnuts whichare iced with various flavoured coatings. To copewith peak demands, we have taken to freezing a quantityof the products. We have observed that progressively duringstorage a crystalline growth appears on the productsWhen they are defrosted the growth disappears.Can you identify why this happens? 427

8.50 After a short period of chilled storage, we observecrater-like crystalline formations on our cheesecaketopping. Do you know why this occurs? 429

8.51 We want to extend the mould-free shelf-life of our flourtortilla (Fig. 8.4) but when we try the dough more acidwe have processing problems. What options could weconsider for achieving our aim? 431

8.52 What are the origins of pappadams? 4328.53 What is kebab bread? 4348.54 What is balady bread? 4358.55 How are chapattis made? 436

Contents xxvii

8.56 What are corn (Maize) tortillas? And how are they made? 4378.57 What is trencher bread and how was it used? 4388.58 What is the product known as a Grant loaf? 440

9. Processes and equipment

9.1 I see many references to ‘no-time’ doughmaking methods.What does this term mean and what is its relevance? 443

9.2 We are considering the purchase of a new mixer for themanufacture of our bread using a no-time dough process.There are two types of mixer which seem to be appropriatefor our plant production needs, the spiral-type and theCBP-compatible type, but before making our decision, weneed to understand any issues with respect to doughprocessing and final bread quality. Can you please advise us? 445

9.3 Can you explain the role energy in the ChorleywoodBread Process? 448

9.4 We are looking to buy a new final moulder for our breadbakery. Can you advise us on the key features whichshould look for and how they might impact on final breadquality? 450

9.5 Why is a bread dough piece coiled after sheeting? Does thenumber coils achieved have any impact on bread quality? 451

9.6 What is the function of four-piecing or cross-panning inbreadmaking? 453

9.7 What is purpose of the ‘knocking-back’ the dough whenusing a bulk fermentation process to make bread? 455

9.8 We have two bread lines running side-by-side with thesame equipment bought at different times. We are usingthe CBP and do not quite get the same volume and cellstructure when making the same pan bread product. Wecompensate by adjusting yeast and improver level but donot get the same crumb cell structure. Can you help usunderstand what is happening? 457

9.9 We have both spiral and twin-arm type mixers and wouldlike to produce a finer cell structure with our sandwichbreads; can you suggest ways in which we might achievethis aim? 459

9.10 We have been freezing some of our bakery products inorder to have products available in times of peak demand.We notice that there is ‘snow’ or ‘ice’ in the bags when weremove them from the freezer. Can you tell us why thishappens and how it can be avoided? 461

9.11 We have been deep freezing bread products and experiencea number of problems with different products. With crustyproducts, we observe that the crust falls off while with someother products we find that longer periods of storage leadto the formation of white, translucent patches in the crumb

xxviii Contents

which are very hard eating. Are the problems related to theperformance of our freezer? 463

9.12 We have seen references to the Milton Keynes Process butcan find very little technical information on the processCan you tell me what it is (was) it and how it is (was) used? 465

9.13 Can you explain the principles of vacuum cooling of bakedproducts and its potential applications? 467

10. Testing methods

10.1 What is meant by hydrogen ion concentration andhow is the pH scale determined? 469

10.2 In some technical literature, there is reference to batterspecific gravity or relative density. What is this?How is it measured? And what is its relevance tocake and sponge making? Why is the volume of thebaked product referred to in terms of specific volume? 472

10.3 What value is there in measuring colour of bakeryproducts and how can we carry out the measurements? 473

10.4 How can we measure the texture of our bread and cakes?Currently, we use a hand squeeze test for bread and applya ‘score’ to the results 475

10.5 How can we measure baked product shape and volume? 47710.6 What is the phosphotase test? 47910.7 What is the Bohn’s spot test and what is it used for? 480

11. What?

11.1 What is the meaning of the term synerisis when appliedto bread? 481

11.2 What is a super-saturated solution? 48311.3 I have heard the terms ‘glycaemic index’ and ‘glycaemic

load’ used when describing bakery products. What arethey and what is the difference? 484

11.4 What are pro- and prebiotics and how can they be usedin our bread products? 486

11.5 Can you please explain the difference between hydrationand hydrolysis? What is their relevance to the manufactureof baked goods? 487

11.6 What is meant by the term ‘glass transition temperature’and what is its relevance to baking? 488

11.7 What does the term MVTR mean when applied topackaging, and what is the relevance to baked products? 489

11.8 What is meant by the term ‘modified atmospherepackaging’ and how can we use this approach in theproduction of baked products? 491

Contents xxix

11.9 We have heard people referring to synergy in the use ofingredients in baking processes, what is this process andcan you identify any examples? 493

11.10 What are polyols and how are they used in baking? 49411.11 What is acrylamide? Where does it come from and how

do we limit it? 49611.12 What is osmotic pressure and what is its relevance

to baking? 49711.13 What is resistant starch? 49811.14 What are the origins of the cottage loaf? 499

Index 501

xxx Contents

Preface to the First Edition

From time to time we all encounter problems in the manufacture of baked

products. Sometimes they are seen as defects in the baked product which

arise for no obvious reasons. On other occasions we simply need to under-

stand what are the most important criteria to consider if we have to or want

to change ingredients or processing conditions.

Solving baking problems has always been the province of the bakery

‘experts’, those mysterious persons who always seems to know how to

restore the loss of quality, or what recipe and process changes to introduce

to achieve a given quality.

To those of us who do not have the necessary expert knowledge, such

persons are often held in awe. Yet problem solving is not as much of a

‘black art’ as we might think. With a methodical approach and keen observa-

tion then the answers to many of our bakery problems are indeed

‘elementary’.

Our expert problem solvers usually have one distinctive advantage �experience. They have seen it all before! Or if they have not, then they know

agood reference book or another expert to consult.

This book owes much to the work of bakers, technologists and cereal

scientists formerly working for the British Baking Industries Research

Association and later the Flour Milling and Baking Research Association,

both based at Chorleywood, Hertfordshire, in the United Kingdom. Over 50

years these experts in cereal science, milling and baking studied and identi-

fied many causes of bakery problems and recorded them for others to access.

In this book we have taken the opportunity to synthesise their work, and to

update and enlarge it from our own experiences.

We hope that you will find some value in our efforts and that the contents

of this book will help you become that mysterious bakery expert.

S.P. Cauvain and L.S. Young

xxxi

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Preface to the Second Edition

In combining Baking Problems Solved and More Baking Problems Solved

into a single edition it was important to bear several things in mind. One was

that while baking technology continues to evolve many baking problems can

still be related to the underlying fundamental principles of baking and so in

one sense remain essentially unchanged. A good number of the problems

and solutions described in this edition will be familiar to readers of the ear-

lier works. Some updating of the information given with each question and

answer will be inevitable because of changes in raw materials, processes and

in response to legislative pressures, market forces and consumer preferences.

Because baking is a continually evolving technology new problems

requiring new solutions emerge and there are a good number of examples in

this edition. Technical knowledge moves on and so in a number of cases it is

possible to provide more relevant or comprehensive answers to known pro-

blems. New problems often emerge when any one of the components of the

complex ingredient-recipe-process balance is changed. “We never used to

have the problem” is a common statement that one hears which only under-

lies the need to have a good grasp of underlying principles. New product

development also throws out its own challenges, especially when traditional

boundaries are over-stepped. In many ways this is good news for baking

because it generates the need for more research to understand what contri-

butes to product quality and loss.

None of the above comments negate the need for a systematic approach

to problem solving though new ideas are always valued, hopefully some of

the additions to Chapter 1, Introduction to Problem Solving Techniques, fall

into this category. So in developing this edition the balance between ‘old’

and ‘new’ information was uppermost in my mind. I hope that I have

succeeded.

Finally, I would like to take this opportunity to thank two people for their

contributions to this second edition. First, the late Linda Young, my

co-author on both previous works, whose support is greatly missed but

whose inspiration lives on. Secondly, my special thanks go to my colleague

and friend Rosie Clark for her sterling efforts in bringing together and recon-

ciling the contents of the two previous titles; her input to this second edition

has been invaluable.

S.P. Cauvain

xxxiii


Woodhead Publishing Seriesin Food Science, Technologyand Nutrition

1. Chilled foods: A comprehensive guide

Edited by C. Dennis and M. Stringer

2. Yoghurt: Science and technologyA. Y. Tamime and R. K. Robinson

3. Food processing technology: Principles and practice

P. J. Fellows

4. Bender’s dictionary of nutrition and food technology Sixth edition

D. A. Bender

5. Determination of veterinary residues in food

Edited by N. T. Crosby

6. Food contaminants: Sources and surveillance

Edited by C. Creaser and R. Purchase

7. Nitrates and nitrites in food and water

Edited by M. J. Hill

8. Pesticide chemistry and bioscience: The food-environment

challenge

Edited by G. T. Brooks and T. Roberts

9. Pesticides: Developments, impacts and controls

Edited by G. A. Best and A. D. Ruthven

10. Dietary fibre: Chemical and biological aspects

Edited by D. A. T. Southgate, K. W. Waldron, I. T. Johnson

and G. R. Fenwick

xxxv

11. Vitamins and minerals in health and nutrition

M. Tolonen

12. Technology of biscuits, crackers and cookies Second editionD. Manley

13. Instrumentation and sensors for the food industry

Edited by E. Kress-Rogers

14. Food and cancer prevention: Chemical and biological aspects

Edited by K. W. Waldron, I. T. Johnson and G. R. Fenwick

15. Food colloids: Proteins, lipids and polysaccharides

Edited by E. Dickinson and B. Bergenstahl

16. Food emulsions and foams

Edited by E. Dickinson

17. Maillard reactions in chemistry, food and health

Edited by T. P. Labuza, V. Monnier, J. Baynes and J. O’Brien

18. The Maillard reaction in foods and medicine

Edited by J. O’Brien, H. E. Nursten, M. J. Crabbe and J. M. Ames

19. Encapsulation and controlled release

Edited by D. R. Karsa and R. A. Stephenson

20. Flavours and fragrancesEdited by A. D. Swift

21. Feta and related cheeses

Edited by A. Y. Tamime and R. K. Robinson

22. Biochemistry of milk products

Edited by A. T. Andrews and J. R. Varley

23. Physical properties of foods and food processing systems

M. J. Lewis

24. Food irradiation: A reference guide

V. M. Wilkinson and G. Gould

25. Kent’s technology of cereals: An introduction for students of food

science and agriculture Fourth editionN. L. Kent and A. D. Evers

xxxvi Woodhead Publishing Series in Food Science, Technology and Nutrition

26. Biosensors for food analysis

Edited by A. O. Scott

27. Separation processes in the food and biotechnology industries:Principles and applications

Edited by A. S. Grandison and M. J. Lewis

28. Handbook of indices of food quality and authenticity

R. S. Singhal, P. K. Kulkarni and D. V. Rege

29. Principles and practices for the safe processing of foods

D. A. Shapton and N. F. Shapton

30. Biscuit, cookie and cracker manufacturing manuals Volume 1:

Ingredients

D. Manley


Biscuit doughs

D. Manley


Biscuit dough piece forming

D. Manley


Baking and cooling of biscuits

D. Manley


Secondary processing in biscuit manufacturing

D. Manley


Biscuit packaging and storage

D. Manley

36. Practical dehydration Second edition

M. Greensmith

37. Lawrie’s meat science Sixth edition

R. A. Lawrie

38. Yoghurt: Science and technology Second editionA. Y. Tamime and R. K. Robinson

Woodhead Publishing Series in Food Science, Technology and Nutrition xxxvii

39. New ingredients in food processing: Biochemistry and agriculture

G. Linden and D. Lorient

40. Benders’ dictionary of nutrition and food technology Seventhedition

D. A. Bender and A. E. Bender

41. Technology of biscuits, crackers and cookies Third edition

D. Manley

42. Food processing technology: Principles and practice Second

editionP. J. Fellows

43. Managing frozen foods

Edited by C. J. Kennedy

44. Handbook of hydrocolloids

Edited by G. O. Phillips and P. A. Williams

45. Food labeling

Edited by J. R. Blanchfield

46. Cereal biotechnology

Edited by P. C. Morris and J. H. Bryce

47. Food intolerance and the food industry

Edited by T. Dean

48. The stability and shelf-life of food

Edited by D. Kilcast and P. Subramaniam

49. Functional foods: Concept to product

Edited by G. R. Gibson and C. M. Williams

50. Chilled foods: A comprehensive guide Second editionEdited by M. Stringer and C. Dennis

51. HACCP in the meat industry

Edited by M. Brown

52. Biscuit, cracker and cookie recipes for the food industry

D. Manley

xxxviii Woodhead Publishing Series in Food Science, Technology and Nutrition

53. Cereals processing technology

Edited by G. Owens

54. Baking problems solvedS. P. Cauvain and L. S. Young

55. Thermal technologies in food processing

Edited by P. Richardson

56. Frying: Improving quality

Edited by J. B. Rossell

57. Food chemical safety Volume 1: Contaminants

Edited by D. Watson

58. Making the most of HACCP: Learning from others’ experience

Edited by T. Mayes and S. Mortimore

59. Food process modeling

Edited by L. M. M. Tijskens, M. L. A. T. M. Hertog and B. M. Nicolaı

60. EU food law: A practical guide

Edited by K. Goodburn

61. Extrusion cooking: Technologies and applications

Edited by R. Guy

62. Auditing in the food industry: From safety and quality toenvironmental and other audits

Edited by M. Dillon and C. Griffith

63. Handbook of herbs and spices Volume 1

Edited by K. V. Peter

64. Food product development: Maximising success

M. Earle, R. Earle and A. Anderson

65. Instrumentation and sensors for the food industry Second edition

Edited by E. Kress-Rogers and C. J. B. Brimelow

66. Food chemical safety Volume 2: Additives

Edited by D. Watson

Woodhead Publishing Series in Food Science, Technology and Nutrition xxxix

67. Fruit and vegetable biotechnology

Edited by V. Valpuesta

68. Foodborne pathogens: Hazards, risk analysis and controlEdited by C. de W. Blackburn and P. J. McClure

69. Meat refrigeration

S. J. James and C. James

70. Lockhart and Wiseman’s crop husbandry Eighth edition

H. J. S. Finch, A. M. Samuel and G. P. F. Lane

71. Safety and quality issues in fish processing

Edited by H. A. Bremner

72. Minimal processing technologies in the food industries

Edited by T. Ohlsson and N. Bengtsson

73. Fruit and vegetable processing: Improving quality

Edited by W. Jongen

74. The nutrition handbook for food processors

Edited by C. J. K. Henry and C. Chapman

75. Colour in food: Improving quality

Edited by D. MacDougall

76. Meat processing: Improving qualityEdited by J. P. Kerry, J. F. Kerry and D. A. Ledward

77. Microbiological risk assessment in food processing

Edited by M. Brown and M. Stringer

78. Performance functional foods

Edited by D. Watson

79. Functional dairy products Volume 1

Edited by T. Mattila-Sandholm and M. Saarela

80. Taints and off-flavours in foods

Edited by B. Baigrie

81. Yeasts in food

Edited by T. Boekhout and V. Robert

xl Woodhead Publishing Series in Food Science, Technology and Nutrition

82. Phytochemical functional foods

Edited by I. T. Johnson and G. Williamson

83. Novel food packaging techniquesEdited by R. Ahvenainen

84. Detecting pathogens in food

Edited by T. A. McMeekin

85. Natural antimicrobials for the minimal processing of foods

Edited by S. Roller

86. Texture in food Volume 1: Semi-solid foods

Edited by B. M. McKenna

87. Dairy processing: Improving quality

Edited by G. Smit

88. Hygiene in food processing: Principles and practice

Edited by H. L. M. Lelieveld, M. A. Mostert, B. White and J. Holah

89. Rapid and on-line instrumentation for food quality assurance

Edited by I. Tothill

90. Sausage manufacture: Principles and practice

E. Essien

91. Environmentally-friendly food processingEdited by B. Mattsson and U. Sonesson

92. Bread making: Improving quality

Edited by S. P. Cauvain

93. Food preservation techniques

Edited by P. Zeuthen and L. Bøgh-Sørensen

94. Food authenticity and traceability

Edited by M. Lees

95. Analytical methods for food additives

R. Wood, L. Foster, A. Damant and P. Key



Woodhead Publishing Series in Food Science, Technology and Nutrition xli

97. Texture in food Volume 2: Solid foods

Edited by D. Kilcast

98. Proteins in food processingEdited by R. Yada

99. Detecting foreign bodies in food

Edited by M. Edwards

100. Understanding and measuring the shelf-life of food

Edited by R. Steele

101. Poultry meat processing and quality

Edited by G. Mead

102. Functional foods, ageing and degenerative disease

Edited by C. Remacle and B. Reusens

103. Mycotoxins in food: Detection and control

Edited by N. Magan and M. Olsen

104. Improving the thermal processing of foods


105. Pesticide, veterinary and other residues in food

Edited by D. Watson

106. Starch in food: Structure, functions and applicationsEdited by A.-C. Eliasson

107. Functional foods, cardiovascular disease and diabetes

Edited by A. Arnoldi

108. Brewing: Science and practice

D. E. Briggs, P. A. Brookes, R. Stevens and C. A. Boulton

109. Using cereal science and technology for the benefit of consumers:

Proceedings of the 12PthP International ICC Cereal and Bread

Congress, 24 � 26PthP May, 2004, Harrogate, UK

Edited by S. P. Cauvain, L. S. Young and S. Salmon

110. Improving the safety of fresh meat

Edited by J. Sofos

xlii Woodhead Publishing Series in Food Science, Technology and Nutrition

111. Understanding pathogen behaviour: Virulence, stress response

and resistance

Edited by M. Griffiths

112. The microwave processing of foods

Edited by H. Schubert and M. Regier

113. Food safety control in the poultry industry

Edited by G. Mead

114. Improving the safety of fresh fruit and vegetables

Edited by W. Jongen

115. Food, diet and obesity

Edited by D. Mela

116. Handbook of hygiene control in the food industry

Edited by H. L. M. Lelieveld, M. A. Mostert and J. Holah

117. Detecting allergens in foodEdited by S. Koppelman and S. Hefle

118. Improving the fat content of foods

Edited by C. Williams and J. Buttriss

119. Improving traceability in food processing and distribution

Edited by I. Smith and A. Furness

120. Flavour in food

Edited by A. Voilley and P. Etievant

121. The Chorleywood bread process

S. P. Cauvain and L. S. Young

122. Food spoilage microorganisms

Edited by C. de W. Blackburn

123. Emerging foodborne pathogens

Edited by Y. Motarjemi and M. Adams

124. Benders’ dictionary of nutrition and food technology Eighth

edition

D. A. Bender

Woodhead Publishing Series in Food Science, Technology and Nutrition xliii

125. Optimising sweet taste in foods

Edited by W. J. Spillane

126. Brewing: New technologiesEdited by C. Bamforth



128. Lawrie’s meat science Seventh edition

R. A. Lawrie in collaboration with D. A. Ledward

129. Modifying lipids for use in food

Edited by F. Gunstone

130. Meat products handbook: Practical science and technology

G. Feiner

131. Food consumption and disease risk: Consumer�pathogen

interactionsEdited by M. Potter

132. Acrylamide and other hazardous compounds in heat-treated foods

Edited by K. Skog and J. Alexander

133. Managing allergens in food

Edited by C. Mills, H. Wichers and K. Hoffman-Sommergruber

134. Microbiological analysis of red meat, poultry and eggs

Edited by G. Mead

135. Maximising the value of marine by-products

Edited by F. Shahidi

136. Chemical migration and food contact materials

Edited by K. Barnes, R. Sinclair and D. Watson

137. Understanding consumers of food products

Edited by L. Frewer and H. van Trijp

138. Reducing salt in foods: Practical strategies

Edited by D. Kilcast and F. Angus

xliv Woodhead Publishing Series in Food Science, Technology and Nutrition

139. Modelling microorganisms in food

Edited by S. Brul, S. Van Gerwen and M. Zwietering

140. Tamime and Robinson’s Yoghurt: Science and technologyThird edition

A. Y. Tamime and R. K. Robinson

141. Handbook of waste management and co-product recovery in food

processing Volume 1

Edited by K. W. Waldron

142. Improving the flavour of cheeseEdited by B. Weimer

143. Novel food ingredients for weight control

Edited by C. J. K. Henry

144. Consumer-led food product development

Edited by H. MacFie

145. Functional dairy products Volume 2

Edited by M. Saarela

146. Modifying flavour in food

Edited by A. J. Taylor and J. Hort

147. Cheese problems solved

Edited by P. L. H. McSweeney

148. Handbook of organic food safety and quality

Edited by J. Cooper, C. Leifert and U. Niggli

149. Understanding and controlling the microstructure of complex

foods

Edited by D. J. McClements

150. Novel enzyme technology for food applications

Edited by R. Rastall

151. Food preservation by pulsed electric fields: From research to

application

Edited by H. L. M. Lelieveld and S. W. H. de Haan

Woodhead Publishing Series in Food Science, Technology and Nutrition xlv

152. Technology of functional cereal products

Edited by B. R. Hamaker

153. Case studies in food product developmentEdited by M. Earle and R. Earle

154. Delivery and controlled release of bioactives in foods and

nutraceuticals

Edited by N. Garti

155. Fruit and vegetable flavour: Recent advances and future prospects

Edited by B. Bruckner and S. G. Wyllie

156. Food fortification and supplementation: Technological, safety and

regulatory aspects

Edited by P. Berry Ottaway

157. Improving the health-promoting properties of fruit and

vegetable products

Edited by F. A. Tomas-Barberan and M. I. Gil

158. Improving seafood products for the consumer

Edited by T. Børresen

159. In-pack processed foods: Improving quality


160. Handbook of water and energy management in food processingEdited by J. Klemes, R.. Smith and J.-K. Kim

161. Environmentally compatible food packaging

Edited by E. Chiellini

162. Improving farmed fish quality and safety

Edited by Ø. Lie

163. Carbohydrate-active enzymes

Edited by K.-H. Park

164. Chilled foods: A comprehensive guide Third edition

Edited by M. Brown

165. Food for the ageing population

Edited by M. M. Raats, C. P. G. M. de Groot and W. A Van Staveren

xlvi Woodhead Publishing Series in Food Science, Technology and Nutrition

166. Improving the sensory and nutritional quality of fresh meat

Edited by J. P. Kerry and D. A. Ledward

167. Shellfish safety and qualityEdited by S. E. Shumway and G. E. Rodrick

168. Functional and speciality beverage technology

Edited by P. Paquin

169. Functional foods: Principles and technology

M. Guo

170. Endocrine-disrupting chemicals in food

Edited by I. Shaw

171. Meals in science and practice: Interdisciplinary research and

business applications

Edited by H. L. Meiselman

172. Food constituents and oral health: Current status and futureprospects

Edited by M. Wilson

173. Handbook of hydrocolloids Second edition


174. Food processing technology: Principles and practice Third edition

P. J. Fellows

175. Science and technology of enrobed and filled chocolate,

confectionery and bakery products

Edited by G. Talbot

176. Foodborne pathogens: Hazards, risk analysis and control

Second edition

Edited by C. de W. Blackburn and P. J. McClure

177. Designing functional foods: Measuring and controlling food

structure breakdown and absorption

Edited by D. J. McClements and E. A. Decker

178. New technologies in aquaculture: Improving production efficiency,

quality and environmental management

Edited by G. Burnell and G. Allan

Woodhead Publishing Series in Food Science, Technology and Nutrition xlvii

179. More baking problems solved

S. P. Cauvain and L. S. Young

180. Soft drink and fruit juice problems solvedP. Ashurst and R. Hargitt

181. Biofilms in the food and beverage industries

Edited by P. M. Fratamico, B. A. Annous and N. W. Gunther

182. Dairy-derived ingredients: Food and neutraceutical uses

Edited by M. Corredig

183. Handbook of waste management and co-product recovery in food

processing Volume 2

Edited by K. W. Waldron

184. Innovations in food labeling

Edited by J. Albert

185. Delivering performance in food supply chainsEdited by C. Mena and G. Stevens

186. Chemical deterioration and physical instability of food and

beverages

Edited by L. H. Skibsted, J. Risbo and M. L. Andersen

187. Managing wine quality Volume 1: Viticulture and wine quality

Edited by A. G. Reynolds

188. Improving the safety and quality of milk Volume 1: Milk

production and processing


189. Improving the safety and quality of milk Volume 2: Improving

quality in milk products


190. Cereal grains: Assessing and managing quality

Edited by C. Wrigley and I. Batey

191. Sensory analysis for food and beverage quality control: A practical

guide


xlviii Woodhead Publishing Series in Food Science, Technology and Nutrition

192. Managing wine quality Volume 2: Oenology and wine quality


193. Winemaking problems solvedEdited by C. E. Butzke

194. Environmental assessment and management in the food industry

Edited by U. Sonesson, J. Berlin and F. Ziegler

195. Consumer-driven innovation in food and personal care products

Edited by S. R. Jaeger and H. MacFie

196. Tracing pathogens in the food chain

Edited by S. Brul, P. M. Fratamico and T. A. McMeekin

197. Case studies in novel food processing technologies: Innovations in

processing, packaging, and predictive modeling

Edited by C. J. Doona, K. Kustin and F. E. Feeherry

198. Freeze-drying of pharmaceutical and food productsT.-C. Hua, B.-L. Liu and H. Zhang

199. Oxidation in foods and beverages and antioxidant applications

Volume 1: Understanding mechanisms of oxidation and

antioxidant activity

Edited by E. A. Decker, R. J. Elias and D. J. McClements

200. Oxidation in foods and beverages and antioxidant applicationsVolume 2: Management in different industry sectors

Edited by E. A. Decker, R. J. Elias and D. J. McClements

201. Protective cultures, antimicrobial metabolites and bacteriophages

for food and beverage biopreservation

Edited by C. Lacroix

202. Separation, extraction and concentration processes in the food,beverage and nutraceutical industries

Edited by S. S. H. Rizvi

203. Determining mycotoxins and mycotoxigenic fungi in food and feed

Edited by S. De Saeger

204. Developing children’s food products

Edited by D. Kilcast and F. Angus

Woodhead Publishing Series in Food Science, Technology and Nutrition xlix

205. Functional foods: Concept to product Second edition

Edited by M. Saarela

206. Postharvest biology and technology of tropical and subtropicalfruits Volume 1: Fundamental issues

Edited by E. M. Yahia

207. Postharvest biology and technology of tropical and subtropical

fruits Volume 2: Acai to citrus


208. Postharvest biology and technology of tropical and subtropicalfruits Volume 3: Cocona to mango


209. Postharvest biology and technology of tropical and subtropical

fruits Volume 4: Mangosteen to white sapote


210. Food and beverage stability and shelf lifeEdited by D. Kilcast and P. Subramaniam

211. Processed Meats: Improving safety, nutrition and quality

Edited by J. P. Kerry and J. F. Kerry

212. Food chain integrity: A holistic approach to food traceability,

safety, quality and authenticity

Edited by J. Hoorfar, K. Jordan, F. Butler and R. Prugger

213. Improving the safety and quality of eggs and egg products

Volume 1

Edited by Y. Nys, M. Bain and F. Van Immerseel

214. Improving the safety and quality of eggs and egg products

Volume 2

Edited by F. Van Immerseel, Y. Nys and M. Bain

215. Animal feed contamination: Effects on livestock and food safety

Edited by J. Fink-Gremmels

216. Hygienic design of food factories

Edited by J. Holah and H. L. M. Lelieveld

l Woodhead Publishing Series in Food Science, Technology and Nutrition

217. Manley’s technology of biscuits, crackers and cookies Fourth

edition

Edited by D. Manley

218. Nanotechnology in the food, beverage and nutraceutical industries

Edited by Q. Huang

219. Rice quality: A guide to rice properties and analysis

K. R. Bhattacharya

220. Advances in meat, poultry and seafood packaging

Edited by J. P. Kerry

221. Reducing saturated fats in foods

Edited by G. Talbot

222. Handbook of food proteins


223. Lifetime nutritional influences on cognition, behaviour andpsychiatric illness

Edited by D. Benton

224. Food machinery for the production of cereal foods, snack foods

and confectionery

L.-M. Cheng

225. Alcoholic beverages: Sensory evaluation and consumer researchEdited by J. Piggott

226. Extrusion problems solved: Food, pet food and feed

M. N. Riaz and G. J. Rokey

227. Handbook of herbs and spices Second edition Volume 1


228. Handbook of herbs and spices Second edition Volume 2


229. Breadmaking: Improving quality Second edition

Edited by S. P. Cauvain

230. Emerging food packaging technologies: Principles and practice

Edited by K. L. Yam and D. S. Lee

Woodhead Publishing Series in Food Science, Technology and Nutrition li

231. Infectious disease in aquaculture: Prevention and control

Edited by B. Austin

232. Diet, immunity and inflammationEdited by P. C. Calder and P. Yaqoob

233. Natural food additives, ingredients and flavourings

Edited by D. Baines and R. Seal

234. Microbial decontamination in the food industry: Novel methods

and applications

Edited by A. Demirci and M.O. Ngadi

235. Chemical contaminants and residues in foods

Edited by D. Schrenk

236. Robotics and automation in the food industry: Current and future

technologies

Edited by D. G. Caldwell

237. Fibre-rich and wholegrain foods: Improving quality

Edited by J. A. Delcour and K. Poutanen

238. Computer vision technology in the food and beverage industries

Edited by D.-W. Sun

239. Encapsulation technologies and delivery systems for food

ingredients and nutraceuticalsEdited by N. Garti and D. J. McClements

240. Case studies in food safety and authenticity

Edited by J. Hoorfar

241. Heat treatment for insect control: Developments and applications

D. Hammond

242. Advances in aquaculture hatchery technology

Edited by G. Allan and G. Burnell

243. Open innovation in the food and beverage industry

Edited by M. Garcia Martinez

244. Trends in packaging of food, beverages and other fast-moving

consumer goods (FMCG)Edited by N. Farmer

lii Woodhead Publishing Series in Food Science, Technology and Nutrition

245. New analytical approaches for verifying the origin of food

Edited by P. Brereton

246. Microbial production of food ingredients, enzymes andnutraceuticals

Edited by B. McNeil, D. Archer, I. Giavasis and L. Harvey

247. Persistent organic pollutants and toxic metals in foods

Edited by M. Rose and A. Fernandes

248. Cereal grains for the food and beverage industries

E. Arendt and E. Zannini

249. Viruses in food and water: Risks, surveillance and control

Edited by N. Cook

250. Improving the safety and quality of nuts

Edited by L. J. Harris

251. Metabolomics in food and nutritionEdited by B. C. Weimer and C. Slupsky

252. Food enrichment with omega-3 fatty acids

Edited by C. Jacobsen, N. S. Nielsen, A. F. Horn and A.-D. M.

Sørensen

253. Instrumental assessment of food sensory quality: A practical guide


254. Food microstructures: Microscopy, measurement and modeling

Edited by V. J. Morris and K. Groves

255. Handbook of food powders: Processes and properties

Edited by B. R. Bhandari, N. Bansal, M. Zhang and P. Schuck

256. Functional ingredients from algae for foods and nutraceuticalsEdited by H. Domınguez

257. Satiation, satiety and the control of food intake: Theory and

practice

Edited by J. E. Blundell and F. Bellisle

258. Hygiene in food processing: Principles and practice Second edition

Edited by H. L. M. Lelieveld, J. Holah and D. Napper

Woodhead Publishing Series in Food Science, Technology and Nutrition liii

259. Advances in microbial food safety Volume 1

Edited by J. Sofos

260. Global safety of fresh produce: A handbook of best practice,innovative commercial solutions and case studies

Edited by J. Hoorfar

261. Human milk biochemistry and infant formula manufacturing

technology

Edited by M. Guo

262. High throughput screening for food safety assessment: Biosensortechnologies, hyperspectral imaging and practical applications

Edited by A. K. Bhunia, M. S. Kim and C. R. Taitt

263. Foods, nutrients and food ingredients with authorised EU health

claims: Volume 1

Edited by M. J. Sadler

264. Handbook of food allergen detection and controlEdited by S. Flanagan

265. Advances in fermented foods and beverages: Improving quality,

technologies and health benefits

Edited by W. Holzapfel

266. Metabolomics as a tool in nutrition research

Edited by J.-L. Sebedio and L. Brennan

267. Dietary supplements: Safety, efficacy and quality

Edited by K. Berginc and S. Kreft

268. Grapevine breeding programs for the wine industry


269. Handbook of antimicrobials for food safety and qualityEdited by T. M. Taylor

270. Managing and preventing obesity: Behavioural factors and dietary

interventions

Edited by T. P. Gill

271. Electron beam pasteurization and complementary food processing

technologiesEdited by S. D. Pillai and S. Shayanfar

liv Woodhead Publishing Series in Food Science, Technology and Nutrition

272. Advances in food and beverage labelling: Information and

regulations

Edited by P. Berryman

273. Flavour development, analysis and perception in food and

beverages

Edited by J. K. Parker, S. Elmore and L. Methven

274. Rapid sensory profiling techniques and related methods:

Applications in new product development and consumer research

Edited by J. Delarue, J. B. Lawlor and M. Rogeaux

275. Advances in microbial food safety: Volume 2

Edited by J. Sofos

276. Handbook of antioxidants for food preservation

Edited by F. Shahidi

277. Lockhart and Wiseman’s crop husbandry including grassland:

Ninth editionH. J. S. Finch, A. M. Samuel and G. P. F. Lane

278. Global legislation for food contact materials

Edited by J. S. Baughan

279. Colour additives for food and beverages

Edited by M. Scotter

280. A complete course in canning and related processes 14th Edition:

Volume 1

Revised by S. Featherstone


Volume 2



Volume 3


283. Modifying food texture: Volume 1: Novel ingredients and

processing techniques

Edited by J. Chen and A. Rosenthal

Woodhead Publishing Series in Food Science, Technology and Nutrition lv

284. Modifying food texture: Volume 2: Sensory analysis, consumer

requirements and preferences

Edited by J. Chen and A. Rosenthal

285. Modeling food processing operations

Edited by S. Bakalis, K. Knoerzer and P. J. Fryer

286. Foods, nutrients and food ingredients with authorised EU health

claims Volume 2

Edited by M. J. Sadler

287. Feed and feeding practices in aquacultureEdited by D. Allen Davis

288. Foodborne parasites in the food supply web: Occurrence and

control

Edited by A. Gajadhar

289. Brewing microbiology: design and technology applications for

spoilage management, sensory quality and waste valorisationEdited by A. E. Hill

290. Specialty oils and fats in food and nutrition: Properties, processing

and applications

Edited by G. Talbot

291. Improving and tailoring enzymes for food quality and

functionalityEdited by R. Yada

292. Emerging technologies for promoting food security: Overcoming

the World Food Crisis

Edited by C. Madramootoo

293. Innovation and future trends in food manufacturing and supply

chain technologiesEdited by C. E. Leadley

294. Functional dietary lipids: Food formulation, consumer issues and

innovation for health

Edited by T. Sanders

295. Handbook on natural pigments in food and beverages: Industrial

applications for improving colorEdited by R. Carle and R. M. Schweiggert

lvi Woodhead Publishing Series in Food Science, Technology and Nutrition

296. Integrating the packaging and product experience in food and bev-

erages: A road-map to consumer satisfaction

Edited by P. Burgess

297. The Stability and shelf life of food Second edition

Edited by Persis Subramaniam and Peter Wareing

298. Multisensory flavor perception: From fundamental neuroscience

through to the marketplace

Edited by Betina Piqueras-Fiszman and Charles Spence

299. Flavor: From food to behaviors, wellbeing and healthEdited by Andree Voilley, Christian Salles, Elisabeth Guichard and

Patrick Etievant

300. Developing food products for consumers with specific dietary

needs

Edited by Wayne Morley and Steve Osborn

301. Advances in food traceability techniques and technologies:Improving quality throughout the food chain

Edited by Montserrat Espineira and J. Francisco Santaclara

302. Innovative food processing technologies: Extraction, separation,

component modification and process intensification

Edited by Kai Knoerzer, Pablo Juliano, and Geoffrey Smithers

303. Steamed breads: Ingredients, process and qualitySidi Huang and Diane Miskelly

304. Handbook of hygiene control in the food industry, Second Edition

Edited by Huub Lelieveld, Domagoj Gabric, and John Holah (Editors)

305. Handbook for sensory and consumer-driven new product develop-

ment: Innovative technologies for the food and beverage industry

Maurice O’Sullivan

306. Early nutrition and long-term health: Mechanisms, consequences

and opportunities

Edited by Jose M. Saavedra and Anne M. Dattilo

Woodhead Publishing Series in Food Science, Technology and Nutrition lvii


Chapter 1

Introduction to Problem-Solving Techniques

You can’t solve a problem with the same type of thinking that caused it.

Einstein

The quote from Einstein may seem like a statement of the obvious, but after

many years of experience in the baking industry, I have seen that the obvious

is constantly overlooked when it comes to trying to solve problems or

develop new products and processes. Indeed, there is relatively little differ-

ence between solving a problem and creating a new product, in both cases,

you are required to use different thinking to that you would normally use for

established products and processes. In essence, both scenarios are vindica-

tions of Einstein’s view.

Problems that show as unexpected variations in bakery product quality

do occur from time to time. Often considerable time, effort and money

are required to identify the causes and solutions concerned. Unexpected

quality variations are not the exclusive province of any particular size of

manufacturing unit: they can occur in both large and small bakeries. Nor are

they exclusive to the production bakery: Even the best-controlled test bakery

or laboratory can experience unexpected fluctuations in intermediates or final

product quality. Because the outcome of a baking operation depends on com-

plex interactions between the raw materials, recipe and process used, it is

often the case that it is only when the final product leaves the oven

that quality defects are detected. There are relatively fewer occasions when

intermediate products (e.g., dough, batter, paste) exhibit quality defects

which require an immediate change to be made.

Many bakery operations still have artisan or craft (small-scale) roots. Even

with the arrival of industrial-scale baking many years ago, the manufacturing

principles still rely on understanding heuristic rules and relatively limited data

analysis. The level of automation and the ability to collect and analyse

data from an industrial bakery still lags a long way behind that of other

1Baking Problems Solved. DOI: http://dx.doi.org/10.1016/B978-0-08-100765-5.00001-1

© 2017 Elsevier Ltd. All rights reserved.

http://dx.doi.org/10.1016/B978-0-08-100765-5.00001-1

manufacturing environments. There is some routine data collection and

analysis for production and business management purposes (e.g., yield from a

given set of raw materials), or for legislative reasons (e.g., baking losses to

determine point-of-sale weight or product moisture content), but the collection

and integration of data on-line for the optimisation of bakery of bakery

processes and products remains meagre (Cauvain, 2015). The challenge lies as

much with knowing what to measure and what data to collect, as it does with

the analysis. In such contexts, the emphasis on delivering the appropriate

product quality will inevitably on combining a methodical approach with

relevant knowledge.

There is no magic to problem solving. It is normally achieved through

critical observation, structured thought processes and access to suitable

sources of information. In this chapter, I offer a guide to some of the meth-

ods that might be employed when trying to solve bakery-related problems.

In doing so, as noted above, we must recognise that baking is a complex

mixture of ingredient and process interactions, so that the solutions to our

problems may not always be instant in nature and because ingredients and

processes change, new solutions are always being discovered. The complex

interactions which underpin baking dictate that there are seldom unique

solutions to individual problems. In the majority of cases, individual quality

defects are overcome by changing a number of ingredient and process

factors some of which will be apparently unrelated though careful study will

often reveal that relationships do exist even where they are masked by more

prominent effects.

It would also be appropriate at this stage to deal with the somewhat

amorphous term ‘quality’. Ultimately, the decision of what is the ‘right’

product quality lies with the consumer, what is acceptable or ‘good’ for one

consumer may be unacceptable or ‘bad’ for another. For the baker perhaps

the best basis for deciding what the right product quality is depends on

getting repeat product sales. In many of the questions and answers related

to bakery production which follow, there is an implicit understanding that a

particular quality defect is delivering unacceptable (bad) final product

quality. In providing potential solutions to particular problem, it is recog-

nised that the choice of a particular solution will depend on many factors,

including cost and practicality of application. The answers given should

be seen as a guide as to possible solutions and so are often given with a

degree of flexibility as to application.

1.1 HOW TO PROBLEM SOLVE

Successful problem solving usually requires a methodical approach. It is

perfectly possible to stumble quickly on the required solution by chance but

more often than not a haphazard approach to problem solving is wasteful of

time, resources and money. In addition, stumbling on the solution by chance

2 Baking Problems Solved

often means that the root cause of the problem remains unidentified and the

opportunity is lost for the systematic assembly of information which may

be valuable for avoiding or solving similar problems in the future. Not all

problems are solved using exactly the same approach but the critical

elements of the problem-solving process are largely common.

In practical problem solving, we normally move from the problem to the

cause and finally to the corrective action. However, we must recognise

that on many occasions, the manifestation of a particular problem does not

necessarily have a unique and identifiable cause and so there may be other

intermediate steps to take into account in determining the real cause of the

problem. This situation can be described schematically as follows:

Problem-primary cause-contributing factors-corrective action

Or in more simple terms as:

What is seen-why-because of-corrective action

The basic process becomes apparent if we consider two examples of

problems in breadmaking; the first low-bread volume and the second

collapse of the sides of an open top pan loaf, often referred to as ‘keyholing’

(see page 4).

1.1.1 Low-bread volume

Externally, we observe that the bread is smaller than we expect, and this

may also have led to a paler crust colour due to the poorer heat transfer to

the dough surface during baking. Internally, the cell structure may be more

open than usual.

As bread volume is a consequence of the expansion of the dough by car-

bon dioxide gas from yeast fermentation and the retention of that gas within

the dough matrix (Cauvain, 2015), there are two potential primary causes of

this problem � Lack of gas production and lack of gas retention. To separate

the two, we will need more observations, and an important one will be

whether the rate of expansion of the dough in the prover and oven was nor-

mal or lower than usual. If the former was the case, then the primary cause

of the problem is likely to be lack of gas production and potential contribut-

ing factors may include the following:

� yeast activity or level too low;

� lack of yeast substrate (food);

� dough temperature too low;

� proving temperature too low;

� proving time too short;

� salt level too high;

� proving temperature/time/yeast combination incorrect.

Introduction to Problem-Solving Techniques Chapter | 1 3

On the other hand, if the dough proving had been at a normal rate and

there was a lack of oven spring, then this would lead us to recognise that the

problem could be lack of gas retention. In this case, the list of potential rea-

sons for the problem includes:

� improver level too low;

� incorrect improver formulation;

� combination of improver and flour too weak for the breadmaking process

being used;

� enzymic activity too low;

� energy input during mixing too low;

� mixing time too short;

� dough temperature too low.

Note that the ‘dough temperature’ too low appears in both lists due to its

effect on yeast activity and the effectiveness of the functional ingredients in

the improver at a given temperature, especially if ascorbic acid and enzyme

additions are used.

1.1.2 Keyholing

Externally, we observe that there is a loss of bread shape but only at

the sides of the product. Internally, we may see the formation of dark-

coloured, dense seams, often referred to as cores (see Fig. 1.1 and Section

4.1.2). The centre crumb may be more open than we normally expect for

the product concerned.

Why has this happened? Clearly, we have no problem with gas produc-

tion since there is no evidence for slow proving and the bread had good vol-

ume. We have clearly retained the carbon dioxide gas produced, otherwise

the bread would have low volume as described above. In this case, the over-

expansion of the crumb in the centre of the loaf leads us to the view that in

fact the gas retention is excessive.

Thus, the primary cause of the problem is excess gas retention arising

from a number of potential individual causes or combinations. The contribut-

ing factors may include:

� improver level too high;

� incorrect improver formulation;

� combination of improver and flour too strong for process;

� enzymic activity too high;

� energy input during mixing too high;

� mixing time too long.

From the foregoing examples, we can see that observation and reasoning

are key elements in problem solving. The former can be readily systematised,


whereas the latter will rely heavily on the availability of suitable information to

use as the basis for comparisons. The potential sources of such information

are discussed below.

It is interesting to consider the process by which one might set about

identifying the particular cause of a problem, such as the keyholing (excessive

gas retention) of bread discussed above. The most likely mental process

is one associated with probability achieved by matching the pattern of

observations with ones previously experienced and remembered. When we

recognise a general similarity between observation and stored image,

we are likely to explore in more detail the factors most likely to contribute

to the pattern we see.

One potential analogy for how we solve problem is that of a tree.

The main line of observation is via the central trunk with the potential to

explore branches at many points. In the case of our bread problem, if we fail

to identify the likely cause of the problem from our first consideration,

then we will close down that line of reasoning, go back to the main theme

(the trunk) and then set off an another branch of investigation. Our route

through the branches of our reasoning or knowledge tree is complex and

FIGURE 1.1 Keyholing in bread.


occasionally we may jump from branch to branch rather than going back to

the trunk before continuing our investigation.

The length of time that we take to identify the cause and the corrective

actions needed varies considerably from occasion to occasion and from

individual to individual, and is more likely to be related to our accumulated

knowledge and experiences rather than logical reasoning. Our abilities to

recognise and match subtle patterns are probably so intuitive that we are

seldom aware of them.

1.2 THE RECORD

It is common for the manufacture of bakery products to be based on some

starting formulation and formal method of processing the ingredients into

the finished product. This will require some form of recorded details of the

ingredients to use, their qualities and quantities, and the equipment, process

settings and timings involved. Consult any standard recipe book for bakery

food preparation, and you will find such details recorded for use by others.

In almost all modern bakeries, a formal production record will be set up

for each of the product types and used by the manufacturing operatives to

prepare the various ingredients and set the equipment.

Invaluable in problem solving is the formal record of what was actually

carried out on a particular occasion. Although many operatives will keep to

the prescribed formulation and processing recipe, small variations about

a given value can occur and lack of information of what the actual values

were for a given mix makes problem solving more difficult. It is normal for

standard production specifications to allow a degree of tolerance for weights

and operating conditions. For example, a temperature specification for a

cake batter may be stated as 206 2�C. However, such a specification allows

for replicate batters to be 18�C or 22�C and 4�C variation coupled with other

small changes may have a larger effect of final product quality than normally

considered.

A formal record of production can encompass many aspects including the

following:

� Any variations in the source of the raw materials. For example,

changes in flour or whole egg batches, or a new supplier of a particular

ingredient.

� Changes in analytical data even where these are still within acceptable

limits because the cumulative effect of small changes in a number of

individual parameters can have a large effect on final product quality.

� The actual quantities of ingredients used compared with the standard

values. For example, in breadmaking, it is common to adjust the water

level added to maintain a standard dough rheology for subsequent proces-

sing. In other cases, deliberate changes from the standard formulation


may have been introduced to compensate for some process change.

For example, in bread dough the yeast level may be adjusted to compen-

sate for a change in prover temperature so that final proving times do

not vary.

� The processing conditions, such as mixing times, energies, ingredients

and batter or dough temperatures. Once again the values may fall within

acceptable ranges but can still have a cumulative effect with other small

changes in recipe and process parameters.

� Process equipment settings which may vary according to ‘operator prefer-

ence’ or due to variations in other factors. For example, an unavoidably

higher laminated paste temperature may result in greater damage to the

laminated structure which may require a compensatory adjustment to

roll gap settings during sheeting.

� Process timings, such as baking or cooling times.

� Changes in packaging materials.

The record may be simplified by using the standard recipe as a pro forma

against which to record variations. Such techniques have been commonly

used to record the weights of individual dough pieces coming from the

divider (see Fig. 1.2) and can be readily adapted for any aspect of bakery pro-

duction. The record may be on paper, by input to suitable computer-based

programs or may be gathered and stored automatically.

In addition to the recipe and process records, it is very important to have

a formal record of finished product quality. Once again, it will be common

to have some form of product specification with appropriate tolerances

against which to make an assessment. Such techniques are commonly the

province of the Quality Control Department. The degree of detail recorded

will vary. Many examples of approaches to quality control techniques for the

baking industry are known and the reader is referred elsewhere (e.g., Street,

1991; Manley, 2000). The role of quality control should be more than that of

the final gatekeeper for product quality, it should provide an important link

between the specifications of raw materials, process data and final product

Productunit weight

(g)

Dough temperature

(ºC)

Time to divider Doughconsistency*S/SS/N/SF/F*

Dividersetting

* Dough consistency codes: S = softer than normalSS = slightly softer than normal N = normal consistencySF = slightly firmer than normal F = firmer than normal

FIGURE 1.2 Example of a divider record sheet.


quality. All too often, the quality control function is divorced from this

integrated chain of information and commonly relegated to a ‘checking’ role.

The manufacture of bakery products is somewhat different from that of mak-

ing many non-food items in that is often impossible to ‘reuse’ product which

is outside specification so the principle of ‘getting it right’ first time is criti-

cal for efficient and cost-effective production. Data gathering is an essential

part of the information chain, integration of the information is critical and

analysis of the data (see below) is vital.

For use in problem solving, the formal product specification or quality

control record may require some adaptation and enlargement as small, but

commonly accepted, variations may hold the vital clue to the particular cause

of a problem. In both, the quality control and problem-solving contexts

relevant data on the finished product may include the following:

� Product size based on height or volume. Devices for measuring product

dimensions may be used off- or on-line. They may be as simple as using

a rule to measure loaf height or measuring product volume by seed

displacement in a suitable apparatus (Cauvain, 2015) or with laser sensors

(Cauvain, 2017).

� Shape may be assessed subjectively and compared with an accepted

standard. The introduction of image analysis offers opportunities for

recording product shape, even on-line (Dipix Technologies Inc, www.

dipix.com).

� The external appearance of the product and the recording of any special

features that may be present or indeed the absence of expected features,

e.g., lack of oven spring in bread.

� Surface blemishes, their size and location on the product.

� The colouration of all external surfaces. Descriptive techniques, compari-

son with standard colour charts, e.g., Munsell (Munsell, no date) or

tristimulus instruments (Anderson, 1995) may be used. Deviations from

the norm should be clearly noted.

� The appearance of the internal structure, if there is one. Most baked

products have some form of internal structure that is an intrinsic compo-

nent of product quality. Assessment of that internal structure may be

subjective and describe the size, numbers and distributions of the cells

(open spaces) which go to make the internal structure. Cell structures

may be unevenly distributed in the product cross-section or form a

‘pattern’ that is characteristic in different products. Deviations from the

norm may be noted. Image analysis is now being used for objectively

assessing internal cell structures (Cauvain, 2003; Whitworth et al., 2005;

Cauvain, 2013; Cauvain, 2017).

� The internal colour may be assessed using techniques described above for

surface colour. It is worth noting that the presence of a cellular structure

has an impact on the perception of colour so it is often common practice


http://www.dipix.com

http://www.dipix.com

to include some form of visual assessment, e.g., brightness, which is

different from the true colour of a product. Some objective image analysis

systems offer a measurement of crumb brightness, e.g., C-Cell (www.

c-cell.info).

� The physical characteristics that contribute to eating quality may be

assessed subjectively with ad hoc or trained panels. Alternatively, some

form of objective test designed to mimic aspects of sensory analysis may

be employed, e.g., texture profile analysis (Cauvain, 1991), squeeze and

puncture tests (Cauvain and Young, 2006a; Cauvain, 2017).

� Product odour and flavour may be assessed subjectively on an ad hoc

basis or with trained panels. The development of the so-called ‘electronic

nose’ may offer a more objective measure but has yet to approach human

sensitivity.

Whatever details are considered to be appropriate for the record, it is

important to have a standardised format for recording the details. This usu-

ally takes the form of a standardised record sheet, paper or electronic,

with blank spaces in which to enter the appropriate data or comments.

Where a product attribute cannot be measured, an attribute ‘scoring’ system

might be used to provide a more objective basis for analysis of the problem.

Any number of scoring systems may be employed. One example is given in

Fig. 1.3, and others are given in the literature (e.g., Kulp, 1991; Bent, 1997a;

Cauvain and Young, 2006a).

1.3 THE ANALYSIS

If a standard record sheet is available, then the initial analysis can be as

simple as considering whether the recorded data deviate from the process

specification and in what direction. The effects of any changes can then be

compared with existing knowledge bases (in whatever form) to provide

the basis of a diagnosis. Sadly, few bakery problems are solved with such a

simplistic approach.

Almost all bakery processes include an element of elapsed time,

e.g., proving, baking and lamination, which must be taken into account when

analysing the causes of problems. Many larger bakery operations involve

continuous production, even though they are batch fed, and this adds a

further complication to take into account in the analysis.

An example from my own experience is that of a plant manufacturing

baked puff pastry shells where deviations in the product dimensions were

identified at the end of the baking process. In this instance, the plant had to

run continuously to be efficient and not compromise product quality (i.e., no

gaps in the pastry sheet or the oven). The operation was batch fed from

the mixer so that the relationship between a given mix batch, and the product

leaving the oven had to be established first. When this was done, it then


http://www.c-cell.info

http://www.c-cell.info

became possible to identify the contribution that any variation in the mix

batch contributed to the problem.

After establishing this relationship, it became clear that batch-to-batch

variation was not the prime cause of the problem observed as simple plots of

dough properties ex-mixer (e.g., temperature or rheology) did not correlate

with variations in product quality even when the elapsed time element had

been taken into account. The solution to this particular problem lay in a plot

of changes in product character with time (see Fig. 1.4), which upon analysis

showed that the variation was more regular than first thought. At first glance,

it appeared to be the well-known ‘shift change effect’ and to some extent

that was true: Not entirely in this case due to the operator effect on process

settings but because each new shift started with a new batch of rework to

add to the virgin paste. As the rework aged, the effects on baked product

character diminished. In this case, a simple trend analysis provides the basis

for the solution of the problem.

Product ..............................................................................................................................

Recipe code .......................................................................................................................

Date manufactured ...........................................................................................................

Date evaluated ..................................................................................................................

Evaluated by .....................................................................................................................

Product weight (g) ....................................................................... Notes on key attributes

Product height (mm or max. 10) .................................................................High Low

Volume (cm3 or max. 10) ............................................................................ High Low

Internal appearance

Crumb cell structure (max. 10) ............................................................... Open Close

Crumb uniformity (max. 10) ................................................................... Even Uneven

Crumb colour (max. 5) ..................................................................................................

Additional comments .................................................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total score (max. 100) ................................................................................

Sensory qualities

Aroma (max. 5) ............................................................................................... Off-odour

Flavour (max. 10) ......................................................................................... Off-flavour

Eating qualities (max. 10) ........................................................................Crumb firmness/softness/crispiness (max. 10) .......................................

External appearance

Uniformity of shape (10 max.) .......................................................... Collapsed Peaked

Crust colour (5 max.) ............................................................................... Dark Light

Crust break (5 max.) ................................................................................ Even Uneven

FIGURE 1.3 Example of product scoring sheet.


One analysis technique that has been applied to cereal science and

technology is ‘root cause analysis’ (Stauffer, 2000). Not all bakery problems

are likely to be potential subjects for this type of analysis as a key element

in this technique is the brainstorming session. Brainstorming usually implies

that more than one person is involved and all too often many of us confront

bakery problems alone or against a timescale that is insufficient to gather

together the necessary team of experts. In manufacturing processes based

on batch production, stopping the line until the problem is solved is an

option; however, for many bakery processes, anything other than a short-

term stoppage is seldom an option. If the problem is a persistent one or of a

catastrophic nature, then root-cause analysis can be a suitable technique to

apply. The role of a team in employing root-cause analysis is invaluable

in solving intractable problems or making changes to product quality. In the

latter case, the technique would be to treat the required change as though it

were a problem; e.g., if I want greater volume in a cake, then by diagnosing

the cause of excess volume, I may well obtain clues as to how to increase

cake volume, or by treating low volume as problem then I may get pointers

as to possible routes to improvement.

The methodology known as Six Sigma has been used to quantify how

bakery processes are performing. At the heart of the operation is the imple-

mentation of a measurement strategy based on no more than 3.4 defects per

million opportunities, with a Six Sigma opportunity being based on the number

of chances of getting a defect. For reasons already discussed, the opportunities

for obtaining objective measurements in many bakeries are limited which

means in turn, so are the chances of using statistical approaches like Six

Sigma as a routine problem-solving tool. Nevertheless, the discipline needed

to implement the Six Sigma methodology has potential relevance for baking.

The Six Sigma DMAIC approach is based on define, measure, analyse,

improve and control, all essential elements in any manufacturing process.

25

30

35

40

45

50

55

60

0 2 4 6 8 10 12

Dough batch number

Pas

try

heig

ht (

mm

)

Fresh re-work

Stored re-work

FIGURE 1.4 Effect of rework on lift in laminated products.


1.4 MODELLING TECHNIQUES

The application of statistical methods of analysis is common in many areas

of food and nonfood manufacturing scenarios, one example is that of Six

Sigma discussed above. The different techniques can be used in problem

solving and quality optimisation, though in the manufacturing environment

modelling methods often tend to be confined to the plotting of trends using

simple graphs as discussed in the example above for a laminated product.

More sophisticated statistical and modelling techniques can play their part in

helping to buildup the information base on what the critical ingredient and

process factors are which determine changes in product quality. Once identi-

fied, these critical factors can be logged and matched with problems when

they occur. Examples of modelling processes associated with baking are often

associated with production or financial planning, and energy management

rather than product quality.

To develop predictive models which deal with product quality, it is

commonly necessary to carry out experiments in a test bakery or trials on the

plant. Although trials on the plant are preferred, they can be wasteful of raw

materials, energy and time so that the most common practice is to carry out

evaluations in the test bakery and ‘translate’ the results to the plant. It is

very important to establish any clear changes that are relevant when translat-

ing test bakery results to a plant environment. A simple example encountered

by the author was the development of a sponge cake recipe in a test bakery

using a planetary-style mixer, whereas the plant used a continuous mixer to

prepare the same recipe batter. In this case, it is necessary to remember that

less carbon dioxide gas will be lost during continuous mixing (due to the

closed nature of the mixer head) than with an open-bowl planetary mixer so

that baking powder levels should be adjusted downwards to compensate for

this difference. A typical adjustment would be to reduce the baking powder

level for a continuous mixer to be about 75% of that used on a planetary

mixer to achieve the same sponge cake volume in both the test bakery and

on the plant (Cauvain and Cyster, 1996).

There are a number of examples of modelling techniques which might be

applied to bakery products. Street (1991) provides a review of suitable tech-

niques that may be applied to the modelling of baked products, and there are

a number of examples in the scientific and technical literature. The concept

behind the development of such mathematical models is that a relatively

limited number of experiments may be used to build models that can be used

to predict changes in bakery product quality as a consequence of changes in

combinations of ingredients and processes.

Once a predictive model has been established, then the information could

also be used for problem solving. For example, suppose that we show by

experimentation how loaf volume varies as a result of an interaction between

the level of ascorbic acid in the dough and mixing time. At some later stage,


we may encounter a problem with low-bread volume, and then we would be

able to use the output from our model to help decide whether the problem

was associated with the level of added ascorbic acid or mixing time, or both.

Furthermore, we might use our model to show which changes were most

likely to restore our bread volume to its original level.

Baking is a complex food process with many ingredient and process

interactions. These interactions lead to complicated models that are often dif-

ficult to apply. For example, for a given set of mixing conditions, we would

observe that bread volume increases with increasing levels of ascorbic acid

reaching a maximum, and thereafter, there will be little change in volume

for increasing additions of ascorbic acid. This occurs because the oxidation

effect of ascorbic acid is limited by the availability of oxygen from the air

incorporated during dough mixing (Cauvain, 2008). The availability of oxy-

gen is affected by yeast activity, so that yeast level becomes an influencing

factor. Both yeast and ascorbic acid activity are temperature sensitive and

proceed at a greater rate when the temperature increases. Dough temperature

is a function in part of ingredient temperatures and in part the energy

imparted to the dough during mixing. Energy transfer in turn is related to

the mixing time. So, too, is gas occlusion to a lesser degree because during

mixing an equilibrium point is reached when the entrainment process is

balanced by the disentrainment process. This equilibrium may occur before

the end of the mixing time.

So for the given example above, although we set out to study the effects

of the level of ascorbic acid and mixing time, we must also ensure that we

measure:

� ingredient temperatures;

� final dough temperature;

� gas occlusion in the dough;

� actual mixing time;

� energy transferred to the dough.

These records are necessary because we cannot independently control

some of the properties concerned, e.g., mixing time, energy and dough

temperature are all interrelated. Whenever we do work during mixing,

we must expect there to be a temperature rise. This relationship also holds

true if a water or other coolant jacket has been fitted to the mixer, and in

this case, we must remember that the coolant temperature in the jacket will

also rise by the time that it leaves the jacket as the result of absorbing some

of the heat generated during mixing.

There tends to be greater variability in product quality for products

manufactured on a plant than one sees in many test bakery environments.

This process ‘noise’ in the data can mask some of the critical issues that con-

trol product quality and therefore weaken the value of any models which

may have been developed. There are a number of statistical techniques that


can be used to help separate such noise from underlying effects, trends and

relationships. In many manufacturing processes, the specified product char-

acteristics can be achieved by many different combinations of formulation

and process conditions. Taguchi methods use experiments to search system-

atically and efficiently for combinations of ‘control’ factors that minimise

product variability in the face of variations in ‘noise factors’ such as ambient

temperature. Taguchi methodology has been applied to the manufacture of

bakery products, in particular in a study of the factors that affect the quality

of puff pastry (DTI, 1993).

In some cases, effective problem solving can be initiated by studying

the effects of small perturbations on the plant. A major issue with carrying

out trials on the plant is the potential loss of production arising from

the manufacture of out-of-specification products. However, there is a

distinct advantage to plant trials in that large numbers of samples are being

made which increases the potential for statistical and practical analysis.

Most product specifications have a degree of tolerance associated with the

final product so that small variations can be accommodated without loss of

production.

The value of statistics in identifying potential differences between

the effects of ingredient or process changes is not doubted. However, as

discussed in the example above where the relationship between ascorbic

acid level and mixing time was considered, there are relatively few simple

relationship in baking. One often hears the comment with regard to experi-

ments in baking that ‘we will change one thing at a time’. Sadly, this is sel-

dom if ever, true for baking. Suppose that want to consider the effect

of reducing the base dough temperature in the manufacture of croissant

and we therefore make two doughs, one at 20�C and the other at 15�C,that ‘simple’ change in temperature will affect gas production by the

yeast, the activity of ascorbic acid and enzyme if added, and most

importantly the rheological properties of the dough during processing.

Differences between trials may indeed show statistical differences in

product quality but due to the range of interactions, the relevance of the

differences with respect to production requirements is not clear and so care

must be taken when implementing actions or models based exclusively on

statistical significance alone.

1.5 MATCHING PATTERNS AND VISUALISING CHANGES

Sometimes when dealing with complex problems, it is an advantage to

sketch out the salient features with a diagram or create some collage of

salient information on a board (like a story board for the creation of a film).

A simple example is illustrated in Fig. 1.4 in which the potential routes

for the migration of moisture in composite bakery products are identified

annotated with relevant data on moisture contents and product masses.


The drawing of diagrams such as that shown in Fig. 1.5 helps to ensure that

all of the relevant processes are considered before carrying out detailed

calculations and investigations.

Human beings have a significant capability for being able to match

patterns in data, and in many ways, when we are problems solving we spend

a lot of time comparing what we see with the patterns which we all hold in

our minds. Subconsciously, we look for a pattern of information in a current

problem and compare that with previous patterns of events and information

to see if they provide clues for solving the current quality problem. There

are many different ways of creating patterns. The creation of knowledge

trees and knowledge fragments is one example and is discussed in more

detail in the following section. The knowledge tree is like a flow diagram

similar to that created by engineers to show the movement of raw materials

through its various stages en route to becoming a finished product. The same

basic principle is used by systems analysts when they are constructing dia-

grams to show the flow of information with different symbols representing

different types of activity or decisions which need to be made.

Cauvain and Young (2006a) illustrated possible examples of pattern

matching for the baking industry using a series of ‘spider diagrams’ to relate

certain characteristics of wheat with that of the subsequent flour, dough and

bread. As well as providing a relatively simple means of developing patterns

relating raw materials and finished products the process of deciding which

characteristics to include in the various diagrams is an important first step in

understanding the cause of quality problems.

When it comes to identifying the key roles of different ingredients and

processes in determining a particular aspect of final product quality, it is

Aw = 0.6, Moisture = 3%Mass = 4% of product

Topping


Filling


Top cake


Bottom cake

FIGURE 1.5 Schematic identifying the characteristics of the different components of a com-

posite cake product and the potential routes of moisture migration.


useful to be able to identify the relative importance of the individual changes.

It may be possible through mathematical modelling to identify the relative

importance of the effect different ingredients, recipes and process or process

changes, but it can sometimes be sufficient in problem solving to use a simple

diagram to understand the different contributions (Cauvain and Young,

2006a). An example of this type of approach is given in Fig. 1.6 which

examines the impact of some process and ingredient factors on the hardness

and crumbliness of cookies. The development of a gluten network in cookie

dough is not usually considered to be desirable, and if this should happen,

e.g., through over-mixing, the resultant product will be harder eating. As the

sugar level in a cookie formulation increases, the resultant product gradually

loses its initial crumbliness and become harder (e.g., as seen with ginger nuts)

while increasing additions of fat give increasingly crumbliness as the fat

interferes with the development of the gluten structure. The angle at which

the individual vectors proceed from the origin in Fig. 1.6 gives an indication

of the relative impact of any changes so that this relatively simple diagram

can provide a first indication of the potential interactions that taking place in

a particular baking environment. For example, from Fig. 1.6, if we wished to

reduce the fat level in a cookie formulation but do not wish to end up with

a harder biscuit then we would consider a reduction in gluten development

by adjusting mixing conditions or methods or changing ingredients, such as

flour type, which contribute to gluten formation.

1.6 THE INFORMATION SOURCES

Not many of the problems that we may encounter in the manufacture of

bakery products are likely to be so unusual that they have not been encoun-

tered and recorded before. Even where an apparently new problem arises,

access to suitable information sources often reveals a problem and solution

so similar that it can be readily adapted to our particular needs. For example,

Harder

Crumblier

Flour proteinGluten development

Sugar

Fat

FIGURE 1.6 The impact of some process and ingredient factors on the hardness and crumbli-

ness of cookies.


most of the problems that we are likely to encounter in the production

of cakes with heat-treated cake flours (see Section 2.2.17) will have similar

solutions to those that would apply if we were using chlorinated cake flours

(see Section 2.2.17). Even though it may be the first time that we have used

a heat-treated flour, we therefore have a suitable base for identifying the

solution to our problem.

The availability of suitable information is a fundamental tool for our

ability to problem solve successfully. Traditionally, such information sources

could be classified as personal and written. More recently, computer-based

sources have become increasingly available sometimes as databases but in

other cases in forms that would not be classified as an electronic equivalent

of the written word.

1.6.1 Personal

Even in today’s fast-moving electronic age, there is no substitute for personal

experience which builds one’s own portable information source. However,

few of us will spend long enough in positions that allow the systematic

buildup of the appropriate knowledge through ‘trial and error’ studies.

Aspects of problem solving may be taught in our years of academic study,

but these are seldom detailed enough to provide us with the comprehensive

information base required.

Personal contacts with experts and consultants can be used to supplement

our individual information base. Contacts with other professional bakers and

professional baking organisations are invaluable because it allows access to a

wider range of experiences. Thus, membership of professional bodies such

as the British Society of Baking, the American Society of Baking and the

Australian Society of Baking, which are linked with one another, has benefits

in developing one’s own knowledge base. Attendance at suitable conferences,

technical meetings, workshops and short courses can also provide relevant

information.

1.6.2 Written

The scientific and technical literature provides the most obvious source

for written material which aids in problem solving. Starting a collection of

‘useful’ articles and some form of index is very helpful in establishing

your own information base. Included in the written form are pictorial

libraries of faults and associated text related to their identified causes.

Such libraries may be built for oneself or may be purchased from a

suitable source.

Over the years, many of the ‘rules’ related to problem solving in baking

have been summarised and published (e.g., Street, 1991; Bent, 1997b;

Cauvain and Young, 2006b). These generally take the form of lists of faults


and associated causes. In many ways, such rules are of limited value because

they seldom consider or assign a likelihood value and so a personal degree

of judgement as to which of the causes to investigate first is required. Such

lists tend to deal only with the more common problems and seldom consider

interactions between ingredients or ingredients and processing. Also the

causes of faults are given equal weighting; thus, there is no expression as to

whether a particular cause is more likely than another.

The values of a personal record can be significantly increased by system-

ising the knowledge record. A series of checklists can be constructed to

identify contributions of ingredients and processes to final products and their

appropriate intermediates (e.g., dough, batter, paste). An example of such an

approach is illustrated for pastry in Tables 1.1�1.6. Checklists may be popu-

lated with the type of information identified in Chapter 3, Key Relationships

Between Ingredients, Recipes and Baked Product Qualities.

A ‘first level’ checklist (Table 1.1) identifies the ingredients that may

be used in the manufacture of pastry and considers the potential impact of

their on the various final product characteristics. Filling in this first checklist

TABLE 1.1 Example of Level 1 Checklist for Recording the Potential Effects

of Ingredients and Their Qualities on Paste and Pastry Characteristics

(Level 1 Checklist � Pastry/Ingredient Qualities)

Paste

Consistency

Paste

Extensibility

Paste

Elasticity

Height/Lift

Shap

e

Colour

SurfaceAppearan

ce

Mouthfeel

Aroma

Moisture

Firm

ness/Tenderness

Flour protein

content

X X X X X X

Flour waterabsorption

X X X

Fat type X X X X X

Fat melting

point

X X X X X

Sugar particlesize

X X

Rework X X X X X

Milk

Egg


TABLE 1.2 Example of Level 1 Checklist for Recording the Potential

Effects of Ingredient Levels of Paste and Pastry Characteristics (Level 1

Checklist � Pastry/Formulation (Ingredient Level))

Paste

Consistency

Paste

Extensibility

Paste

Elasticity

Height/Lift

Shap

e

Colour

SurfaceAppearan

ce

Mouthfeel

Aroma

Moisture

Firm

ness/Tenderness

Fat X X X X X

Sugar X X X X X

Added water

level

X X X X X X

Milk X X X X X X X X X

Egg X X X X X X X X X

Rework X X X X X

TABLE 1.3 Example of a Level 1 Checklist for Recording the Potential

Effects of Processing Conditions on Paste and Pastry Characteristics

(Level 1 Checklist � Pastry/Processing)

Paste

Consistency

Paste

Extensibility

Paste

Elasticity

Height

Shap

e

Crust

Colour

SurfaceAppearan

ce

Mouthfeel

Aroma

Moisture

Firm

ness/Tenderness

Mixing X X X X X X

Resting X X X X

Sheeting X X X X

Cutting/

blocking

X X X

Baking time X X X X X X

Baking

temperature

X X


TABLE 1.4 Example of a Level 2 Checklist for Recording the Potential Effects of Ingredient Qualities on Paste and Pastry Characteristics

(Level 2 Checklist � Past/Ingredient Qualities)

Paste

Consistency

Paste

Extensibility

Paste

Elasticity

Height/Lift

Shap

e

Colour

Surface

Appearan

ce

Mouthfeel

Aroma

Moisture

Firm

ness/

Tenderness

Stiff

Slack

More

Less

More

Less

More

Less

Better

Poorer

Darker

Lighter

More

Moist

Less

Moist

Firm

er

More

Tender

Flour protein

content

Higher X X X

Lower X X X

Flour water

absorption

Higher X X

Lower X X

Fat type

Fat melting

point

Higher X X X

Lower X X X

Sugar type

Sugar

particle size

Larger

Smaller

Rework Old X X X

New X X X

Milk

Egg

TABLE 1.5 Example of Level 2 Checklist for Recording the Potential Effects of Ingredient Levels of Paste and Pastry Characteristics [Level 2

Checklist � Pastry/Formulation (Ingredient Level)]

Paste

Consistency

Paste

Extensibility

Paste

Elasticity

Height/Lift

Shap

e

Colour

Surface

Appearan

ce

Mouthfeel

Aroma

Moisture

Firm

ness/

Tenderness

Stiff

Slack

More

Less

More

Less

More

Less

Better

Poorer

Darker

Lighter

More

Moist

Less

Moist

Firm

er

More

Tender

Fat Higher X X X

Lower X X X

Sugar Higher X X X

Lower X X X

Added

water level

Higher X X

Lower X X

Milk Higher X X

Lower X X

Egg Higher X X

Lower X X

Rework More X X X

Less X X X

TABLE 1.6 Example of a Level 2 Checklist for Recording the Potential Effects of Processing Conditions on Paste and Pastry Characteristics

(Level 2 Checklist � Pastry/Processing)

Paste

Consistency

Paste

Extensibility

Paste

Elasticity

Height/Lift

Shap

e

Colour

Surface

Appearan

ce

Mouthfeel

Aroma

Moisture

Firm

ness/

Tenderness

Stiff

Slack

More

Less

More

Less

More

Less

Better

Poorer

Darker

Lighter

More

Moist

Less

Moist

Firm

er

More

Tender

Mixing Longer X X X X

Shorter X X X X

Resting Longer X X X X

Shorter X X X X

Sheeting Thicker X X

Thinner X X

Cutting/

blocking

Baking

time

Longer X X

Shorter X X

Baking

temp

Higher X X X

Lower X X X

is merely a question of identifying whether a particular ingredient has

an effect or not; those that do have an effect could be marked with an ‘X’.

In Table 1.1, the different quality of the flour, fat and sugar are known to

have an effect and so are marked for consideration. Rework has been

included as an ‘ingredient’ due to the profound effect that it has on both the

paste and the final product; the rework quality would be controlled by its

age, temperature and length of storage time (as noted above).

Consideration is then given to whether varying the ingredient level

will impact on paste characteristics and final product quality. The example

illustrated in Table 1.2 does not include flour as it is common practice

to assess the impact of ingredients with respect to flour at a standard

level in the bakery (Cauvain and Young, 2006a). At this stage, there is no

need to consider the direction of impact. The final level 1 checklist considers

the impact of the processing steps applied in the manufacture of the bakery

product concerned. In Fig. 1.3, some examples related to the mixing,

processing and baking of pastes are included. Again, it is only necessary to

identify whether there is an impact or not from a particular process step.

The level 1 checklists help focus the subsequent line of reasoning which

might be applied in problem solving or product development. The ‘second

level’ checklist considers the impact of the level of the different recipe

ingredients and process settings. In this case it will be necessary to consider

the direction of change for given product characteristics (e.g., larger, smaller)

and link these with changes in ingredient level (e.g., higher, lower) or process

conditions (e.g., mixing time longer or shorter). Examples of level 2 checklists

are illustrated in Tables 1.4�1.6, and they show the type and range of infor-

mation which might be included. If an ingredient or process parameter was

identified at level 1 then it is carried through to level 2. Entries at level 2 can

be directional (as illustrated) or if hard data exist (e.g., from mathematical

modelling) these can be entered instead to give the level 2 checklists a more

‘predictive’ capability.

Missing from the checklist approach is the ability to directly record complex

interactions, but they can be a useful first step in assembling the complex

knowledge required for solving bakery problems. They can also be useful for

gathering and systemising the information required for the development of

computer-based knowledge systems (see Section 1.6.3).

1.6.3 Constructing knowledge trees and knowledge fragments

Another approach to recording technical information in visual form can

be the construction of knowledge trees and fragments. Usually the construc-

tion of the tree starts at the top and works downwards to the ‘roots’.

In practice, the information that it holds can be used from the ‘bottom-up’

for product development and from the ‘top-down’ for product and process

quality optimisation.


The construction of the knowledge tree starts with the identification

of a final product or intermediate property of interest and proceeds by

identifying all those factors which contribute to the identified property or

characteristic, both individually and collectively. An example of this

approach is given in Fig. 1.7 for lift in laminated puff pastry. Moving from

the top of the tree downward, we can see that the approach is to progres-

sively break down complex interactions until single contributing factors are

identified; these may be considered as the roots of the tree, even if not all

of them are ‘planted in the ground’. Cauvain and Young (2006a) provide

another example of a knowledge tree for the eating quality of bread and

cake products. As complex as these diagrams appear, they only partially

address the issues of the complex ingredient�recipe-process interactions

which underpin baking.

Sometimes, it is not possible to develop a full knowledge tree, and it

is easier to break the structure down into a series of knowledge fragments.

This is a technique which we have pioneered and used in many situations.

An example of a knowledge fragment is illustrated in Fig. 1.8 and is one

relevant to ascorbic acid oxidation in breads made using the Chorleywood

Bread Process. The fragment identifies a number of the key interactions

which take place in mixing and how they relate to the qualities of the final

product.

Knowledge fragments are visual aids which help you to quickly see

relationships between pieces of knowledge. They can express or define

information and knowledge about an ingredient, a term used in baking or

a processing step or about any information you may wish to structure so

that it is easy to use again, either as an aide-memoire or to help in your

Pastry lift

Re-work Processconditions

Productionmethod

e.g. English

Number of fatlayers

Integrity ofthe layers

Rest periodsTemperature

Sheetingprofile

FatMixing time(energy)

Quality(SFI)

Ratioto

dough

Base doughtemperature

Flour quality

Temperature

AgeLevel

FIGURE 1.7 Part of a knowledge tree identifying the factors that contribute to pastry lift.


understanding of a topic. They are constructed in a similar way to a ‘flow

diagram’. The items of knowledge can be linked together using lines

and arrows. They need to be structured and classified in a simple way and

saved so that they can be retrieved easily when needed. They might be

considered as a ‘diagrammatic knowledge data-base’. The key terms used in

them can be indexed so that retrieval is easy. If faults or quality defects are

shown in the fragments, they can be used to identify the questions that need

to be asked to determine a solution to a baking problem or quality defect.

Example of a knowledge fragment ©BakeTran 2008

Oxidation in CBP

Uneven shape/holes/unevenstructure

Change in doughrheology–greaterrestistance todeformation

Risk of mouldingdamage

Affectsovenspring

Lack of gasretention

Under-oxidation

Coarsestructure/lowvolume

Excess of gasretention

Over-oxidation

Over expansion ofcentre crumb

Results incollapse in liddedbread

Poor shape/unevenstructure

Optimum energy

Mixingrequirement inCBP - 2–5 min

Mixer headspacepressure/vacuumratio duringmixing

Processing BakingMixingIngredients–

Ascorbic acid–

E300

Oxidation of flour proteins

Lack ofovenspring

Under-oxidation

Over-oxidation

Excess ofovenspring(less likely)

Lack of gasretention

Excess ofgas retention

Optimumoxidation

High volume/good ovenspring /finestructure/softcrumb

AA + Oxygen + flourproteins + ascorbicoxidase

Dehydroascorbicacid

Improves dough gasretention

FIGURE 1.8 Example of a knowledge fragment related to ascorbic acid oxidation in the

Chorleywood Bread Process.


They can help you to link all the technical information that you acquire

about baking. In the example provided, oxidation in the Chorleywood Bread

Process (CBP), much of the relevant knowledge about oxidation is illus-

trated. The mechanism by which ascorbic acid takes part in oxidation, the

links to mixing and energy requirements, and possible processing issues are

shown. The contribution of oxidation to dough gas retention is flagged. The

result of under- or over-oxidation for the product being considered, in this

case generic plant bread, can be inserted. By referencing some of the key

terms used in the fragments e.g., gas retention, gas production, fault-low vol-

ume, fault-coarse structure, etc., the relevant fragments can be identified and

examined when a product exhibits a particular fault e.g., coarse structure.

Any fragments showing this fault can be used in the trail to find the cause of

the fault and its correction. Such knowledge fragments can have considerable

value in their own right as they provide detailed information focussed on one

or two aspects of a larger and more complex structure.

1.6.4 Knowledge (computer)-based systems

Computing technology offers a special opportunity to help with problem

solving, quality optimisation and product development. In particular, reason-

based programmes, commonly known as ‘expert systems’, these have been

previously used in fault diagnosis and linked with corrective action. The

Flour Milling and Baking Research Association at Chorleywood was the pio-

neer in applying such technology to the baking industry with work being

continued in the Campden and Chorleywood Food Research Association

(Cauvain and Young, 2006b; Cauvain, 2015).

Expert or knowledge-based systems as they are now commonly referred to

can combine facts and rules to solve problems. The ‘rules’ can take several

forms including mathematical models, ‘rules of thumb’ and ‘intuitive’ rules.

The latter may well take the form of ‘if I increase the level of ingredient X

then property Y in the product will change in a positive direction’ (cf. the

checklist approach discussed above). Such rules may not quantify the degree

of change, only the direction.

Knowledge-based systems can contain many rules which should be

capable of validation. They should not contain opinion but rather concentrate

on facts. Such systems can perform a fault diagnosis within a few minutes

and are capable of considering large information bases very quickly. They

can consider many interactions and are often written to provide degrees of

likelihood in the answers so that the process of identifying corrective actions

and assigning priorities is more readily possible. Images and text can be inte-

grated and displayed to provide pictorial display of product characteristics.

In some cases, it may be possible to diagnose faults with a knowledge-based

system based solely on images run using touch-screen computing technology

(Young, 1998a).


Unlike humans, knowledge-based systems never forget and always

consider all the necessary information. However, they are not perfect

because they rely on human programming and so are only as good as the

information they contain. Nevertheless, they can play an important role in

aiding problem solving, quality optimisation and product development

(through ‘what if?’ questioning) and offer a significant advantage over the

classical written fault diagnosis text lists.

Knowledge-based systems have been applied for problem solving in

the production of bread (Young, 1998a), cake (Petryszak et al., 1995; Young

et al., 1998) and biscuits. In addition to their application for problem solving,

they may be used in product development (Young, 1997), process optimisation,

e.g., retarding (Young and Cauvain, 1994; Young, 1998b) and for training

(Young, 1998a).

1.6.5 The ‘Web’

The development of the World Wide Web and social media has increased

the range of options available for information and contacts to help with

problem solving. There are many sites that can be accessed for providing

information on problems in baking but it is important to try to ensure that

the information received has some validity and credibility. It is therefore

best to deal with reputable and well-known sources.

Developments in web-based technologies will considerably increase the

availability of computer-based tools such as knowledge-based systems. Work

has been undertaken to provide access to such programs on an on-line basis,

linked with the transfer of appropriate baking technology (Young, 1999), but

such approaches still have yet to achieve their full potential in the baking

and allied industries.

A number of professional bodies associated with baking offer their

problem-solving services via web-based systems, and there are also commer-

cial organisations who offer assistance with problem solving, commonly on a

fee-paying basis. Details of their services can be obtained from their relevant

websites.

1.7 NEW PRODUCT DEVELOPMENT

Much of the information and advice that has been given so far in this

chapter is related to problem solving. However, there are significant similar-

ities between the processes involved in problem solving and in developing

new bakery products. For example, it is a common practice before undertak-

ing a new development to consider the properties that are sought in the

new product and compare them with existing product qualities. If the quality

differences between the new and existing product are treated as though

they are quality defects, then the information and techniques which are


commonly used in problem solving are now equally applicable to new

product development. In this process, the question is not ‘How do I solve

this problem?’ rather it is ‘How do I move the product quality in a given

direction?’ Knowledge fragments and knowledge trees can have significant

roles to play in new product development because they will contain the

information which allows the product developer to make informed decisions

as to which ingredient, recipe or process changes to make to manipulate

product quality and should also contain some identification of the key

product interactions.

When new products are developed, the techniques described above

should assist in moving the quality of the concept product under develop-

ment smoothly to the finished product ready for launch in the marketplace.

However, occasionally, it can be forgotten that there needs to be a structure

to the product development process itself. In the worst cases, the point can

be reached where a great deal of money is expended without achieving a

robust sustainable product. The list below can be used as a guide to success-

ful product development. It is not exhaustive and can be augmented for local

circumstances. At each major stage, it is advisable to consider a ‘Go/No go’

decision for the product so that it is developed on a sound commercial and

technological basis.

1.7.1 Concept

Discussion about product feasibility with:

� Marketing

� R&D

� Engineering

� Quality control

� Production

� Procurement

Consumer research

� Market studies

� Trend analysis

� Product positioning

� Focus group testing

Defining the product

� Characteristics

� Specifications

� Eating quality

� Appearance/dimensions etc.

� Shelf-life requirements � Both organoleptic and mould-free


� Formulation

� Engineering requirements/equipment

� Any legislation issues

� Nutritional issues

� In-house capability

� Preliminary product costings/ commercial viability of product

� Consumer acceptance

� Budget investigation

� Project manager and team � Propose

� Criteria for success � Define

� Can the product be made easily and efficiently?

� Can it be sold for the right price and make a profit?

Go/no go decision point

1.7.2 Product development investigation � prototype product

� Budget

� Define timeline for the prototype product development

� Define areas of responsibility

� Formulation development for constituents of product e.g., biscuit, cream,

filling, coating

� Flavour profile development

� Ingredient assessments

� Lab pilot-scale development of the product (including tasting)

� Records of development of prototype, including photographs

� Investigation of needs for processing equipment e.g., have we got

suitable equipment, can we buy it off the shelf, is it a one-off

� In-house expertise for product development and production

� Is the input of consultants or other specialists required?

� Will operator training be required?

� Are consumer acceptance trials needed?

� Assessment of lab pilot-scale products

� Quality analysis

� shelf-life

� stability

� rheological properties

� organoleptic properties

� flavour profiling

� are other analytical tests required?

� Potential market � Route

� Costings for the product

� Criteria for success � Revisit



1.7.3 Scale-up to commercialisation assessment

� Budget

� Timeline

� Process development for large-scale production

� Engineering work required � Equipment development/modification

� Do we need to increase production or baking capacity?

� Manufacturing and baking specifications

� Risk assessments

� Packaging development/integrity testing/shelf-life issues

1.7.4 Prototype trials on the plant

� Budget

� Timeline

� Ingredient procurement and assessment

� Equipment � Purchase/recommendations, set-up, liaison with production

schedule, skills required, personnel training, expertise to be brought in

� Keeping/shelf-life trials

� Consumer trials

� Marketing input


1.7.5 Pre-launch trials

� Specification and procurement of ingredients

� Purchase of equipment if required

� Marketing input

� Packaging design

� Tasting trials with consumers

� Labelling

� Quality control requirements

� Plant/housekeeping/production team

� Assessment of production product

� Shelf-life trials continued


1.7.6 Launch

� Marketing

� Advertising

� Packaging

� Pricing

� Procurement


� Handover to production team as a portfolio product

� Setup quality assessment

1.7.7 On-going product maintenance/handover

� Confirmation of product specification definition e.g., archive of recipe

and ingredient specifications, processing details etc.

� Quality control specifications and reports

� Scheduling considerations

� Consumer acceptance

� Crisis management plan for potential disaster/mishaps e.g., change of

ingredient, change in legislation, plant breakdowns

� Marketing plans

� Keeping trials

1.8 CONCLUSIONS

Many of us will be faced with the need to solve problems associated with

baked products, whether we work in a bakery or the industries which supply

it. Some will be minor and some extensive in nature, but they will all be

important. To a large extent identification of the cause of the problem will

be based on sound observation and the application of appropriate knowledge

in a systematic manner. As bakers, we have to deal with a mixture of complex

ingredients and their many interactions with one another and the production

processes we use. For practical bakers many of the causes of problems are

‘hidden,’ for example, a change in flour properties is seldom obvious until

a defective product leaves the oven.

There is always a need to find the ‘quick’ solution, and traditionally, this

was based on training and experience. Today’s bakers seem to get little of the

former and are seldom given the time to obtain the latter. Modern information

technologies can go some considerable way in providing suitable problem-

solving tools for the modern baker. However, there is no single unique source

that can provide all of the necessary solutions to baking problems but keen

observation, a methodical approach and good information sources will almost

always help identify cause and solution.

References

Anderson, J., 1995. Crust colour assessment of bakery products. AIB Technical Bulletin, XVIII, (3),

March.

Bent, A.J., 1997a. Confectionery test baking. In: Bent, A.J. (Ed.), The Technology of

Cakemaking, sixth ed. Blackie Academic & Professional, London, UK, pp. 358�385.

Bent, A.J., 1997b. Cakemaking processes. In: Bent, A.J. (Ed.), The Technology of Cakemaking,

sixth ed. Blackie Academic Professional, London, UK, pp. 251�274.

Cauvain, S.P., 1991. Evaluating the texture of baked products. South Afr. J. Food Sci. Nutri.

3 (November), 81�86.


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Manley, D., 2000. Technology of Biscuits, Crackers and Cookies,, third ed. Woodhead

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Munsell, A.H. (no date) Munsell System of Colour Notation, Macbeth, Baltimore, USA.

Petryszak, R., Young, L.S., and Cauvain, S.P., 1995. Improving cake product quality. In:

Proceedings of Expert Systems 95, the 15th Annual Conference of the British Computer

Society Specialist Group on Expert Systems. December, pp. 161�168.

Stauffer, J.E., 2000. Root cause analysis. Cereal Foods World 45, 320�321.

Street, C.A., 1991. Flour Confectionery Manufacture. Blackie Academic & Professional, London, UK.

Whitworth, M., Cauvain, S.P., Cliffe, D., 2005. Measurement of bread cell structure by image

analysis. In: Cauvain, S.P., Salmon, S.E., Young, L.S. (Eds.), Using Cereal Science and

Technology for the Benefit of Consumers. Woodhead Publishing Ltd, Cambridge, UK.

Young, L.S., 1997. Water activity in flour confectionery product development. In: Bent, A.J.

(Ed.), The Technology of Cakemaking, sixth ed. Blackie Academic & Professional, London,

UK, pp. 386�397.

Young, L.S., 1998a. Baking by computer � passing on the knowledge. In: Proceedings of the

45th Technology Conference of the Biscuit, Cake, Chocolate and Confectionery Alliance.

London, pp. 63�67.

Young, L.S., 1998b. Application of knowledge-based systems. In: Cauvain, S.P., Young, L.S. (Eds.),

Technology of Breadmaking. Blackie Academic & Professional, London, UK, pp. 180�196.

Young, L.S., 1999. Education and training for the future. In: Proceedings of the 86th Conference

of the British Society of Baking, British Society of Baking, London, pp. 13�16.

Young, L.S., Cauvain, S.P., 1994. Advising the baker. In: Proceedings of Expert Systems 94, the

14th Annual Conference of the British Computer Society Specialist Group on Expert

Systems. December, pp. 21�33.

Young, L.S., Davies, P.R., Cauvain, S.P., 1998. Cakes � getting the right balance, applications

and innovations in expert systems VI. In: Mackintosh, A. (Ed.), Proceedings of the 18th

Annual Conference of the British Computer Society Specialist Group on Expert Systems.

Cambridge, December, SGES Publications, Cambridge, UK, pp. 42�55.






































Chapter 2

Raw Materials

2.1 WHEAT AND GRAINS

2.1.1 Can you explain the functions of the differentcomponents in the wheat grain and, after milling, theircontributions to the manufacture of baked products?

Shapes vary among the various cereal grains though their main components

are surprisingly similar in major constituents though not their ratios. In the

preparation of wheat flour, we are dealing with the seed of the plant formed

during its growing cycle. The individual seed grains are the next generation

of plants and contain all the nutrients and specialist components to start the

growing cycle under appropriate conditions.

The individual seed grains are composed of a series of different tissues,

each with its own special function in the life cycle of the plant. In broad

terms, we describe wheat as being composed of a series of outer layers

variously referred to as the seed coat or bran skins, an inner endosperm

and the embryo. Unfortunately, there is confusion in the use of the latter

term, and in common usage, it is often referred to as the germ of the grain.

The term germ is most commonly used within a milling context and

refers to an embryo-rich fraction of the grain obtained during milling

processes.

For the seed, the functions of the different components is relatively

clear; the bran layers enclose and protect the food reserves (the endosperm)

for the growth of the future plant, whereas it is from the embryo that

the proto roots and shoots will spring when conditions are appropriate.

The physical structures and chemical composition of the seeds are far too

complex to describe in a book on baking, so the reader is referred elsewhere

for such detail.

The overall proportions of the three main wheat seed components vary

slightly according to the wheat variety and the conditions under which it is

grown, but the variations are relatively small. To add to the confusion that

commonly surrounds the different components of wheat grains, the definitions



http://dx.doi.org/10.1016/B978-0-08-100765-5.00002-3

of bran, endosperm and embryo are fuzzy, but in broad terms, the grains

(on a dry matter basis) are composed of 15% bran, 83% endosperm and 2%

embryo. The moisture content of grains will vary depending on environmental

factors; figures of 12�20% in the field are not uncommon, whereas in the

mill 12�15% are more likely.

In whole grain, an approximate analysis (% dry matter) would be:

Sugars 2.5

Starch 71.5

Pentosans (soluble proteins) 3.5

Protein 15.0

Lipids (fats) 2.5

Cellulose 3.0

Minerals 2.0

The distribution of the different components throughout the grain is not

uniform with the cellulose and minerals, more likely to be found associated

with the bran and germ and most of the starch in the endosperm. Thus, in

the different milling processes employed to manufacture white flours,

there is a concentration of some of the grain components into the different

milling fractions.

In the manufacture of bread and fermented products, it is the proteins

which are of greatest concern as they have the ability to form a gluten

network capable of trapping the carbon dioxide gas generated by bakers’

yeast fermentation; both the quantity and the quality impact on the dough

gas retention and processing properties. The most functional proteins for

breadmaking are those largely found in the endosperm of the grain.

The pentosans, or soluble proteins, make a significant contribution to the

water absorption capacity of the flour due to their ability to absorb about

seven times their own weight of water which is three to four times more

than any other flour component. However, because they are present at

low levels in flour, their overall contribution to water absorption capacity

is small.

Starch plays a number of roles in baked products. During the manufacture

of many baked products, starch in the presence of water and upon heating

undergoes a transformation known as gelatinisation, and in this form, it is

a significant contributor to structure formation, especially in cakes. In bread,

the gelatinisation of starch and its subsequent retrogradation in the loaf

during storage is a key element of the staling (firming process). During the

wheat milling process, some of the starch is physically damaged which

contributes to it functionality in baking.


Cellulose is most often linked with the bran content of the flour which

tends to have a negative effect on flour properties, especially dough gas

retention (see Sections 2.2.1 and 2.2.2) but makes a positive contribution to

dietary fibre.

The naturally occurring sugars in wheat grains is not usually considered

to be important, but it is worth noting that in the manufacture of bread and

fermented products, they do contribute to supporting yeast fermentation. The

minerals and vitamins present in wheat grains contribute to the nutritional

value of flours.

The lipids present in wheat flour are mostly associated with the germ and

to a lesser extent the bran. Their role in baking has not yet been clearly

defined, in part because to study them, it is first necessary to extract them

from wheat flour, and this may lead to a modification of their functionality

which is not representative of how they would work in the original flour.

Further reading

Cauvain, S.P., 2015. Technology of Breadmaking, third ed. Springer Publishing International,

Switzerland.

Cornell, H., 2012. The chemistry and biochemistry of wheat. In: Cauvain, S.P. (Ed.), Bread Making:

Improving Quality, second ed. Woodhead Publishing Ltd, Cambridge, UK, pp. 35�76.

Lorenz, K.J., Kulp, K., 1991. Handbook of Cereal Science and Technology. Marcel Dekker Inc,

New York, NY.

Raw Materials Chapter | 2 35








2.1.2 We understand that millers often use a mixture ofdifferent wheats to manufacture the flours that they supply to us.Can you explain why they do this?

In every country where wheat is grown there are many varieties, in some

cases the numbers may run close to or exceed 100. Modern wheat varieties

are the result of selective breeding over many years as humankind matched

wheat variety with climate and soils in the different parts of the world.

The type of wheat grown is largely determined by environmental conditions

such as the nature and length of the growing season. In the United Kingdom

and elsewhere, it is possible to sow and grow wheat over-winter and

harvest in the autumn, but in some parts of the world, the severity of the

winters may restrict wheat growing to spring planting alone. Often the focus

of selective wheat breeding in the past was related to agronomic and

economic factors such as increasing yield and building disease resistance.

It is perhaps only in the last 40�50 years that greater attention has been paid

to developing wheat varieties for their baking and end-use performance.

Many bakery products and processes are closely linked with and

traditionally based on the qualities of the locally grown and available wheat.

In practice, this means that taking wheat grown in one part of the world and

using it to make a different product in another part of the world is not always

successful without recipe or process adjustment. Try making a baguette with

100% strong Canadian wheat and the product is quite different from using

French-grown wheats, and the reverse would be largely true in that French-

grown wheats that would not make good quality North-American pan bread

without adjusting the recipe and process used.

The milling characteristics of individual wheats also vary. There are

few examples of wheats which yield the ‘perfect’ flour for a given bakery prod-

uct and process. Even if there were it is important to recognise that the quality

characteristics of wheat drift with time. This is a well-known botanical problem

seen with all plants. In practice, new wheat varieties need to be developed on a

regular basis to ensure an adequate supply of wheat of the appropriate quality

for bakers. Even bakery processes change with time, and this presents new

challenges for millers to match their flours to those changes.

The choice of wheats used by millers in their grist is influenced by

factors such as the availability of different wheat types, both local and

imported, and the manner in which their milling process is structured.

Not all millers blend wheats before milling, some may mill wheat varieties

separately, and then blend the individual flours before sending the final

product to the baker. There are advantages and disadvantages to the two

ways of milling, but discussion of these is outside the scope of this book.

In summary, millers will have an intimate knowledge of the wheats

available for their use and the likely performance characteristics of the

flours that they will produce. By accessing and blending different wheat

varieties, they are seeking to deliver flours with the required performance

characteristics and consistency for bakers.


2.1.3 Why are there so many varieties of wheat and how arethey classified?

The classification of wheat varieties is most commonly associated with the

‘strength’ of the gluten network which can be developed during mixing of a

dough. Gluten strength is a relative nebulous term which refers to both

the protein content of the flour as well as the rheological properties of the

mixed dough. References are therefore commonly made to strong, medium

and weak flours, with the main differentiation being made on protein

content. For example, a strong flour may have 12% or more protein (on the

basis of a 14% moisture content), medium 10�12% and weak less than

10%. However, within such categories variations of protein (gluten) quality

may be expected (see Section 2.2.5).

The strength of the flour from a given wheat variety may also be based

on the bakery product area in which it may be used; thus, wheats may be

classified as suitable for breadmaking, cake cookies and general purposes.

This is not really a useful classification because the particular flour proper-

ties required for any bakery purpose are not universal and will be tailored to

individual requirements.

The multiplicity of wheat varieties arises for a number of reasons.

Wheat agronomics are complex and farmers will be seeking wheats capable

of growing under a variety of environmental conditions. Farmers have two

very special requirements from wheat; disease resistance and yield,

and these two requirements are uppermost in the minds of companies who

breed and commercialise wheat and are competing for the same agronomic

markets. Each company will be trying to provide a unique variety for the

different end-uses.

With the new advances in breeding science and technology, new wheat

varieties will be developed for the agronomic market. Each wheat variety

takes many years of development before it reaches the farmer. Typically, the

period is 8�12 years, and during that time, the potential quality attributes

are being continually assessed. In the early stages of development, the range

of evaluation tests is limited, but with successive trial years, the quantity of

available wheat increases and the range of evaluation methods become more

extensive.

A further reason for developing new wheat varieties is related to the

nature of the wheat plant. To grow a new crop on an annual basis, it is

necessary to retain a small portion of years crop; this retained portion is

being used for subsequent planting. With successive cycles of planting and

saving, the efficiency of the retained seed begins to decline; in particular, its

resistance to diseases diminishes. There may also be changes in yield and

a loss of functionality which adds to the desirability of introducing new

genetic stock on a regular basis.


To cope with the introduction of new varieties and the marketing of

wheat in general, different geographical regions have evolved standardised

protocols or classifying wheats grown in those regions. There are many

differing facets to the classification processes, and readers are referred to

some of the examples given in the Further reading section.

Sources of further information on wheat varieties

� UK www.nabim.org.uk/wheat/wheatvareieties

� Australia http://wheatquality.com.au/classification/

� Canada https://www.grainscanda.gc.ca/wheat-ble/classes/classes-eng.htm

� USA www.uswheat/org. buyerinformation. buyersguide


http://www.nabim.org.uk/wheat/wheatvareieties

http://wheatquality.com.au/classification/

https://www.grainscanda.gc.ca/wheat-ble/classes/classes-eng.htm

http://www.uswheat/org%3ebuyerinformation%3ebuyersguide



2.1.4 We have heard several experienced bakers talking aboutthe ‘new harvest effect’ and the problems that it can cause. Canyou explain what is behind this phenomena and how we canmitigate its effects?

The ‘new harvest effect’ is one of the great mysteries of the cereals world. It

has been much discussed in the cereals industry but a lot of the evidence for

its existence is apocryphal. There have been a number of scientific investiga-

tions related to the topic, generally with inconclusive results. It is said to be

responsible for a number of different, usually unexpected, and occasionally

catastrophic bread quality losses which occur around the period when wheat

is newly harvested; these have included loss of bread volume and cell struc-

ture, but most commonly, dough processing problems are the main issues

that are identified by bakers.

The basis for any effect is not clear but has variously been attributed to the

ripeness of the wheat at harvesting, the short-term age of the wheat before it is

incorporated into the milling grist and even the short-term age of the flour before

it reaches the bakery. It is relatively uncommon for millers to make a complete

transition from 100% ‘old’ crop to 100% ‘new’ crop; usually, they will gradually

increase the proportion of the new harvest wheat in the grist. In many parts of

the world, the global trading of wheat further complicates the transition as

millers may be incorporating different new crop wheats at different moments in

time. It is true that wheat quality does vary with different crop years, but millers

usually take this into account through suitable quality testing and adjust the

mixed grist of wheats that they use accordingly (see Section 2.1.2).

Milling and baking processes have changed considerably in the last 40 years,

and it may be that some of the past experiences that are retold by bakers are no

longer relevant. Those breadmaking processes which rely exclusively on the

quality of the gluten network in the dough are likely to be the most sensitive to

the any changes in flour properties with harvesting year. In breadmaking

processes where improvers and dough conditioners are added, then the effects

of small variations in flour quality are less likely to be noticeable. It is interest-

ing to note that improver suppliers are known to make small changes to the

formulation of the bread improvers around the new harvest period.

The ‘new’ harvest effect is not usually associated with minor changes

rather with more significant and unexpected quality losses. A common

feature of these catastrophic failures is that they often disappear without

apparent reason after a short period of time using the new flour has elapsed.

One possible explanation is that in larger bakeries, the process conditions

have been settled and optimised for many months and are sensitive to the

small changes in wheat quality which inevitably occur from crop year to

crop year. After a period of trial and error, the problem usually dissipates

as the plant is reoptimised to the new primary raw material quality. We are

sorry that we cannot give you a more explicit explanation.


2.1.5 We are a bakery working with a local farmer and millerto produce a range of local breads and want to use somedifferent varieties and forms of malted grains that we areproducing. Can you advise us on any special issues that weshould be aware of?

Adding grains in different forms to breads is a good way of introducing a

variety of flavours and textures into your products. There are a few matters

that you need to take into account to get the best results in your product.

Wheat, barley and rye can be used to make malted grains and turned into a

variety of granular products for adding to bread dough. One thing that you do

need to be careful of is that the grain products are not hard and dry when you

make them as they can potentially cause unpleasant eating qualities if they are

large particles. Two forms of grains are commonly used; crushed or flaked

and kibbled. The former will be prepared with a higher moisture content to

aid preparation and so will be susceptible to mould growth. Steaming is com-

monly used to prepare grains for flaking. Kibbling yields much smaller pieces

of broken grain which is very useful as a surface decoration.

A key factor for you to consider is that the malting process initiates a

significant level of enzyme activity in the grains, and these enzymes will

remain active in the dough. The amylase activity may cause problems with

dough softening and contribute to side-wall collapse in the baked product

(see Section 4.1.2) or even keyholing in severe cases (Fig. 1.1). If you do

have this problem, then you may want to reduce the additions of other

enzyme active materials, such as malt flour, or use a less enzyme-rich

improver if you are using a no-time dough process.

There will be other enzymic activity to watch out for, most notably

proteolytic activity which contributes to dough softening and a weakening of

the gas retention properties of the dough.

The malting process generates complex sugars, and these will also be

carried into the dough with the malted grains. These should not be a

problem, but if you notice that the product crust colour becomes darker,

you may want to reformulate to reduce it.

You may need to increase the protein content of the flour that you are

using, as the dough system will need to carry the non-functional malted

grains.

Further reading

Pyler, R.E., Thomas, D.A., 1991. Malted cereals: production and use. In: Lorenz, K.J., Kulp, K. (Eds.),

Handbook of Cereal Science and Technology. Marcel Dekker, Inc, New York, NY,

pp. 815�832.






2.1.6 Can we mix oats or oat products with our wheat flours tomake bakery products? If so, are there any special issues that weshould be aware of?

Oats, in common, with many other grains are composed of outer bran layers,

an embryo (germ) and starchy endosperm; the latter, in contrast with

many other grains contains significant amounts of protein and is rich in oil.

The first stage in oat milling is to remove the husk or outer hull to yield

clean ‘groats’. Oat milling follows a similar pattern to wheat milling but is

less complex. The groats may be cut, flaked, milled or ground to yield oat

flour, sometimes with the bran being taken off separately.

The high level of oil in oats (typically 5�9%) is distributed relatively

uniformly through the oat components which are also rich in lipase. Unless

the lipase is inactivated by heat, oat products are very quickly prone to

rancidity. The process of inactivating the lipase enzyme is known as

‘stabilisation’ and comprises heating the oats with steam and heat for up to 2 h

at over 100�C. The stabilisation process also contributes to the development of

a ‘nutty’ aroma and flavour in oat products.

Cut oats are usually milled to oatmeal of different size grades, and it is

these products which are most commonly used in baking. Perhaps, the best

known bakery products which use oatmeal are biscuits and cookies, oats may

be included on their own or along with fruits and nuts. Oatmeal biscuits have

a strong regional bias associated with Scotland, and they are a dense and fria-

ble biscuit with a distinctive flavour. There are other regional products which

use oatmeal such as Staffordshire Oatcakes (see Section 8.43).

The consumption of oat bran has been linked with the potential for

lowering blood cholesterol in the human digestive system, and this has led to

its inclusion in a number of food and drink products. The ‘active’ ingredient

in this context is the soluble fibre gum, beta-glucan.

Oat flakes may find use along with other flaked grains in the manufacture

of bread and rolls, either as part of the dough or as a surface dressing to

provide texture.

Oat bran and oatmeal are included in some breads where the distinctive

aroma and flavour are seen as beneficial. The oat products are usually added

to a strong white flour base as oats do not have the potential to contribute to

the formation of a gluten network in the dough. There is a tendency for the

bread products to have a slightly dry mouthfeel, but when combined with a

suitable filling, e.g., prawn mayonnaise, they make a popular sandwich type

in the United Kingdom. Oat bran is also a key component of some speciality

cake muffins.

Further reading

Welch, R.W., McConnell, J.M., 2001. Oats. In: Dendy, D.A.V., Dobraszczyk, B.J. (Eds.),

Cereals and Cereal Products. Aspen Publisher, Inc., Gaithersburg, MA, pp. 367�391.





2.1.7 What is micronised wheat?

The micronising process involves the treatment of grain by infrared irradia-

tion and is not to be confused with ultra-fine grinding by the ‘Micronizer’

fluid energy mill. When infrared rays penetrate, they cause the molecules of

the material to vibrate at a frequency of 60,000 to 150,000 megacycles per

second. This results in rapid internal heating and a rise in water-vapour

pressure. The grains become soft and turgid causing them to swell and

fracture. Immediate rolling or flaking gelatinises the starch, considerably

enhancing digestibility and feed value of the grain.

Micronising drastically reduces the counts of bacteria and moulds.

The counts from two sample wheats are given below:

Sample Count per gram

Bacteria Mould

Untreated wheat 540,000 1200

Micronised wheat ,100 ,10

The effect on the milling is less efficacious. For example, in a

measured experiment, a control wheat conditioned to 15% moisture con-

tent, yielded 67.3% flour, and a micronised wheat similarly conditioned

yielded only 36.4% of flour. The micronised wheat flour produced was of

poor colour, and clean-up of bran was unsatisfactory. It was concluded

that micronised wheat was unsuitable for the normal roller mill process to

produce white flour.

The flour from micronised wheats would not be suitable for normal

bakery products as the gluten quality would be spoilt by the heat generated

in the micronising procedure but often finds use where the thickening

properties of the gelatinised starch have value, e.g., soups.


2.2 FLOURS

2.2.1 Can you explain what the ash content means and shouldwe ask for it to be determined on our flours?

The ash test is based on the incineration of a known weight of a flour sample

at 900�C in a suitable furnace; the material which remains after incineration

comprises the inorganic minerals and is referred to as the ash (ICC, 2005).

There are alternative testing methods which use a lower temperature for

heating the sample, e.g., the AACC method for ash determination uses a

temperature of only 600�C (AACC, 2008). Whichever the testing method is

applied, the aim remains the same.

The minerals in cereal grains are concentrated in the bran layers which

surround the inner endosperm. Thus, as a general principle the higher the ash

content of a ‘white’ flour, the greater the proportion of bran which can

be present in the sample. The complex geometry of the wheat grain and the

physical properties of the materials concerned means that the bran skins

cannot be ‘pealed’ from the endosperm-like layers on an onion, and even in

the most efficient of flour mills, it is inevitable that some fragments of the

bran layers will find their way into the white flour which essentially comes

from the endosperm. The ash test may therefore be seen as an indicator

of the ‘purity’ of white flour; in that, the more of the bran which is incorpo-

rated with the wheat endosperm, the higher the ash level will be. It follows

that as wholemeal flours are 100% of the grain, the ash content will be

considerably higher than that of white flours.

In the United Kingdom (and elsewhere), there is a statutory requirement

for white flours to be fortified with calcium carbonate at levels between

235 mg and 390 mg/100 g (Bread and Flour Regulations, 1999) before the

flour leaves the mill. This requirement is related to the nutritional status of

flour. Calcium carbonate is an inorganic substance which remains a part

of the ash residue on testing. However, unlike bran, it has no technological

impact in baking. As calcium carbonate would measure as ash using the test,

United Kingdom flours will yield a higher value and distort the application

of the information for bakery purposes.

In the light of the above scenario, UK millers do not routinely use the

ash test to monitor final flour quality, instead they use a test commonly

referred to as the ‘grade colour figure’ (see Section 2.2.2). This test, carried

out with a ‘Colour grader’ with a specified light source (Cauvain, 2009), is

based on the assumption that higher levels of bran will yield a darker flour

colour. There is a broad agreement between ash and grade colour

figure (GCF) (see example in Fig. 2.1), but one value cannot be used to pre-

dict the other with any degree of certainty. This is because the distribution of

minerals is not uniform throughout the wheat bran layers, and the particle

size of the bran also distorts the relationship.


Although neither test can be used to predict the results of the other,

both have relevance to the breadmaking potential of a given white flour. In

its simplest form, the higher the ash value or GCF, the poorer the gas

retention capacity of the flour in breadmaking. This, in turn, means that

loaf volume will fall if the ash or GCF increases. Cauvain (2016) provides

relevant ash data for a range of mill fractions included in an example of a

straight run white flour.

In broad terms, the ash level has been equated with the ‘extraction rate of

flours’ (i.e., the proportion of the original grain turned into flour). Kent and

Evers (1994) published data relating milling extraction rate to ash values and

showed that an increase in extraction rate from 70% to 85% increased the

measured ash level in the flour from 0.44% to 0.92%. However, ash levels

should not be taken as an absolute indicator of extraction rate because as

noted above, the minerals in the wheat grain are not uniformly distributed in

the grain components and milling techniques can skew the data.

References

AACC, 2008. Approved Methods, 10th ed. AACC International, St. Paul, MN.


and Applications, second ed. DEStech Publishing, Lancaster, PA.

ICC � Interntational Association for Cereal Science & Technology, (2005). Determination of

ash in cereals and cereal products, ICC Standard Method 104/1, Vienna, Austria.

Kent, N.L., Evers, A.D., 1994. Technology of Cereals, fourth ed. Elsevier Science Ltd.,

Oxford, UK.

The Bread and Flour Regulations, (1999). SI 1999, No. 1136 � SI 1998, No. 141, HMSO,

London, UK.

00.20.40.60.8

11.21.4

–2 0 2 4 6 8 10 12 14Grade colour figure

Ash

(%)

FIGURE 2.1 Relationship between flour ash and grade colour figure.







2.2.2 What does the term grade colour figure mean in flourspecifications? How is it measured? What are the implicationsfor bread quality?

GCF (sometimes written as Colour Grade Figure or Flour Colour Grade) is

a measure of flour colour. The technique uses light reflectance at a specific

wavelength from a flour�water paste held in a glass cell. It was developed

by Kent-Jones and Martin (1950) and refined by Kent-Jones et al. (1950).

The ‘Colour Grader’ has undergone a number changes to improve its reli-

ability and sensitivity. In many countries, GCF is an accepted method for

the evaluation of mill performance and flour quality. Although generally

accepted as a measure of the level of bran present in white flours,

it is appreciated that GCF is affected by a number of other factors,

including the intrinsic colour of the wheat endosperm (Barnes, 1986) and

the impact of any bleaching processes which may be carried out (the

practice of bleaching white flours is becoming less common in modern

mills).

In the United Kingdom, the mandatory addition of chalk to white flour

means that the measurement of ash as a predictor of the breadmaking

potential of the flour was misleading because the measured ash value was

raised by the addition of the chalk (see Section 2.2.1). Thus, GCF came to

be used more readily as an indicator of the level of bran ‘contamination’ in

white flour. The form of wheat grains, especially the crease, means that it is

difficult to completely separate the bran layers from the starchy endosperm,

and it is inevitable that small particles of bran ‘powder’ find their way into

white flour. The bran particles have the same size as the endosperm frag-

ments and so cannot readily be separated by sieving. The level of bran parti-

cles may be reduced through aspiration (in purifiers) as they are less dense

than the endosperm fragments but complete separation is seldom achieved.

In general, the higher the GCF value, the higher the level of bran present

in a given white flour, the poorer the gas retention properties in bread dough

and the darker the bread crumb colour. This statement does not convey the

complete picture for white flours which are a composite of many different

‘white’ machine flours obtaining during wheat milling. The level of bran var-

ies in each of these flours according to the layout and operation of the mill.

Cauvain (2017) provided examples of the variation in GCF amongst machine

flours with relevant bread volume data.

There is a general relationship between the two measured flours properties

(see example in Fig. 2.1), but GCF cannot be accurately used to predict flour

ash and vice versa. It should be noted that when the GCF test was developed,

it was intended to be used with white flours and so measurements on brown

or wholemeal have limited relevance.


Machine flours which are high in bran content (i.e., high ash or high

GCF) may often be referred to as ‘low grade’ flours to indicate their rela-

tively poor breadmaking potential. The quantity of such flours produced and

present in straight run flour is usually relatively small, so the overall impact

on flour GCF and loaf volume arising from their addition is limited. Flours

which are especially low in bran (i.e., low GCF and low ash) may often

be referred to as ‘patent’ or ‘top patent’ flour. Such flours have good

breadmaking potential even though their protein content may be lower than a

straight run flour.

The GCF measurement method is not normally used to assess the quality

of wholemeal flours; not least because the reliability of the measurements

can be affected by the size on the bran particles which are present in the

flour. In white flours, the bran particles will be no bigger than the largest of

the wheat endosperm fragments which are present.

References

Barnes, P.J., 1986. The influence of wheat endosperm on flour colour grade. J. Cereal Sci. 4, 143�155.



Kent-Jones, D.W., Martin, W., 1950. A photo-electric method of determining the colour of flour

as affected by grade, by measurements of reflective power. Analyst 75, 127�133.

Kent-Jones, D.W., Amos, A.J., Martin, W., 1950. Experiments in the photo-electric recording of

flour grade by measurements of reflective power. Analyst 75, 133�142.












2.2.3 We have the water absorption capacity of our flourassessed regularly but find that this is different to the actualwater level that we use in the bakery. What are the reasons forthis difference and is it important for breadmaking?

The level of water that you add to flour for breadmaking depends on many

factors, some determined by the properties of your flour, some by the

requirements of the product you are making and some by the mixing and

processing methods you use. The water absorption capacity of the flour tends

to have less relevance in the manufacture of cakes, biscuits and pastries due

to the different technologies employed.

There are a number of different methods by which the water absorption

capacity of wheat flour is measured. They are all commonly based on the

principle of making a flour�water dough and measuring the rheological

properties of that dough during mixing. As the dough mixes, it exerts torque

on one of the mixing arms, and that torque is transmitted to a recording

device, commonly a chart or digital display. The chart has a number of hori-

zontal and parallel lines on it and is moving at a constant speed. As the flour

begins to hydrate, the rheological properties of the flour�water mixture

change, and these are recorded on the chart.

For flour-water absorption estimation, one of the horizontal lines is

chosen as representing the desired consistency and the amount of water

added to allow the mixture to reach the chosen line is taken as the

water absorption capacity of the flour. To some extent, the chosen line is

arbitrary and linked with a sensory (albeit expert) evaluation of the ‘ideal’

dough consistency.

The choice of dough consistency for the standard method cannot take

into account all of the potential recipe and process variations that are used in

breadmaking and so the flour-water absorption capacity value you are given

should only be seen as a guide as to what may be used in the bakery and

more importantly perhaps, as a prediction of any changes that you may need

to make to accommodate variations in flour properties.

Contributions to the measured water absorption capacity of flour come

from a number of individual flour properties. These include the following:

� The moisture content of the flour; the higher the moisture, the lower the

water absorption capacity.

� The protein content of the flour; the higher the protein content, the higher

the water absorption capacity.

� The level of damaged starch in the flour; the higher the damaged starch

level, the higher the water absorption capacity.

� The fibre content; wholemeal, bran-supplemented and fibre-enriched

flours will always have a higher water absorption capacity than white

flours.


Other contributions come from variations enzymic activity and the level

of pentosans (soluble carbohydrates), but these are usually relatively small

by comparison with the effects of the main flour components.

The optimum consistency for a bread dough is hard to define because

much depends on how the dough will be processed. Hand processing allows

for sensitive handling of the dough with ready adjustment of the pressures

which will be applied during moulding and shaping. When dough is mechan-

ically processed, the processing equipment cannot adjust its pressures, so

there is a much greater need for the consistency of the dough to be optimised

and to remain as unvarying.

In general, doughs which will be baked in a pan tend to have higher

added water levels than those which will be baked on trays or the oven sole

(i.e., free-standing). In the former case, a soft dough will more readily flow

into the corners of the pans, whereas in the latter case, a stiffer dough will

more readily retain its shape. For example, it is common to use lower water

levels in the manufacture of UK-style bloomers which traditionally have a

round or oval cross-section. Too much water and the dough will flow during

proof and yield an uncharacteristic and unacceptable flat shape (Cauvain and

Young, 2008).

Some bread types depend on the production of a soft dough to achieve

the required characteristics. In the manufacture of traditional French

baguette, the added water levels may be several percentage points above

the measured flour-water absorption capacity and above that used for pan

bread production. The soft dough contributes to the ease of dough mould-

ing and avoidance of the squeezing out of the large gas bubbles which sig-

nificantly contribute to the creation of the characteristic open cell structure

of baguette. The individual dough pieces are proved in cradles of some

form which stops them from flowing, and the soft dough also contributes

to the rapid expansion of the dough piece in the oven which yields a high

specific volume product.

Cauvain and Young (2008) discuss the role of dough consistency and its

impact on bread-cell structure. They show how the gas bubble structure in

stiff dough can be broken down and contribute to the formation of areas of

damaged structure in the bread comprising coarse cell structure and dull-

coloured crumb (see Sections 2.2.11).

Although dough consistency may vary with product and process, there is

one dough property that is commonly avoided in all cases, namely dough

stickiness. In the bakery problems, dough stickiness are usually associated

with the water level added during dough mixing, and a common reaction to

excessively sticky dough in the bakery is to reduce added water levels.

A reduction in added water level may well improve the processability of the


dough, but high water levels per se are often not the main cause of dough

stickiness (Cauvain, 2015). In many cases, dough stickiness arises because of

lack of dough development in the mixer; the greater the dough development,

the higher the added water level may be. The other major contributor to

apparent dough stickiness comes from subjecting the dough to shear forces

during processing, such as during moulding, if these can be minimised then

water levels can be optimised without compromising dough rheology and

bread quality.

References


Switzerland.

Cauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture and Quality: Water Control &

Effects, second ed. Wiley-Blackwell, Oxford, UK.






2.2.4 What effects will variations in flour protein content haveon baked product quality? How is the property measured?

The protein content of flour is probably the single most important property

of wheat flour. Perhaps more correctly, we should refer to wheat proteins as

there is more than one type of protein present. The scheme established by

Osborne (1907) is most commonly used for the groups of proteins in wheat

which comprise:

� Albumins, soluble in distilled water.

� Globulins, soluble dilute salt solutions.

� Prolamines, soluble in 70% aqueous ethanol.

� Glutelins, soluble in dilute acid.

The two most important groups for bread and fermented goods are the

prolamines and the glutelins. They contain the gluten-forming proteins which

give wheat flour its almost unique ability to form a dough capable of retain-

ing gas and increasing in volume under the influence of heat and carbon

dioxide gas released by yeast fermentation. The properties of wheat gluten

were recognised as long ago as 1729 (Bailey, 1941).

Gliadin and glutentin are the two wheat protein components which gives

wheat gluten its special properties. These can best be appreciated by making

a dough of flour and water and hand kneading it under running water. As

time proceeds, a milky-white liquid is washed out, this is the starch and other

insoluble components. Eventually, all that is left is greyish, light brown mass

with an extensible but also an elastic character. This is the gluten, and its gas

retention properties can be shown by placing the mass of gluten in the oven

and watching it swell. The quantity of gluten that can be extracted varies

with the protein content of the flour.

Bread and other fermented product volumes are directly related to the

quantity of protein present; the higher the protein content of the flour, the

greater the product volume. This positive relationship has been reported by a

large number of observers for many different breadmaking processes and

products (e.g., Cauvain, 2015). Thus, in answer to your question, variation in

protein content will result in potential variations in bread and fermented

product volume. They will also affect the lift obtained with laminated pro-

ducts but will have no significant effect on the volume of other baked pro-

ducts, though variations in protein content may affect other product

attributes, e.g., eating quality in cakes.

Protein absorbs water, 1.3 g of water for each 1 g protein (Cauvain,

2015), so variations in protein also affect flou-water absorption.

Wheat proteins contain nitrogen and protein measurement methods are

based on that basic measurement. For many years, the standard ‘wet chemis-

try’ method was the Kjeldahl (Cauvain, 2017). The method involves the

digestion of the flour using sulphuric acid in the presence of a catalyst. The


Kjeldahl nitrogen value so determined is converted to protein using a factor,

for wheat this involves multiplying by 5.7. More recently, Kjeldahl protein

determination has been replaced by the Dumas method based on combustion

in the presence of oxygen (Cauvain, 2017).

Flour protein is also commonly measured using near infrared reflectance

(NIR) technology (Cauvain, 2017). This provides a fast and simple to use

method which can also be applied to on-line processes in the flour mill.

However, it should be noted that NIR protein is calibrated against an

accepted ‘chemical’ method as it does not represent a fundamental measure-

ment of protein.

References

Bailey, C.H., 1941. A translation of Beccari’s lecture concerning grain. Cereal Chem. 18,

555�561.

Cauvain, S.P., 2015. Technology of Breadmaking, third ed. Springer Publishing International

AG, Switzerland.

Cauvain, S.P., 2017. ICC Handbook of Wheat, Flour, Dough and Product Testing: Methods and

Applications, second ed. DEStech, Lancaster, PA.

Osborne, T.B., 1907. The Proteins of the Wheat Kernel. Carnegie Institute of Washington,

Washington, DC.











2.2.5 There are many references to protein and gluten qualityin the technical literature, how important are these propertiesfor bread and other baked products?

As discussed in the previous question, flour protein content is probably the

most important of all flour analyses due to its relationship with gluten quan-

tity. In gluten washing experiments with different flours, we cannot only

observe different quantities of gluten, but for the same gluten mass from two

different flours, we may observe that the rheological character (i.e., the way

it stretches and deforms) of the gluten varies.

The variations in gluten ‘quality’ which come from different flours are

important in many aspects of baking. In particular, they directly affect the

way in which flours will behave when subjected to the stresses and strains of

processing. The key qualities that we need to consider are as follows:

� Resistance to deformation.

� Elasticity.

� Extensibility.

� Stickiness.

Gluten has all of these properties and is described as a visco-elastic

material, that is, its behaviour can be described by considering both viscous

and elastic properties.

In the production of bread and fermented goods, we are seeking to

preserve the gas-bubble structure which has been created during mixing

and to obtain a considerable degree of expansion during proof and baking.

We therefore seek to have a gluten which has low resistance to deformation,

minimal elasticity and maximum extensibility. Bread and other fermented

doughs generally only experience problems with stickiness when they are

subjected to shear, e.g., as in moulding or with excessive recipe water

levels.

The sheeting of dough as for the production of laminated products, pastries,

crackers and biscuits, also requires that they have an extensible but not elastic

gluten. However, as recipe water levels in such products are lower than used in

breadmaking, the gluten tends to have a more elastic nature. To overcome this,

it is common to use resting periods during processing to allow the gluten to

become softer and less elastic. It is not so easy to use resting periods with

fermented products due to the gas production by the yeast.

In batter-type products, such as cakes, gluten quality is considerably less

important, mainly because it cannot form in the initial mixing stages due to

low viscosity of the system that makes the transfer of sufficient energy and

therefore gluten development difficult.


2.2.6 I have seen that there are several different methodswhich can be used to assess flour protein quality, which onegives the most meaningful results?

There are indeed many ways to assess the quality of protein present in flour.

As they are all related to some aspect baking performance, they will all give

meaningful results but because they all have a different basis for assessment,

it can be very difficult to compare data from one test to another. The other

common problem that one encounters is that almost without exception the

methods are not based on the same formulation, mixing or processing condi-

tions that are now in common use in baking. Indeed, the basis of many of

the flour quality tests originates from the days when breadmaking using bulk

fermentation was the norm. Today, no-time doughmaking processes dominate,

so this means that the output from flour quality tests needs a degree of ‘expert’

interpretation to obtain the most meaningful results. Over a period of time,

experts can readily learn to extrapolate from protein quality data to end prod-

uct quality and so comparison between flours can be readily achieved.

Some of the more protein quality tests that are commonly used are given

below:

� Farinograph

This test is based on mixing a flour and water dough under prescribed

conditions. This is commonly used in the determination of flour-water

absorption. Evaluation of the mixing curve can supply data on protein

quality using the parameters dough development time, dough stability

and degree of softening.

� Extensograph

In this test, a flour�water�salt dough is mixed using the Farinograph.

The resultant dough is moulded and rested under prescribed conditions.

After resting the dough, pieces are stretched over two set pins by a

moving hook. The test mimics the stretching of the dough in a bakers

hands. The resistance to extension and extensibility to the point of the

dough snapping are measured. The piece may be remoulded, rested again

and retested.

� Alveograph/Consistograph

In the Alveograph test, the water level added to the flour is fixed, and

after mixing, the dough is extruded and shaped. After a resting period,

the dough is clamped over a metal ring and inflated by air pressure.

The resistance of the dough due to expansion and the point of rupture are

recorded. Typically, a curve is produced, the area of which is related to

flour strength. The weakness of the Alveograph was the fixed dough

water content which has now been replaced with an optimised water level

in the Consistograph test, otherwise the procedure is similar.


� Roberts/Dobraszczyk dough inflation

This device can be fitted to standard texture analysis machine. The dough

is prepared under standard conditions and air pressure used inflates a

bubble to the point of rupture.

� Fundamental dough rheology measurements

A number of devices and methods are based on small-scale deformation

of dough between two oscillating plates. The data can be related

to fundamental rheological measurements, but as dough is visco-elastic

(i.e., has both viscous and elastic properties) and deformation forces are

so low, the relationship between such measurements and dough behaviour

remains as tenuous as with other tests.

� Large-scale deformation testing

A number of tests have been developed by workers seeking to more

closely mimic the behaviour of dough under normal bakery conditions.

The tests tend to be product or project specific and not in common use as

standard methods.

Further reading

Cauvain, S.P., 2015. Technology of Breadmaking, third ed. Springer Science1Business Media,

Switzerland.



Dobraszczyk, B.J., 1999. Measurement of biaxial extensional rheological properties using bubble

inflation and stability of bubble expansion in bread doughs. In: Campbell, G.M., Webb, C.,

Pandiella, S.S., Niranjan, K. (Eds.), Bubbles in Food. American Association of Cereal

Chemists, St. Paul, Minnesota, USA.

Faridi, H., Faubion, J.M., 1990. Dough Rheology and Baked Product Texture. Van Nostrand

Reinhold, New York, USA.













2.2.7 We have been using a flour ‘fortified’ with dry glutenfor breadmaking. The bread is satisfactory when made on ahigh-speed mixer but so less when we use a low-speed mixer.What is ‘dry gluten’ and can you explain why we get differentresults when we change mixers?

Dry gluten is obtained by washing out the starch from a wheat-flour dough.

The process of milling used to extract the wheat proteins differs from stan-

dard wheat-flour milling and is best described as ‘wet milling’. The wheat

flour from which the dried gluten is to be prepared is mixed with water to

form a dough or batter is formed. A rubbery mass is formed as the gluten

hydrates and the dough is kneaded (much as happens in breadmaking).

The starch is washed out, and the gluten mass which is left is carefully dried

using controlled procedures designed to retain the maximum ‘vitality’ of the

gluten, i.e., its ability to form gluten after hydration and dough mixing.

Typically, the protein content of the dry gluten will be in the region of

70�75% dry matter. In some variations, the wheat flour may be suspended

in alkaline or acidic solutions to aid the separation of the proteins.

Dry gluten absorbs about 1.5 times its own weight of water when it is

used in breadmaking. The addition of dry gluten may be used to boost the

level of the natural flour protein to improve the gas retention properties of

the dough. It may be added to the flour in the mill, or it may be added as a

dry ingredient in the bakery. Dry gluten does not usually require prehydra-

tion before dough mixing. The wheat source of the vital wheat gluten is not

usually considered to be important and provided that there has been no heat

denaturation of the proteins, then the overall functionality of the dried gluten

is largely dictated by the protein content of the material used.

The input of energy during dough mixing is an essential part of the

development of a gluten structure capable of retaining gas during baking.

Different mixers impart different levels of energy to the dough for a given

mixing time and so are more or less effective at developing a gluten struc-

ture. High-speed mixers impart higher energy levels to the dough during

mixing than low-speed mixers. This difference remains true even when the

dough mixing time with low-speed mixers is lengthened. This is because

the low speed of mixing results in a low rate of energy transfer.

Gluten development, as manifested by improved gas retention, is known to

be linked with the rate of energy input to the dough with faster rates of energy

input improving dough gas retention for many flours (Cauvain, 2015). This

effect is especially true for gluten-fortified flours, and it appears that mixers at

low speeds are less able to make full use of dry gluten additions. However,

the full reasons for the difference are not completely understood.

Reference


AG, Switzerland.




2.2.8 Why is the protein content of wholemeal bread flourtypically higher than that of white flours but the bread volume iscommonly smaller with the former?

Proteins are distributed throughout the different components of the wheat

berry but that distribution is not-uniform. There tends to be less the protein

in the central endosperm portions of the grain (Kent and Evers, 1994).

This non-uniform distribution of wheat protein is mirrored by an increase in

the starch content. The protein/starch ‘gradient’ in the grain cross-section

reflects the manner in which the endosperm develops in the growing plant as

the different components are synthesised. The starch granules are packed

into cells with the protein fragments. The cell walls of wheat endosperm are

mainly composed of arabinoxylans. Surrounding the starchy endosperm

is the aleurone layer with dense, thick cell walls. Further out in the grain

cross-section are the different layers which characterise the bran.

As the distribution of protein is not uniform throughout the grain, the

protein content of the flour is often a reflection of the milling processes used

to manufacture the flour. By definition, wholemeal flour represents all of the

grain crushed into flour so the protein content of the final flour should be

the same of the original starting grain. White flour is based on the separation of

the starchy endosperm from the surrounding bran layers, and they tend to have

around 1% less protein than the original grain (viz. wholemeal flour). The pre-

cise difference in the protein content of the grain and the white flour produced

from it varies slightly according to the milling technique employed.

The presence of bran reduces the gas retention properties of the dough

which commonly yields lower volume in the finished product unless

modifications are made to the breadmaking recipe and process. Although

there are proteins in the bran particles, they do not readily form a gluten

network as is the case with the proteins in the endosperm cells; in practice,

this protein may be considered as ‘non-functional’.

The mechanism by which bran particles reduces dough gas retention are not

fully understood. Some views suggest that the particles of bran ‘puncture’ the

gas cell walls in the dough. However, it is more likely that the bran particles

represent areas of discontinuity and weakness in the gluten network which

more readily allow the coalescence of smaller gas bubbles as they expand

during proof and the early stages of baking and so permit the escape of some of

the carbon dioxide gas being produced by the yeast. For the reasons given

above, it is common practice to produce wholemeal flours with much higher

protein contents than that of white flours. This is done either by choosing a

higher protein wheat within the milling grist or through the supplementation of

the milled flour with dried, vital wheat gluten (see Section 2.2.7).

Reference

Kent, N.L., Evers, A.D., 1994. Kent’s Technology of Cereals, fourth ed. Elsevier Science Ltd.,

Oxford, UK.




2.2.9 We get a significant variation in the quality of ourwholemeal bread and rolls depending on which flour wepurchase. What characteristics should we look for in awholemeal flour specification to get more consistent results?

Wholemeal flours fall into two main categories; stoneground and roller-

milled. A key difference between the two is the particle size distribution; in

general, stoneground flours have a greater proportion of fine bran particles

than the roller-milled type. The presence of high levels of bran in whole-

meal flours is responsible for the lower bread volume that is achieved by

comparison with white flour from the same wheat, despite the fact that the

white flour has a lower protein content. It is also known that finer bran par-

ticles tend to have a proportionally greater volume depressing effect than

coarse particles.

In addition to the bran particle size difference, there may be differences

in the endosperm particle size of the two types of wholemeal flour. It is

likely that the endosperm particle size of the stoneground flour is coarser

than that of the roller-milled type because the endosperm particles are

subjected to considerably fewer grinding passages. One possible conse-

quence of this difference is that the endosperm particles take longer to

hydrate, and if your mixing times are short, you may not see the same

extent of gluten formation. You can check this with a few simple trials

with extended mixing times.

The protein content of your wholemeal flour should certainly be speci-

fied. This will reflect the protein content of the wheats chosen by the

miller. It is possible to add vital wheat gluten to boost the protein content

of your mix, but gluten fortification is less effective with slower speed

mixers (see Section 2.2.7).

The specification of the Hagberg Falling Number (or a similar

measure) is as important with wholemeal flours as it is with white flours,

and you should also consider whether you should specify the water absorp-

tion capacity of the flours. You will need to remember that the water

absorption capacity is only a guide as to what water level you will need to

actually use for dough mixing (see Section 2.2.3). In the case of whole-

meal flour, this is an especially important point to bear in mind as the

bran and larger endosperm particles will be slow to hydrate. This often

means that wholemeal flour doughs become stiffer during post-mixer pro-

cessing, and this can have a negative impact on dough handling properties

and contribute to moulder damage and other product quality losses. You

should try to maximise the water additions made to wholemeal flours, the

initial tackiness that you observe when the dough has finished mixing should

begin to disappear within a few minutes during processing. Optimising the

added water level will also help you optimise dough development and the gas

retention properties of the dough.


2.2.10 What is the Falling Number of a flour, how is itmeasured and what values should we specify for our flour miller?

The Falling Number of a flour is related to the level of cereal alpha-

amylase which is present in the wheat after harvesting. The production of cereal

alpha-amylase is encouraged within the wheat grains if their moisture content

is sufficiently high towards in the last few weeks before harvesting. Such condi-

tions are most likely to happen if the period concerned is particularly wet.

The full name for the test is the Hagberg Falling Number test and it was

originally developed in Sweden. It takes its name from the basis of the test.

A flour�water suspension is heated within a tube held in a boiling water

bath. The mixture is stirred for 60s to ensure uniformity of the mixture.

At the end of the stirring period, the stirrer is brought to a predetermined

point at the top of the tube, released and the time taken for the stirrer to fall

through the mixture to a lower fixed point in the test tube is measured. The

time taken for the stirrer to fall down the tube is known as the Falling Number.

The test is based on the action of the cereal alpha-amylase on the

gelatinising starch present in the flour which is progressively broken down by

the amylase action. The temperature in the test is designed to give maximum

enzymic activity in the flour�water mixture and the Falling Number changes

according to the level of cereal alpha-amylase present; the higher the cereal

alpha-amylase level, the quicker the flour�water paste thins, the faster the

stirrer falls and therefore the lower the Falling Number. The Falling Number

includes the 60s stirring time so that the lowest theoretical number is 60.

In practice, Falling Numbers over 250 are suitable for most breadmaking

processes. As well as having too much cereal alpha-amylase activity, it is pos-

sible to have too little and Falling Numbers above 350 indicate that the flour

should be supplemented with a form of amylase (Cauvain, 2015) to maintain

gas production through the provision of maltose for yeast activity. We suggest

you specify that your Falling Number lies between 250 and 280, though the

actual level you require will be specific to your products and processes.

The higher the cereal alpha-amylase level, the greater formation of dextrins

during breadmaking and the more likely that there could be problems with bread

slicing in all breadmaking processes. In bulk fermentation, high cereal alpha-

amylase levels will lead to dough softening during the bulk standing time.

Reference


AG, Switzerland.

Further reading








2.2.11 What is damaged starch in flour? How is it damaged andhow is it measured? What is its importance in baking?

Starch granules in flour have a flattened roughly spherical shape which is

sometimes described as lenticular. They range in size from about 10 to

50 μm. Each starch granule has a surface or skin. Within the developing

wheat grains, the starch granules are embedded in a protein matrix in the

endosperm. During the flour milling process, the endosperm is fragmented

by the action of the millings rolls or stones. Some of the starch granules are

exposed to high pressures during the milling process, and their surfaces may

be become mechanically ruptured or damaged. The damage to starch gran-

ules typically occurs during the reduction (smooth rolls) stage of roller mill-

ing. Here, the roll gaps and speed differentials between the rolls may be

adjusted to give more or less starch damage according to the requirements

for the final flour.

Damaged starch is susceptible to attack by alpha-amylase, and this action

provides the basis for the different methods which have been and continue to

be used for the measurement of the damaged starch level in flours. A long-

standing method on the basis of the enzymic hydrolysis of starch was that

devised by Farrand (1964), and for many years, the level of damaged starch

in flours was referred to in Farrand Units. More recently, the most important

methods of measuring damaged starch are as follows:

� The Megazyme method based on a two-stage enzymic assay (Gibson

et al., 1992).

� The AACC method (Donelson and Yamazaki, 1968; AACC, 1995) based

on digestion of the damaged starch by fungal alpha-amylase with the

value expressed as a percentage.

� With the Chopin SDmatic test which provides an automatic measurement

of damaged starch (Cauvain, 2017).

� Using NIR spectroscopy with calibrations that are related to other stan-

dard methods of analysis.

The importance of damaged starch is mainly for breadmaking. Damaged

starch absorbs twice its own weight of water in contrast with undamaged

starch which only absorbs around 40% of its own weight. This high water

absorbing capacity means that the damaged starch may account for about

16% of the total flour-water absorption, a value which is similar to that for

the protein itself (Cauvain, 2015). The contribution that damaged starch

makes to flour-water absorption has made it an essential element of bread

flour specifications.

The upper limits for starch damage are not well defined nor understood.

The link between damaged starch and alpha-amylase activity is an

important one as excessive amylase activity leads to dextrin formation


and the release of water into the dough which, in turn, can cause dough

softening during with breadmaking processes which employ periods of

bulk fermentation.

Very high levels of starch damage may lead to loss of bread quality,

including a more open (larger average size) cell structure and greying of the

crumb colour. Farrand (1964) observed such quality losses and related

these to the starch damage and flour protein levels. His premise that the

damaged starch level should not exceed, the (protein)2 divided by 6 is no

longer absolutely relevant, but the principle, that the higher the flour protein,

the higher the starch damage that can be accommodated remains a relevant

‘rule of thumb’.

References

AACC, 1995. ninth ed. Approved Methods of the American Association of Cereal Chemists,

March. St. Paul, Minnesota, USA, Method 76-30A, Digestion by alpha-amylase under

specified conditions.


AG, Switzerland.



Donelson, J.R., Yamazaki, W.T., 1968. Enzymatic determination of starch in wheat fractions.

Cereal Chem. 45, 177�182.

Farrand, E.A., 1964. Flour properties in relation to the modern bread processes in the

United Kingdom, with special reference to alpha-amylase and starch damage. Cereal

Chem. 41 (March), 98�111.

Gibson, T.S., Al Qalla, H., McCleary, B.V., 1992. An improved enzymic method for the

measurement of starch damage in wheat flour. J. Cereal Sci. 15, 15�27.



















2.2.12 What characteristics should we specify for white breadflour and why?

The breadmaking potential of flour is strongly influenced by the protein

present in the wheat. These proteins hydrate and with the input of energy

during mixing form the gluten network which provides much of the gas

retaining properties of bread dough. However, there are other flour properties

which should be taken into account when deciding on a particular flour speci-

fication, and there are process factors to consider, such as which breadmaking

process you are using and what type of product you are making.

As a guide, you should consider the following as a minimum for white

flour:

� Protein content � Around 13% on a dry matter basis. This

figure should increase by about 1% if you are using a process which

uses bulk fermentation to mature the dough before processing or if you

are making ‘free-standing’, hearth- or oven-bottom type breads. As a

general rule, the higher the protein level in the flour the greater its gas

retention potential and therefore the greater the resultant bread volume

and crumb softness.

� A measure of the ‘purity’ of the white flour; that is the level of bran

particles which are present. This is often measured as ash or GCF

(see Sections 2.2.1 and 2.2.2). The presence of bran has a negative

impact; the higher the level of bran present, the poorer the gas retention

of the dough.

� The water absorption capacity of the flour as this is an indicator of

how much water will need to be added at the doughmaking. A number of

different factors affect the water absorption capacity (see Section 2.2.3).

The measured water absorption capacity is only a guide as to the level

that will be used in the bakery. It is usual for the actual level of water

added to dough to be reduced when making free-standing breads as this

helps the dough to retain the required product shape during processing

(Cauvain and Young, 2008).

� Hagberg Falling Number � Typically, this should be above 250 seconds

(see Section 2.2.10).

� Protein quality � This is usually assessed by measuring the rheological

properties of a flour�water dough. In general, the flour should possess

reasonable resistance to mixing or stretching, sufficient extensibility and

good stability. There are a number of different tests which can give

you this information. For a summary of the methods, see Section 2.2.5,

and for more detailed information, see Cauvain (2016).

� Flour treatments and additives � Ideally, the flour should be untreated,

but if this is not possible, any additions should be kept to a minimum.

Common additions are ascorbic acid (AA) as a bread ‘improver’ and


alpha-amylase. If you are using a breadmaking process in which the flour

would benefit from the addition of bread improvers it would be better to

add them in the bakery as part of the recipe. Any additions to the flour

should be discussed with your miller supplier.

References

Cauvain, S.P., 2017. Applications of Cereals, Flour and Dough Testing: Methods and

Applications, second ed. DEStech Publications, Lancaster, PA.








2.2.13 As enzymes such as alpha-amylase are inactivated byheat during baking, is it possible to use heat treatment of flour toinactivate the enzymes in low Hagberg Falling Number floursbefore baking?

The temperature at which alpha-amylase is inactivated depends on its source.

There are three common sources; fungal, cereal and bacterial which are

inactivated at increasingly higher temperatures (Cauvain, 2015). As you

are asking about flour, the source of the alpha-amylase is referred to as

cereal (commonly from wheat, rye or barley).

The exposure of flour to heat brings about a number of different changes.

In addition to inactivation of the alpha-amylase there will be:

� A loss of moisture.

� The potential for denaturation of the protein.

� Changes in the swelling and gelatinising characteristics of the starch.

When heat is applied to flour, it quickly loses moisture, but as the

moisture content falls to around 8%, the rate of moisture loss with continued

heating slows down. It appears to be that from this point on that some of the

more profound changes take place in flour properties.

At low levels of heat input, a reduction in the extensibility of the flour

is usually observed. Prolonged heating leads to complete denaturation of wheat

proteins and they lose their ability to form a cohesive gluten network in dough.

Dry heat treatment of flour brings about changes in starch properties

which are analogous to chlorination, and this type of treatment is used to

replace chlorination for flours intended for the manufacture of high-ratio

cakes and some other baked products (see Section 2.2.17).

Heat treatment of flours should not be used where the product is intended

for breadmaking due to the potential for partial or total denaturation of the

gluten-forming proteins. Thus, inactivation of alpha-amylase by heat should

not be seen as a means of reducing the adverse effects of cereal amylase in

breadmaking.

In some speciality flours, i.e., those destined for use in the manufacture

of soups and sauces, inactivation of alpha-amylase is beneficial. In these

cases, the changes to the proteins and starch are acceptable as they contribute

to a discernable increase in batter viscosity. The changes which heat brings

about increase the susceptibility of starch to amylase attack which would

reduce the batter viscosity. With the amylase inactivated, batter viscosity can

be maintained at an acceptable level.

Reference


AG, Switzerland.




2.2.14 We are considering making traditional German-type ryebreads and have researched the recipes and production methods.Do you have any suggestions as to what characteristics weshould have in the rye flour?

Rye grain is more susceptible to pre-harvest sprouting than wheat. The starch in

rye flour gelatinises at a lower temperature than wheat starch, and therefore, rye

flour is much more susceptible to enzymic degradation by alpha-amylase.

Another fundamental difference is that the proteins present in rye do not form a

gluten network to any significant degree, and the pentosans in rye are essential

for water binding to form a dough. Thus, although some of the grain and testing

methods are common to wheat and rye flours, different emphases are placed on

the results when incorporated into flour specifications.

The key quality requirements for rye flours are as follows:

� Minimum Hagberg Falling Number of 90 s.

� Pentosan content of 7�10%.

� Water absorption capacity 68�75%.

The water absorption capacity of rye flour is typically higher than that of

wheat flour due to the much higher level of pentosans in rye flour.

It is common practise to measure the gelatinisation characteristics of

rye flour. The technique comprises heating a rye flour�water mixture at a

constant rate from 30 to 90�C and following the changes in viscosity which

occur over this temperature range while the mixture is stirred. A typical

instrument used for this purpose would be the Brabender Amylograph which

records changes in viscosity in Amylograph Units (AU). The AU value will

be related to the enzymic activity in the flour, the lower the AU value the

higher the enzymic activity and consequently the poorer the shape of the

loaves and the lower their volume. At very low AU values, splits and other

defects may be seen in the bread crumb (see Fig. 2.2).

A range of rye flours are often available varying from 100% whole grain

through to a refined flour with low bran content which allow the production

of a wide range of rye bread types. It is worth noting that the acidification of

rye dough and on occasions the pretreatment of the flour with heat (scalding)

are two common ways of restricting the enzymic activity in the final dough.

Flour with >1000 430 110 (AU)

FIGURE 2.2 Rye bread made with flours with different Amylograph viscosities (reproduced

with permission of Brabender GmbH & Co. KG).


2.2.15 We wish to add non-wheat fibres to some of our bakedproducts to increase their healthiness. What fibres can we used,in what products and what potential technical problems shouldwe be aware of?

There are a large number of fibres from many different sources that might be

and have been proposed as additions to baked products. The range is so wide

that it is not possible in a short answer to do more than offer some general

pointers and a few examples.

If you are going to make health claims, then it is important that you

first make sure that the fibres that you are proposing to use are permitted

as additions to bakery foods and to identify any restrictions that might apply.

You should also carefully check the potential validity and permissibility of

any health-related claims which might be used on the product packaging or

in any advertising and marketing promotions that you might wish to under-

take. Health-related claims are becoming increasingly restricted to avoid

misleading consumers.

One of the more difficult issues will involve the definition and measure-

ment of dietary fibre. As yet there is no universally accepted definition.

A statement by the European Food Safety Authority (EFSA) to the European

Commission in 2007 concluded that a definition of dietary fibre ‘. . .shouldinclude all carbohydrate components in foods that are non-digestible in the

human small intestine.’ and went off to list such components as including

‘. . .non-starch polysaccharides, resistant starch, resistant oligosaccharides

with three or more monomeric units, and other non-digestible, but quanta-

tively minor components when naturally associated with dietary fibre poly-

saccharides, especially lignin’. In the same statement, EFSA commented on

analytical methods available for the measurement of dietary fibre and consid-

ered that for practical purposes a single assay would be advisable but did not

recommend what that might be. The definition of dietary fibre has also been

considered by the Codex Alimentarius Commission of the Food and

Agricultural Organization of the United Nations.

A common technical issue when you add fibres to bakery product recipes

is the ability to absorb water which necessitates an increase in recipe

moisture levels. This is not usually a problem with bread dough or cake

batters but can be a problem in the manufacture of biscuits and pastries

where the requirement is to ensure that the extra water is baked out so the

final products retain their crisp and hard eating characters.

It is almost certain that any fibres that you add will contribute little

or nothing to the formation or stabilisation of bakery products structure.

This poses a number of issues, mainly for bread and cakemaking. In the case

of bread, you may need to add extra protein or adjust the dough conditioner/

improver formulation to ensure that there is no loss of product volume. In

cake recipe balance, the extra water that is added along with fibres to


maintain a suitable batter viscosity may also require adjustment of the sugar

levels in the recipe to be made. You will need to be careful that the sugar

and liquid levels do not exceed acceptable levels for the flour that you are

using (e.g., treated or untreated). In practice, the level of fibre addition is rel-

atively low and can usually be included as ‘flour’ when balancing recipes.

Fibres come in many different forms from fine powder through flakes to

whole grains and seeds. Choosing the form you want to use will depend on the

product effect that you want to create; for example, whether you want the fibre

to be visible, whether you want it as a surface finish or whether you want it

incorporated directly into the dough or batter. Some of the fibrous grains and

seeds have other interesting attributes related to their nutritional properties.

In many cases, the attraction of using a particular fibre is that they have a

colour which is lighter than that of wheat bran and similar to that of wheat

flour. The addition of such materials allows you to increase the fibre content

of the product without detracting from the appearance of its crumb. This is

often seen as an advantage in delivering the nutritional benefits of fibre to

children.

Further reading

Hartikainen, K., Katina, K., 2012. Improving the quality of high-fibre baking. In: Cauvain, S.P.

(Ed.), Bread Making: Improving Quality, second ed. Woodhead Publishing Ltd, Cambridge,

UK, pp. 711�745.

Lorenz, K.J., Kulp, K., 1991. Handbook of Cereal Science and Technology. Marcel Dekker,

New York, NY.

McCleary, B.V., Prosky, 2001. Advanced Dietary Fibre Technology. Blackwell Science, Oxford, UK.









2.2.16 Why is flour particle size important in cakemaking?

White flour which is used in cakemaking is composed mainly of endosperm

fragments which have been separated from the surrounding bran during

the milling process. The maximum particle size is fixed by the screen sizes

in the plansifters in the mill but typically falls around 150 μm. If we were

to examine a straight run white flour, we would find some fragments of

the original protein matrix (,15 μm), some starch granules freed from the

protein matrix (up to 45 μm) with the remainder being endosperm fragments

of varying sizes up to the maximum screen size.

In cakemaking, the wheat starch plays a significant role in forming

the cake structure as it controls the batter viscosity during heating and

helps retain the expanding gases, carbon dioxide (from the baking powder),

air (trapped during mixing) and steam (from the added water). This is

particularly true for the so-called high-ratio flours which may undergo

further treatment with heat or chlorine gas to enhance their cakemaking

properties.

The key processes in cakemaking depend on the surface activity of many

materials and so increasing the surface area of the available starch becomes

important in aiding stability of the batter. The separation of the starch gran-

ules from the protein matrix can be readily achieved by re-grinding (e.g., pin

milling) and/or air classification. The aim of regrinding is to free the starch

granules from the surrounding protein and lower the maximum particle size

of the flour, typically to less than 90 μm, or lower.

Air classification enables fractionation of the flour into components with

narrow particle size ranges using air currents. Two or three fractions may be

separated using this milling technique. Typically, the cut-off points in the air

classifiers are set to deliver fractions as follows:

� Less than 15 μm, comprising fragments of free wedge protein and small

starch granules. The protein content will be very high, typically .20%.

� Between 15 μm and 45 μm, comprising mainly starch granules and smaller

fragments of endosperm. The protein content will be low, typically around

8%.

� Greater than 45 μm, comprising the large fragments of endosperm. The pro-

tein content is usually close to that of the base flour, typically around 10%.

Treated flours without particle size reduction yield cakes which collapse

during baking and have a dense cell structure. Progressive reduction of the

maximum particle size decreases the degree of collapse in the cake. It is com-

monly considered that the maximum particle size for cake flours should be

90 μm. The application of heat treatment or chlorination to the flour can be

carried out before or after particle size reduction which emphasises the impor-

tance of flour particle size in cakemaking. Significant proportions of larger

particles in cake flours can also be responsible for collapse in sponge cakes.


2.2.17 What is heat-treated flour and how can it be used?

The modification of wheat to produce heat-treated flour or the direct heat

treatment of flour may be used to achieve a number of different changes in

the final flour properties. We can broadly classify the type of heat treatment

as wet (steam) or dry.

Steam treatment of wheat is commonly used to inactivate the enzymes

which are present so that the subsequent flour may be used as a thickening

agent, for example, in the production of soups. Without inactivation, any

cereal alpha-amylase which is present would act on the damaged starch and

the subsequent release of water would cause thinning of the soup or sauce.

Steam treatment of both wheat and flour may be used to induce a degree

of gelatinisation in wheat flour which helps with its potential function as a

thickening agent. Steam treatment may also have a small reducing effect on

the numbers of viable microorganisms present in the flour, but the treatment

is usually insufficient to sterilise the material.

Dry heat treatment of wheat and flour has a long history. In the earlier

years of the 20th century, it was used to modify the extensibility of gluten

from some wheat varieties (Kent-Jones, 1926), but such uses are no longer in

common practice.

The main application of dry heat treatment to wheat and flour is in the

preparation of high-ratio cake flours as an alternative to chlorination (see

Section 2.2.18). A number of patents were developed which established the nec-

essary heating conditions required to achieve the necessary modification of

flour properties (Doe and Russo, 1968, Cauvain et al., 1976). Treatment tem-

peratures normally exceed 100�C rising to around 140�C, and as the treatment

temperature increases, the residence time required to achieve the modification

decreases from several hours to a few minutes.

The mechanism of the improving effect from dry heat treatment is not

clear but is likely to be associated with some modification of the surface

properties of the starch present in the final flour. At the end of the treatment

process, the flour is very dry and it is clear that the loss of moisture is asso-

ciated with achievement of the necessary changes in the flour, but the low

moisture content of the flour is not part of the mechanism of improvement.

When the dry flour is rehydrated considerable heat can be given off �known as heat of hydration � and unless compensatory steps are taken, this

may lead to undesirable increases in cake-batter temperatures and premature

release of carbon dioxide gas.

References

Cauvain, S.P., Dodds, N.J.H., Hodge, D.G., Muir, D.D., 1976. BP 1,444,173. HMSO, London, UK.

Doe, C.A.F., Russo, J.V.B., 1968. BP 1,110,711. HMSO, London, UK.

Kent-Jones, D.W. (1926) A Study of the Effects of Heat upon Wheat and Flour, Especially in

Relation to Strength. Thesis presented to London University, UK.




2.2.18 What is chlorinated flour and how is it used?

The treatment of flour with chlorine gas was first identified in the 1920s

and was used for the modification of the cakemaking properties of flours

for many years in the United Kingdom, the USA, Australia, New Zealand,

South Africa and many other countries. The use of chlorination for cake

flour treatment was withdrawn from the United Kingdom in 2000 (The

Miscellaneous Food Additive (Amendment) Regulations, 1999). In many

countries, it had never been permitted, and in many other countries where

it had been permitted, it has also been withdrawn. The USA remains the

main country where it is still permitted to modify the cakemaking proper-

ties of flour.

Chlorine treatment of flour permits the raising of recipe sugar and

liquid levels to make the so-called high-ratio cake (i.e., a recipe in which the

added sugar and water levels both exceed the flour weight). The principle

benefit of the high-ratio cake recipe is that product moisture levels can

be increased without adversely affecting the mould-free shelf-life of the

product. The higher moisture level confers a more tender eating quality to

the final product. If the flour has not been chlorinated and is used with a

high-ratio recipe than the cake structure will collapse, with loss of crumb

structure, the formation of dense, dark-coloured streaks and the product

eating quality becomes pasty.

Chlorine treatment of flour is achieved by blending the gas through

the flour. Typical levels of treatment lie between 1200 and 2500 ppm chlo-

rine on the basis of flour weight. The higher levels are commonly used to

treat flour intended for the manufacture of fruited cakes. The gaseous treat-

ment has a number of effects on flour quality, but only a small proportion of

the gas used actually confers the beneficial effects to the flour. In summary,

the chlorine gas is used as follows:

� Around 50% of the level used is absorbed by the flour lipids (typically

around 2% of the flour mass) but appears to play no significant part in

the improving action.

� Around 25% denatures the flour proteins (i.e., prevent the formation of

gluten) but plays no major role in the cake improving effect.

� The remaining 25% or so react with the starch granules, and this is the

main cake improving effect. It appears that the chlorine reacts with

the proteins associated with the starch granules and makes them more

hydrophobic. There is also evidence that chlorine treatment increases

the exudation of amylose from within the starch granules, but that there

is no change in the gelatinisation temperature of the starch (Cauvain

et al., 1977).


� The action of chlorine is to bleach the flour pigments so that a whiter

flour and brighter product crumb colour are achieved.

� The flour pH is lowered, and commonly this effect is used as a crude

measure of the level of chlorination achieved. More accurate assessment

of the level of chlorine treatment requires the use of a chloride meter.

In the United Kingdom and elsewhere the heat treatment of flours for

cakemaking has replaced chlorination (see Section 2.2.18).

References

Cauvain, S.P., Gough, B.M., Whitehouse, M.E., 1977. The role of starch in baked goods. Part 2.

The influence of the purification procedure on the surface properties of the granules. Starke

29 (March), 91�95.

The Miscellaneous Food Additive (Amendment) Regulations, 1999. S.I. 1999 No. 1136. HMSO,

London, UK.








2.2.19 What characteristics should we specify for cake flour?

In cakemaking, the main structure building block is the wheat starch rather than

the protein, and this means that when it comes to specifying the flour, many of

the protein-based measurements have limited relevance. Enzymic activity is

limited in cake batters, in part by the low water activity due to the sugar content,

and this also has an impact on the list of properties which need specifying.

In general, cake flours are derived from soft-milling wheats and tend to

have low protein content. Traditionally, this would have been set up in an

attempt to limit gluten formation in the batter. Although such thinking has

little relevance today, it remains the case that cake flours are specified with

low protein contents. The exception is flour intended for the manufacture of

fruit cakes where the presence of extra protein contributes to the suspension

of the fruit and other particulate materials in the batter and baked product.

Cake flours which are intended for use in high-ratio cakemaking are usually

treated in some way. High-ratio cakes recipes are characterised by having sugar

and liquid levels which are individually and collectively higher than the weight

of flour. Two forms of treatment are used, both of which modify the gelatinisa-

tion properties of the starch in the flour though by quite different means. One

form of treatment is with chlorine gas (see Section 2.2.18), but the use of chlori-

nation has become increasingly restricted around the world. Dry heat treatment

(see Section 2.2.17) has replaced chlorination in many countries. The level of

chlorination or heat treatment applied in the manufacture of cake flour may

vary according to the potential use of the flour. For example, high-protein flours

intended for the production of fruited cakes may receive greater treatment than

those intended for sponge or bar cake production.

Another key property for high-ratio cake flours is the reduction of the

particle size of the flour (see Section 2.2.16) either by regrinding or air

classification or a combination of both milling techniques.

Unlike many bread flours, it is not usual to add technologically functional

ingredients to cake flours. Statutory or voluntary nutritional additions may

be made.

You will only need to specify a limited number of characteristics for

cake flours. Typically, they would be:

Flour characteristic Low-ratio cake flour High-ratio cake flour

Moisture (%) 14 14

Protein content (% as is) 8�10 (up 12 for fruit cake) 7�10 (up to 12 for fruit cake)

Particle size (μm) Up to 150 ,90

Treatment None Chlorination or dry heat

Traditionally, some cake flour supplies contained raising agents to

provide carbon dioxide during baking. They are referred to as ‘self-raising’

flours and most often encountered for the home-baking market. The base

flour tends to meet the specification for low-ratio cake flour.


2.2.20 We have had some wholemeal flour in stock for a whileand noticed that it has passed its use by date. Can we still use it?And what are there any related issues with white flours?

The quality of all wheat flours changes with storage time; in some cases,

the changes may be advantageous and in others detrimental. Wholemeal

flour has a higher lipid content than white flours and is more prone to pro-

blems associated with rancidity. The low moisture content and water activ-

ity of wholemeal flour will ensure that microbial spoilage is unlikely to

occur. However, there is a potential for rancidity from enzyme catalysed

changes in the flour oil, and this is a key factor in limiting its shelf-life.

The other point to consider is the potential for insect infestation which

might occur. We recommend that you do not use the wholemeal flour in

question and try to implement stricter control on your flour stocks to avoid

a similar problem in future.

Most of the studies in the long-term storage changes in flour have been

carried out using white flours. As storage time increases, the breadmaking

potential of white flours changes, and a progressive loss of volume in the

final product is likely. Such changes take place slowly and appear to be

associated with changes in the flour lipid composition and in particular

with the release of free fatty acids. The loss of volume may be overcome

with the addition of extra fat or some other form of lipid, e.g., emulsifiers.

The restoration of the breadmaking potential of white flours through the

addition of a suitable lipid, e.g., higher levels of breadmaking fat or a

suitable emulsifier, could be achieved with white flours even after they had

been stored for 48 months.

Historically, long-term storage of flours has been used to enhance

the baking performance of flours. This appears to be in contradiction to the

findings described above, but it should be noted that there has been a funda-

mental change in most breadmaking processes in the last 100 years with a

move from extended periods of bulk fermentation to no-time dough systems

in one form or another. With the latter breadmaking systems, the role of

fat in assisting gas retention is more critical, and this may account for the

apparent reversal of the storage effects.

The cakemaking qualities of flours are also considered to improve with

long-term storage and some natural bleaching appears to occur.


2.2.21 What are the active components in self-raising flour?

Self-raising flours contain sodium bicarbonate and a suitable food grade acid.

When used in baking, the bicarbonate and acid react to generate carbon dioxide

gas. Self-raising flours are most commonly sold through the retail trade and

find greatest use in the domestic market. They may be used in smaller bakeries

as an alternative to separate additions of plain flour and baking powder.

The level of added baking powder is usually governed by a form of

regulation which specifies the volume of carbon dioxide gas that is evolved

at the point of final use. As there may be a small degree of reaction between

the active components and loss of carbon dioxide gas during the relatively

long storage periods for such flours, the rates of addition to the fresh flour

will be somewhat higher than required by legislation. For example, the UK

Bread and Flour Regulations (1996) specifies that self-raising flour should

yield not less than 0.4% of available carbon dioxide, but commonly rates of

addition will deliver around 0.8% when freshly prepared. The latter level

equates to 1.56% of the flour weight being sodium bicarbonate with the

level of acid addition being dependent on the choice of acid.

A number of different food acids may be used in the production of

self-raising flour. They include the following:

� Acid calcium phosphate (ACP), monocalcium phosphate (MCP).

� Sodium acid pyrophosphate (SAPP).

� Sodium aluminium phosphate (SALP).

� Cream of tartar, potassium hydrogen tartrate.

� Glucono-delta lactone.

Each acid component will be added according to its neutralising power with

sodium bicarbonate (Thacker, 1997) (see Section 2.6.8). The rate at which car-

bon dioxide gas is released depends on the type of acid being used. Sometimes,

a mixture of two acids may be used to provide a so-called ‘doubleacting’ baking

powder which provides for both early and late carbon dioxide release during the

manufacturing process (see Section 2.6.9).

References

Thacker, D., 1997. Chemical aeration. In: Bent, A.J. (Ed.), The Technology of Cake Making,

sixth ed. Blackie Academic & Professional, London, UK, pp. 100�106.

The Bread and Flour Regulations, 1996. S.I. 1996/1501. HMSO, London, UK.






2.2.22 We have changed suppliers of our self-raising flour andfind that we are not achieving the same product volume asbefore. If we adjust the recipe by adding more baking powderwe, find that the products tend towards collapse. Can youexplain why and how do we overcome the problems?

Self-raising flours contain the mixture of food grade acids and sodium or

potassium bicarbonate that is required for the generation of carbon dioxide

gas (see Section 2.2.21). It is possible for the loss of gassing power to occur

with storage time, but this is not usually a significant problem as long as the

flour is kept dry.

In many parts of the world, there are standards governing the volume of

carbon dioxide gas which should be released from self-raising flour, but

these are usually set as minimum rather than absolute levels. It may be that

your previous flour supply was providing more than the required minimum,

and this is why you are suffering from a lack of volume. However, the fact

that your products collapse when you add extra baking powder suggests that

this is not the most likely cause of your problem.

The different food grade acids which are permitted for use in self-raising

flour have different rates of reaction with sodium or potassium bicarbonate

(see Section 2.6.8). This is important in controlling the release of carbon

dioxide during processing; too early and the products tend to lack volume,

too late and the products may tend to collapse. The data in Fig. 2.3 compare

the rates or reaction for two commonly used food grade acids with sodium

bicarbonate. From the description of the problem that you have given,

it would appear that your new source of self-raising flour is giving an early

release of carbon dioxide, and the level of extra baking powder that you

have added to compensate is simply too high; try gradually reducing

the level that you add and you should find a point at which you retain the

product volume while avoiding collapse.

020406080

100120140160180200

0 2 4 6 8 10

Time (minutes)

Gas

vo

lum

e (

ml)

SAPP 10MCP

FIGURE 2.3 Rates of reaction of food grade acids.


2.2.23 What are ‘organic’ flours, how do they differ from otherflours and what will be the differences to the baked product?

The term ‘organic’ refers to the manner in which the wheat has been farmed

and turned into flour and subsequently baked products. Organic farming uses

more traditional methods of treating the land during the farming cycle and in

particular does not use ‘artificial’ fertilisers or apply pesticides, insecticides

or herbicides. Organic wheats will be segregated and milled separately from

other sources of wheat. The agricultural processes involved will be the

subject of inspection and certification by specialist bodies.

In principle, any breadmaking wheat types may be used in the production

of organic wheat flour. However, as the farming process relies totally on

the application of natural fertilisers, there is a tendency for the protein of

many wheat varieties to be lower than that which could be obtained with

non-organic farming methods.

The lower protein of some organic flours may present a potential problem

for the production of bread of similar volume to that typically seen with non-

organic flours. The other ingredients which may be added to manufacture

organic bread are also closely specified, and the majority must also come

from organic sources, e.g., dried gluten which could be used to boost bread

volume. You should consult the UK Soil Association or similar body for

comprehensive advice. In the event that you wish to make organic bread,

you will need to obtain the necessary accreditation from a specified body.

In summary, you should not expect organic baked products to be sub-

stantially different from non-organic ones. However, you may need to make

some adjustments to your formulations to maintain product quality.


2.2.24 What characteristics should we specify for our biscuitand cookie flours?

The range of biscuit and cookie products is quite wide, so it is difficult to

provide a flour specification that will cover all types. The flour properties

required can be roughly split into two groups based on whether gluten devel-

opment in the dough is desirable or not. The level of gluten development in

biscuits is much less than that required for breadmaking (Cauvain and Young,

2007a), and we would reasonably expect that in general, biscuit and cookie

flours will be lower in protein with modest gluten-forming potential.

Even for laminated biscuit types like crackers, the required protein

content will be modest though slightly higher than that for semi-sweet

sheeted biscuits which in turn, may be slightly higher than that for rotary

moulded, short-dough biscuits. The grist for biscuit flours will be based on

the softer milling wheats with a limited, but often necessary, proportion of

harder milling wheats. Typical biscuit flour protein contents will vary from

9% to 11% based on a 14% moisture basis.

Protein quality may be measured using standard tests such as the

Brabenderr Extensographr or the Chopin Alveograph (Cauvain, 2017). Such

tests are more applicable to biscuit types which undergo some form of sheeting

during processing. The sheeting contributes to gluten formation and high levels

of gluten formation will exacerbate shrinkage of the products during proces-

sing and baking. In general, flour with low Extensographr resistance with

significant extensibility is preferred (Cauvain and Young, 2007b).

The flour ash or colour may be specified though there is limited evidence

to suggest that these properties are directly related to flour performance in

the manufacture of biscuits. The specification of flour-water absorption

capacity is not necessary, even for cracker flours, because most biscuit

and cookie doughs are made with as little water as possible to reduce the

potential for gluten development and to limit the amount of water that must

be removed during subsequent baking.

Most flours destined for biscuit production are now untreated and any

modification to the flour performance is usually carried out in the bakery

through recipe additions, e.g., the addition of proteolytic enzymes or sodium

metabisulphite to reduce its gluten-forming potential.

References



Cauvain, S.P., Young, L.S., 2007a. Baked Products: Science, Technology and Practice.


Cauvain, S.P., Young, L.S., 2007b. Flours for sweet goods. f2m Baking 1 Biscuit International:

Reference Guide of Industrial Processes and Market Analysis. f2m Multimedia GMBH,

Hamburg, Germany, pp. 54�57.











2.3 FATS

2.3.1 What are the critical properties of fats for making bread,cakes and pastries?

To answer your question, it is first necessary to be clear about our defini-

tion of a fat. In the bakery, this is usually the term given to a material

which is a blend of liquid oils and solid fats from different sources,

usually vegetable in origin. Podmore (1997) provides a comprehensive

review of the nature and structure of fats. The basic building blocks of fats

are the fatty acids of which there are three. The fatty acids of the triglycer-

ide may be the same as one another or different. All natural oils and fats

are mixtures of glycerides, and the properties of the individual fats and

oils depend on the quantity and distribution of the different glycerides

which may be present.

As fat properties are related to the glycerides which are present a detailed

knowledge of the composition of a compound fat can be useful. This is com-

monly obtained using gas chromatography or high performance liquid chro-

matography. However, such analytical techniques require expensive and

specialised equipment which is not within the scope of many laboratories.

The fatty acid composition is related to other more readily measurable prop-

erties of fats and oils.

A readily known measurement is the iodine value which measures the

proportion of double carbon bonds in the fat and indicates the degree of satu-

ration present. In some fatty acids, adjacent carbon atoms in the chain may

be joined by a double bond so that fewer hydrogen atoms are attached than

theoretically possible and they are called ‘unsaturated’. In ‘saturated’ fats,

two bonds form between two carbon atoms in the chain, whereas the two

remaining bonds are formed with two individual hydrogen atoms.

Traditionally, the ‘slip’ or ‘melting point’ of a fat was used to character-

ise its performance in baking. However, as many commercial fats are com-

pound mixtures of triglycerides the melting point is often spread over a wide

range of temperatures so it has limited value. It is now more common to

refer to the solid fat index (SFI) of a fat which considers the proportion of a

compound fat which is solid at a given temperature.

Fat SFI’s are commonly measured using Nuclear Magnetic Resonance

(NMR), and sometimes, NMR values for fat are quoted rather than SFI.

Whichever nomenclature is used the temperature at which the measurement

is made should be quoted, e.g., NMR20 indicates the percentage of solid fat

present at 20�C (see Fig. 2.4).

In the past, measures of fat firmness using cone penetrometry have

been used to indicate the characteristics of given fats, e.g., ‘C’ values

(Haighton, 1959). The firmness of a fat at a given temperature is strongly


influenced by the proportion of oil to solid; however, this is not the only

relevant property of fat to be considered. Solid fats may exist in different

crystalline forms depending on its temperature history in production

and use. The size of the fat crystals also affects their functionality. Small

crystals have a larger surface area relative to large ones and are more able

to retain large quantities of liquid oil within the crystal matrix. The crystal-

line form of a fat is not usually assessed or measured even though it may

affect the fat performance.

References

Haighton, A.J., 1959. The measurement of the hardness of margarines and fats with cone penet-

rometers. J. Am. Oil Chem. Soc. 36, 345�348.

Podmore, J., 1997. Baking fats.. In: Bent, A.J. (Ed.), The Technology of Cake Making. Blackie

Academic and Professional, London, UK, pp. 25�47.

FIGURE 2.4 Examples of solid fat index profiles.








2.3.2 Can you explain the different terms used to describebakery fats? What are the functionalities of the different forms inbaking?

Chemically, all fats and oils consist of atoms of carbon (C) hydrogen (H)

and oxygen (O). They have the same basic structure which consists of

a molecule of glycerol combined with up to three fatty acids. The basic

nomenclature is mono-, di- and tri-glyceride according to whether 1, 2 or 3

fatty acids are attached to the glycerol molecule. The term oil is used

to describe a fat in its liquid form. All fats become oils if the temperature

is raised high enough and all oils become solid fat if the temperature is

sufficiently reduced. The term oil is most commonly used for fats which

exist as liquids at temperatures around 15�25�C. Fats used in bakery

practice are commonly a mixture of liquid and solid fat components, and

this may be expressed as the melting profile or SFI of the fat concerned


Fatty acids are one of the key building blocks of animal and plant tissues.

There are different fatty acids, and their physical and chemical form varies

according to their chain length and absence/presence of carbon double bonds

(C~C) in the chain. The significant impact of the different fatty acids is on

the melting point of the fat, and this determines whether the fat is solid or

liquid at a given temperature.

The degree of saturation in fats describes the number of carbon double

bonds which are present. As the number of carbon double bonds increases,

the degree of saturation decreases and so does the melting point of the

fat; the downwards progression is from saturated to monounsaturated to

polyunsaturated so that highly saturated fatty acids tend to be solid.

Saturated fats tend to be very stable and have a long shelf-life. They also

tend to have highly functional roles in the manufacture of baked products;

such as improving the gas retention properties of bread dough (Cauvain,

2015), aid air incorporation in cakemaking (see Section 5.2) and provide lift

in laminated products (see Section 7.1.1). However, they also tend to have a

negative health image.

The proportion of the different forms of saturation varies according to the

source of the oil/fat. Today, there has been a significant move away from

animal fats in bakery products (with the possible exception of butter) to

vegetable-based fats because many of them are low in saturated fats.

However, this means that they are also mainly in the liquid form and so do

not have the baking functionality of the solid fats. The main exception is

palm oil which is about 50% saturated and 40% monounsaturated fat.

It is possible to modify the physical and chemical characteristics of natural

oils. One method is hydrogenation in which the oil is reacted with hydrogen

gas at high temperatures and pressure. The process converts polyunsaturates

to monounsaturates and then to saturates and increases the functionality of


the fat for different baking processes. The process of hydrogenation produces

saturated fats but no significant levels of trans fats.

However, partial hydrogenation which had become more popular due

to concerns over the consumption of saturated fats generates significant

levels of trans fats. Although these fats retain functionality for baking,

their ‘healthiness’ in the diet has been questioned. The process of partial

hydrogenation produces different levels of trans fats from different types of

fat. The trans form of fat exists because there are two physical ways for a fat

to form with the same combination of CHO atoms; the trans is one form and

the other is known as the cis form. Trans fats do occur in nature and are

present in products such as butter, milk and eggs.

There are alternative ways to hydrogenation for providing baking fats

with the functionality necessary for baking. Oils from natural sources, for

example, palm oil as discussed above, are a mixture of solid and liquid

fractions and so the physical separation of the different fractions can be used

to prepare a range of different fats with specific functional properties. Using

this technique, it is possible to prepare stearine oil fractions with melting

points of up to 60�C. The process is referred to as fractionation and has also

been applied to butter to provide specific fractions which are better suited to

processing at higher temperatures.

Interesterification involves enzyme (lipase)-assisted modification of the

oil or fat composition. Any oil or fat combination can be interesterified.

Solid fats may exist in a number of crystalline forms depending on how

they have been prepared in commercial practice. It is largely the cooling

of liquid fats which determines the crystalline form though the form may

change during subsequent storage. It is said that fats exhibit polymorphism,

and the three crystalline forms are denoted as α, β0 and β. The α crystals

have the lowest melting point and are small, unstable crystals. The transition

is from α to β0 and then to β; the latter form tends to be the largest crystals

and have the highest melting points. The crystalline forms of the fats have

been linked with their functionality in baking (e.g., Cauvain, 2001).

References

Cauvain, S.P., 2001. The production of laminated products. CCFRA Review No. 25. Campden

BRI, Chipping Campden, UK.


AG, Switzerland.

Further reading

Stauffer, F.E., 1993. Fats and fat replacers. In: Kamel, B.S., Stauffer, C.E. (Eds.), Advances in

Baking Technology. Blackie Academic and Professional, Glasgow, UK, pp. 336�370.

Street, C.A., 1991. Flour Confectionery Manufacture. Blackie and Son Ltd, Glasgow, UK.










2.3.3 Our bread doughs prove satisfactorily but they do not risein the oven. On some occasions, they may even collapse andblisters form on the dough surface in the corners of the pans.What is the cause of these problems?

A lack of oven spring or collapse of the dough piece in the oven usually

signifies a lack of gas retention in the dough. This may arise for a number of

different reasons but your comment on the formation of blisters on the dough

surface in the corner of the pans strongly suggests that your problem comes

from a lack fat or other suitable lipid (e.g., emulsifier) in your improver or

bread formulation. The problem can be too low a level or an inappropriate

character of the fat.

In modern, no-time breadmaking systems, e.g., the Chorleywood bread

process (CBP), the addition of a fat or emulsifier is important in ensuring

adequate gas retention in the dough (Cauvain and Young, 2006). It has been

known for quite some time that it is only the solid portion of the fat which

can affect dough gas retention, and in no-time doughmaking processes, it is

important that a proportion of any added fat should remain as solid in the

dough at the end of final proof. As typically final proof is carried out at

around 40�45�C, this requires that the final melting point of the fat to be

above 45�C.The necessary level of solid fat to achieve the required effect at 45�C can be

quite small, and values as low as 0.02% flour weight have been quoted.

However, it is known that the minimum level of fat required varies with flours.

In general, higher levels of fat appear to be required with stronger white flours

and a general recommendation of 0.7% of a compound bakery shortening was

the original blanket recommendation in the CBP because this ensured that a suf-

ficiently high level of solid fat remained in the dough at the end of proof.

Improved gas retention with wholemeal and brown flours requires consid-

erably higher levels of added fat than white flours. Cauvain (2015) provides

an example for wholemeal bread made by the CBP where maximum bread

volume was obtained when added fat levels reached 4% of the flour weight.

It is also known that the loss of gas retention which comes from prolonged

storage of flour can be compensated with the addition of high levels of a

suitable fat.

It is most likely that the fat confers improved gas retention in bread

dough by helping to control gas bubble size and stability. Composite bakery

shortenings are a mixture of oil and solid fat at dough temperatures, but it

is only the solid fat portion that can play the necessary gas bubble stabilis-

ing role. The molecules of the solid fat portion align themselves at the inter-

face of the gas bubble and the liquid dough phase and play a part in

determining the size of the gas bubbles as well as their stability. As the tem-

perature rises in the dough some of the fat molecules melt and lose their

ability to stabilise the gas bubbles. Eventually, all of the fat melts and other


materials, principally the gluten, are left to maintain gas bubble stability.

A key role for fat may be the prevention of coalescence of gas bubbles in

the dough in the early stages of baking.

Emulsifiers are commonly used to replace fat in bread doughs on the

basis that they can be used at lower levels. In simplistic terms, they may be

considered as specialised fats with a high melting point. They play a similar

role to fats in stabilising gas bubbles in the dough. However, their melting

profile is quite different from that of fats in that they remain solid to much

higher temperatures in the dough, typically around 60�C. More recently,

the addition of lipase enzymes (Cauvain, 2015) has been considered to play

a role in conferring gas bubble stability.

The blisters that you observe on the dough are gas bubbles which have

become excessively expanded and are unstable. When the dough reaches

the oven, the gluten network is unable to cope with the rapid gas bubble

expansion, and individual bubbles become over-expanded, perforate and

collapse. Collectively, they lead to total dough collapse. The addition of a

suitable level of a high melting point fat or emulsifier should overcome this

problem.

References


AG, Switzerland.

Cauvain, S.P., Young, L.S., 2006. The Chorleywood Bread Process. Woodhead Publishing Ltd,

Cambridge, UK.






2.3.4 What is the role of fat in the manufacture of puff pastry?

In the manufacture of puff pastry, fat may be added to the paste in two

ways, as part of the base dough formulation and as fat layers formed between

two adjacent doughs layers. The latter is by far the more important of the

two uses and contributes most to the formation of the characteristic layered

structure and flaky eating character.

It is not common to add aerating agents to puff pastry, yet considerable

expansion of the structure occurs as the dough layers are forced apart during

baking. The pressure for the expansion comes from the water present in

the dough layers as it turns to steam. As the steam tries to escape to the

atmosphere, the melting fat acts as a barrier to its progress and the dough

layers move apart (Cauvain and Young, 2008).

To obtain maximum pastry lift, it is important that the fat layers remain

separate and discrete from the dough layers for as long as possible so that

careful attention should be paid to the processing temperature for the paste.

For example, butter has a low SFI at 20�C and pastes made with all butter

benefit from processing at temperatures around 12�14�C which gives work-

able fat layers but ones which will not be so brittle as to break during

sheeting.

As the aeration mechanism involves the fat, it is reasonable to assume

that the characteristics of the fat play a part in the degree of lift during

baking with lift depending on the following characteristics:

� The level of added fat, with higher fat levels giving greater lift.

� The SFI, with higher SFI giving greater lift.

� The firmness of the fat at point of use, with greater firmness giving

greater lift.

� The crystalline form, with smaller crystal size giving greater lift.

Although pastry lift benefits from a higher SFI, there may be some loss

of eating qualities as fats with very high melting points tend to give a greasy

mouthfeel and ‘palette cling.’

The addition of fat to the base dough has a small adverse effect on pastry

lift and gives a more tender eating quality to the final product.

The impedance of steam by the fat layers also plays a part in the

aeration of Danish pastries and croissant, though in these cases, lift is

affected by the activity of the yeast which contributes to the expansion of

the dough layers.

Reference

Cauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture and Quality: Water Control and

Effects, second ed. Blackwell Science, Oxford, UK.




2.3.5 Our puff pastry fails to rise sufficiently even though webelieve that we are using the correct level of fat. Are we usingthe correct type of fat?

The lift in laminated products can be affected by two properties of the

laminating fat; the SFI and the size of the crystals in the solid fat portion.

The laminating fat plays a significant role in the aeration mechanism in

puff pastry by impeding the movement of steam from the dough layers to

the surrounding atmosphere (see Section 7.1). Solid fat layers form a greater

barrier than liquid ones and so the proportion of laminating fat which

remains solid as the pastry begins to bake is an important characteristic.

As discussed above, we can measure the solid fat to liquid oil ratio in a

given fat using a number of techniques, for example NMR. For a given

temperature, the ratio is described as the SFI with the value given being the

solid fat portion in the mixture. Such measurements are typically made at

three of four different temperatures to establish the solid fat profile.

The higher the SFI, the greater the puff pastry lift will be (see Fig. 2.5), but

the increase in solid fat may lead to an unacceptable change in eating charac-

teristics. It is particularly important that the proportion of solid fat at 40�C is

restricted because it does not melt in the mouth and confers an unpleasant

waxy eating quality commonly described as ‘palate cling’. We suggest that any

laminating fat you use should not have more than 5% solid fat at 40�C.The storage and processing temperatures used also affect the performance of

the laminating fat, so it is important to avoid unnecessary warming and cooling

of the stocks of fat. The temperature at which the pastry manufacturing process

is carried out can also affect lift and it is best process the pastry at a temperature

which is lower than the melting point of the fat.

If you are work softening the fat by means of pumping or extrusion then

you may notice some changes in performance, so it is important to keep and

any work softening activities as constant as possible.

Further reading

Cauvain, S.P., 2001. The production of laminated products. CCFRA Review No. 25. Campden-BRI,


FIGURE 2.5 Effect of large (left) and small (right) fat crystals on puff pastry height.




2.3.6 What is the role of fat in cakemaking?

The main function of fat in cakemaking is assist with the incorporation of air

into the batter during mixing. It also affects the air bubble size in the batter

and bubble stability before and during the early stages of baking.

Cake batters are essentially a ‘foam’, that is a system in which air bubbles

are trapped and held in an aqueous phase. Foam systems are characterised by

the fact that all the air bubbles are separated from one another by a thin film

of stabilising material. During baking, the foam changes to a sponge (in the

generic sense), that is a system in which all of the air cells are interconnected

and vapours and liquids can move through the matrix. The moment at which

the foam in a cake batter makes the conversion to a sponge has much to do

with the recipe formulation and the stability of the air bubbles while the tem-

perature is rising makes a major contribution to final cake volume.

The protective film which forms around the gas bubbles may come from

a number of sources. Solid fat crystals can contribute to the protective films

in the batter foam, and they are typically located at the interfacial film

between the air bubbles and the sucrose solution. The crystalline form of

the solid portion of the fat is important in determining the functionality

of the fat in cakemaking. Of the three fat polymorphs commonly encoun-

tered, the volume of air which can be incorporated into the batter is greatest

with the β0, less with the α and least with the β form.

As the batter temperature rises in the oven, the solid fat turns to liquid oil

and the natural buoyancy of the air bubbles causes them to try and move

upwards to escape. The longer the bubbles are retained in the batter the greater

the cake volume will be. This requires that the fat has a high melting point.

However, dispersion of the solid fat crystals is important if they are to be effec-

tive and a liquid oil component is necessary to achieve that ready dispersion.

Fats and oils contribute to the soft and tender eating properties which

are required for cakes. In part, this benefit comes from the effect on batter

aeration and in part from the lubricating effect that fat has in the mouth.

Further reading

Cauvain, S.P., Young, L.S., 2006. Baked Products: Science, Technology and Practice. Wiley-

Blackwell, Oxford, UK.




2.3.7 We are making ‘all-butter’ cakes but find that after bakingthey lack volume and have a firm eating character. Why is thisand is there any way to improve the cake quality?

Butter is often chosen in cakemaking due to its quality attributes related to

flavour and mouthfeel, and its potential marketing value through the associa-

tion with ‘naturalness’ and ‘quality’. However, being a ‘natural’ product, it

can be the subject of natural quality variations and has characteristics which

are not always best suited to cakemaking.

Butter is a mixture of butter oils, water and often salt. Commonly,

the level of water must not exceed a fixed value (16% in the United

Kingdom) and salt levels may also be fixed. Thus, if butter is used to

replace an oil or bakery shortening, then the level of addition should

be increased to about 1.2 times the recipe shortening level. A weight for

weight replacement of shortening with butter will therefore result in

a lower fat level in the recipe which will reduce batter aeration and

cake volume. Butter oils and butterfats are available which can be used

on a one for one replacement basis because they do not contain water

(Rajah, 1997).

Generally, the ability of butter to contribute to batter aeration, and thus,

cake volume is inferior to bakery shortenings or cake margarine. This is

because the SFI at 20�C for butter is lower than that generally recommended

for use in cakemaking, typically, around 24% of a fat should be solid

at 20�C. Butter SFIs at 20�C vary according to their source, in part due to

differences and changes in the feeding habits of the cows.

The tempering of butter can improve its functionality in cakemaking.

We suggest that you hold the butter at 28�30�C for 18�20 h before use.

This tempering period permits a beneficial increase in the crystal size of the

solid fractions in the butter. You should ensure that full equilibration of tem-

perature has taken place because often the slabs of butter may be stored on a

pallet or in a large block which slows down the rate of heat penetration to

the centre of the stack.

Considerable improvements in cake volume, softness and eating quality

can be obtained by adding a low level of glycerol monostearate (GMS) to

the batter. The GMS is more effective than the butter at stabilising the foam

structure of a cake batter. We suggest the addition of a level of 1% (GMS

solids) of the total batter weight. The GMS should be in the alpha form

and may be added as a stabilised gel.

Reference

Rajah, K.K., 1997. Cream, butter and milk fat products. In: Bent, A.J. (Ed.), The Technology

of Cake Making. Blackie Academic and Professional, London, UK, pp. 48�80.





2.3.8 We have been using oil in the production of our spongecakes, but we wish to change to using butter. Can you advise onhow to do this?

There are two courses of action open to you; either melt the butter and add it

as a warm oil or add it in the solid form.

The practice of melting fats to incorporate them into sponge batters has

been known for quite some time. The traditional ‘butter sponge’ utilises a

basic sponge recipe to which the melted butter is added after all of the other

ingredients at the very end of the mixing process. The butter should only be

heated until it is just liquid; otherwise, the hot oil may increase the batter

temperature high enough to cause a premature reaction of the baking powder.

You may find some benefit in using a little more baking powder in the

formulation to compensate for any losses which may occur. If you are not

already doing so you may find some advantage in the addition of a

suitable emulsifier to the formulation.

If you are going to use the butter in the solid form, we certainly recom-

mend the addition of an emulsifier to the formulation; otherwise, you will

not achieve the product volume that you are seeking. You may experience

some difficulty in dispersing the butter, so it may be better to use an all-in

mixing method. You may also wish to adjust the baking powder level in the

formulation.

If you wish to make any claim regarding the use the term ‘butter’ as part

of the baked product descriptor, you will need to ensure that the level of

added butter conforms to the relevant regulations or codes of manufacturing

practice. For example, the following Code of Practice applies in the United

Kingdom:

� At least 5% butterfat for the claim ‘contains’ butter.

� 100% for the claim ‘made with butter’ or the descriptor ‘butter sponge’.


2.3.9 We wish to produce a softer eating sponge cake and havebeen trying to add fat or oil but cannot get the quality we areseeking. Is the addition of fat to sponge batters possible and whatdo we need to do to achieve the quality we are seeking?

In a traditional sponge recipe composed of flour, sugar and egg, the mixing

action of the whisk draws small air bubbles into the batter during mixing.

The egg proteins, principally the lipoproteins, align themselves at the inter-

face of the air bubbles with the aqueous phase. At the interface, they provide

stability to the air bubbles and prevent them from rising to the batter surface

and escaping to the atmosphere.

This bubble stabilisation of the batter ‘foam’ is particularly important in

the early stages of baking when the increase in temperature increases the ten-

dency of the air bubbles to rise. Later during baking, the solid part of the

foam begins to set, the gas bubbles begin to burst and the gases diffuse out

leaving behind a sponge structure (here, the term ‘sponge’ is used in the

generic sense referring to a structure in which the individual cells are inter-

connected and gases and liquids may diffuse through the matrix).

When oils or solid fats are added to a traditional sponge batter, they inhibit

the inclusion of air into the batter and displace the egg proteins at the gas bub-

ble/aqueous phase interface. This change allows many is gas bubbles to escape

from the batter, especially during baking when any solid fat is turning to liquid

oil. The result is that the mechanical aeration is much reduced and the resul-

tant cake volume is small. For these reasons, many traditional methods of pro-

ducing sponge cakes encourage the scalding of the mixing bowl to remove

any traces of fat before the start of mixing.

Oils or fats may be added to sponge cakes to improve the eating quality

by carefully blending them into the batter towards the end of baking. In the

case of fats which are solid at bakery temperature, it is advisable to heat

the fat until it is liquid.

Alternatively, you can add an emulsifier, such as GMS to the sponge

formulation to take over the main air bubble stabilising role from the egg

proteins. The level of addition needs to be sufficiently high to ensure that

bubble stability is maintained during baking up to the point of conversion

from foam to sponge. Oils are more suitable for the production of enriched

sponges though the addition of solid fat is possible, sponge cake volume and

texture are less satisfactory.

Further reading

Cauvain, S.P., Cyster, J.A., 1996. Sponge cake technology. CCFRA Review No. 2. Campden





2.3.10 We want to make a range of bakery products usingbutter as the main or only fat in the recipe. Can you advise us ofany special technical issues that we need to take into when usingbutter?

The composition of butter is usually fixed by local regulations. It is an

emulsion of water-in-oil and typically contains more than 80% fat, less than

2% milk solids and less than 16% water. Despite having a fixed composition

its performance in baking can vary. The best known variation comes with

the twice yearly change in the feeding patterns for cows in many parts of the

world (Rajah, 1997). With the change of feed come small but important

changes in the underlying fatty acid composition and solid fat content which

can affect its ability to incorporate air during creaming processes in the

manufacture of baked products (e.g., cakes and biscuits).

Butter contains significant amounts of butyric acid (a low molecular weight

fatty acid) which is volatile and makes a significant contribution to the flavour of

the fat. The release of traces of this acid through the process of hydrolysis makes

butter particularly susceptible to rancidity. To avoid any potential problems, the

butter will be delivered chilled and should be stored at the same temperature,

typically around 4�6�C. You should always use the butter within its designated

shelf-life and will find it helpful to set up a strict stock rotation system.

The solid fat content of butter at different temperatures is given in

Table 2.1. The data highlight some of the technical problems with using butter.

As the solids fat content is very high at low temperatures, it cannot be used

straight from the refrigerator but must have its temperature raised, before it can

be used. This ‘tempering’ process takes time and requires careful control to

ensure uniformity of processing performance (see also Section 2.3.11).

Achieving the optimum processing temperatures with butter is very

important for its effective use. For examples of relevant processing tempera-

tures for laminated pastry products (see Section 7.1.17).

The solids content of butter is lower than normally considered suitable

for cakemaking and there is a tendency for ‘all-butter’ cakes to lack volume.

Adding a suitable emulsifier to the recipe (e.g., GMS) commonly solves the

problem (see Section 2.3.7).

Reference

Rajah, K.K., 1997. Cream, butter and milk products. In: Bent, A.J. (Ed.), The Technology of

Cake Making. Blackie Academic & Professional, London, UK, pp. 48�80.

TABLE 2.1 The Solid Fat Content of Butter at Different Temperatures

Temperature (�C) 5 10 15 20 25 30 35

Solid Fat (%) 53 48 35 24 17 10 7





2.3.11 We are using butter in several of our bakery productswhich comes in chilled at about 4�C (as cartons on pallets) andare encountering problems with variability in its processing.We recognise that is likely to be associated with thetemperature of the butter when we are using it. What is thebest way to treat the butter to get a more consistentperformance?

To get a consistent processing and baking performance from butter, you

need to use it at temperatures between 14�C and 20�C, depending on the

product. In the manufacture of cake batters and creams, the butter plays a

major role in the necessary air incorporation and so must be sufficiently plas-

tic at the time of mixing; temperatures at the higher end of the above range

are most suitable in such cases. For pastry making, temperatures towards the

lower end of the range may be used but a significant degree of plasticity is

still required (see Section 7.1.17).

As your butter is arriving in the chilled form you will need to raise its

temperature by quite a few degrees before it is in its optimum temperature

range. The best way to raise the butter temperature is to store it in warm

environment, for example, at temperatures between 20�C and 25�C (no

more than 30�C), but to obtain consistent performance, it is crucial that the

temperature of the whole carton reaches these temperatures. To achieve

this, you will need to make sure that there is sufficient air circulation

around each carton and that you allow sufficient time for equilibration of

the carton temperature to occur. The whole process can take several days,

and we suggest that you allow at least 4�8 day’s equilibration before

trying to use the butter.

Do not be tempted to use high air temperatures to ‘speed-up’ the process

as this can lead to significant ‘oiling’ on the surfaces of the butter in the

cartons and loss of functionality. Butter which has oiled and then cooled

ends up with a different (larger) crystal structure which makes it unsuitable

for the manufacture of most bakery products.

Radio-frequency heating and microwave have been suggested and used

for tempering butter. This can reduce, but not replace, the storage time.

Once again oiling of the butter should be avoided.

In the manufacturing process, the butter may well be pumped or extruded

before use. The mechanical action that these processes involve help in

achieving a more uniform temperature distribution throughout the fat but

should not be used to try and replace sound tempering procedures.


2.3.12 We are seeking to reduce the level of fat that we use insome of our cake recipes but find that simply taking fat outadversely changes our product quality. What are the possibilitiesof using ‘fat replacers’ to help us with our strategy?

There are two key roles for fats in cakemaking; one is to help with the soft

and tender eating qualities that we associate with cakes and the other to help

with foam promotion and bubble stability in the batter (see Section 2.3.6). If

you are going to reduce fat levels in your recipe, you will need to take both

into account and this can lead to conflicting results. You may also experi-

ence some loss of flavour from your product.

A typical effect of simply reducing fat level in your recipe without

making any recipe changes is illustrated in Fig. 2.6. The product has a lower

volume, denser crumb and firmer eating qualities which are often quickly

detected by consumers.

You can overcome the loss of foam creation and bubble stability when

you reduce fat level through the addition of a suitable emulsifier such as

GMS. However, you will find that the cake eating qualities may become a

little firmer. You may find some advantage in reducing the egg level in your

recipe (and adjusting water accordingly), but you need to be cautious as low

levels of egg solids can result in increasing fragility of cake crumb and even

the formation of unwanted cracks due to the lowering of protein levels. If

this does happen then you could raise the protein content of the flour.

There are claims for a wide range of fat replacers, but it is worth bearing

in mind that none of them delivers exactly the same qualities as fat and that

their use in a reduced-fat cake recipe will always need other recipe changes

to produce a satisfactory cake product. In a broader aspect, fat replacers

can be placed in one of three categories; carbohydrate-based, protein-based

and fat/lipid analogues. A significant number of the fat replacers are aimed

at reducing the calorific value of the final product and so weight for weight

they deliver significantly fewer calories than fat.

In many cases, the carbohydrate-based fat replacers are composed of

fibrous materials and so require the addition of extra water to the recipe to

FIGURE 2.6 Effect of lowering fat level in cakes; left, standard recipe and right, reduced fat recipe.


maintain a sufficiently fluid batter for processing. It is mainly the presence

of the extra water that delivers the fat-mimicking properties of the material,

but the extra recipe water can lead to unbalancing of other recipe compo-

nents and will result in a higher moisture content in the final product.

Unfortunately, although the fat replacer may hold the water in the batter in

most cases, it does not sufficiently bind water in the baked product with the

result that the product is more susceptible to mould growth. Similar issues

apply to the protein-based fat replacers.

The position with fat/lipid analogues is slightly different as such ingre-

dients do tend to more closely mimic the ‘lubricant’ effect of fat with

respect to cake eating quality. However, these materials still lack the foam

promotion and bubble stabilisation properties of fat and so commonly

recipes incorporating them require the use of an emulsifier.

If you are thinking of using any of the available fat replacers, it would be

advisable to check on whether they are permitted in cakes and what, if any

special ingredients declarations need to be made.


2.4 SUGARS AND SWEETENERS

2.4.1 What type of sugar (sucrose) should we use for thedifferent products that we make in our bakery?

Sugar (sucrose) has a number of different functions in baked products; in

addition to the obvious contribution to product sweetness, it also has an

impact on the formation of product structures which, in turn influences

texture, eating qualities and shelf-life, both sensory and microbial (Cauvain

and Young, 2008).

Sucrose is available in a number of crystalline and liquid forms (various

types of syrups). In summary, the main forms of sucrose that are used in the

manufacture of baked goods are:

� Granulated � Usually, the coarsest crystalline, refined white form.

� Caster � Smaller crystals separated from the preparation of the granulated

form.

� Pulverised � May be manufactured by regrinding a crystalline form.

� Icing sugar � A fine, powdered sugar obtained by grinding crystals.

� Demerara � A light brown, crystalline sugar with pigments derived from

the natural sugarcane.

� Soft brown � A mixture of small crystalline sugar and molasses.

� Molasses � A dark-coloured syrup, the residue of the sugarcane-refining

process.

Many of the functions of sugar in baked products require that it should

be in solution in the mix. This does not necessarily mean that you have to

prepare a sugar solution in the bakery. Sugar has a high solubility (typically

sucrose dissolves in half its weight of water at 20�C), but the quantity that

can actually get into solution depends on the level of available water and the

temperature of the mix. The size of the crystals is important in determining

the rate at which they dissolve and in low water systems (e.g., biscuit

dough), this can be a critical factor in deciding which form to use.

Some of the key requirements for sugar properties are summarised for the

different baked product groups below.

� Bread

Levels of sugar addition may range from zero to as much as 20% of flour

weight in the recipe in the manufacture of breads around the world. The

water levels are relatively high and dough processing times from mix to

oven are relatively long by comparison with other baked products, and

usually, there is sufficient time is available for any added sugar to readily

dissolve. This means that most of the crystalline forms can be used with-

out creating any specific problems.

� Fermented products (e.g., rolls and buns)

Sugar is commonly added to rolls, buns and other similar fermented pro-

ducts to improve product sweetness and crust colour. The levels of


addition still tend to be low enough to allow for the use of all the crystal-

line forms. You should note that high level of added sugar can have an

inhibitory effect on yeast activity.

� Sponges and cakes

Caster sugar is the form most commonly used in the manufacture of

sponges and cakes. While granulated sugar will readily dissolve in

the water present in sponge and cake batters, there can be problems with

recystallisation on the surface of the baked product. A common phenome-

non when sugar recystallisation occurs is the formation of small white

spots on the crust (see Section 5.19), and in less extreme cases, the brown

crust colour may be tinged with a grey haze arising from many sugar crys-

tals too small to be seen with the naked eye. A crystalline form of sugar is

preferred for many cake mixing procedures as it helps with the dispersion

of the recipe fat and the incorporation of air into the mix (see Section 5.2).

� Fruited cakes

In cakes, where a high proportion of dried fruit is added to the mix (e.g.,

celebration cakes), it has become traditional to use a proportion of brown

sugars and syrups to add to the colour and flavour profile of the baked

product.

� Biscuits and cookies

Commonly, the finer grades of sugar, e.g., pulverised, are used in the

manufacture of biscuits and cookies. This is because the added water

levels are relatively low, so there is a significant potential for sugar

recrystallisation of the surface of the products. In some biscuits, brown

sugars or syrups may be added to confer colour and flavour.

� Pastries

Caster or pulverised sugar is usually preferred for the manufacture of pas-

tries to avoid sugar spotting on the surface of the baked pastries.

� Other bakery products

Icings, toppings and fillings often use a proportion of the finest sugar

grades, e.g., icing sugar.

If you are not able to access or store a range of sugar types, you may

have to consider modifying your mixing procedures. For example, with the

coarser grades, you may have to dissolve the sugar in the recipe water before

adding it to the other ingredients. If the sugar levels in your product are high

with respect to the water levels, you may still have problems with

recrystallisation.

Further reading

Cauvain, S.P., Young, L.S., 2006. Baked Products: Science, Technology and Practice. Blackwell

Publishing, Oxford, UK.


Effects, second ed. Wiley Blackwell, Oxford, UK.






2.4.2 Can you explain some of the main features of alternativesugars to sucrose, and how they might be used in baking?

The sugars which are used in baking fall into two main groups classed as

mono and disaccharides. Monosaccharides are sometimes called ‘simple’

sugars because they consist of one glucose molecule while the disaccharides

comprise two glucose molecules in different configurations.

There are a number of key differences between sucrose and the other

sugars which may be used in baking; important ones are related to the

impact on the gelatinisation characteristics of wheat starch and therefore

product structure, their impacts on product water activity and in turn

product shelf-life, and their relative sweetnesses (see Table 2.2). All sugars

contribute to the Maillard browning reaction which forms the crust colour

of baked products.

The main monosaccharides are fructose and glucose both of which occur

naturally in fruits. Fructose is an isomer of glucose (that is a glucose mole-

cule with a different arrangement of the same atoms in the molecule) which

can be obtained in the crystalline and liquid forms. It is a sugar which is

often used in diabetic products because its initial metabolism in the human

digestive system does not require insulin. Fructose may be used in a syrup

form (high fructose corn syrup, mainly a mixture of fructose and dextrose)

which is readily fermentable by yeast.

Glucose may be used as a powder (dextrose monohydrate) or as a syrup

(containing about 20%) water with different amounts of dextrose. The per-

centage of reducing sugars in the syrup is given by its dextrose equivalent.

Glucose syrups are found mainly in jams and fondants though they may find

use in cake and biscuit making. Dextrose solids are often used to extend the

mould-free shelf-life of cakes, but their level of addition may be limited by

the browning reaction which occurs.

TABLE 2.2 Relative Sweetness of Sugars

Sugar Relative sweetness

Sucrose 1.0

Fructose 1.7

Maltose 0.35

Lactose 0.27

Glucose syrup 0.30


The main disaccaharides (in addition to sucrose) are maltose and lactose.

Maltose finds its way into baked goods usually as part of malted wheat

or barley products and finds use in bread and other fermented goods. It is

commonly available in the form of a syrup with a low degree of browning.

In its purer, crystalline form, maltose has been used to slow down starch

retrogradation.

Lactose is present in milk products. Its use is limited because of its low

solubility. It is a reducing sugar which explains why the addition of milk

powders increases the richness of crust colour in baked products. Lactose

may also come as a component of hydrolysed whey products.


2.4.3 Why are sugars added to some bread recipes but notothers?

The addition of sugars to bread recipes is made for a variety of reasons.

Perhaps, the most obvious reason is to confer flavour, principally sweetness.

As the flavour of fermented products is very personal thing, there are wide

variations in the types of sugars added and the levels of addition used. When

recipes are compared around the world, it is commonly observed that pan

and hearth breads in northern and western Europe have no added sugar, in

Mediterranean Europe, the Middle East and the Americas low or modest

levels will be present, whereas in Asia levels, it tends to be the highest.

Sugar levels in all parts of the world tend to be higher in buns and rolls

where sweet flavours are more commonly expected. The most common types

of sugars used are sucrose, dextrose and high fructose corn syrup. Each of

these sugars confers a different level of sweetness if added on a common

solids basis (see Section 2.4.2).

A common perception is that sugars are added to support fermentation. It

is certainly true that yeast will break down sugars during the fermentation

process to yield carbon dioxide and alcohol. However, the fermentation of

sugars by bakers’ yeast is a complex process which depends mainly on the

availability of a substrate (yeast food), fermentation time and temperature.

Bakers’ yeast may be described as a ‘fussy feeder’, in that, it does not use

all sugar sources at the same time, though its suite of enzymes is perfectly

able to deal with both mono and disaccharides.

Most wheat flours contain low levels of fermentable sugars, typically

around 1% comprising fructose, glucose and sucrose. The action of alpha

and beta amylases on damaged starch results in the generation of maltose

during fermentation, and this can also be used by the yeast.

The key element of yeast activity is that it utilises readily the monosac-

charides for the production of carbon dioxide but a group of enzymes

commonly held in the double cell wall of yeast and commonly referred

to as ‘invertase’ is required to break down disaccharides like sucrose to

monosaccharides before they can be used. In short of or no-time dough

systems, there may be insufficient time for the yeast to convert sufficient

sucrose, and so in terms of gas production, the presence of such sugars is

largely irrelevant.

Yeast activity in dough is profoundly affected by a process referred to

as osmotic pressure (see Section 11.12). This concept is related to the con-

centration of soluble materials in the solution in which the yeast cells are

held, in contrast with the concentration of soluble substances with the yeast

cell. If both concentrations are equal, then the yeast cell is not stressed and

can function normally. On the other hand, if the two concentrations are not

equal, then there will be a movement of soluble materials through the yeast

cell wall which stresses the cells.


Being readily soluble, recipe sugars increase the concentration of soluble

solids in the dough liquor surrounding the yeast cells, and the high concen-

tration can actually inhibit yeast activity and gas production. The effect of

increasing levels of sucrose on gas production during proof is illustrated in

Fig. 2.7. In this example, the inhibitory effect of sucrose on gas production

in a no-time dough is linked with the increase in proof time required to

deliver a standard pan dough height prior to baking. In practice, proof times

would not be lengthened to accommodate the lower rate of gas production,

rather yeast levels would be raised. However, this action may not be entirely

successful because the osmotic pressure effect of high sucrose levels will

continue to have an inhibitory effect on the yeast.

0

10

20

30

40

50

60

0 2 4 6 8 10 12 14 16

Incr

ease

in p

roof

tim

e (m

in)

Level of sugar (% flour weight)

FIGURE 2.7 Effect of sucrose on gas production during proof.


2.5 OTHER INGREDIENTS

2.5.1 The chocolate fondant on our cream eclairs has beenfalling off the top of the casing and gathers on the trayunderneath as a sticky syrup. What causes this and how can weprevent it?

The chocolate fondant contains undissolved sugar particles which tend to

make it hygroscopic, that is, likely to absorb water. As more water is taken

up by the fondant, then the fondant becomes more liquid and likely to flow.

If you are putting the fondant on to the curved top of the eclair shell, then it

can readily flow down the sides.

The water which causes this problem will come from the other components

of the eclair. Usually, the source will be the cream which has a very high

water activity (equilibrium relative humidity, ERH) and the moisture readily

diffuses thought the porous and dry choux shell. The moisture which gathers

at the shell-fondant interface acts like a lubricant and helps the fondant flow.

This is not an easy problem to eliminate because of the diverse nature of

the three components in the composite product. Some points to consider are:

� The fondant will always contain undissolved sugar and therefore be

hygroscopic properties. However, these may be reduced to some extent

by replacing some of the sucrose with a glucose syrup, adjusting the

water as necessary.

� Adding a small quantity of fat to the fondant, say 5�6%.

� Lowering the ERH of the cream to reduce the driving force for moisture

migration. The options may be limited though sucrose or even glycerol

additions may help.

� A change to a slightly more permeable packing may help by allowing

some loss of moisture to the external atmosphere, but beware that this

may lead to the whole product drying out too quickly.

� Try icing the base of the eclair shell because this is usually flatter in shape.

� Look carefully at the tray in which you stand the eclairs. If the eclair

does not stand level in the tray, then there is always a potential for the

fondant to flow under the influence of gravity.

Further reading

Cauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture & Quality: Water Control and





2.5.2 When we changed our supply of bun spice we were usingin our Hot Cross buns, we experienced problems with slowgassing in the prover and flowing of the buns during baking.What can we do to avoid these problems?

Many spices have an adverse effect on yeast and will inhibit gas production.

The higher the concentration of the spice the greater will be the effect.

It appears that the change from one spice supply to another has resulted in you

inadvertently adding a more concentrated form to the dough, that is,

the equivalent of a higher spice level even though the weight of added spice has

remained constant. Alternatively, the new spice formulation you are using may

have a greater concentration of one or more spices which have a significant

effect on gas production.

The problem you describe can occur whether you are using a liquid or

dry spice. You should try to make sure that the yeast and the spice are kept

separate for as long as possible in the mixing process. In the case of a liquid

spice and some mixing operations, you may be able to hold the liquid spice

until after the yeast has been fully dispersed.

The flowing that you see almost certainly comes about due to the same prob-

lem. Direct contact between the spice and the yeast may have caused disruption

of the yeast cells with subsequent leakage of the proteolytic enzymes and gluta-

thione which both weaken the gluten network in the dough. If sulphur dioxide

or sodium metabisulphite have been used as preservatives in the spice, residues

of these chemicals can act as reducing agents and weaken dough structures.

If the problem persists after you have taken suitable precautions during

mixing or after adjusting the levels of addition, you might try using less

spice in the dough and more in the glaze for the products to maintain product

flavour profile.


2.5.3 We wish to use milk powder in our fermented goods andhave heard that it is advisable to use a heat-treated form. Canyou explain why this is so?

The use of fully heat-treated milk or milk powder products is essential if you

are to avoid losses in product volume. In the case of liquid milk typical, heat

treatment conditions would require raising the temperature to around 80�Cand holding it at that temperature for some 30 minutes before cooling and

use. If dried milk powders are to be used, it is important that they have been

subjected to a similar temperature profile to that given above.

Similar problems with loss of volume can occur if inadequately treated

milk powder is used in the production of sponge cake goods. On some

occasions, a collapse of the cake structure and the formation of a ‘core’

(an area of coarse dark-coloured cell structure) may occur.

The adverse effects of inadequately treated milk arise because the

globulin proteins normally present have not been denatured. The normal

pasteurisation process applied to milk does not denature the globulins which

can interfere with the stability of the gas bubbles in the proving dough or

baking cake.

The suitability of a milk powder for baking can be assessed with a small-

scale baking test or by employing the Swortfiguer cloud test (Swortifguer,

1958). A clear or slightly cloudy solution at the end of the test indicates that

the milk powder has been adequately treated.

Reference

Swortifguer, M.J., 1958. Is there a simple method by which we may determine whether a sample

of non fat dry milk has received proper treatment? Baker’s Digest October, 78




2.5.4 What are the functions of salt in baking, and how do setabout reducing the levels that we use?

Salt (sodium chloride) has a number of different functions in the manufacture

of bakery products, some of which are product specific. The most immedi-

ately recognised one is to contribute to the flavour profile of the product.

Salt has its own characteristics and is considered as one of the five basic

tastes (the others are sweet, acid, bitter and the recently added, umami).

In addition to its own distinctive flavour, salt plays a significant role in

enhancing other, often more subtle, flavours. Reductions in added salt

levels in baked products are usually detected very readily by consumers,

so we recommend that you make small but progressive reductions over

a period of time so that the palate of your customers becomes ‘educated’

for lower salt levels.

Sodium chloride is one of very few chemicals which confer a salty

flavour, and it is not easy to ‘replace’ the flavour contribution with other

ingredients. Potassium chloride may be used to replace the sodium salt, but

as the level of potassium chloride increases, there is a development of an

unacceptable level of bitterness in the product. Each of the salt ‘replacers’

which are offered has a distinctive flavour profile but all are different from

sodium chloride. Other flavours enhancers are offered for use in lower salt

foods, but their suitability for use depends on the food in which they are to

be used. In breadmaking, a possible route to increase the flavour of bread

is by using fermentation of all or part of the dough in the manufacturing

process. However, it should be noted that the overall flavour profile of the

final product will be different and may be less acceptable to all consumers.

Again it may be a matter of educating the consumer palate.

The other universal function of salt in baked products is that of a preser-

vative. Additions of salt have been used to extend the mould-free shelf-life

of cakes and many other bakery products (Cauvain and Young, 2008).

Weight of weight, salt is 11 times more effective than sucrose in reducing

the water activity of a baked product, so it has been a common addition to

many recipes. If you are going to use lower salt levels, then you may have

to compensate for the increase in water activity with other anti-microbial

strategies. In high water activity products (e.g., bread, hot-plate goods), the

impact of salt on product mould-free shelf-life is very small. However,

the water activity levels in such products are marginal for rope spoilage

(see Section 4.1.4), so reductions in added salt levels should be approached

with some caution. Rope spoilage is more likely to be a problem in whole-

meal, and mixed grain breads as the spore-forming bacteria are associated

with the other layers of grains so spore counts are likely to be higher.

Salt plays some technological roles in the manufacture of bread and

other fermented products. One of these is to limit the activity of bakers’

yeast in the dough. Reductions in added salt levels will lead to increased


gas production by the added yeast such that the dough may become ‘over-

proved’ in a standard proof time in the bakery. In such cases, it may be

necessary to either reduce proof times or lower added yeast levels in the

dough; the latter is most commonly preferred as the length of time used

for dough proving has other technological benefits related to the rheological

properties of the gluten in the dough; most notably to contribute to the

uniformity of oven spring when the product is baked.

Salt also makes a contribution to dough development and bread volume.

Danno and Hoseney (1982) showed that Mixograph times to peak were

shorter when salt levels were reduced, whereas other studies (Miller and

Hoseney, 2008) have shown that loaf volumes were optimised at around 2%

flour weight and that volume decreased when salt levels were both increased

and decreased. Any losses in bread volume can be compensated for by

other ingredient and recipe adjustments. Lowering salt levels in bread dough

does lead to some adverse changes in dough rheological properties after

mixing. In particular, there is an increase in dough stickiness which may be

of concern in highly automated plants or where ambient dough processing

temperatures are high.

References



Danno, G., Hoseney, R.C., 1982. Effect of sodium chloride and sodium dodecyl sulphate on

mixograph properties. Cereal Chem. 59, 202�204.

Miller, R.A., Hoseney, R.C., 2008. Role of salt in baking. Cereal Foods World, Jan�Feb, 4�6.

Further reading

Kilcast, D., Angus, F., 2007. Reducing Salt in Foods: Practical Strategies. Woodhead Publishing

Ltd, Cambridge, UK.












2.5.5 We are using walnuts in our gateau buttercream fillingand find that it turns black. It does not appear to be mould.What is the cause of this discolouration?

You are quite right the problem is not one of the mould growth. The most

likely cause is a reaction of the tannin in the walnut pieces with any traces

of iron which may be present in the cream, perhaps picked up from the

mixing utensils that you have used. The colour may take several days to

appear. Sometimes, the colour may be purple rather than black, depending

on the product pH.

We suggest that you try to use stainless steel utensils and avoid using any

iron utensils which are scratched or damaged. You should also try to ensure

that any cut cake surfaces do not come into contact with iron surfaces.


2.5.6 What is the role of emulsifier in the production of spongecake products?

The key role for the emulsifier added to sponge cake batters is assist in the

incorporation and stabilising of the air bubbles mixed into the cake batter.

The most common emulsifier used in sponge cakemaking is GMS though

polyglycerol esters are also used. In both cases, the emulsifier can be

considered as a molecule which has a hydrophobic (water-hating) head

and a hydrophilic (water-loving) tail. Thus, when the emulsifier is used

in a cake batter, the hydrophobic head aligns itself at the interface of

the liquid and air phases, whereas the hydrophilic tail is located in the

liquid phase. These actions confer stability to the air bubbles incorporated

during mixing.

Sponge cakes may be made without any emulsifier, and in this case,

the egg proteins play the bubble stabilising role. However, if any fat or oil is

present in the formulation, then the egg proteins cannot maintain gas-bubble

stability during baking and the cake may exhibit collapse and core formation

(see Section 5.41). To overcome this problem when using fat or oil, it is

necessary to add an emulsifier. In this case, the emulsifier takes over the gas

bubble stabilising role of the egg proteins. It is important to ensure that suffi-

cient emulsifier is added to maintain gas bubble stability in both the cold

batter and during baking. Cauvain and Cyster (1996) showed how core for-

mation was made worse when a low level of GMS was added to the batter

but was eliminated as the level progressively increased.

Gas bubble size and therefore sponge cake cell structure is directly

affected by the level of emulsifier. Cauvain and Cyster (1996) studied the

effects of GMS and found that the minimum gas bubble size, and therefore

finest cell structure, was obtained at about 0.6% batter weight with their for-

mulation (see Fig. 2.8). Increasing the level of added GMS had no effect on

gas bubble size, but at 1.5% batter weight, the cake was unacceptable, hav-

ing a loose crust, many surface blisters and a very close cell structure. This

can be interpreted as over-stabilisation of the batter with a layer of GMS so

thick around the gas bubbles that they were unable to rupture (i.e., convert

from foam to sponge) at the correct moment during baking.

The volume of gas that can be incorporated into the batter is also related

to the level of emulsifier used. The higher the level of emulsifier, the

greater the volume of air that can be incorporated and the lower the batter

relative density that can be achieved. This in turn can lead to greater prod-

uct volume provided that sufficient emulsifier is present to ensure bubble

stability during baking.

To ensure that the emulsifier is effective as a bubble stabiliser, it is

important to use it in its most appropriate form. In the case of GMS, there


are a number of different forms in which it can exist, depending on its con-

centration in water and the temperature of the preparation. Krog and Larsen

(1968) studied the phase diagram for GMS and water and showed that the

most effective form for cakemaking occurred over a limited range of concen-

trations and temperatures. The most appropriate form is often called the

‘alpha gel’ form. Commonly, cake emulsifiers are used in a ready-prepared

gel form and may contain a ‘co-emulsifier’ to prevent GMS reversion when

the mixture is cooled.

References

Cauvain, S.P., Cyster, J.A., 1996. Sponge cake technology. CCFRA Review No. 2. CCFRA,


Krog, N., Larsen, K., 1968. Phase behaviour and rheological properties of aqueous systems of

industrial monoglycerides. Chem. Phys. Lipids 2, 129�135.

Further reading

Whitehurst, R.J., 2004. Emulsifiers in Food Technology. Blackwell Publishing, Oxford, UK.

FIGURE 2.8 Effect of level of emulsifier on bubble size in sponge cake batter.








2.5.7 What ingredients are commonly used as preservatives?Are there any particular benefits associated with different ones?

The choice of preservative depends on the product type and the potential

microogranisms which are prevalent in causing spoilage. Microbial spores

are airborne in the bakery environment and also present in the dry ingredi-

ents (flour), their packaging and through contact with contaminated equip-

ment and surfaces. Preservatives only inhibit spoilage � they do not destroy

the microorganisms and so good hygiene is a necessary adjunct to using

preservatives.

A comprehensive list of preservatives for use in bread and fine bakers’

wares is given by Cauvain (2015). Breads and other fermented products are

high in moisture and are susceptible to microbial attack. Table 2.3 shows

some of the commonly used preservatives along with their recommended

levels of use within the European Union; there are other local limits for their

addition and these should be checked before use. Using the materials at their

recommended levels should ensure an extension of mould-free shelf-life by

2�3 days at temperatures of 20�C. Vinegar is used to combat ‘rope’ bacterial

spoilage and has a small inhibiting effect against moulds (see Section 2.5.8).

For flour confectionery products, such as cakes and muffins with

intermediate moisture levels, the commonly used preservatives are sorbic

acid and its salts. They are not efficacious in bread and fermented products

as the levels required render the dough sticky and difficult to process, inhibit

the action of baker’s yeast and yield products with poor volume and coarse,

open structure (unless added in their encapsulated form). Sorbic acid and

its easier handled salt � Potassium sorbate � can be added up to 2000 ppm

(in the finished product). The levels used depend on the product water activ-

ity and pH. Adding preservatives to give more than a 50% extension to

shelf-life is not usually recommended (Cauvain and Young, 2008) as the pre-

servative flavour can often be detected by the consumer. The lower the pH

of the product, the greater the preservative effect as shown in Fig. 2.9.

Acetic acid and its salts may be used in many bakery products although

they are less effective than others mentioned here. In some cases, the use of

TABLE 2.3 Common Preservatives for Bread and Fermented Products

Preservative Recommended usage (% of flour weight )

Calcium propionate 0.2

Propionic acid 0.1

Sodium propionate 0.2

Sodium dipropionate 0.2


acetates rather than propionates and sorbates may reflect local legislation or

commercial preferences. As with all preservatives, high levels of addition

produce distinctive odours and taste in the products, and once consumers

have become accustomed to these, it may be difficult to interchange them.

For products such as Danish pastries with relatively short shelf-life,

preservatives are less commonly used. If the pastries are fermented, then the

preservatives used in breads would be suitable and for cake-like ones sorbic

acid and its salts would be appropriate. For low moisture biscuits and cook-

ies mould growth is not usually a problem and so the addition of preserva-

tives is not common.

In some cases, it may be appropriate to use a combination of preservatives

to achieve the desired effect on shelf-life. This is because there are many

different types of moulds and each of them can tolerate a slightly different set

of conditions and type of preservative. In most manufacturing environments it

is unlikely that the full range of moulds types contaminating a product will be

known. There are some very common ones (e.g., Penicillium sp., Aspergillus sp.)

and usually the addition one preservative is all that is required. However, in some

cases, a ‘broad spectrum’ approach with a mixture of preservatives (and other

inhibitory processes) may be used to ensure maximum impact. With mixtures of

preservatives, the extension of the mould-free shelf-life of the product may be

increased beyond that achieved with a single preservative though the overall

impact may be difficult to quantify.

References


AG, Switzerland.



Additional days shelf-life for cake at different pHstreated with 1000ppm sorbic acid

050

100150200250300350

5 5.5 6 6.5 7pH

Extr

a da

ys s

helf-

life

at21

°C

ERH 92%ERH 86%ERH 80%

FIGURE 2.9 Additional days’ shelf-life obtained in cakes of different pHs when treated with

sorbic acid at 1000 ppm product weight.






2.5.8 What effect does vinegar have on bread and whyis it added?

Vinegar has the advantage of being considered by many as a natural

preservative. The chemical name for vinegar is acetic acid (E260) and it is

sometimes known as ethanoic acid. It has been used for many years as an

inhibitor for the growth of rope bacteria (Bacillus subtilis) in bread. As a

preservative, it has little intrinsic antimicrobial activity and so is added to

increase the acidity (reduce the pH) and retard the initial growth of

the bacteria. Rope spores are present naturally in the soil and can be found

on the outer parts of the wheat grain. They are also present in the air and

can be passed on in flour or by equipment which has been in contact with

contaminated dough (see Section 4.1.4).

The white spirit form of vinegar is diluted to a give a 12.5% solution and

added at the rate of about 1 L per 100 kg flour; equivalent to a rate of acetic

acid addition of 0.125% based on flour weight. Such levels reduce the bread

crumb to a pH of about 5.4; the general level suitable for protection from

rope. The level of addition required for wholemeal breads is slightly higher.

To achieve a pH of 5.4, the amount of vinegar added will vary from one

type of bread to another depending on the pH of the ingredients, the natural

buffering effect of the flour and whether the flour has been fortified with

calcium carbonate. All flours have a buffering effect on the efficacy of

the acetic acid with the buffering being greater in flours with higher levels

of bran. Fig. 2.10 shows the effect of acetic acid addition on the pH of

breads. Vinegar has a small effect on the gassing rate of yeast, so yeast

levels may be slightly increased to counter this and reduce the impact on

proof time.

4.6

4.8

5

5.2

5.4

5.6

5.8

6

0 0.05 0.1 0.15 0.2Acetic acid addition (% on flour weight)

Bre

ad p

H

White Wholemeal

FIGURE 2.10 The effect of acetic acid addition on the pH of breads.


2.5.9 We have heard that alcohol can be used as apreservative. How is this achieved?

The use of alcohol as a preserving agent has been known for many years.

Heavily fruited celebration cakes are often treated with alcohol after baking

to add flavour and benefit from the preservative and anti-staling properties.

Ethyl alcohol can be an effective preservative for breads. Added at levels

between 0.5% and 3.5% of loaf weight, it gives good extension of shelf-life

(Legan, 1993). Fig. 2.11 shows the percentage increase in mould-free shelf-

life obtained when ethyl alcohol is added. The effect is typically obtained

when the alcohol is sprayed onto all surfaces of the loaf before packing and

sealing. If the alcohol is coated on the inside of the bag before inserting the

loaf and sealing, the increase in shelf-life is similar. The alcohol acts as a

vapour pressure inhibitor and discourages moulds from growing. In the case

of bread, addition of alcohol at levels higher than 1% of product weight can

usually be detected by the consumer.

If adding, alcohol to fermented products or cakes checks should be made

on possible local excise duties payable and on any labelling issues. Although

it may be costly to use alcohol as a preservative, it has significant potential

for its antimicrobial properties and for antistaling in bread and cakes

(Cauvain, 2015).

References


AG, Switzerland.

Legan, J.D., 1993. Mould spoilage of bread: The problem and some solutions. Int. Biodeterior.

Biodegrad. 32, 33�53.

–50

0

50

100

150

200

250

300

0 0.5 1 1.5

% by weight of 95% alcohol

% In

crea

se in

mou

ld-f

ree

shel

f-lif

e

FIGURE 2.11 Relationship between alcohol concentration applied and percentage increase in

mould-free shelf-life.







2.5.10 What are the possible alternatives to chemicallybased preservatives?

With the desire for ‘clean’ labels, bakers have sought the help of ingredients

with natural preservative properties. Bakers have known for centuries the

preservative effect of using dried fruit, e.g., raisins, in their cakes and other

products. Sorbic acid salts develop on the skins of the fruit as they dry and

together with the higher concentration of sugar within the fruit contribute to

the longer shelf-life of the product. Such preservatives will inhibit microbial

growth but will not prevent bacterial activity. It should be noted however

that for a truly ‘natural’ dried fruit, the fruit should not have been treated

with sulphur dioxide during the drying process. Many red-berried fruits have

sorbic acid present as part of their composition and if added as a fruit

concentrate might add a small preservative effect.

In many cases, the preservatives found in fruits act best at low pHs,

e.g., circa 2.0 and so are effective when used in acidic products such as fruit

juices but will have a limited effect in the higher pH bakery products (as a

general rule bakery products lie in the pH range 5.0 to 6.5). Benzoates which

are found naturally in cranberries also work best at low pH.

Using acid dough components, such as fermented wheat flour, in bread

can provide a preservative effect. This is based on the natural lowering of

the pH of the dough from the actions of lactic and acetic acid bacteria.

To speed up acidification, a special culture of lactobacilli is added. For white

breads, sufficient acid dough should be added to bring the pH to below 5.0.

To prevent rope, an addition of 10% of acid dough in the final dough mix

should be sufficient. It is also claimed that the lower bread pH has the

benefit of improving the flavour of the bread; however, there are many

groups of consumers who do not like the ‘sour’ taste of bread when the pH

is very low.

Salt (sodium chloride) is a natural preservative. It occurs in sea water and

also is mined. It works by locking up the water in the bakery product so that

the moulds cannot use the moisture for growth. However, its addition is

limited by taste and more recently by concerns over the level of sodium

chloride in the diet. Similarly, sugar can be used to extend shelf-life and

again its addition has to be carefully considered as it may have an effect on

the processing and the final product quality.

Many of the chemically based preservatives are ‘nature identical’ and

have been given E numbers to denote their acceptance for use in food

products. Often, they have been derived from organisms that occur in nature.

Their dosages and effectiveness are well known. The variability in the poten-

tial effectiveness of ‘natural’ (non-chemically based) preservatives needs to

be considered when relying solely on them in products.


2.5.11 What are the differences between diastatic and non-diastatic malt powders, and how can they be used in baking?

Malt flours are most commonly made from wheat, barley and to a lesser

extent oats. After the malting process, the products of the different cereals

have slightly different characteristics, but essentially, they fall into two

categories; diastatic in which a range of enzymes remaining active and non-

diastatic in which the enzymes are inactivated.

The malting process is based on the partial germination of the grains.

Initially, the cleaned grains are ‘steeped’; that is, mixed with a predetermined

quantity of water and stored under conditions which encourage the grains to

germinate. After the requisite time, germination is arrested by removing

water with the application of gentle heat. The ‘malt’ is mixed with water and

a liquor extracted. It is the malt liquor extract which is dried under varying

conditions to deliver a range of malt powders with different characteristics.

As all enzymes are heat sensitive, the greater the heat input during drying,

the lower the enzymic activity which remains in the product. Also the greater

the heat input the darker the malt powder will be.

All malt powder products have a slightly sweet, roasted flavour;

the degree of flavour intensity varying with the degree of heat treatment

used in the preparation. This distinctive malt flavour is carried through to the

baked product with the intensity varying according to the grade of malt flour

used and its level of addition. Clearly, the more malt flour that is added to

the product, the more pronounced the flavour will be. If your main interest

in using malt is to confer flavour to products, then you can use either the

diastatic or nondiastatic forms.

The term diastatic activity refers to a suite of different enzymes which

are present in the malt flour. The germination process in the grain is based

on the conversion of starch to sugars to provide food for the early stages

of plant growth. This means that the amylase enzymes, especially alpha-

amylase, are a significant component of diastatic malt flours. As is well

known increases in the alpha-amylase levels in dough increases its gas reten-

tion properties. However, high levels of cereal alpha-amylase can lead to

quality problems such as ‘keyholing’, caving in on the side crust (see

Fig. 1.1 and Section 4.1.2) as well as potential stickiness in the bread crumb

and slicing problems (see Section 4.1.35).

Other enzymes may be active in the malt powder, and these include

proteolytic enzymes which can have adverse effects on gluten structures.


2.5.12 We read a lot about the different enzymes which arenow available and how they might be used in baking. Can youtell us what they are and what functions they have?

There are many different types of enzymes in the natural world, and they are

an essential part of the natural reactions in life. They may be described as

organic or biological catalysts which accelerate the rates of critical reactions

in plant and animal systems. They have a similar structure to proteins. They

are described as biological catalysts and are very specific in action; that is,

they can only catalyse one specific reaction. All enzymes originate within

the cells of which plants and animals are composed. For example, in the

bakers’ yeast cell are all of the enzymes that it requires to break down sugars

and other nutrients for reproduction and growth.

Various microorganisms are the main source of industrial enzymes.

Specific microorganisms (commonly moulds) are developed under appropri-

ate fermentation systems in a similar manner to that of bakers’ yeast. At the

end of reproduction and growth period, the cells are disrupted and the cell

contents refined to separate out the different specific enzymes which are

present. Commercial enzymes are usually of a high purity, but most of them

will have some residual, or ‘side-effects’, associated with other enzymes

which are present in the sample. The commercial product is usually too

concentrated to be used in baking without being diluted, and it is in this

diluted form that enzyme preparations are used in the flour mill and bakery.

Many ingredients used in baking (e.g., wheat flour, yeast, soya flour,

malt flour) are enzymically active. The main groups of enzymes used as

‘extra’ additions in the manufacture of baked goods are discussed below.

However, it is important to recognise that enzymes require suitable condi-

tions for them to work effectively. A suitable moisture level is one of

the key requirements and enzyme activity in dry ingredients is low. If the

moisture level is low the enzymes remain inactive but when the moisture

level increases, they can quickly become active. As might be expected for a

biochemical reaction, enzyme activity is temperature sensitive with activity

gradually increasing as the temperature is increased. All enzymes are eventu-

ally inactivated by heat though thermal inactivation temperatures vary

according to the particular enzyme, its source and the environment in which

it is being used. In baking, most (but not all) enzymes are inactivated by

the temperatures achieved in the product during oven heating. Other factors

which will affect enzyme activity include the pH (acidity) of the environ-

ment in which it used, the availability and condition of the substrate on

which it acts and the water activity of the dough or batter.

Before discussing the types of enzymes and their application in baking, the

question of specificity of action must be considered. As stated above, enzymes

are highly specific in their action, and this specificity can extend beyond the

action of an enzyme on a particular substrate to include very specific sites of


action within the substrate molecular structure. It is this increasing knowledge

of the specificity of enzymes that has partly accounted for the increase in the

range of products which are now available for use in baking.

The addition of enzyme active materials to baked products is highly

regulated, and in most cases, the source of that enzyme is specified. In many

parts of the world, legislation does not currently require enzymes additions

to baked goods to be labelled, and they fall into the general category of

‘processing aids’. Even as processing aids, they will have required formal

approval for use in the production of food.

� Amylases

These are the best known groups of enzymes used in baking. There are

two main types of amylase; known as alpha and beta. Together, they are

responsible for progressively breaking down starch (a complex carbohy-

drate composed of glucose chains) into dextrins, high molecular weight

sugars and finally to simple sugars such as maltose (which can be used by

bakers’ yeast). Both alpha- and beta-amylase are present in wheat flour.

The level of alpha-amylase activity varies depending on a number of

factors, not least of which is level of moisture in the maturing wheat ears.

Beta-amylase is usually abundant in wheat flours, but alpha-amylase levels

may be low, so it is a common practice to augment its level through the

addition of a suitable enzyme active material in the flour mill (Cauvain,

2017). The measure of cereal alpha-amylase activity in wheat flour is

measured using the Hagberg Falling Number test (see Section 2.2.10).

This description of the action of amylases is simplistic. Starch gran-

ules in flour are made up of two components; amylose a straight chained

molecule and amylopectin a branched molecule. The action of alpha-

amylase is commonly described as random with respect to the amylose

and amylopectin molecules while that of the beta form is more specific

and it cleaves relatively small molecules from the starch components

(Cauvain, 2012). Thus, the combined action of the two forms of amylase

is critical in the use of amylase enzymes as bread improver.

A key function of alpha-amylase in bread production is to improve

dough gas retention and in consequence bread volume and softness

(Cauvain and Chamberlain, 1988). The source of the alpha-amylase has a

significant impact on the overall effect (Kulp, 1993; Cauvain, 2015).

Some forms of amylase are known to have anti-staling effects in bread.

This arises from the generation of high molecular weight sugars which

penetrate the starch granules helix structure and inhibit the recrystallisa-

tion process after baking (see Section 2.5.13).

� Hemicellulases

The action of hemicellulases is on plant cell wall materials � hemicellulose.

The endosperm of wheat is composed of small cells which hold the

starch, protein and lipids. The cell walls are composed of the large poly-

mers mainly based on the sugar xylose. Hemicellulases (sometimes


referred to as xylanases) act on the cell walls to break the material

down into mainly xylose and arbinose. The net result of the addition of

hemicellulase is to increase dough gas retention and to affect dough

water absorption capacity. The effect of this group of enzymes

is complex and the impact on dough water absorption capacity may

be negative in some doughmaking situations, with the addition of the

enzyme causing an increase in dough stickiness.

� Lipases

The addition of lipases has been shown to improve dough gas retention

and bread volume. Their action is on triglycerides (fats, lipids) and the

breakdown products of that action are in order diglycerides, monoglycer-

ides and finally fatty acids. The monoglycerides formed from the action

of lipase in dough are known to contribute anti-staling properties in

bread, and it is seen as a potential replacement for emulsifiers in bread

recipes (Rittig, 2005).

� Proteolytic enzymes

This group of enzymes include proteases and proteinases and their action

is on the gluten network formed in the dough. They are usually added to

‘weaken’ the dough system and are sometimes used in biscuit production.

They reduce dough gas retention and modify dough rheology making it

softer and more readily processable (Kulp, 1993). They should be used

with great care, if at all in breadmaking.

� Oxidases

Glucose oxidase enzymes are sometimes used in breadmaking. In

the presence of oxygen, they catalyse the oxidation of the beta form

of glucose and in doing so produce hydrogen peroxide. The ability of

the hydrogen peroxide generated in the dough to aid the formation of the

disulphide bonds is said to be the basis of the improvement in dough gas

retention (Vemulapalli et al., 1998).

References

Cauvain, S.P., 2012. Breadmaking: Improving Quality, second ed. Woodhead Publishing Ltd,

Cambridge, UK.

Cauvain, S.P., 2016. The ICC Handbook of Cereals, Flour, Dough and Product Testing: Methods


Cauvain, S.P., Chamberlain, N., 1988. The bread improving effect of fungal alpha-amylase.

J. Cereal Sci. 8 (Nov), 239�248.

Kulp, K., 1993. Enzymes as dough improvers. In: Kamel, B.S., Stauffer, C.E. (Eds.), Advances

in Baking Technology. Blackie Academic & Professional, Glasgow, UK, pp. 152�178.

Rittig, F.T., 2005. Lipopan F BG � unlocking the natural strengthening potential in dough.

In: Cauvain, S.P., Salmon, S.E., Young, L.S. (Eds.), Using Cereal Science and Technology

for the Benefit of Consumers. Woodhead Publishing Ltd, Cambridge, UK, pp. 147�151.

Vemulapalli, V., Miller, R.A., Hoseney, R.D., 1998. Glucose oxidase in breadmaking systems.





















2.5.13 How do anti-staling enzymes work? Can they be used incake as well as in bread and fermented products?

There has been significant interest in using enzymes as anti-staling agents

to augment the effect of emulsifiers or to replace them. When we refer to

staling, it is in the context of slowing down the firming of bread and cake

crumb which comes from the retrogradation of starch during storage. This is

in contrast to the increased softness which can be obtained by higher moisture

levels in the baked product or through the increase of product volume (the

latter is commonly a result of adding enzymes to bread formulations).

There are two main groups of enzymes with anti-staling effects in baked

goods, and these are specific types of alpha-amylase and lipase; as is well known

the former acts on damaged wheat starch breaking it down progressively to

maltose, whereas the latter acts on triglycerides to eventually yield fatty acids.

The starch polymer consists of a series of sugar molecules linked together

as linear chains of amylose and branched amylopectin structures. Alpha-

amylase is able to cut through these linkages at different points but very

specific points depending on the types of amylase to yield different sugars of

varying molecular weights. Sugars are known to function as anti-staling ingre-

dients in starch-based foods, probably by raising the glass transition tempera-

ture (see Section 11.6) and suppressing the recrystallisation of the

amylopectin (the main component responsible for staling in bread).

In the case of lipase the specific action is to generate monoglycerides in

situ in the dough and monoglycerides are proven anti-staling agents in bread.

Again, the specific type of lipase will dictate which specific monoglyceride

is generated and at what rate and level in the bread dough.

The anti-staling effect of some enzymes is now well established in bread.

In cakes, it is less well established. As the action of the specific anti-staling

alpha-amylases is based on the production of a variety of sugars, it is

difficult to see why this should be of significant benefit in cakes which

already by virtue of their formulation contain high levels of sugars. There is

some evidence which supports increased softness values for cake crumb

containing specific lipases. This is perhaps more understandable due to the

generation of the monoglyceride which is known to have crumb softening

effects in cakemaking.

It is likely that any observable anti-staling effects of enzymes will depend

heavily on the type of cake being produced and is more likely to be observed

in low-fat cakes, such as sponge, or low-ratio cakes where the levels of sugar

are lower.

Further reading

Cauvain, S.P., 2012. Breadmaking: Improving Quality, second ed. Woodhead Publishing Ltd,

Cambridge, UK.




2.5.14 What is lecithin and how is it used in baking?

Lecithin is a naturally occurring emulsifier found in animal and

vegetable products such as milk, eggs (in the yolks) and soya beans, now the

major source of the material. It is a liquid at temperatures around 20�C and

is soluble in oil. Purified and modified forms are available as a plastic liquid

and in powder form (often blended with another food grade powder for ease

of handling). The main constituent of lecithin in terms of its functionality is

a mixture of phospholipids with the combination of the different types being

specific to its animal or plant source.

As a component of egg yolk, lecithin plays a role in helping to stabilise the

air bubbles that are mixed in during the preparation of cake batters. This role is

especially important in the preparation of sponge products which tend to have

low levels of added fat or oil. The lecithin phospholipids are part of the egg

lipoproteins which are found at the interface of the air with the aqueous phase

in cake batters and aid bubble stability at the time in the oven when the cake

batter system changes from a water-in-oil to oil-in-water emulsion. Lecithin is

often used along with other emulsifiers, such as GMS, in sponge cakemaking.

The addition of lecithin at low levels in the manufacture of cake dough-

nuts is said to reduce fat absorption during frying and to confer tenderness to

the final product eating qualities.

Lecithin may be used in the manufacture of some bread types. It enhances

gas retention in the dough to a degree but less so than other more commonly

used emulsifiers. In crusty breads, it tends to give a thicker, denser crust which

retains its crispness for longer periods of time (Cauvain, 2015).

In biscuits, lecithin may be used as a means of reducing fat levels by up to

10% without adversely affecting biscuit quality. Dissolving the lecithin in fat

makes it easier to handle (Manley, 2000), and it may help with the dispersion

of the fat throughout the dough giving it a smoother feel. In higher sugar cook-

ies, the addition of lecithin helps with the restriction of flow during baking.

In the bakery, low levels of lecithin (around 5%) are often found as a

component of oil-based pan greasing agents.

References


AG, Switzerland.

Manley, D., 2000. Technology of Biscuits, Crackers and Cookies, third ed. Woodhead

Publishing Ltd, Cambridge, UK.

Further reading

Silva, R., 1993. Lecithin and phospholipids in baked goods. In: Kamel, B.S., Stauffer, C.E.

(Eds.), Advances in Baking Technology. Blackie Academic & Professional, Glasgow, UK,

pp. 223�253.












2.5.15 We have been having some problems with the quality ofour bread, pastries and biscuits and one solution that has beenrecommended to us is that we should add a reducing agent toour recipes. Can you tell us more about reducing agents, andhow they function in baked products?

We should first start by defining what we mean by reduction. In chemical

terms, it is used to describe reactions in which hydrogen is added to an

element or compound, or in which oxygen is removed from a compound.

It is the opposite of oxidation. Although both terms are used empirically to

cover a number of similar reactions, in baking, the reduction and oxidation

reactions which take place are very close to the formal definition.

A key reaction during mixing is the formation of disulphide bonds

between the protein chains in the dough (Cauvain, 2015). Their formation

is promoted by oxidation, and they contribute to the elasticity of dough.

The origins of this property are associated with the ratio of glutenin to

gliadin proteins in the wheat flour though oxidation processes which occur

during dough mixing also make a contribution. If the dough is too elastic

after mixing then it may be difficult to process, and it is common to consider

adding a reducing agent to reduce the number of disulphide bonds which

have been formed.

A commonly used reducing agent in the preparation of fermented dough

is L-cysteine, a naturally occurring amino acid used in the hydrochloride

form to improve its solubility. The addition of L-cysteine hydrochloride

is often recommended to reduce the level of work input required for the

manufacture of bread by the CBP or sponge-and-dough processes when

using very strong flours or encountering difficulties with dough moulding.

This approach should only be used when there is no alternative, more

suitable flour available as the result of using L-cysteine hydrochloride are

often unequivocal.

The addition of L-cysteine hydrochloride has been shown to be beneficial

in the manufacture of other fermented products and has become a common

ingredient in dough conditioner and improvers added in the production of

rolls, pizza bases (Cauvain, 2015) and hamburger buns. With all of these

bakery products, the main effect of the L-cysteine hydrochloride is to reduce

the elasticity of the dough and to assist in achieving the desired shape

without causing undue damage to the dough pieces during moulding.

Lcysteine hydrochloride also finds potential use in the manufacture of

short and laminated pastes to improve the blocking and sheeting processes

involved. The gluten structure is less well developed in short pastry making

than with laminated pastes, but both can benefit from the addition of a reduc-

ing agent. In pastry making, an alternative to the addition of L-cysteine

hydrochloride is sodium metabisulphite. Both of these reducing agents need


to be used with care in the manufacture of pastry products because the

recycling of trimmings can lead to their progressively increasing concentra-

tion in the recipes being used with subsequent excessive softening of the

paste. Long delays in paste processing can also lead to excessive softening

of the paste when reducing agents are present in the recipe.

Sodium metabisulphite has found use as a reducing agent in the manufac-

ture of biscuits, especially the low-fat, low-sugar types embraced by the

generic term ‘semi-sweet’. The level of gluten development occurring during

the mixing of semi-sweet biscuit dough is considerably less than that

achieved in bread dough mixing, but with stronger flours, it is still sufficient

to contribute to biscuit shrinkage. This shrinkage may be seen during the

sheeting processes but is commonly seen when the biscuit units have been

cut from the sheet. In severe cases, the shrinkage is immediately after cut-

ting, whereas in less severe cases, it may only be observed as shrinkage after

the biscuit has been baked. In this case, the biscuit dimensions will differ

from those used in cutting and round biscuit shapes commonly develop

eccentricity. The use of sodium metabisulphite is not universally accepted

(Manley, 2000), and common ‘additive-free’ approaches are to more closely

specify the qualities of the flour to be used or to add more water during

dough mixing to yield a less elastic gluten network.

The concern over the addition of chemical reducing agents has led

to consideration of more ‘natural’ forms. Bakers’ yeast cells are a rich

source of the natural reducing agent glutathione (Bonjean and Guillaume,

2003). In scratch breadmaking the yeast cells are intact and the glutathione

has no direct contact with the dough proteins. However, if the yeast cell

membrane is damaged, then there is potential for the glutathione to react

with the protein network. Freezing yeast and yeasted doughs leads to irrep-

arable damage to the cell membrane, and the effect of the glutathione

is undoubtedly one of the contributing factors to the loss of gas retention in

frozen bread dough. Commercial extracts of yeast cell contents are avail-

able for use as a reducing agent. Glutathione (and L-cysteine hydrochloride)

may be used in the manufacture of pasta to denature the gluten in the dough

(Kent and Evers, 1994).

Glutathione occurs naturally in flour. It is among the low molecular

weight thiol compounds though the amounts are present in flour are small.

Low molecular weight thiols diffuse rapidly through the dough, so despite

their low concentrations, they are likely to be active in affecting the rheolog-

ical properties of the dough. In some instances, changes in glutathione level

have been linked with the ‘freshness’ of flour and its performance in baking

(Chen and Schofield, 1996). Glutathione levels do vary with wheat type

and the ash content of the flour (Sarwin et al., 1992). The content of low

molecular weight thiols (including glutathione) is known to be affected by

oxygen, probably during the milling of wheat to flour and almost certainly


during dough mixing. Keiffer et al. (1990) found that dough resistance fell

and flour extensibility increased as the level of glutathione increased.

No discussion of the use of reducing agents in baking is complete without

including some discussion of the role of ascorbic acid (AA). Chemically, AA

is a reducing agent, but its conversion to dehydro-ascorbic acid (DHA) is

responsible for its oxidising effects in breadmaking (Cauvain, 2015). The

availability of oxygen for the conversion is crucial in this context, but as

been shown, oxygen depletion can occur quite quickly in bread dough

(Cauvain and Young, 2006). This suggests that in the anaerobic environment

in the dough which is attained after mixing, the AA present has the potential

to act as a reducing agent and practical experiments show that if AA is

present in fermenting dough, then there can be loss of bread volume

(see Section 4.1.24). However, if the dough is re-mixed (e.g., as during

knock-back, see Section 9.7), then the reintroduction of oxygen allows for

some further oxidation effect from the AA.

References

Bonjean, B., Guillaume, L.-D., 2003. Yeast in bread and baking products. In: Boekhout, T.,

Robert, V. (Eds.), Yeasts in Food. Woodhead Publishing Ltd, Cambridge, UK, pp. 289�308.


AG, Switzerland.


Cambridge, UK.

Chen, X., Schofield, J.D., 1996. Changes in glutathione content and breadmaking performance

of white flour during short-term storage. Cereal Chem. 73, 1�4.

Keiffer, R., Kim, J.-J., Walther, C., Laskawy, G., Grosch, W., 1990. Influence of glutathione and

cysteine on the improving effect of ascorbic acid stereoisomers. J. Cereal Sci. 11, 143�152.

Kent, N.L., Evers, A.D., 1994. Technology of Cereals, fourth ed. Elsevier Science Ltd., Oxford, UK.


Publishing Ltd., Cambridge, UK.

Sarwin, R., Walther, C., Laskawy, G., Butz, B., Grosch, W., 1992. Determination of free reduced

and total glutathione in wheat flour by an isotope dilution assay. Z Lebensm Unters Forsch

195, 27�32.

Further reading

Kulp, K., Lorenz, K., Brummer, J., 1995. Frozen & Refrigerated Doughs and Batters. AACC,

St. Paul, MN.

Weiser, H., 2015. The use of redox agents. In: Cauvain, S.P. (Ed.), Bread Making: Improving

Quality, second ed. Woodhead Publishing Ltd., Cambridge, UK, pp. 447�469.



























2.6 AERATION

2.6.1 I have heard that yeast requires oxygen before it canwork correctly, is this true?

As long ago as 1875, Louis Pasteur showed that fermentation could take

place in the complete absence of oxygen. He also showed that the presence

of oxygen inhibited fermentation but increased yeast growth and respiration.

Pasteur’s observation that ‘fermentation is life without air’ is a well-known

quotation in food science.

If oxygen is introduced in increasing quantities into a fermenting sugar

solution, fermentation slows down and respiration takes over. The process

can be described chemically as follows:

C6H12O61 6O2 5 6H2O1 6CO2

Glucose1 oxygen5water1 carbon dioxide

In practice, the theoretical respiration equation is never realised because

much of the carbon dioxide which is liberated combines with other materials

to form yeast cell substance. The yeast manufacturer makes use of the

effect of oxygen by blowing large volumes of air through the fermenter to

discourage fermentation and so maximise the yield of yeast.

Some confusion about the relationship between yeast and oxygen may

arise because of the well-known effect of yeast scavenging oxygen molecules

from a bread dough during mixing. The importance of this observation is

that it explains why the effect of ascorbic acid as an oxidising agent is lim-

ited to the mixer in breadmaking (see Section 2.7.3).


2.6.2 How does baker’s yeast produce carbon dioxide inbreadmaking?

Yeast produces carbon dioxide gas in breadmaking by fermenting the sugars

which are present in the ingredients or the formulation. The basic reaction is

represented in the following manner:

C6H12O65 2C2H5OH1 2CO2

Glucose5 ethyl alcohol1 carbon dioxide

You will notice a significant difference in the reaction compared

with that given in the previous question. In particular, fermentation yields

ethyl alcohol whereas respiration does not. Anaerobic fermentation does not

require the presence of oxygen.

The yeast cell contains large numbers of enzymes which are required for

the fermentation and respiration. These enzymes are held within the cell

membrane provided the cell wall remains intact. About 14 different enzymes

are involved in the fermentation process.

When a dough is made, the yeast first feeds on the naturally occurring

sugars in the flour (glucose and sucrose). As these are used up, the enzyme

complex begins to provide more sugars by breaking down other flour compo-

nents. The damaged starch is important in this context due to its conversion

ultimately to maltose through the combined actions of alpha and beta amy-

lases. This is why we are concerned with the enzymic activity and damaged

starch levels in the flour that we use (see Section 2.2.11). If we cannot pro-

vide a substrate (food) for the yeast, it will stop working and carbon dioxide

production will cease.

In modern no-time breadmaking processes, we are only concerned with

the production of carbon dioxide by the yeast. Respiration and growth are

not required. Indeed, the conditions within a bread dough formulation

and the production timescales concerned are unlikely to be suitable for either

respiration or growth to take place to any significant degree.


2.6.3 Are there any particular precautions that we should takein handling, storing and using bakers’ yeast in the compressedform?

To optimise the performance of bakers’ yeast (Saccromyces cerivisii) in the

manufacture of bread and fermented products, it is important to ensure that it

is kept in its optimum condition. Individual yeast cells are characterised by

having a membrane which encloses the cell contents (Cauvain, 2015). It is

the enzymes in the latter that provide the yeast with its ability to produce

carbon dioxide and ethanol. In addition to providing a container for the cell

contents, the membrane plays a critical role in regulating the flow of nutri-

ents into and by-products (e.g., carbon dioxide) out of the cells. The flow of

nutrients is controlled by osmotic pressure (Cauvain and Young, 2008) (see

Section 11.12).

Compressed yeast is prepared under carefully controlled conditions in

the factory (Cauvain, 2015). A key requirement is that the cells (approxi-

mately 15 thousand million per g) are intact (undamaged) and viable

(alive). To ensure this and to minimise activity in the block compressed,

yeast is commonly delivered at refrigerated temperatures, typically 4�8�Cand should be held at these temperatures until required for use (see

Section 2.6.3).

The particular precautions that you should take include:

� Transfer the yeast into refrigerated storage as soon as possible after

delivery. Prolonged exposure to warm temperatures can lead to loss of

activity though autolysis. This process is characterised by a darkening

of the corners of the compressed blocks which may also spreading along

the edges of the blocks (see Section 2.6.4).

� Avoid having large quantities of yeast standing in the warm bakery

waiting to be used. Try to establish a working pattern which draws out

sufficient yeast for 1�2 hours of production throughout the day.

� Break down large blocks into a coarse crumble before adding them to the

mixer as this will aid dispersion throughout the dough. You may want to

disperse the crumbled yeast into some of the recipe water before you use

it, but this is not essential with modern yeast strains and breadmaking

practices.

� Do not keep using the yeast after its shelf-life date has expired. There is a

slow but progressive loss of gas production power in the yeast during stor-

age, even under ideal refrigeration conditions (see Fig. 2.12). This will

result in an increase in proof time or require the addition of extra yeast to

maintain product proof volume. It may also lead to loss of bread volume

through the action of glutathione from any yeast cells which have died.

� Do not leave compressed yeast blocks unwrapped for long period on time

as they can dry out and lose activity.


� Ensure that the conditions under which the yeast is stored remain

optimum. It is important that the cell membranes remain intact. Amongst

the cell contents are a powerful reducing agent known as glutathione.

This material is able to reduce the gas retention properties of gluten and

also causes excessive flow of dough in the prover.

� Fluctuations in storage temperatures can lead to the formation of

unwanted mould colonies on the surfaces of the blocks if they have been

exposed unwrapped to the atmosphere and so should be avoided.

� Avoid freezing the blocks as the formation of ice crystals inside the cells,

their growth during storage and subsequent defrosting results in rupturing

of the cell membranes and the release of the cell contents.

References


AG, Switzerland.



330310290270250230210190170150

0 28 56Storage time (days)

Vol

ume

per

prod

uced

in 5

h (m

l)

FIGURE 2.12 Effect of yeast storage time on gas production.






2.6.4 What are the causes of the dark brown patches wesometimes see on compressed baker’s yeast, and do they haveany effect on baked product quality?

The brown patches that you have observed are autolysis and comprise dead

yeast cells. They usually come from having kept the yeast too long or at too

high a storage temperature. There is no food available for the yeast cells in

the compressed block. Storage at around 4�C limits the activity of the cells,

but if the temperature rises sufficiently, then oxidation processes begin and

the cells break down. This means that there will be a loss of gassing activity

when the yeast comes to be used in the dough.

In addition to the loss of gassing potential, the contents of the affected

cells may leak out of the ruptured membranes. The yeast cells contain a suite

enzymes and other chemicals. The release of proteolytic enzymes and gluta-

thione (a reducing agent) are bad news for breadmaking because both materi-

als will attack the gluten structure of the dough and weaken it. Subsequently,

the affected doughs will exhibit a lack gas retention, i.e., a loss of volume

and a more open cell structure. In more severe cases, the doughs may

become sticky and difficult to process.

We suggest that wherever possible you do not use the affected yeast and

that you check the settings and efficiency of your refrigerator.


2.6.5 We have been advised to store our compressed yeastin the refrigerator but our dough temperature is much higher, isthis the correct thing to do?

The advice that you have been given is absolutely correct. Once compressed,

yeast has been prepared; it should be kept under refrigerated conditions

(4�C) until it is required for doughmaking. Storing yeast at higher than

refrigerated temperatures results in the progressive loss of its gas production

potential. Cauvain (2015) provides data to show how dough proof times

were increased when compressed yeast was stored at 10�C and 15�C. By the

time that the yeast had been held for 14 days at 15�C, the proof time

required for the dough had doubled. Storing compressed yeast at dough tem-

peratures would be a disaster!

It is therefore very important that the yeast is stored under the best possi-

ble conditions. Storing at 4�C reduces the potential for unwanted activity

within the block (see Section 2.6.3). The compressed yeast is usually trans-

ported under refrigerated conditions and on delivery should be moved as

quickly as possible to storage at a similar storage temperature. The blocks

should be left in the refrigerator as late as possible before use. Once dis-

persed into the dough, the cells soon warm and produce carbon dioxide.

Variations in gassing activity will show as variations in proof volume for

a given time. If you are not able to adjust the proof time to compensate for

this variation (few bakeries can), then you will get variations in bread volume

and problems with product shape, e.g., ragged breaks from under-proof (see

Section 4.1.3).

Reference


AG, Switzerland.




2.6.6 We have seen references to a ‘lag phase’ for bakers’yeast; what does this means and what are the implications forbaking?

Bakers’ yeast (S. cerivisii) is one of many different types of yeast which may be

used or found in foods (Boehhout and Robert, 2003). Like all microorganisms

when placed in a suitable environment they begin to feed, and multiply. This

process starts very slowly but as time progresses the rate of activity increases if

the temperature remains constant and there is a ready supply of food.

The key function of bakers’ yeast in baking is the production of carbon

dioxide gas. Modern strains of bakers’ yeast are far more reliable than

those which have been used traditionally. In the flour there is an initial

supply of naturally occurring sugars, typically 1�1.5% by weight and these

are fermentable by the yeast. Later, as the combination of alpha- and beta-

amylases in the dough get to work on the damaged starch granules more

sugar in the form of maltose becomes available to support fermentation.

Sugars may be added to the dough formulation though in no-time dough

processes the addition of extra sugar to support fermentation is not usually

necessary but it may be added for its contribution to flavour and colour.

Once the yeast has been added to the dough it takes a short while before its

activity is sufficient for the generation of carbon dioxide gas and there is little

change in the dough density, this is often referred to as the ‘lag phase’. If we

were to measure the density change with time after mixing we would see little

change for some minutes. Later dough density begins to fall as the carbon diox-

ide gas comes out of solution in the liquid phase of the dough and begins to dif-

fuse into the gas bubbles trapped in the dough and causing their expansion.

Typically, the lag phase lasts around 10 minutes. This has limited impact when

bulk fermentation processes lasting some hours are used for breadmaking but in

no-time dough production the impact can be significant.

The main effect of the yeast activity post lag-phase with no-time dough

production will be seen in the divider and in particular on divider weight

control. If a large bulk of dough is being divided volumetrically, it is not

unusual to see a drift in the weight of individual pieces with dough standing

time in the hopper. One of the advantages gained from the yeast lag phase is

that it will limit dough density changes and thereby improve divider weight

control. Thus, in larger automated bakeries it can be of particular advantage

to keep dough batch size at a level which requires the production and proces-

sing of an individual batch of dough in less than 10 minutes or so (Cauvain

and Young, 2008).

References

Boehhout, T., Robert, V., 2003. Yeasts in Foods. Woodhead Publishing Ltd, Cambridge, UK.







2.6.7 What different types of bakers’ yeast are available?Would there be any particular advantages for us to use analternative to Saccromyces cerivisii in the manufacture of ourfermented products?

Yeast suppliers have many forms of S. cerivisii for use in the manufacture of

bakery products. The compressed or block form used in many countries is

both economical and practical. The yeast blocks are paper wrapped to limit

exposure to air and to maintain humidity and limit moisture migration which

ensures better keeping qualities and active shelf-life. The blocks come in

varying sizes from small cubes of 40 g up to blocks of 2.5 kg. It can also be

purchased as crumbled yeast. It should be stored in a refrigerator running at

between 2 and 10�C, ideally around 4�C (see Section 2.6.3). The shelf-life of

compressed yeast kept under the conditions recommended by the suppliers is

between 4 and 8 weeks. Cauvain (2015) showed how storing high activity

compressed yeast at 15�C for 14 days has a reduced activity to such an

extent that that proving time of the dough in which it was used roughly

doubled. Poorly kept compressed yeast quickly displays visible signs of

deterioration, such as dark brown patches (see Section 2.6.4).

Dried and granulated (Fischer and Volker, 2008) yeasts are popular where

a longer shelf-life product is required or where refrigeration is not practical,

e.g., in warm climates. It comes in standard or instant dried forms. The

instant form of dried yeast is available in vacuum packs and can be incorpo-

rated directly into the dough, whereas the standard dried yeast needs to be

hydrated before it is used. In their various forms, dried yeasts have shelf-lives

of up to 2 years. Some forms of dried yeast may also be incorporated into

premixes for bakery products.

Liquid or cream yeast is increasingly popular in modern plant bakeries

as it is easily accurately and automatically dispensed into the mixing bowl.

It is held in storage tanks which are gently agitated to prevent separation. In

baking terms, 1.5 kg liquid yeast is equivalent to 1 kg of compressed yeast

for gas production. The shelf-life of the product is much shorter than the

other bakers’ yeast forms in between 10 and 14 days. Care needs to be taken

to keep its storage temperature between 2 and 4�C, and the storage tanks

should be cleaned out on a regular basis to reduce the risks of contamination

with unwanted yeasts, moulds or bacteria which may result in the develop-

ment of sour aromas and flavours in the dough.

Frozen forms of bakers’ yeast are also available from some suppliers.

These products should be stored at 218�C and have shelf-lives of up to 2 years.

They are usually added to the dough in the frozen form.

The dry matter varies in the different forms of yeast from approximately

20% for liquid yeast to 95% for the dried yeast. If you are going to change

from one form to another then the water level added to the dough will need

to be adjusted according to the dry matter content of the different forms.


There are different strains of S. cerivisii available, and the yeast supplier

will cultivate these to offer specific yeasts for different baking products and

processing methods. For example, the strain used for doughmaking in the

CBP is able to generate carbon dioxide at a faster rate than other strains and

avoids a ‘dip’ in gas production at the critical moment when the dough

pieces reaches the oven (Cauvain, 2015). Although such yeast strains have

a high fermenting power, they tend to be less stable and have a shorter

shelf-life than other strains.

For the production of sweet dough which are high in sugar (usually

sucrose or dextrose), there are osmo-tolerant yeasts. These are able to cope

with the increased osmotic pressure in the dough rather than being inhibited

by the presence of the sugars (Cauvain, 2015). There are strains which

are better adapted for use in acid, low pH dough and other which are able to

better perform when calcium propionate is present in the recipe.

In principle, any microorganism which is able to ferment sugars to

produce carbon dioxide gas could be used in breadmaking. There are a large

number of yeasts that would fit into that category which may come from the

distilling and wine-making industries. Indeed yeasts from the brewing and

distilling industries were the traditional source of gas production for bakers.

Improved growth, osmo-tolerance, freeze-tolerance or aroma applications,

have suggested the use of strains from Candida or Torulaspora. A few non-

typical baker’s yeast strains have been patented for cold dough and nutrition

applications and especially for stress tolerance; these include Saccromyces

rosei, Saccromyces rouxii and Torulaspora delbrueckii.

The availability of strains of S. cerivisii specifically for use in the

manufacture of fermented products in bakeries is now highly developed, and

discussions with your supplier should help to identify the type of yeast that

is the most appropriate for the manufacture of your own products.

References


AG, Switzerland.

Fischer, G., Volker, L., 2008. Granulated yeast. f2m Baking 1 Biscuit International 6, 40�43.

Further reading

Boekhout, T., Robert, V., 2003. Yeast in Food. Woodhead Publishing Ltd, Cambridge, UK.








2.6.8 What are the correct proportions of acids and alkali touse in baking powders?

The principal alkali used in baking powders is sodium bicarbonate, and it is

this ingredient that supplies the carbon dioxide gas which inflates powder

raised goods such as cakes and sponges. For the gas to be evolved at the

most suitable time during baking, a food acid is added to the formulation.

Sodium bicarbonate will release carbon dioxide by thermal decomposition

at 90�C, but this is far too late to be of use in baking because by that

temperature, the structure of the product is effectively set and unable to

expand any further.

A number of suitable organic acids are available, each having a different

rate of reaction (ROR) with sodium bicarbonate and each leaving a different

residual salt in the baked product. Both properties are important, the first

because it affects the overall expansion of the product, and the latter because

it affects the flavour.

The correct proportion of acid to sodium bicarbonate varies according to

the chemistry of the acid. The correct proportion of acid to sodium bicar-

bonate is normally considered to be that which takes the reaction to comple-

tion and is referred to as the neutralising value. For the most commonly

used acids, the required proportions for one part of sodium bicarbonate are

as follows:

� Mono (acid) calcium phosphate (MCP, ACP) � 1.25

� Tartaric acid � 0.9

� SAPP � 1.33

� Cream powder (SAPP on a neutral powder base) � 2.0

� SALP � 1.0

� Cream of tartar (potassium hydrogen tartrate) � 2.2

� Glucono-delta lactone (GDL) � 2.12

Some baking acids are available in different grades (that is degrees of

fineness) which affects their ROR with sodium bicarbonate. Different grades

of sodium bicarbonate are available and this will also affect the ROR.

If potassium or calcium chlorides are used as a part replacement for

sodium bicarbonate, then the level of acid required to neutralise the mixture

will need adjusting, you should consult with your suppliers for the required

adjustment when mixtures of bicarbonate sources are used.


2.6.9 What is meant by the term ‘double-acting’ bakingpowder, and what is the value of using such products?

Double-acting baking powders usually comprise a mixture of at least two bak-

ing acids and sodium (or some other) bicarbonate. The overall composition of

the baking powder will be balanced taking into account the neutralising value

of both the acids used with respect to the sodium bicarbonate. Each of the

acids will have a different ROR and the intention is to spread and control

the release of carbon dioxide gas over an extended period of time in the

baking process.

Double-acting baking powders are most commonly used in the manufac-

ture of cakes and are especially useful in the delivery of carbon dioxide

production in the oven which helps give cakes extra volume � almost the

cake equivalent of oven spring in bread. The process is shown schematically

in Fig. 2.13.

The level of sugars used in the manufacture of cake batters delays the

gelatinisation of the wheat starch � the main structure forming agent in

cakes. This means that cake batters are fluid until relatively late on in

the baking process. Although the batter is fluid, it is capable of expansion.

With many of the faster-acting baking acids, the release of carbon dioxide is

mostly completed during mixing and the first few moments of baking which

may lead to a restriction of cake volume and a tendency for the products

to have a peaked shape. This is commonly overcome by increasing the level

of addition.

Another advantage of using a double acting baking powder is that the fla-

vour of the residual salt in the baked cake can be modified by using different

baking acids. It is also possible to aid sodium reduction in baked products

without unduly compromising product quality by using two different types

of acids in the baking powder.

Depositing

Release of carbon dioxide

Mixing Baking

Starchswelling

Gelatinisation

FIGURE 2.13 The release of carbon dioxide from double-acting baking powder in cake baking.


2.6.10 Why is sodium bicarbonate frequently used alone or inexcess to the normal in baking powder for the production ofginger products?

The idea of using an excess of sodium bicarbonate in ginger products is

no doubt based on traditional practices related to the availability of suitable

chemical aerating agents.

Despite its traditional basis, the practice does have a practical advantage.

Under the influence of moisture and heat carbon dioxide is liberated from

any sodium bicarbonate left after the normal acid�base reaction and sodium

carbonate remains as a residue. The carbonate is alkaline and will react with

sugars, particularly invert sugar to form complex carbon compounds which

are brown in colour. In this way, the excess of sodium bicarbonate aids the

formation of the dark brown colour which characterises ginger products.

If you look closely at the cut surface of baked ginger cakes, you may

see that the colour is more intense toward the base and sides of the cross-

section. These are the areas which are baked first and so have been held

for a longer time at the oven temperature, and the browning reaction has

proceeded further than the moister centre areas of the cake.

The residual sodium carbonate has a characteristic ‘washing soda’ taste

which is why we normally seek to neutralise the sodium bicarbonate in most

baked products. However, the strong flavour of ginger will commonly mask

some of the carbonate after-taste.


2.7 IMPROVERS

2.7.1 What are bread improvers and why are they used?

The term ‘bread improver’ is used to embrace a wide range of materials

which can be added to wheat flour and dough to improve some aspect of

dough behaviour and final bread quality. The use of the term is common and

most often applied to the addition of several ingredients at low levels

blended with a ‘carrier’, a material which may or may not have functional

properties but which aids dispersion and provides a more conveniently

handled composite material. The formulation of bread improvers will be

influenced by legislative control over the list of permitted ingredients which

may be used in breadmaking.

Alternative names for bread improvers which may be encountered in the

baking industry include:

� Dough conditioners, a specific reference to the fact that the material

addition changes dough rheology.

� Processing aids, which implies a similar function to dough conditioners.

� Oxidising agents, which implies a more specific role concerned with the

formation of the gluten network in the dough.

� Additives, more commonly applied to specific ingredients.

� Concentrates, similar to an improver but with a greater range of ingredients

present (e.g., fat, sugar and salt) and are commonly used at higher rates

of addition.

Almost any material added to a flour and water dough will have some

improving effect. For example, the addition of yeast improves the lightness

and palatability of bread, whereas salt changes the handling properties of

wheat flour doughs and the flavour of the baked bread. However, the term

bread improver is now commonly restricted to materials which are typically

added at much lower levels of addition than yeast or salt with the intention

of improving gas production or gas retention in the dough, retaining bread

crumb softness and obtaining a whiter crumb colour.

Some of the more common ingredients used in bread improvers are

noted below. The classification used is arbitrary since the complex actions

of most materials in breadmaking means that they might be classified in

more than one group. For example, the addition of enzyme preparations

brings about changes in dough rheology which makes it easier to process

doughs but also results in improved oven spring, a manifestation of improved

gas retention.

� Aids to dough processing.

� Enzyme active preparations, e.g., malt flour, proteolytic enzymes.

� Reducing agents.


� Aids to gas production.

� Yeast foods, such as ammonium chloride.

� Aids to gas retention.

� Oxidising agents, such as AA and potassium bromate.

� Enzyme active materials.

� Emulsifiers.

� Aids to bread softness.

� GMS and other emulsifiers.

� Enzyme active materials.

� Aids to improving crumb colour.

� Soya (soy) flour.

Further reading


AG, Switzerland.




2.7.2 What are the differences between dough conditioners andbread improvers? What consideration should we take intoaccount when choosing which one to use?

There is no precise definition of these terms. It could be argued that the term

dough conditioner could include the use of materials to modify any dough-

based product which would include bread, biscuit and pastry doughs, whereas

the term ‘bread improver’ suggests that any effects are confined exclusively to

bread and fermented products. However, in practice, both terms are commonly

used interchangeably and this can create some confusion.

Both terms are used to describe a functional ingredient or a mixture of

functional ingredients which are added at low levels to beneficially modify

one or more characteristics of the final qualities of bread and fermented pro-

ducts or their processing intermediaries, i.e., the dough. All of the ingredients

which would fall into this category will modify final product qualities, and

the vast majority will also modify the rheological properties of the dough. In

a number of cases, it is the modification of the dough rheology which deli-

vers the improvement to the final product.

The compositions of dough conditioners and bread improvers are compli-

cated and varied according to the particular bread product being made and

processes used to make them. They may also vary with time as the formula-

tions are adapted to changing raw material inputs, such as any changes in

wheat and flour quality from one harvest year to the next, and to legislative

and consumer pressures.

When you are considering which dough conditioner or bread improver to

use, you should consider first what quality changes you wish to effect and

then identify which functional ingredient will deliver those quality changes

that you are seeking.

Examples of improvement categories and the functional ingredients

which contribute to those improvements include the following:

� Improved dough processing � Enzymes and reducing agents (e.g.,

L-cysteine hydrochloride, see Section 2.7.8).

� Improved product volume � Oxidants (e.g., AA), emulsifiers, enzymes.

� Improved cell structure � Oxidants.

� Improved crumb softness � Emulsifiers, enzymes.

� Extended product shelf-life � Emulsifiers, enzymes.

� Increased mould-free shelf-life � Preservatives.

The individual ingredients that you will be able to choose from will

be governed by local legislation and you should check carefully as to what is

permitted for your country.


2.7.3 What are the functions of ascorbic acid in breadmaking?

AA is commonly known as vitamin C and is present in large quantities in

many green vegetables and fruits. As such it is an essential component in

the diet. Its use in breadmaking was recognised many years ago with a UK

patent (BP 455,221) existing from 1936. It is a commonly used oxidant

(improver, additive), and in many cases (e.g., within the European Union),

it is the only one permitted for use in breadmaking.

In breadmaking, it is used to improve dough gas retention through its

effect on the gluten structure. In terms of its chemistry, AA is a reducing

agent (and sometimes referred to as an anti-oxidant), but during dough

mixing, it is readily converted to DHA (see Fig. 2.14) in the presence of

oxygen and ascorbic oxidase enzyme. The oxygen for the conversion comes

from the gas bubbles incorporated during dough mixing and the conversion

is enabled by the ascorbic oxidase enzyme occurs naturally in wheat flour.

The chemistry of the AA oxidation process in dough mixing is complex

(Cauvain, 2015) but probably involves the oxidation of the sSsH (sulphydryl)

groups of gluten-forming proteins and the formation of sSsSs (disulphide)

bonds. The net result of the AA effect is to improve the ability of the dough

to retain gas (as seen by increased oven spring) and to yield bread with a

finer (smaller average cell size) crumb cell structure. These changes also

result in bread crumb which is softer to the touch yet has the resiliency to

recover much of its original shape after compression. This helps to convey the

impression of improved freshness to the consumer.

The dependency on oxygen for the AA to DHA conversion means that

the quantities of air incorporated during dough mixing play a significant role

in promoting oxidation. This means that AA-assisted oxidation varies with

mixer type due to the ability of different mixers to occlude different quanti-

ties of air (Cauvain, 2015). Some mixing regimes have been developed

which increase the total quantity of air occluded during mixing so that

greater AA-assisted oxidation can be achieved; two examples are mixing

in an oxygen enriched atmosphere and the use of the so-called ‘pressure-

vacuum’ mixer (Cauvain, 2015). There has been a tendency to consider that

it is not possible to ‘over-treat’ with AA due to the limiting effect associated

FIGURE 2.14 Ascorbic acid changes in dough.


with oxygen availability. With the advent of the pressure�vacuum mixer,

such statements should be viewed with caution.

The oxidising effect of AA is mainly limited to the dough mixing period

because bakers’ yeast will remove any oxygen remaining in the air bubbles

by the end of mixing or soon after its completion. Thus, in the dough which

leaves the mixer, the gaseous mixture of nitrogen (from the air) and carbon

dioxide (from yeast fermentation) which remains provides an environment

in which AA can act as a reducing agent. If AA is used in doughmaking pro-

cesses with extended periods of fermentation, then the opportunity exists for

the reducing effect of AA to weaken the gluten structure with subsequent

loss of gas retention in the dough. AA is thus best suited to no-time dough-

making systems.

The action of AA during mixing also brings about changes in the rheol-

ogy of the doughmaking it more resistant to deformation by comparison with

doughs treated with an addition of potassium bromate which does not exert

its full effect until the dough reaches the late stages of proof and the early

stages of baking.

Reference


AG, Switzerland.




2.7.4 We have heard that soya flour is added in breadmaking tomake the bread whiter. Is this true, and if so how does it work?

Full-fat, enzyme active soya flour has commonly been used as a functional

ingredient (improver) in breadmaking since the 1930s. It is often used

as a ‘carrier’ for other functional ingredients, e.g., oxidants, to facilitate the

addition of the small quantities that are commonly used. The soya bean

contains a high percentage of natural oil and has a distinctive ‘beany’

flavour which can be unpleasant if used at high levels of addition but not at

the 1 or 2% level normally used with bread improvers.

Soya flour three basic functions; it gives a white bread crumb, it contri-

butes to gas retention through oxidation, and it increases the level of water

which needs to be added to the dough. The first two functions are caused by

the actions of the natural enzyme systems which are present, and so it is

important that the enzyme active form of soya flour is used.

Soya flour is rich in the enzyme lipoxygenase which plays a major

role in its bleaching action. With the help of the enzyme, the intermediate

oxidation compounds formed during dough mixing transfer oxygen from the

atmosphere to bleach the yellow-coloured carotinoid pigments present in

the flour. By this mechanism, the flour is bleached and the bread crumb

becomes whiter. The greater the availability of oxygen the greater the bleaching

effect.

The oxidation effect appears to come from freeing of bound lipids from

specific sections of the gluten proteins thereby allowing the proteins to

become hydrophillic and helping to form the visco-elastic surface of the air

bubbles in the dough (Frazier et al., 1973).

Soya flour and its derivatives have found other uses in baking, including

as an egg replacer and in ‘gluten-free’ breads (Cauvain, 2015). There are

some concerns with respect to soya allergies.

References


AG, Switzerland.

Frazier, P.J., Leigh-Dugmore, F.A., Daniels, N.W.R., et al., 1973. The effect of lipoxygenase action

on the mechanical development of wheat flour doughs. J. Sci. Food Agric. 24 (4), 421�436.







2.7.5 I understand that an enzyme called alpha-amylase can beadded to flour or dough to improve bread quality but that thereare several different forms. I have tried several and get differenteffects on bread softness. Which one(s) should I use?

The alpha-amylases are a group of enzymes which facilitate the breaking

down of the hydrated starch granules, both amylose and amylopectin, in flour

doughs into shorter chained, unbranched molecules known as dextrins.

This action creates sites for the beta-amylase which is present in wheat flour

to convert the starch to individual maltose molecules. Wheat flours usually

contain sufficient beta-amylase but levels of alpha-amylase vary and in

many cases may be so low that the starch to maltose conversion is limited.

As part of the amylase actions water molecules which were previously held

with the damaged starch granules may be released into the dough matrix.

Maltose is fermented by bakers’ yeast to provide carbon dioxide gas

in the dough, and thus, a key role for alpha-amylase is to support gas pro-

duction. Although this was the original reason behind the addition of

sources of alpha-amylase to wheat flour doughs; in many cases, its addition

also leads to improvements in gas retention, bread volume and softness

(Cauvain and Chamberlain, 1988), and this has now become the main

reason for its addition.

The traditional source of alpha-amylase for breadmaking was from

malted barley or wheat flour, but today, it is more common to use amylases

derived from the fermentation of microscopic fungi (e.g., Aspergillus oryzae)

or a bacterial source. The main difference between the amylases lies with

their heat stabilities (Cauvain, 2015). The more heat stable the amylase the

greater the breakdown of the starch during baking. In general terms, fungal

alpha-amylase is inactivated before cereal (malt) which, in turn, is inacti-

vated before bacterial. The so-called maltogenic amylases are derived from

modified bacterial sources and have a profile more similar to that of the

fungal source.

The heat stability of the amylase source (see Fig. 2.15) is important in

providing a balance between good and bad effects in baking. In the dough,

the amylase attacks the damaged starch granules and breaks down the starch

molecules. As heating proceeds, especially during baking, the swelling and

later gelatinising starch provides a larger quantity of available substrate for

the amylase enzymes which are now working at a faster rate due to the high-

er temperature. The positive benefits are the improvements in gas retention

through a more extensible gluten network, whereas the disadvantages are

related to the formation of sticky dextrins (see also Section 4.1.35).

To maximise the benefits, you should use the fungal source. The malto-

genic form can be used due to its greater anti-staling effect which gives


softer bread. However, if used at too high a level, you may find difficulties

in slicing the bread due to its enhanced initial softness. Avoid using the tra-

ditional bacterial form as this may survive the baking process and lead to

unwanted liquification of the product crumb during storage.

References


AG, Switzerland.


J. Cereal Sci. 8 (Nov), 239�248.

FIGURE 2.15 Effect of temperature on alpha-amylase activity.







2.7.6 Why are emulsifiers used in bread improvers? And howdo I decide which one I should be using?

Emulsifiers are used in bread improvers for a number of different reasons

including:

� to help control gas bubble size,

� to improve gas retention,

� to improve dough stability and

� to improve crumb softness.

Each of the emulsifiers permitted for use in breadmaking contributes

something to all of the above dough and bread properties to greater or lesser

degrees depending on the particular emulsifier.

The most commonly used emulsifiers and their likely contribution to

dough character and bread quality are as follows:

� Diacetylated tartaric acid esters of mono and diglycerides of fatty acids

(DATA esters, DATEM). They are thought to reduce the average gas bub-

ble size in bread doughs which leads to a finer cell structure. They are

known to improve dough gas retention which contributes to improved

bread volume and crumb softness. Levels of addition are usually up to

0.3% flour weight in a variety of bread and fermented products.

� Sodium steoryl-2-lactylate (SSL). Improves dough gas retention, bread

volume and crumb softness but weight for weight is less effective than

DATA esters. Commonly preferred in the production of sweeter fermen-

ted products, e.g., buns and doughnuts.

� Glycerol monostearate (GMS). Best used in the hydrated form but can be

added as a powder. Does not greatly contribute to dough gas retention of

bread volume but does act a crumb softener through its proven anti-staling

effect.

� Lecithins. A group of naturally occurring, complex phospholipids commonly

derived from soya. Used in baguette and other crusty breads they do improve

dough gas retention to a degree and contribute to crust formation.

As no single emulsifier will equally perform all of the tasks required

in breadmaking, it becomes a case of choosing a given emulsifier to fit with

the main product and process requirements. Or a blend of emulsifiers may be

used. Price may also influence your final choice.

Further reading


AG, Switzerland.






2.7.7 What is L-cysteine hydrochloride, and what is it used forin bread improvers?

Cysteine is a naturally occurring amino acid due to its sulphydryl group

(sSsH) is able to act as a reducing agent on the disulphide (sSsSs) bondspresent in the gluten structure of wheat flour doughs. It is most commonly

used in the hydrochloride form to improve its solubility.

It came into common use in breadmaking in the 1960s when it was a key

component of the breadmaking process which became known as activated

dough development (ADD) (Cauvain, 2015). In ADD, L-cysteine hydrochlo-

ride was combined with potassium bromate and AA to give an improver

capable of delivering both chemical reduction and oxidation processes during

doughmaking. ADD was designed to allow bakers to obtain the benefits of

making no-time doughs without the need for the high-speed mixers associ-

ated with the CBP. ADD remained very popular with smaller bakers until

superseded by the use of spiral mixers (Brown, 1993; Cauvain, 2015).

In some ways, the chemical reduction of gluten disulphide bonds by

L-cysteine hydrochloride can be equated to the mechanical disruption of such

bonds in the CBP. This view has led to the consideration that one of the

benefits derived from the use of L-cysteine hydrochloride is that work levels

can be reduced in the CBP.

More certain is that the reducing effects of L-cysteine hydrochloride bene-

ficially modify dough rheology and improve its processing performance. For

example, its addition to so-called ‘bucky’ doughs in the USA (i.e., doughs

having high resistance and lacking extensibility) improves dough moulding,

and in the CBP, ‘steaks and swirls’ in the crumb may be reduced, but not

eliminated (Cauvain, 2015).

Additions of L-cysteine hydrochloride may be made to fermented pro-

ducts which are sheeted, e.g., pizza base, and to laminated and short pastries

to reduce dough and product shrinkage.

References

Brown, J., 1993. Advances in breadmaking technology. In: Kamel, B.S., Stauffer, C.E. (Eds.),

Advances in Baking Technology. Blackie Academic & Professional, London, UK.


AG, Switzerland.






2.7.8 Can we add a reducing agent during doughmaking so thatwe can reduce the energy input required during the mixing?

The input of energy during mixing is an essential part of the development of the

gluten structure; however, this energy input is accompanied by an increase in

the temperature of the combined ingredients. This temperature rise increases as

the level of energy input increases, the relationship is essentially linear.

Optimum development is commonly associated with energy input, in

some process (e.g., the CBP). This may be to a defined total energy level,

though in most cases it equates to the length of mixing time. For there to be

a transfer of energy, the dough ingredients, as they combine to form a dough,

must resist the movement of the impeller blade. To overcome the resistance

of the dough the work (energy) required by the mixer motor increases, and

of course so does the dough temperature.

Reducing agents, when added to dough (and pastes), interact with the

disulphide bonds which are a component of gluten development. In essence,

they reduce or break the bonds which weaken the dough and lower its

resistance to deformation during mixing. In this way, the energy input is

lowered and with it the temperature rises.

In this context, the addition of a reducing agent may be seen as having a

negative impact on dough development and therefore dough gas retention.

However, the development of a gluten network depends on a number of

complex molecular interactions. These are often described as redox reactions

which encompass both reduction and oxidation processes. In modern bread-

making, AA, through its conversion to DHA, is the most common oxidising

agent. When AA is used in conjunction with a reducing agent, such as L-cys-

teine hydrochloride, the result of the combined action can be improved

dough development (gas retention).

The use of redox improvers was, in the past, associated with breadmaking

processes like ADD which was designed for use with lower speed mixers

and to deliver improvements to dough gas retention similar to those with

mechanical dough development processes like the CBP. It is for this histori-

cal reason that the addition of reducing agents has become associated with

the potential for energy reduction during mixing.

The results of using a reducing agent to lower energy input for the

manufacture of pan breads are equivalent in terms of improvements in

volume though there may be greater potential for improvements in product

cell structure. The latter effect may be associated with a continued effect of

the reducing agent postmixing and during dough processing. This leads to

a reduction in the resistance of the dough which in turn, may reduce the

likelihood for rupture of the gluten network during the moulding.

The addition of a reducing agent is most often seen in the manufacture of

hamburger buns where the changes in the rheological properties of the dough

included lower viscosity which in turn, helps the dough pieces more readily flow

to fit the pan indents during proof and so deliver a more uniform product shape.


2.7.9 What is deactivated yeast and how is it used?

In essence deactivated yeast comprises the contents of the yeast cell without

the integrity of the cell itself. In normal yeast cells the various enzymes

and natural chemicals which are required for cell activity are contained

within the ‘cell wall’. This cell wall or membrane is responsible for control-

ling the flow of nutrients into the cell which are required for reproduction of

the cells. The flow of the by-products of fermentation � typically carbon

dioxide and alcohol � out of the cell is also controlled by the cell wall

membrane.

A wide range of enzymes and natural chemicals are contained within the

yeast and their activity is not dependent on the integrity of the cells. In the

context of deactivated yeast the bias is towards those materials which have

an impact on the rheological properties of the gluten�forming properties of

the wheat proteins. Specifically, deactivated yeast is commonly used for its

reducing effect on gluten and so in this context is seen as a ‘natural’ alterna-

tive to other chemical reducing agents in the manufacture of bread and other

baked products.

Two key groups of activate materials which are implicated in the

reducing effects are proteolytic enzymes and gluthothione. To some extent,

the term ‘deactivated’ is misleading as the naturally occurring reducing

agents remain active in the chemical sense. The term refers to the lack

of gas-producing capabilities in the yeast, in part because the cell wall

membranes have been disrupted and in part, because the methods used in the

preparation of the deactivated products bias activity against the gas-

producing enzymes. As a ‘natural’ reducing agent, deactivated yeast may be

seen as an alternative in the manufacture of bread and fermented products to

L-cysteine hydrochloride. As such, it may be considered complementary

to the use of oxidants, such as AA, to collectively improve dough rheology

and gas retention. In some processes (e.g., the CBP), it may be considered to

lower the work input required for doughmaking or reduce the ‘bulkiness’

associated with strong flours, e.g., in sponge and dough.

Reducing agents, in one form or another, are seen as beneficial in the

manufacture of sheet-cut fermented products and rolls and buns. Other bakery

products where the addition of reducing agents are considered to be benefi-

cial include the manufacture of laminated products (e.g., croissant, Danish,

puff pastry), crackers and some sheeted biscuits and cookies, in such pro-

ducts, the addition of deactivated yeast may be used to modify the sheeting

characteristics of the dough.


Chapter 3

Key Relationships BetweenIngredients, Recipes and BakedProduct Qualities

3.1 INTRODUCTION

Examples of the important contributions that the primary raw materials make

to bakery product qualities have already been shown in Chapter 2, Raw

Materials; however, the successful manufacture of bakery products and opti-

misation of their qualities are only achieved by an understanding of the key

ingredient�recipe-process interaction which are an integral part of what sets

bakery products apart from the manufacture of many bakery foods (Cauvain

and Young, 2006). In this context, the ‘quality models’ which are applicable

to the various bakery product groups vary in detail but remain firm on the

basis of the use of wheat flour and the management of the development of a

gluten network to a greater or lesser degree in the product matrix. In this

context, Cauvain and Young (2006) have highlighted the key role played by

the presence and levels of sugar and fat in bakery product recipes, but there

are many other ingredient, recipe and process factors which will influence

the end product result, and no comprehensive bakery treatise can identify

and enumerate all of the potential influences involved. This chapter aims to

illustrate how an understanding of the complex ingredient�recipe-process

interactions provides the basis of the solutions which are offered to the vari-

ous problems and answers to the question which are discussed in the subse-

quent chapters. While addressing this aim, the concept of ‘recipe’ balance

will be identified, discussed and illustrate the principles with the help of a

few examples. In the following discussion, recipe balance is considered to be

more than the ratio of ingredients to one another. These are very important

but they must be placed in the process context to fully understand how to

manipulate end product quality. As already discussed, suitable mathematical

models for the manufacture of bakery products are limited, and in practice,

many bakers use intuitive rules which have been passed on or learnt through

trial and error.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00003-5

As discussed in Chapter 1, Introduction to Problem Solving Techniques,

one possible route to optimise bakery product quality lies in the ability to

break problems down in a manner which allows the critical factors to be iden-

tified and to provide a basis for quality optimisation. In the following sections,

some guidelines are offered for the major bakery product groups with the aim

of providing summaries of some key ingredients and process factors which

affect final product qualities on the basis of specific product characteristics. In

the examples which are given some key interactions between ingredients, rec-

ipe and process are identified to illustrate how readers can develop their own

personalised databases, checklists, knowledge fragments and knowledge trees.

3.2 STRUCTURE OF BREAD AND FERMENTEDPRODUCT RECIPES

It remains a common practice for bread and fermented products recipes to be

structured using flour as the ingredient against which other ingredient ratios

are determined; this approach and the rationale behind it has been discussed in

Chapter 1, Introduction to Problem Solving Techniques. In essence, it is the

bakers attempt to balance the ratios of ingredients on the basis of functional-

ity. There are no specific ‘rules’ for balancing bread and fermented product

recipes though key relationships will involve the adjustment of recipe water

level to take into account variations in flour characteristics (see Section 2.2.3)

and the relationship between salt and yeast in the context of controlling fer-

mentation processes. Bread and fermented product recipes vary considerably

around the world and are to a large extent determined by local consumer pre-

ferences (Cauvain, 2015) so that variations in what constitutes a ‘bread recipe’

are to be expected. However, there is significant commonality in the ingre-

dient�recipe-process interactions, and their ultimate influence on product

quality to warrant identification of some of the key relationships.

3.3 SOME KEY RELATIONSHIPS IN THE MANUFACTURE OFBREAD AND FERMENTED PRODUCTS

The primary factors which underpin the manufacture of bread and other

fermented products can be identified under the following headings:

� Cell creation

� Gas production

� Gas retention

� Dough development

� Dough rheology

All the five primary factors make significant contributions to final product

qualities, as discussed below, and are profoundly influenced by the identified

examples of recipe balance and process factors. Readers should note combina-

tions of factors may contribute to more than one product characteristic.


Product volume will be influenced by the balance between:

� Positive input of flour proteins and the negative input of ash (bran).

� Recipe water levels based on flour properties and inputs from other

ingredients.

� Level of flour protein and the input of mechanical energy during mixing.

� Level of recipe yeast, dough temperature and fermentation time.

� Improver level, composition and dough temperature.

� Inputs from final prover temperature, humidity and time.

Products shape will be influenced by the balance between:


ingredients.

� Level of flour protein and the input of mechanical energy during mixing.


� Improver level, composition and dough temperature.

� Final prover temperature, humidity and time.

� Dough piece dimensions and oven temperature.

Product crust colour will be influenced by the balance between:

� Recipe sugar levels and oven temperature.

� Dough enzymic activity and fermentation time and temperature.

Product crumb cell structure will be influenced by the balance between:



ingredients.

� Ascorbic acid assisted oxidation and the availability of oxygen from the

action of the chosen mixer.

� Dough temperature, yeast level and processing time.

3.4 STRUCTURE OF LAMINATED PRODUCT RECIPES

The key relationships in laminated product recipes revolve around the rela-

tionship between the base dough and the level of laminating fat. Base dough

recipes for laminated product are relatively straightforward, and as with

bread dough, the main ingredient ratios are those of water to flour, with other

ingredient additions covering a wide range of largely individual preferences.

It is largely the ratio of laminating fat to base dough which characterises

laminated products (see Section 7.1.11) though there is also an important

interaction with the level of lamination to be taken into account (Cauvain,

2001). With few other ingredients to consider, the structure of laminated pro-

ducts is relatively simple and there are no major ‘rules’ of recipe balance to

consider.

Key Relationships Between Ingredients, Recipes and Baked Product Chapter | 3 147

3.5 SOME KEY RELATIONSHIPS IN THE MANUFACTUREOF LAMINATED PRODUCTS

The primary factors which underpin the manufacture of laminated products

are very similar to those for breadmaking, in part because of the need for a

degree of gluten development to for its impact on product lift and structure.

The primary factors may be summarised as follows:

� Dough development

� Paste rheology

� Gas retention

� Gas production

In the case of laminated product, paste rheology is especially important

in maintaining the integrity of dough and fat layers. Gas retention in this

product group is also associated with layer integrity so that steam pressure is

generated between the dough layers (see Section 7.1.1). Gas production

mostly refers to the manufacture of yeast-raised laminated products like

croissant and Danish pastries.

Product lift (volume) will be influenced by the balance between:

� Flour characteristics and processing conditions.

� Energy input during mixing, numbers of laminations and length of resting

periods.

� Laminating fat characteristics and processing temperature.


� Flour characteristics and processing conditions


periods.

Product cell structure will be influenced by the balance between:



periods.

� Laminating fat level and numbers of laminations.

Product eating qualities will be influenced by the balance between:

� Laminating fat level and quality characteristics.

� Laminating fat level and numbers of laminations.

3.6 STRUCTURE OF SHORTCRUST PRODUCT RECIPES

Shortcrust pastry recipes are characterised by whether they are for the manu-

facture of savoury or sweet products; the essential feature of the latter being

the addition of sugars to the recipe. There are no significant rules of recipe


balance for shortcrust pastry products other than the consideration that the

higher the level of recipe fat the ‘shorter’ the eating quality of the product is

likely to be. This effect is based on the inhibition of gluten formation by the

recipe fat, either through the effect of level of addition or the method

employed for mixing the paste (Cauvain and Young, 2006).

3.7 SOME KEY RELATIONSHIPS IN THE MANUFACTUREOF SHORTCRUST PASTRIES

The main, if not the only primary factor associated with shortcrust pastry

production, is paste rheology, and while recipe water level does play a role

in its determination, the level and type of recipe fat probably play the most

significant roles. Even in the manufacture of sweet shortcrust pastry, the role

of sugar is limited.



� Level and type of recipe fat and processing conditions.

Product eating qualities will be influenced by the balance between:

� Recipe water, fat and sugar levels, mixing and processing conditions.

3.8 CAKES � HIGH- AND LOW-RATIO RECIPES

In the construction of cake recipes, it is traditional to use the flour as a base

on which to determine the levels of the other ingredients being used. The

classical construction of cake recipes is based on the functionality of the indi-

vidual ingredients and their contribution to the development of a cake struc-

ture. In this respect, a key role is played by the level of sugar in the recipe as

this ingredient has a significant effect on the gelatinisation characteristics of

the starch in the wheat flour. As starch is the main building block of the

cake structure, any changes to its gelatinisation characteristics will have a

significant effect on cake quality. The addition of sugar in a cake recipe raises

the gelatinisation temperature of the starch and so delays the ‘setting’ point of

the cake structure (the foam to sponge conversion).

The other key ingredient in controlling the gelatinisation characteristics

of starch is water. The level of water in the recipe is important for dissolving

the sugar and providing moisture for the starch granules to hydrate, swell

and ultimately gelatinise. Empirical work has shown that a sucrose concen-

tration of around 0.5 delivers acceptable cake quality (Cauvain and Young,

2008), so this means that there is a direct relationship between the sugar and

water levels used in a cake recipe.

The terms low- and high-ratio are used to define the recipe types used in

cakemaking. Low-ratio implies that the level of sugar and water (sometimes,

this is referred to as ‘liquid’ which is the sum of ingredients such as egg or


milk, but only the water component of these ingredients should be consid-

ered) in the recipe are individually lower than the level of flour, whereas

high-ratio implies that they are individually greater than the flour weight.

For the flour to be able to support a higher level of sugar and liquid, it is

necessary for it to have been treated in some way; such treatment may be

with chlorine gas (see Section 2.2.18) or with dry heat treatment (see Section

2.2.17). In addition, there is a tendency for high-ratio recipes to use fat in

which an emulsifier has been added to aid batter aeration and stability.

The external characteristics of high- and low-ratio cakes appear very sim-

ilar, and internally, the high-ratio product tends to have a finer and more uni-

form texture (see Fig. 3.1). However, when it comes to assessing the crumb

characteristics of the two products, the high-ratio cake products exhibit softer

and more tender eating properties. In part, this comes from the higher mois-

ture level which usually remains in the baked high-ratio products; typically,

this will be in the order of 3�6% higher (Cauvain and Young, 2006).

The key characteristics of low- and high-ratio recipes may be summarised

as follows:

Ingredient Low ratio High ratio

Flour treatment None Dry heat (or chlorine gas)

Sugar Equal to or less than theflour weight

Greater than theflour weight

Water (fromall sources)

Equal to or less than theflour weight

Greater than theflour weight

Fat type No special form Fat with emulsifier

3.9 CAKES AND SPONGES � THE ROLE OF RECIPE BALANCE

In the case of cake manufacture, there are some empirical rules which have

evolved to consider the balance of ingredients in a recipe with respect

to final cake qualities. These are sometimes found in older baking books

(e.g., Bennion and Stewart, 1958), and the rules commonly date to a period

FIGURE 3.1 Comparison of (left) high- and (right) low-ratio cakes.


on time when cake production was being influenced by the introduction of

so-called high-ratio recipes based on the use of chlorinated flour.

The ‘rules’ of cakemaking may be summarised as follows:

� The ratio of sugar to flour is the first rule that is considered, and this is

commonly defined on the basis of whether the recipe is ‘low’ or ‘high’

ratio (see above).

� The egg and fats levels are usually balanced against one another. This

rule is related to the impact of these two ingredients on the eating quali-

ties of the final products; egg protein imparts a firming/toughening effect

on the eating quality while fat delivers tenderness.

� Once the level of egg has been decided, it is necessary to choose the final

liquid level in the recipe. This should be balanced with the sugar level to

deliver a suitable sucrose concentration in the batter (see above). The

liquids should include the egg, milk (if used as liquid milk) and water.

You will need to be sure that you have identified all sources of water.

Although you can work with the liquids in their added form, you may

find it more useful to separate out the water from egg and milk when

doing your calculations.

� Some traditional rules set the baking powder level according to the egg:

flour relationship on the basis that egg protein deliver part of the aeration

required in cake batters.

You should view any rule set with caution as they tend to apply to a

restricted set of cake types. Many of the rule sets were developed for loaf-

style cakes and do not necessarily apply to the more highly aerated sponges.

In addition, the nature of baking ingredients has changed as the rules were

first developed, and this has resulted in the adaptation of the traditional rule

sets and changed the boundaries of the acceptable ingredient levels.

The value of such ‘rules of thumb’ is that they are founded on a signifi-

cant knowledge base and at the very least, identify the role of the different

cakemaking ingredients in forming the basic structure of modern cakes.

3.10 SOME KEY RELATIONSHIPS IN THE MANUFACTURECAKES AND SPONGES

The primary factors which underpin the manufacture of bread and other

fermented products can be identified under the following headings:

� Cell creation

� Gas production

� Batter viscosity

The list of primary factors underpinning the manufacture of cakes and

sponges is shorter than that for bread, mainly because of the relatively insig-

nificant role that gluten development plays in the determining end product


quality. Cell creation and gas production remain as key factors and batter

viscosity may be considered as comparable with dough rheology.

Product volume will be influenced by the balance between:

� Recipe ingredients.

� Level and type of baking powder.

� Mechanical and chemical aeration.


� Recipe ingredients.

� Mechanical and chemical aeration and heat input during baking.

Product crust colour will be influenced by the balance between:

� Recipe sugar levels and oven temperature.

Product crumb cell structure will be influenced by the balance between:

� Mechanical and chemical aeration and heat input during baking.

References

Bennion, E.B., Stewart, J., 1958. Cake Making, third ed. Leonard Hill [Books] Limited, London,

UK.

Cauvain, S.P., 2001. The production of laminated bakery products. CCRA Review No. 25.

Campden BRI, Chipping Campden, UK.


AG, Switzerland.
















Chapter 4

Bread and Other FermentedProducts

4.1 BREAD

4.1.1 We are producing a range of pan breads, some bakedin a rack oven and others in a deck oven, and find that there arelarge indents or cavities in the base of many of the loaves.What is the cause of this effect and how can it be overcome?

When the pans enter the oven dough expands to touch all of the sides

of the pan. As the temperature continues to rise, the dough piece can

no longer expand outwards due to the pan sides and so starts to grow

upwards.

Even though there is some friction between the side of the pan and the

expanding dough, the dough will continue to move upwards until the temper-

ature conditions against the pan sides are suitable for the formation of the

side and bottom crust of the loaf. This normally happens fairly quickly due

to the heat conductivity of the metal pans. As the crust begins to set steam

which has been lost from the hot dough begins to diffuse up the side of the

pans and is normally lost to the atmosphere.

The centre of the dough continues to expand after the bottom crust has

formed so that dough becomes compressed against the sides of the forming

loaf. In some cases, this extra compression causes a strong seal to form

between the baking dough, and the sides of the pan and pockets of steam

become trapped between the forming crusts and the pan. The steam pressure

can become so great that areas of the baking dough may be forced away

from the pan sides and base and the cavities or large dents that you see are

formed (see Fig. 4.1).

The simplest solution to the problem is to use pans with small holes

drilled at the angle where the base of the pan joins the sidewalls. It is usually

only necessary for there to be three holes, each 1 to 2 mm in diameter, down

each of the two longer sides or up to six holes around the circumference of a

round pan.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00004-7

A number of other aspects may contribute to the problem. For example:

� Using pans which are too small for the mass of dough being used (i.e.,

over-scaling, or simply having the wrong size of pan).

� Having too much bottom heat in the oven, such as might be the case in

the deck oven.

� Packing the pans too closely together which slows down the rate of heat

transfer and sets the bottom crust before the side crusts, this may be the

case in your deck oven.

Tight fitting lids may also contribute to this problem and in some extreme

cases lidded loaves have been known to literally blow apart within the pan

during baking.

It is somewhat ironic that one only sees this particular problem when the

dough has good gas retention. Although weakening the dough gas retention

(e.g., by using less mixing energy or a lower dough temperature) is seen as a

means to solve the problem, it should be avoided because of the loss of other

desirable bread properties, e.g., volume and crumb softness.

FIGURE 4.1 Example of ‘pan-lock’ in bread.


4.1.2 We are experiencing a problem with the sides ofsandwich loaves caving in. Sometimes, the lid also showsthe same problem, though to a lesser degree. Is the problemassociated with overbaking?

It is true that when the baking time for bread is extended the sides may tend

to cave-in; however, this is not the primary cause of your particular problem

which lies more with the gas retention properties of the dough than the bak-

ing conditions in the oven. This problem is often seen as a sign of ‘weak-

ness’ in the dough but in fact it is the reverse.

The early stages of baking are associated with expansion of the dough

before the yeast is inactivated. As indicated in the previous question when

the dough reaches the sides of the pan, the crust begins to form and expan-

sion stops. However, as dough is a poor conductor of heat, expansion of the

dough centre continues for sometime after the side crusts have formed. This

results in compression of dough layers against the side crusts. In some cases,

the expansion of the dough centre can be considerable so that if we were to

measure the crumb density at various points in a slice cross-section, we

would find that the centre crumb was considerably less dense than at the

sides. This lower crumb density results in a centre less able to cope with the

changes of internal and external pressures during cooling and the sides pull

inwards as the loaf cools.

The most common cause of the problem is changes associated with an

increase in dough gas retention. These may come from a number of sources,

including:

� The flour being too strong for the breadmaking process being used.

� Too high and improver level or too ‘strong’ and improver.

� Excessive enzymic activity, most commonly excessive alpha-amylase

activity.

Other contributing factors may come from faster proof when using raised

yeast levels or normal proof times with lower dough and prover temperatures

and higher yeast levels. Long baking times using low oven temperatures may

also contribute to this problem.

Bread and Other Fermented Products Chapter | 4 155

4.1.3 We are producing hearth-style (oven-bottom) breads,baguettes and French sticks and are experiencing problems withragged cracks appearing along the sides of the loaves. What arethe likely causes of this problem?

The problem that you describe suggests that your doughs are under-proved

before they enter the oven. The main function of proof is to expand the

dough bubble structure using carbon dioxide gas generated from yeast fer-

mentation. It is common to try to achieve around 85�90% of your required

final product volume in the prover leaving the remaining 10% or so to come

from oven spring during baking.

The crust forms quickly on oven-bottom breads because they are not

shielded from the heat of the oven by the sides of any pans. Quickly, the

dough surfaces become dehydrated and inflexible, but as with all breads,

there will be continued expansion of the centre of the dough. If the dough is

under-proved then the potential for crumb expansion is considerable and the

forces which are generated begin to crack the already rigid crust along any

lines of weakness (see Fig. 4.2).

During proof the changes in dough rheology make it more extensible,

less elastic and less resistant to deformation. Such changes depend more

on time than on temperature. By making the dough more extensible, it is

better able to withstand the considerable stresses and strains it will experi-

ence during the early stages of baking and so expansion is more even. An

even expansion of the dough is most often seen as uniform oven spring.

FIGURE 4.2 Example of ragged crust break with bread.


We suggest that you look closely at final proof time and the yeast level

that you are using. Times less than 40 minutes, especially with higher yeast

levels, are likely to lead to problems with under-proved doughs.

We also suggest that you look at some factors, such as:

� The level of recipe water. Commonly hearth bread are made with slightly

lower water levels to help retain their bold shape, but if the dough is par-

ticularly stiff, it will be more prone to the ragged breaks that you

describe.

� The weight of the dough pieces you are using, high dough piece weights

are more likely to lead to this problem.

� Your dough temperature. Low dough temperatures, especially with high

yeast levels are more likely to lead to this problem. You may want to

check the core temperatures of the dough pieces as they exit the prover.

Typically, the core temperature will be a few degrees lower than the

prover temperature. However, if you put cold doughs into a warm prover

and do not give enough proof time, then the temperature gradient

between surface and centre will be greater and contribute to this problem.

� Under-fermentation. If you are using a breadmaking process which relies

on bulk fermentation to develop the dough.


4.1.4 We have noticed the development of a ‘fruity’ odourin our breads after they have been stored. The problem isparticularly noticeable with our wholemeal products.What is the cause of this problem and are there any remedieswe can apply to prevent its occurrence?

The odour that you are describing comes from a problem that bakers refer to

as ‘rope.’ The problem gets its name from the fact that in the later stages of

development, the crumb will become soft and sticky and when cut surfaces

of the loaf are slowly pulled apart thin strands or ‘ropes’ can be seen stretch-

ing from one surface to the other.

The problem comes from contamination of your product by a bacterium,

Bacillus subtilis, which occurs naturally in the soil. Rope bacteria are com-

monly present on the outer parts of vegetables and grains. Wheat may become

contaminated with rope-forming spores in the field, and these may pass

through the flour milling system into the flour. Wholemeal flours may have

higher numbers of rope spores present than white flours because the spores

are mostly associated with the outer bran layers. The crease in wheat makes it

a difficult task for the miller to remove all of the rope spores.

The rope-forming spores can readily survive the bread-baking process.

The water activity of the crust surfaces is normally low enough to limit bac-

terial growth after baking, but the conditions in the loaf centre, with a water

activity of 0.9 to 0.95 and temperatures below 95�C, are well suited to the

development of rope when the product cools down and is stored for any

length of time. The time taken for the problem to be manifest depends on

the level of contamination, and the conditions of storage, particularly the

temperature, the heavier the contamination and the warmer the conditions

the faster, will be rope development.

As the source of the problem is natural, the strategy should be to try and

contain the problem rather than eliminate it. This may be achieved using one

or more of the following tactics:

� Do not allow any stale bread or bakery returns into the same area as fresh

production. Stale bread can be an extra source of contamination because

some rope development may have already occurred.

� Minimise areas where dust and bread crumbs may collect.

� Try to reduce the risk of air-borne contamination from outside of the bakery.

� Add to the dough either propionic acid at 0.1% flour weight, calcium pro-

pionate at 0.2% flour weight or 1 L 12.5% acetic acid solution (vinegar)

per 100 kg flour (n.b. Check local regulations concerning permitted addi-

tions and levels) as rope inhibitors. These act by lowering dough pH and

making the conditions less suitable for rope development. You may have

to slightly increase yeast levels because they will also slow down gas

production by the yeast.


4.1.5 When viewing the crumb appearance of our sliced bread,we notice the appearance of dark streaks and patches whichhave a coarser cell structure and firmer texture than the restof the crumb. Is this a problem with uneven mixing?

As the mixing process is solely responsible for the incorporation of the gas

bubbles which eventually become the bread crumb cell structure with no-

time doughs, it is perfectly reasonable to assume that mixing can be respon-

sible for variations in crumb cell structure you observe. However, unless you

have a grossly inefficient mixer or your doughs are grossly under mixed,

whether because of too little energy or too short a time, we do not feel that

this is the main cause of your problem.

In general, the larger the size of the cell in the crumb, the deeper it is and

the darker will be the shadow that it casts when viewed in oblique lighting

(see Fig. 4.3). When doughs leave the mixer, the gas bubbles which become

cell structure are the smallest size that they can be. During the journey to the

oven, carbon dioxide gas from yeast fermentation inflates the bubbles and

makes them larger. The size to which the gas bubbles can grow is limited by

the ability of the gluten film surrounding them to stretch without rupturing.

In the event that the gluten film ruptures small gas bubbles may coalesce

(join together) to form larger ones. The displaced gluten film may well con-

tribute to improving the strength of the remaining larger bubble. Thicker cell

walls also contribute to darker crumb colour.

Bursting and coalescence gas bubbles in the dough may occur if the sur-

rounding material is unable to maintain bubble stability during processing,

especially in those operations which place the dough under stresses and

FIGURE 4.3 Dark patches in bread crumb.


strains, e.g., dividing and moulding. We would suggest that your problem

arises because your dough lacks the necessary bubble stability, and the glu-

ten network is being broken down (damaged) by the moulding actions. This

lack of bubble stability may come from a number of sources, including:

� Using a flour which is too weak for the breadmaking process being

employed.

� Under-developing the dough, e.g., too little energy or mixing time too

short.

� Not using a suitable improver with a no-time dough, e.g., one which

lacks hard fat or an emulsifier.

� Too little water in the dough, tight doughs are more susceptible to

moulder damage than soft ones (Cauvain and Young, 2008).

� Using cold doughs which yield stiff and under-developed doughs.

� Insufficient first proof which gives a dough which is not sufficiently

relaxed for final moulding.

� Incorrect moulder settings, essentially excessive pressure at any moulding

stage. The dark patches may form characteristics patterns in the final loaf

which can indicate their point of origin in moulding.

Other possible causes for variations in crumb cell structure of the type

that you describe may come from the inclusion of old, fermented dough dur-

ing the later stages of mixing or accidentally during moulding and processing,

or from skinning of the dough pieces before or between moulding stages.

Reference

Cauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture and Quality: water Control and

Effects, second ed. Blackwell Science Ltd., Oxford, UK.

Further reading

BakeTran, 2012. Unwanted holes in bread: why they form and how to limit them. Chorleywood

Bookshelf Monograph No. 1. BakeTran, Witney, UK (www.baketran.com).




http://www.baketran.com

4.1.6 Periodically, we observe the formation of large holesin the crumb of our pan breads and suspect that the adjustmentto the pressure set on the moulding board on our final moulderis faulty; can you confirm our suspicions?

You are correct in assuming that your moulding board pressure settings

(height) play a part in the formation of the large holes that you see in your

breads, but it may not simply be a case of finding the correct settings on the

moulder to eliminate the problem. There is a strong interaction between the

dough and the moulder performance, and you must bear in mind that any

moulder is inanimate and can therefore only react to the material that it

receives.

In the previous question, we considered how the stability of gas bubbles

was affected by dough development and the stresses and strains introduced

by moulding. Even in doughs with optimised development damage to the gas

bubble, structure may occur during moulding. Large gas bubbles formed

from the coalescence of smaller ones have a lower internal pressure than the

smaller ones around them. This lower internal pressure means that the carbon

dioxide gas generated from yeast fermentation is more likely to diffuse into

the large gas bubbles rather than the smaller ones. In consequence, the large

gas bubbles may continue to grow to such an extent that they may form

holes in the final crumb.

A key to avoiding this type of problem is to ensure that the dough rheol-

ogy is optimised by the time of moulding (Cauvain, 2015). To minimise

stresses and strains during processing, you need a dough which lacks resis-

tance to moulding and is not elastic. Such ‘relaxed’ doughs come from

ensuring full development with optimised water levels. Cold doughs should

be avoided, and sufficient first proof should be given to lower dough resis-

tance to deformation for the second-moulding stage. You need a dough

which is extensible, and this comes from optimising gluten formation.

A common response to the problem that you describe is to ‘tighten’ the

mould by increasing the pressure exerted during moulding. In many cases,

increasing moulding pressure leads to greater damage to the structure and is

more likely to exacerbate the problem than cure it. The moulding board set-

ting should just be enough to deliver the shape of dough piece you require

and nothing more. In some types of moulders, the moulding board length is

too short to achieve the required dough size without subjecting the dough to

considerable pressure during the final stages of moulding. The aim of mould-

ing should be to shape the dough piece but preserve the gas bubbles intact.

This approach is best seen in the production of baguette where a very soft

dough and gentle moulding allows the retention of large gas bubbles in the

dough to deliver the characteristic open cell structure.


Other factors which may influence the formation of holes in the crumb

include any skinning of the dough which may occur before moulding, the

use of hot pans and excessive bottom heat in the oven. In the latter case, the

holes which form may well occur towards the bottom of the loaf and may

have a ‘triangular’ shape.

Reference


AG, Switzerland.

Further reading







4.1.7 We have been having problems with holes appearing indifferent places in our pan breads. Can you explain where theycome from and how to eliminate them? Is there any relationshipbetween the holes that we see inside dough pieces coming fromthe divider and the problems that we are experiencing?

First, we should point out that it is almost impossible to make bread without

having problems with holes from time to time. There are a number of differ-

ent origins for the holes, and there are a wide range of factors which contrib-

ute to their formation. When we refer to holes in bread crumb, we usually

mean features which are substantially larger than the holes which we call the

cell structure. In pan bread, the latter ranges from 1 to 2 mm for sandwich-

type bread up to 5�6 mm for farmhouse-type products. Large holes in bread

crumb are a particular problem, but equally, a large number of smaller holes

in the crumb can be a cause for concern. To help us understand the origins

of holes and consider how might eliminate them, it is useful to know some-

thing about their key features and their location within the loaf.

A useful diagnostic feature of holes is the appearance of the crumb which

comprises their internal walls. The first clue of their origins is given by

whether they have smooth walls or whether strands of crumb extend across

the hole (see Fig. 4.4). In some cases, the strands may be broken and leave

the hole with the appearance of a limestone cavern with stalactites and sta-

lagmites. In the case of the smooth-surfaced hole (see Fig. 4.5), it is an indi-

cation that the sides had never touched while a rough-surface to a hole

suggests that some force ripped apart the crumb in the region of the hole.

The other key feature for diagnostic purposes is the position of the hole

within the loaf, bearing in mind the type of bread which is being made.

At the end of mixing, all bread doughs have small pockets of air trapped

within their bulk. Some of these air pockets will carry through the divider to

reach the dough moulding and processing stages. The survival of trapped air

pockets during these stages depends in part on the moulding actions which

are employed. If a first moulding step is employed, there is some potential

FIGURE 4.4 Stranded holes.


for air pockets to be ‘moulded out’ though, as discussed below, the degree to

which this happens is very dependent on the dough processing methods

being employed. In broad terms, many of the trapped gas pockets greater

than the sheeting gap employed during final moulding cannot survive

because they will be burst by the action of the rolls. However, the rheologi-

cal properties of bread dough is usually such that some trapped gas pockets

become elongated in the direction of sheeting and remain trapped in the final

dough piece, albeit in a modified form.

The degassing of dough and moulding out trapped air pockets has been

and still remains a popular theme in treatises on bread dough processing.

Such actions can certainly be accomplished with some breadmaking pro-

cesses but less so with others. For example, as much as 70% of the volume

of a bulk dough after fermentation and before it reaches, dividing (Cauvain,

2015) can comprise large pockets of gas and the expanded and relaxed

nature of the gluten structure offers limited resistance to degassing actions.

In contrast, the gas levels in dough prepared by a no-time dough mixing pro-

cess will typically comprise less than 20% of the dough volume and have a

rheology more resistant to deformation. In such doughs, eliminating trapped

gas pockets would require the application of significant forces during mould-

ing, and such forces have significant potential for damaging the dough struc-

ture leading to the formation of areas of coarse cell structure in the crumb

cross-section (see Section 4.1.5). A common approach when holes are

observed in the bread crumb is to increase the pressure put on the dough as

it passes under the moulding board of the final moulder but this often only

increases the risk of moulder damage (see Section 4.1.6).

FIGURE 4.5 Smooth-sided hole.


The gas cells trapped in a dough piece have a wide range of sizes from a

few microns to 1�2 mm, or more depending on the dough type. The larger

gas cells have lower internal pressures relative to the smaller cells. This dif-

ference is an important factor in the growth of the gas cells when carbon

dioxide is produced by bakers’ yeast. As carbon dioxide cannot form a gas

bubble in dough (Baker and Mize, 1941), it will migrate preferentially to the

areas of lower pressure, that is, the larger gas cells. The process is known as

disproportionation, and its consequences are that larger gas cells will grow

proportionally larger than small gas cell in the dough. This process has a sig-

nificant impact in the context of the formation of holes in bread.

The position of the holes in the baked loaf provides a number of important

clues as to their origins. Many unwanted holes come from the inclusion of gas

pockets during the curling action after dough sheeting (see Section 9.5) and as

the dough passes under the moulding board on the final moulder. In a loaf

moulded from a single dough piece, the relationship is fairly straightforward

but with four-piece bread it is not so clear.

The tightness of the initial curl of the dough pancake as it exits the sheet-

ing rolls contributes to gas pocket occlusion (see Fig. 4.6). Usually, the holes

in the loaf are centrally placed, have smooth sides and run horizontally

through the product. Although the gas pocket may start in the centre of the

dough piece, it does not necessarily end up in the centre of the final slice

cross-section. In pan breads much of the expansion of the dough in the

prover occurs in the lower half of the piece (for an illustration of this effect

see Whitworth and Alava, 1999), and the original ‘centre’ may well end up

about two-thirds of the way up the loaf. In the four-piecing of dough, the

reorientation will mean that this type of gas pocket is still in the centre of

the dough but largely confined to each of the two central portions and run-

ning at right angles to the pan length (see Fig. 4.7). A further clue that the

holes come from trapped gas pockets in curling is that they may follow the

curling lines and so have a curved or crescent shape (see Fig. 4.8).

FIGURE 4.6 Air occlusion in the dough pancake at the curling stage.


The curling action in final moulding forms a rough cylinder, the ends of

which are ‘open’ (Cauvain, 2015) with the potential for trapping gas in the

final stages of processing under the moulding board. A traditional role for

the moulding board is the elimination of trapped gas which has already been

discussed, this depends on the dough condition at the time of moulding.

Under the moulding board, the dough is often constrained by two ‘guide

bars’ running the length of the moulder. The dough is ‘screwed’ against

these guide bars by the rolling action to ‘seal’ the ends of the piece. It is at

this time that gas pockets may be trapped. If the gas pockets are not elimi-

nated they are commonly seen as holes towards the ends of the loaf in both

single and four-piece products.

FIGURE 4.7 Potential site of trapped air pocket (shaded section) from the curling stage (see

Fig. 2.15) in single (upper) and four-piece bead (lower).

FIGURE 4.8 Trapped air pockets following dough moulding lines.


There is no single unique solution to eliminating holes in bread dough.

To minimise the appearance of holes in bread, you will need to pay particu-

lar attention to the rheological properties of the dough and the different set-

tings that you are using during dough processing. In general, you are looking

to create a dough which has limited resistance to the deformation processes

at work in the moulding stages. This implies optimising the level of water

addition during mixing but also includes ensuring that dough development

has been optimised; both under- and over-developed doughs contribute to the

potential for trapping gas pockets and the risk of moulder damage.

References

Baker, J.C., Mize, M.D., 1941. The origin of the gas cell in bread dough. Cereal Chem. 18,

19�34.


AG, Switzerland.

Whitworth, M.B., Alava, J.M., 1999. The imaging and measurement of bubbles in bread dough.

In: Campbell, G.M., Webb, C., Pandiella, S.S., Niranjan, K. (Eds.), Bubbles in Food.

AACC, St. Paul, MN, pp. 221�232.

Further reading














4.1.8 We are making open-top pan breads and find that the topcrust of some of our loaves is being lifted off during the slicingprocess. Sometimes, there is a hole underneath the crust,whereas on other occasions there is not. Do you have anexplanation for this problem? We have tried making the doughstronger by adding more improver but without any reduction inthe problem; in fact, it may have been slightly worse

The weakness that you are experiencing just underneath the top crust proba-

bly has more to do with the dough moulding process rather than the

‘strength’ of the doughmaking system. Your own observations that adding

more improver did not solve the problem tend to support this conclusion.

Looking closely at the pictures of bread slices that you sent through, you

can see quite a few small holes throughout the crumb of the loaf. On their

own, these are not something that you would worry about but quite a few

clearly follow the moulding lines formed in the dough when it is being

curled-up after sheeting. They are smooth-sided and therefore originate as

small pockets of trapped gas (see Section 4.1.7).

The example of the holes that you are getting (see Fig. 4.9) follows the

curve of the loaf crust and appears to be associated with the tail of the dough

sheet formed in the final moulder. With hand panning, the practice would be

to place this ‘seam’ on the bottom of the pan (see Section 4.1.22) where the

gas pressure created in the dough against the bottom of the pan is likely to

prevent the small gas pockets becoming larger. With mechanical panning, it

is not possible to ensure where the seam ends up with respect to the pan. If

it ends up against the side of the pan, the chances of the trapped gas pockets

becoming a hole is also reduced.

However, if as has happened in the illustrated example, the seam ends up

towards the top of the loaf, then there is the opportunity for the gas pockets

to expand. There is some restriction to crumb expansion once the crust has

formed but this often means that the trapped gas pockets coalesce along the

FIGURE 4.9 Hole formed by the ‘unzipping’ of air pockets.


moulding lines to form larger holes. This appears to be the case with the

illustrated example as the small gas pockets have ‘unzipped’ along the inter-

face of the dough curl.

If the unzipping effect does not form a large hole, then it leaves behind a

weakness just under the crust which creates your problems at slicing. The

problem will be more evident at the top of the loaf due to the extra expan-

sion that the dough must accommodate. You are less likely to see this prob-

lem with lidded breads, though it does occur, and you may also experience

some weakness just under any of the crusts.

The weakness to which we refer is not related to the gas retention properties

of the dough and the factors which contribute to that dough property but to a

physical weakness in the manner in which the bread crumb is attached to the

crust. In addition to the contribution made by trapped gas pockets, the differen-

tial in moisture content in the first few mm of the bread slice plays a role. We

note that the crust colour on your loaves is quite dark because your customers

prefer a heavier bake. This does make a contribution to your problem because

it reduces the flexibility of the critical area where crust and crumb meet.

As you are automatically panning your dough pieces, there is no way you

can guarantee the final location of the dough piece seam in the pan so you

will need to try and reduce the risk of trapping gas pockets in the dough dur-

ing curling. We suggest that you examine the potential for increasing the

level of water that you are using in doughmaking so that it is easier to sheet

the dough and help with the elimination of trapped gas pockets in the final

moulder. The degree to which you can do this depends on the operational

conditions in your plant. Certainly, you should look to reduce the risk of

dough pieces skinning during processing.

You should also examine your bread cooling process and see if there is

an opportunity to reduce overall moisture loss and certainly try to minimise

the moisture differential between crust and crumb. In this respect, you might

want to check the relative humidity in your bread cooler.

Further reading





4.1.9 We are using the Chorleywood bread process to developour doughs and apply a partial vacuum during mixing to producea fine and uniform cell structure in the baked loaf. Sometimes,we observe that the cell structure becomes more open eventhough the vacuum pump is still working. Can you explain thecause of this problem?

The application of partial vacuum (typically 0.5 bar) during dough mixing

with the Chorleywood bread process (CBP) is used to produce a finer (smal-

ler average cell size) and more uniform cell structure in the final baked loaf

(Cauvain, 2015). It does this because the size of the gas bubbles changes

with changes in mixing chamber pressure; in particular, the transition from

partial vacuum to atmospheric pressure at the end of mixing causes the gas

bubbles which are present in the dough to shrink. At the same time, it

reduces the total quantity of gas in the dough which gives improved divider

weight control and yields a dough which feels ‘drier’ to the touch. The latter

effect has allowed users of the CBP to increase the added water content at

dough mixing to deliver a dough consistency similar to that obtained with

bulk-fermented doughs with lower water contents (Cauvain, 2015).

The process of dough expansion depends of the presence of nitrogen gas

bubbles in the dough, the nitrogen comes from the air bubbles originally incor-

porated during mixing with the oxygen being lost because of yeast action

(Cauvain and Young, 2006). The nitrogen gas bubbles provide the sites into

which the carbon dioxide gas generated by yeast fermentation can diffuse. This

nucleating role is critical as carbon dioxide itself cannot form a gas bubble in

bread dough (Baker and Mize, 1941). Without sufficient nitrogen gas bubbles

being present in the dough, you cannot form a ‘normal’ bread cell structure.

The numbers of gas bubble nuclei in the dough are considerably reduced

as the mixer headspace pressure falls closer to 0 bar absolute (1 bar vacuum).

In practice most vacuum pumps fitted to CBP-type mixers are designed to

run around 0.3�0.5 bar (absolute) because lower pressures tend to give

coarser and more open cell structures. The sample of bread you supplied did

not suggest a breakdown of the gas bubble structure rather that it had not

formed correctly in the first place. We suggest that you discuss the operation

of your vacuum pump with your engineers and equipment suppliers. Though

rare, it does appear that the source of your problem is that the pump at times

is operating at pressures much lower than 0.5 bar (absolute).


In addition to the coarse, open cell structure a characteristic of this prob-

lem is that there is extensive blistering of the crust which also has a waxy,

greasy or oily appearance, somewhat similar to that seen on retarded pan

breads (Cauvain, 2015).

References

Baker, J.C., Mize, M.D., 1941. The origin of the gas cell in bread dough. Cereal Chem. January.

18, 19�34.


AG, Switzerland.

Cauvain, S.P., Young, L.S., 2006. The Chorleywood Bread Process. Woodhead Publishing Ltd.,

Cambridge, UK.









4.1.10 We are seeking to improve the quality of our breadproducts and are getting conflicting advice on what the optimumdough temperature ex-mixer should be. Can you advise us ashow to decide what is the optimum temperature to use?

The control of the temperature of the dough delivered at the end of mixing is a

critical factor in ensuring consistent final product quality due to its contribution

to gas retention in the dough, gas production by bakers’ yeast and dough rheol-

ogy for processing. Whatever your choice of final dough temperature, it is very

important to ensure that you are consistent from dough to dough.

Choosing the appropriate dough temperature to aim for after mixing is

independent of producing a dough with a consistent final temperature. In

general, higher final dough temperatures will encourage the yeast to work

faster, and this will speed up fermentation. One of the disadvantages of this

will be that the bulk dough density will change more rapidly with time; as

the bulk dough density decreases, this can lead to greater problems with

divider weight control while processing the batch. As the yeast will be more

active, you may find that you can slightly reduce the level that you are using

provided you do not compromise final proof time and oven spring.

If you are using an improver then by using higher dough temperatures

you will gain increased activity from the ascorbic acid (AA) present which

should improve dough gas retention. There will also be an increase in the

contribution of the enzymic activity in the dough, and you will need to make

sure this does not adversely affect dough processing. In general, raising the

dough temperature will make the dough easier to mould into shape, but in

some circumstances, you may find that the dough becomes stickier and you

may need to reduce added water levels.

Warmer doughs not only tend to ferment faster, they also tend to

prove more uniformly and this can lead to a more uniform and sometimes

shorter bake.

The key advantage in reducing the dough temperature is that you can

better control gas production in the early stages of dough processing and

limit the potential impact of dough stickiness. However, lower dough tem-

peratures have an adverse impact on gas retention and so there can be a loss

of product volume and crumb softness. If you have a fixed proof time then

you will need to add more yeast with colder doughs to maintain proof vol-

ume for the same time. This can lead to problems of product uniformity in

the oven arising from the increased temperature differential between the sur-

face of the dough piece and its centre. A common problem arising from

using cool doughs and high yeast levels can be the development of ragged

crust breaks (see Section 4.1.3).

The ex-mixer dough temperatures commonly used in baking range from

24 to 32�C with bulk fermentation processes using the lower end of the

range and no-time doughmaking processes the higher end.


4.1.11 How can I calculate the amount of ice I need to replacesome of the added water when my final dough temperatureis too warm?

Using an ice slush (a mixture of water and crushed ice) or crushed ice to

keep control of the dough, temperature at the end of mixing is a practical

solution to unacceptably high dough temperatures in the summer months, in

countries with hot climates and with stronger flours which may require long

mixing times or high mixing energies. The cooling capacity of ice is at least

four times that of cold water as heat energy is used up in converting the ice

to water at 0�C. The ice must be in a form which is easily dispersed and can

quickly use up the heat in the dough.

To calculate the quantity of ice needed to replace added water, a ‘heat

balance’ approach must be used. The heat to be removed from the added

water (to cool it to the required temperature), must be balanced against the

heat required to convert the ice to water and then heat that melted ice to the

required water temperature. The following formulae can be used to deter-

mine the quantity of ice which must replace a portion of the recipe added

water to obtain the required water temperature to control the final dough

temperature. A ‘heat balance’ is achieved as shown in Fig. 4.10. The formu-

lae using metric standards are given.

FIGURE 4.10 Heat balance calculation.


Wi 5 weight of ice

Ww 5 required weight of recipe added water

Tt 5 temperature of tap water in �CTr 5 required water temperature in �CHeat, Q1, to be removed from added water 5 (Ww � Wi)3 (Tt � Tr)34.186

Specific heat capacity of water 5 4.186 J/kg/�CHeat, Q2 needed to melt ice and heat resulting water to the required water

temperature 5 Wi 3 334.6 1 Wi 3 Tr 3 4.186

Latent heat of ice 5 334.6

For heat balance

Q15Q2

Ww 2Wið Þ3 Tt � Trð Þ3 4:1865Wi 3 334:61Wi 3Tr 3 4:186ð4:1Þ

For example, 40 kg of water is required for a dough mix. Temperature of

tap water is 20�C. Required temperature of water for the dough is 10�C.Calculate how much of the added water would need to be ice.

To cool (40 kg 2 wt of ice) of water from 20 to 10 requires Q1 heat to

be removed.

Q1 5 402Wið Þ3 202 10ð Þ3 4:186

5 402Wið Þ3 41:86

This is the heat ‘available’ to melt Wi kg ice, and to heat that ice water

to 10�C

Q2 5Wi 3 334:61Wi 3 ð102 0Þ3 4:1865Wi ð334:61 41:86Þ

Using heat balance (Eq. 4.1),

402Wið Þ3 41:865Wi 334:61 41:86ð Þ41:863 40� 41:86Wi 5 376:46Wi

418:32Wi 5 1674:4Wi5 4

Of the 40 kg of water required for the recipe, 4 kg should be added as ice

and 36 kg added as tap water at 20�C.It is worth remembering that the water which is ‘locked-up’ as ice at the

start of the mixing is not available to dissolve ingredients or start the hydration

processes of the damaged starch and proteins in the flour. The likely impact

on dough development will be small but may be more significant if a very


large mass of ice is used. In practical terms, it is better to use crushed ice as

this aids the rapid dispersion of the small ice particles through the dough. In

theory, cube ice may be used but this should be avoided as much as possible.

If you are going to routinely add ice to your doughs make sure that you

have a large enough icemaking capacity. You will not only need to calculate

the mass of ice that you are likely to need for your mixings but also need to

take into account the ability of your icemaking machine to deliver ice at the

required rate. You may need to have some form of buffer container to hold

the ice ready for use in the bakery.


4.1.12 We are using spiral mixers for our bread doughs.What is the best mixing time to use?

There is no simple answer to your question because it depends in part on the

type of spiral mixer you are using, your product range and the product qual-

ity you are seeking. Most spiral mixers have two operating speeds; a slow

one mainly used to disperse the ingredients and a faster one used to develop

the dough.

Spiral mixers typically operate at lower speeds than CBP-compatible

mixers and thus in a given mixing time cannot impart as much energy to

the dough. The actual transfer of energy to the dough with spiral mixers

depends to a large extent on the configuration of the mixing blade and

those designs which have more than one mixing blade will transfer a

greater quantity of energy to the dough in a given time. The presence of

a fixed central bar will also have a significant impact on the rate of

energy transfer.

Thus, for a given mixing time, we will expect to see differences in those

aspects of bread quality which are related to dough gas retention, such as

volume and softness, and to a lesser extent fineness of cell structure. We can

expect that the greater the energy transfer the larger the bread volume and

the softer the crumb.

For any given spiral mixer, increasing the mixing time will increase the

total energy transferred to the dough. The longer the mixing time, especially

on second speed, the greater the total energy and the larger the bread vol-

ume. However, as spiral mixers operate at lower speeds than CBP-

compatible mixers, we cannot expect to achieve the same total energy levels

as are possible with the CBP.

To determine your optimum mixing time, we suggest that you carry out a

series of trials in which you start with your existing mixing times, if you

have them, and raise the second speed mixing time by 2 minutes for succes-

sive doughs. If you do not have an established second speed mixing time

start at say 6 minutes, use eight for the next dough, and so on. You will

probably find that you need not go beyond 14 minutes.

It is important to have the same final dough temperature at the end of

mixing so that you can make true comparison. The longer the mixing time,

the greater transfer of energy and so the greater the temperature rise in the

dough. This can be compensated for by lowering the water temperature that

you use in doughmaking. Each 1�C that the dough temperature requires

adjustment by it will require at least 2�C change in water temperature.

It is also important that any trials are carried out with the same dough

mass in the bowl because energy transfer with spiral mixers depends on the

degree of interaction between dough and spiral beater. For a given mixing

time this interaction increases as the mass of dough goes down, within limits

and vice versa.


When you have completed your trials you will probably see that bread vol-

ume increases as mixing time increases (see Fig. 4.11), reaches a maximum

and then begins to fall slightly. This will indicate the optimum mixing time

for your particular spiral mixer. The same time can be used for a range of dif-

ferent bread types, assuming that maximum bread volume and crumb softness

are your aim.

FIGURE 4.11 Example of the effect of mixing time with a spiral mixer (L-R, 3, 5, 7, 9 min

second speed).


4.1.13 Why is it necessary to control the temperatureof bread doughs?

The control of final dough temperature to a constant value is essential to

ensuring consistency of product quality whatever the breadmaking process

that is being used because almost all of the chemical and biochemical pro-

cesses involved in breadmaking are temperature sensitive. In addition, many

of the physical properties of dough which influence its processing are also

directly affected by changes in temperature.

A complex series of enzymic actions take place in fermenting dough, and

all of these are temperature sensitive. As with yeast, enzymic activity

increases as the temperature rises though the temperature at which maximum

activity varies according to the particular enzyme. In breadmaking processes

which employ significant periods of bulk fermentation as part of the devel-

opment stage, then variations in dough temperature will have a profound

effect on final bread quality.

Even chemical reactions in dough, such as AA-assisted oxidation are

affected by temperature. Lower temperatures give less oxidation and hence

yield doughs with a reduced ability to retain gas in the oven and deliver

lower bread volume.

If the temperature of the dough at the end of mixing varies then so does

the rheology of the dough; higher temperatures make it less viscous and eas-

ier to deform and vice versa with lower temperatures. In turn, this results in

variation in the effect of mechanical moulding with higher temperatures

tending to result in less moulder damage. However, if the dough temperature

is raised too high then it becomes too soft to process. If the dough tempera-

ture falls, then the dough becomes stiffer and moulder damage will increase.

An obvious part of breadmaking that is temperature sensitive is gas pro-

duction by the yeast and variations in dough temperature will influence

dough volume the end of proof. Even a well-controlled prover environment

cannot compensate for variations in dough temperature. In the vast majority

of bakeries variations in proof volume cannot be compensated for by chang-

ing proof time and so variations in bread volume and quality will follow if

the temperature of the dough entering the prover is not constant.

The ultimate choice of dough temperature to use is closely linked with

the breadmaking process being used, with higher dough temperatures being

used with no-time doughs than those which will experience bulk fermenta-

tion or significant processing times.

The control of the temperature of bread and fermented dough is probably

the single most critical control point in the bakery.


4.1.14 We have been experiencing some variationin crust colour on our bread products. What causesbread crust colour and why should it vary?

The crust colour on bread is principally formed by Maillard-type reactions

involving reducing sugars and amino compounds (free amino acids and ter-

minal amino-groups in soluble proteins). For colour formation, you need

both factors to be present in appropriate amounts. These reactions typically

occur from around 115�C.A small amount of the main reducing sugar, maltose, may be present in

the flour but in fermentation, proving and the early stages of baking, the

alpha- and beta-catalysed hydrolysis of the starch in the flour increases

the amount of maltose present. Amylases are slow to attack intact starch, so

the main source of starch for hydrolysis is the damaged starch. Thus, the bal-

ance of enzymic activity and flour starch damage becomes important for cor-

rect crust formation.

Other sugars which may contribute to colour formation are glucose and

fructose, sucrose or lactose if non-fat milk solids in present in the recipe.

Caramelisation may also occur, even in the absence of Maillard-type reac-

tions but it occurs at much higher temperatures, usually above 155�C.The variations in colour that you are experiencing may therefore come

from a number of sources. Assuming that the baking conditions are not to

blame then the most likely causes are variations in damaged starch levels in

the flour or enzymic activity, whether in the flour or from the improver. You

may want to have these checked.

Remember that enzymic activity is temperature sensitive so that varia-

tions in dough temperature may contribute to variations in crust colour.

Processing delays may cause darker than usual crust colours due to the lon-

ger time available for enzyme action. Even retarded doughs can show pro-

blems of dark crust colours due to enzyme activity in the dough. If you are

using a fermentation process to develop your dough, you should check that

the bulk time and fermentation conditions are being carefully controlled.

There are generally adequate amounts of naturally occurring amino com-

pounds in bread flour, but if you continue to get pale crusts, then an addition

of non-fat milk solids or an ammonium salt can help. Reducing a dark crust

is harder to achieve because it requires the removal of material which may

be already in the flour or improver.

Further reading

Perez-Lucas, C., Yaylayan, V.A., 2010. The Maillard reaction and food quality deterioration.

In: Sibsted, L.H., Ribo, J., Andersen, M.L. (Eds.), Chemical Deterioration and Physical

Instability of Food and Beverages. Woodhead Publishing Ltd, Cambridge, UK.





4.1.15 Why is the surface of some bread doughs cutbefore baking?

Many types of breads, especially crusty forms, have a distinctive pattern of

cuts showing on the baked surface. These cuts are usually made when the

dough leaves the prover and before it enters the oven.

The most obvious reason for the cuts is to provide a distinctive surface

pattern which distinguishes one loaf from another. Each characteristic pattern

will have originated many years ago and has now become so enshrined in

the product character that they have become part of the authenticity of a par-

ticular product and part of consumer perception of product quality. If it has

been cut like a bloomer and baked like a bloomer, then at first glance in a

display of other breads it meets customer expectations of a bloomer and they

will be attracted to it.

Probably, surface cuts were first used by bakers for quite different rea-

sons. While dough is proving its rheology begins to change and in particu-

lar it becomes less elastic, but this change is slow and time is an

important element of achieving the required effect. If doughs enter the

oven after only a short while, they are essentially under-proved and the

still elastic nature of the dough prevents uniform expansion in the oven.

Cutting the surface of dough pieces creates points of weakness which can

be exploited by the expanding dough so that cutting can be used to pro-

duce controlled oven spring. A rule of thumb is that if doughs are not

fully proved you cut deeply, whereas if doughs are over-proved you make

the cuts shallow.

There is a common tendency to worry about cutting doughs deeply

because they may collapse and fail to rise in the oven. The main cause of

such collapse is not usually the cutting (unless the doughs are grossly

over-proved) but rather that the doughs lack gas retention. Doughs which

have been fully developed can be cut quite deeply, and even if they col-

lapse after cutting, they can regain their correct size and shape in the

oven.

Bread doughs bake by receiving heat through their surfaces and because

dough is a poor conductor of heat one way in which to speed up heat transfer

is to increase the surface area available for heating by cutting the dough.

This increase in surface area also helps with flavour development in the

product because cutting often increases the proportion of crust relative to

that of the crumb. As much of the bread flavour comes from the crust, the

greater the proportion of crust the more flavourful the product.


Cutting should always be carried out with a clean, sharp knife and should

follow the traditional pattern closely. Each bread type will have its own dis-

tinctive pattern and method of making the incisions and without the right

procedure then you will not get the authentic product.

Cutting of the dough at the end of proof contributes to the contrast of the

darkening crust yet paler interior which has burst out of the dough in the

oven. Such features are commonly an intrinsic part of final product quality,

perhaps exemplified by the French baguette. Cutting of dough pieces before

into the proves is sometime practiced, but the lack of contrast in crust

appearance will be lost and may not have the same appeal to consumers.


4.1.16 What are the best conditions to use for provingbread dough?

The main purpose of the proof stage in baking is to expand the dough piece

and modify its rheology to obtain further expansion and structure develop-

ment in the oven. To achieve this, we need to generate carbon dioxide gas

from yeast fermentation. So our first consideration is to provide the best pos-

sible conditions for yeast activity. Yeast will produce carbon dioxide gas

over a range of temperatures running from around 0�C. As the temperature

rises, gas production increases reaching a maximum at around 43�C. By the

time that the temperature has reached 55�C, all yeast activity has ceased and

the cells are dead.

Usually, we seek to achieve around 90% of our required product volume

in the proved dough leaving the last 10% or so to come from oven spring.

The time that it takes for this point to be reached in the prover depends

mainly of the proof temperature and the level of yeast that is present in the

dough, and to some extent, the dough temperature when it enters the prover.

The greater the quantity of yeast the shorter will be the proof time to a given

volume. Thus, if our sole criteria for deciding on proof conditions is to leave

the dough in the prover for as short a time as possible, then we would choose

a high yeast level and a temperature around 40�43�C, and to a large extent

this is the norm in most bakeries.

The other issue we have to consider is the relatively poor conductivity of

heat by dough. The dough commonly enters the prover at a lower tempera-

ture than the air in the prover. As proof proceeds, the outer layers quickly

warm while the dough centre remains cooler. If the yeast level is very high,

the outer layers will quickly become over-proved and lose gas retention

properties. Large temperature differentials in a dough piece by the end of

proof tend to give poorer product quality shows as lack of volume and

uneven cell structure.

The other condition that we must pay attention to is the relative humidity

of the air surrounding the dough. The dough relative humidity lies around

90�95% and so there is considerable potential for surface evaporation unless

we take steps to raise the prover humidity. Typically, we raise this to around

85% to minimise surface evaporation or skinning.

In summary, the best proving conditions to use are the ones which are

most ‘dough-friendly.’ This would suggest temperatures similar to those that

we achieve in doughmaking, but this would give extended proof times

unless we raise yeast levels to such an extent that we may incur

unacceptable flavour changes or unnecessary high ingredient costs. The prac-

tical compromise suggests temperatures from 35�C to 40�C with appropriate

humidity control.


If cooler proof conditions are chosen, then yeast levels and proving times

will need to be adjusted, as will the prover relative humidity. Cooler proof

temperatures will reduce the differential between surface and core tempera-

tures which delivers a more uniform proof and oven spring.

Further reading


AG, Switzerland.








4.1.17 Can we freeze our unproved dough pieces and storethem for later use?

The freezing and storing of unproved bread and other fermented doughs is

perfectly possible but does require some attention to all aspects of dough

production, processing and subsequent use on defrosting. The following

guidelines highlight some of the most important areas for attention:

� Use a no-time doughmaking process as periods of fermentation before

freezing have an adverse effect on bread quality.

� Use ingredients and a dough formulation which gives good products by

scratch production. Freezing and thawing cannot improve product

quality.

� Raise your recipe yeast level to compensate for the loss of gas production

from yeast cells which are killed during the freezing and storage. Or use

a yeast strain which has a greater tolerance to freezing.

� Freeze the dough as quickly as possible after moulding to minimise gas

production.

� You may need to adjust product dimensions before freezing as doughs

may sometimes spread during freezing and fail to fit pans when you take

them out for thawing.

� Use a blast freezer but avoid air temperature less than 230�C due to

adverse effects on product quality.

� Ensure that products are fully frozen, aim for a core temperature of at

least 210�C before passing to storage to minimise quality losses.

� Expect progressive loss of final product volume as frozen storage time

increases so compensate with increased proof times.

� Thaw the products using low temperatures and long times to minimise

temperature differentials between the dough centre and its surface when

it reaches the end of proof.

� Select carefully the products that you wish to make with frozen dough.

Products with small diameters like rolls and baguette will be more suc-

cessful than thicker products like pan breads

Further reading

Cauvain, S.P., 2014. Frozen dough and par-baked products. In: Zhou, W. (Ed.), Bakery Products

Science and Technology. Wiley Blackwell, Oxford, UK, pp. 523�538.


Switzerland.

Kulp, K., Lorenz, K., Brummer, J., 1995. Frozen and Refrigerated Doughs and Batters.

American Association of Cereal Chemists Inc., St. Paul, USA.

Stauffer, C.E., 1993. Frozen dough production. In: Kamel, B.S., Stauffer, C.E. (Eds.), Advances

in Baking Technology. Blackie Academic & Professional, London, UK, pp. 88�106.












4.1.18 What happens when dough bakes?

In simple terms, when dough enters the oven it expands, loses moisture, the

crust darkens and it sets to form bread. Behind this simple explanation are many

different physical and chemical changes which are summarised as follows:

� Gas production by the yeast continues as the dough temperature rises in the

early stages of baking. When all of the dough exceeds 43�C, the rate of gas

production falls and eventually ceases by 55�C. Although the dough surface

is rapidly heated and yeast activity ceases, the poor heat conductivity of

dough means that the centre continues to produce carbon dioxide gas for

some time after the crust has formed. The force which is created by the

expanding centre means that tin dough springs upwards creating oven spring.

� The dough is also being expanded by steam pressure and the expansion

of trapped gases which are present.

� For the dough to continue to expand during baking, it must be able to

retain the gas which is being released. The stresses placed on the dough

during the early stages of baking are much greater than those placed on it

during proof, and it is only in the oven that doughs which truly lack the

correct gas retention properties are exposed. Commonly, lack of gas reten-

tion is seen as lack of oven spring or in more extreme cases as collapse.

� The dough loses moisture with increasing baking time. The moisture

losses are greatest from the crust, and this encourages the formation of a

crisp eating, crusty layer.

� The Maillard reactions begin to develop the crust colour (see Section

4.1.14).

� The starch begins to swell and gelatinise. At this time, more of it

becomes susceptible to the action of any alpha-amylase enzymes which

are present, and the breakdown to sticky dextrins and maltose is acceler-

ated by the higher temperatures.

� In the dough, the gas bubbles which are present, are separated from one

another by a thin protective film. As they are not connected with one

another, they are commonly described as a ‘foam.’ As baking proceeds,

the loss of water makes the gluten protective film become more rigid,

and the pressures within the gas bubbles rupture the protective films. At

this moment, the foam in the dough is converted to a sponge, that is, a

system in which all of the cells are open and interconnected. At this time,

the volume of the baking loaf falls slightly as the internal and external

gas pressures are equalised.


� Moisture continues to be lost while the product remains in the oven.

� All of the necessary changes from to baked product are usually achieved

by the time that the product centre reaches a temperature between 92 and

96�C.

Further reading


AG, Switzerland.








4.1.19 We make crusty breads in a retail store, and recently,we have been having complaints about our products going softquickly. We have not changed our recipe or process. Can youhelp us understand what has happened?

When crusty products leave the oven, the moisture content of the crust is

much lower than that of the centre crumb. Typical values can be as widely

apart as 12 and 42%, respectively. From the moment of leaving, the oven

this moisture differential provides a driving force for moisture migration

from the crumb centre to the crust. This moisture migration continues as the

product begins to cool and carries on during subsequent storage. Eventually,

the crust moisture content rises to a level at which the product is no longer

crisp or crusty.

The rate and extent to which the moisture migrates from the crumb to the

crust depends on several different factors, including the storage temperature.

The lower the storage temperature the lower the rate of moisture migration,

but note that the rate on non-moisture-related firming (staling) will increase


The usual process for the movement of moisture in crusty bread is from

crumb to crust as nature tries to achieve moisture equilibrium between the two

components. The moisture content of the crumb falls and that of the crust

rises. If the product is unwrapped, then the crust generally loses moisture to

the surrounding atmosphere, provided that the atmosphere relative humidity is

lower than that of the loaf. In practice, this is mostly the case and air draughts

which sweep across the product surface carry the moisture away. This lost

moisture is replaced by more migrating for the crumb and the whole product

dehydrates and loses consumer appeal.

To prevent this dehydration, we wrap bread in a suitable protective film

but if we put crusty bread into a moisture-impermeable film (e.g., a polyeth-

ylene bag), then the moisture which would have been swept away remains

and the bread quickly comes to equilibrium with the atmosphere in the wrap-

per. The result is that crustiness is quickly lost. The alternative is to use a

semi-permeable film to let some of the migrating moisture escape through

the holes in the wrappers and help keep crust crispness for a longer time.

Commonly perforated films are used for the purposes, the size and distribu-

tion of the perforations being used to control the rate of moisture loss.

A common cause of loss of crust crispness, even when perforated films

are used comes from wrapping bread too warm. In many bakeries, bread

freshness is wrongly equated the product being hot, and staff may be encour-

aged to wrap the product while still warm. This practice has three main

disadvantages:


1. Moisture will be lost from the warm bread and condense within the wrap-

per. The moisture will be reabsorbed by the product crust, so in the case

of crusty breads, it encourages softening of the crust.

2. The loss of crust crispness leaves the bread susceptible to crushing on the

shelf and in the shopping basket.

3. Condensation encourages the localised raising of product water activity

and so encourages the growth of moulds.

In fact, your problem arose due to a subtle change in the type of perfo-

rated film that you were using. Feedback from the check-out staff in the

store had indicated that bits of crust were contaminating the scanner and so

you changed to a film with smaller diameter perforations. Doing this reduced

the scanner problem but also reduced the rate at which moisture was lost

from the product, in effect the system behaved more like an impermeable

bag and the crust softened more rapidly.

The way to reduce the scanner problem is certainly to reduce the perfora-

tion diameter, but you need to increase the number of perforations per unit

area of film so that the moisture vapour transpiration rates (see Section 11.7)

of the two films are equal. The smaller diameter perforations will reduce the

size of the crust particles which fall through, and the increase in the numbers

will maintain the loss of moisture at a level similar to that which you were

getting before.

Further reading






4.1.20 We have been comparing our bread with that of ourcompetitors and find that the crumb of our bread is firmer.Can you explain why?

There are a number of reasons why we can have differences in bread crumb

softness, some are related to the ingredients that are used, whereas others are

directly affected by the processing methods. The first element to look at is

whether there are any differences in the moisture content of the crumb of the

breads concerned, the higher the crumb moisture content the softer the bread

will be.

Bread softness is directly related to bread volume, and the greater the vol-

ume of the bread the softer it will be. Even when breads have the same volume,

we may still see differences in softness which are related to the density distribu-

tion in the crumb cross-section. If we want to make the crumb of pan breads

softer, then one possibility is to create greater expansion of the centre crumb to

lower its density and resistance to compression. We can do this by increasing

the gas retention in the dough using ingredients such as oxidants, fat, enzymes

and emulsifiers or by improving dough development during mixing.

However, producing a crumb which is less resistant to compression is

only part of the answer to making fresher bread. We also need to make a

crumb which will largely recover its original shape after the consumer

squeeze test. This again can be achieved by improving dough gas retention.

In particular, we would want to create a fine (small average cell size) crumb

cell structure with thin cell walls separating the cells. This can best be

achieved by creating a gas bubble structure in the dough which consists of

many small bubbles and expanding them uniformly without excessive dam-

age to the dough during moulding.

All bread goes firmer during storage, even if moisture is not lost from the

crumb. This firming process is the one most often referred to as ‘staling’ and

is largely associated with the recrystallisation (retrogradation) of the starch

in the bread. A number of factors will influence the rate at which bread

stales including:

� The storage temperature. Bread staling increases as the temperature of

storage falls reaching a maximum at about 4�C. Check the temperatures

in your despatch and storage areas and see if they can be made warmer

but watch out for the potential for greater microbial spoilage.

� The presence of emulsifiers in the formulation. Some emulsifiers work to

improve crumb softness by improving dough gas retention or through

reducing gas bubble size in the dough. Additions of Glycerol monostea-

rate (GMS) can be used to slow down the starch retrogradation process,

but it is important that the GMS is added in its active alpha form, com-

monly as a hydrated gel.


� Maltogenic amylases can be added to the dough and these also affect

starch retrogradation. In this case, the bread will not only start softer but

firm at a lower rate.

You should also look at your oven baking conditions. Generally, softer

bread is obtained is you can bake at a higher temperature for a shorter time,

but of course there are limitations. Also check your cooling process and

whether you can shorten the time being taken to cool the product. The short-

est possible cooling time will be dictated by the temperature at which you

can slice or wrap your product. You do not want to encourage condensation

in the wrapper which can encourage mould growth.

Further reading


AG, Switzerland.








4.1.21 We are having problems keeping a uniform shape withour bloomers. They tend to assume a bent or ‘banana’ shape.This happens even though we take great care to straighten themwhen they are placed on the trays. Can you explain why we getthis problem?

This can be a common problem in the production of free-standing breads

and can easily be explained, though in some cases the solution can be quite

difficult to achieve. The banana shape (see Fig. 4.12) is actually created

towards the end of the final moulding stage. As the dough piece passes under

the moulding board on the final moulder and is extended in shape by the

rolling action, the ends of the piece touch the side guide bars. The effect of

the guide bars is to slow down the progress of the two ends of the dough

piece while the centre continues to move at a higher speed. If you look

closely at the dough pieces as they travel under the final moulding board,

you will see this happening and observe that the dough piece already has the

banana shape you refer to (Fig. 4.13).

During the passage of the dough under the moulding board the ends and

the centre of the dough piece are subjected to different levels of ‘twisting’

force. This means that even though you are straightening the dough pieces

FIGURE 4.13 Schematic of bloomer dough piece passing under the moulding board.

FIGURE 4.12 Bloomer with bent shape.


by hand, and even though you are giving them 45-minute proof, there is suf-

ficient elasticity left in the piece for it return to the shape that it had taken

on during moulding. This problem is more severe in bloomers because the

dough often has a stiffer consistency to help with retaining the traditional

round cross-section after baking.

The final moulder should be set to reduce the variation in twisting forces

between the different parts of the dough piece. You should try to reduce the

pressure exerted by the moulding board raising it up so that the dough piece

only reaches its full length after half way under the board, ideally about two-

thirds of the way down the length of the board. If you cannot do this without

compromising other aspects of shape (e.g., sealed ends), then the ideal solu-

tion would be to use a moulder with a longer moulding board.

You may find similar problems with any free-standing cylindrical shaped

products. If you are taking a larger dough piece and cutting it into smaller

individual pieces, you are likely to find that uneven moulding contributes

significantly to variations in dough piece dimension after baking.

You can gain some benefit by proving the dough at a lower temperature

for a longer time. The longer time and the reduced temperature differential

in the dough piece both help to yield a more ‘relaxed’ dough piece entering

the oven which should expand in a more uniform manner. If you do reduce

the proving temperature, remember to slightly reduce the humidity as well

otherwise the dough pieces will begin to flow and lose their shape.

If you cannot make adjustments to the moulder or proving conditions, you

might try a slight increase in added water level, but there is a delicate balance

here because more water in the dough can cause the bloomer to assume a flat-

ter appearance (Cauvain and Young, 2008). You may also find that it helps to

mix the dough longer as you are using a spiral mixer, making sure that you

keep the final dough temperature the same as for normal production.

Reference






4.1.22 We have been taught to always place the seam of ourmoulded bloomer dough pieces downwards on the tray beforeproof, but we do not take the same precautions with our panbreads. Can you explain the relevance of placing the bloomerdough piece ‘seam’ down? Should we also do thiswith our pan breads?

The ‘seam’ to which you refer is the tail-end of the sheeted dough pancake

formed after it has been curled. It is seen as a curving line on the final

moulded dough piece. Even with hand moulding a seam will be formed by

the last portion of the piece to be moulded. In bakeries where dough pieces

are panned by hand, the traditional practice is to place them on a tray or in a

pan with the seam on the bottom, that is, in direct contact with the metal

tray or sling.

There are a number of reasons for this procedure. The first is related to

the appearance of the baked product. The portion of the dough which com-

prises the seam may not always be ‘sealed’ in the final stages of moulding

and often has the propensity to uncurl in the prover and the early stages of

baking. Placing the seam downwards uses the pressure of the dough mass

during expansion to reduce the risk of the seam unravelling. If the seam is

placed on the sides or top of the dough pieces, then any unravelling will

cause unsightly splits in the crust.

In principle, the seam should be placed on the bottom for all dough

pieces. In automatic plants, this is not generally possible when making pan

breads as there is no human intervention at the panning stage. This tends not

to cause significant problems for the quality of lidded pan breads because

the impact of the lid reduces the potential for unravelling of the dough curl.

Similarly, there is a reduced risk of unravelling when four-piecing of the

dough is used (see Section 9.6), even when open-top bread is made. The

greatest risk of quality losses from the random positioning of the seam is

likely to occur with open-top single piece bread.

One contribution of the seam location not often appreciated is the potential

contribution to the formation of unwanted holes in the product crumb. There

is the potential for damage to the dough during sheeting (Cauvain and Young,

2008) and for the trapping of small gas pockets during curling both of which

contribute to the formation of unwanted holes (see Section 4.1.7). If the seam

is placed downwards on the tray or in the pan, the pressures in the dough

mass tend to squeeze out some of the larger gas pockets but if the seam is

located in some other part of the dough piece the pressures may be insufficient

to eliminate the gas pocket and this can give rise to unwanted holes.

Reference






4.1.23 Can we make bread without using additives?What will be the key features of the ingredients and processthat we should use?

There are many different types of bread and fermented products which are

made without using additives, i.e., with just flour, water, yeast and salt. To

develop the properties of the gluten network in the dough and improve its

ability to retain carbon dioxide gas and expand during baking, it is usual to

give a significant period of fermentation to the dough. The first stages of

dough fermentation are usually carried out with the dough still in its bulk

form, i.e., before it is divided into unit pieces for processing, proving and

baking. The length of the bulk fermentation period varies according to the

strength of the flour. In general, low protein flours are given shorter periods

of bulk fermentation than high protein flours. This is because it takes longer

for the natural enzyme-induced changes to modify the dough gluten quality

with high protein flours.

The length of the bulk fermentation time will also affect the development

of flavour in the final bread. It is commonly considered that a bulk fermenta-

tion period of at least 3�4 hours is required for there to be a significant

change in bread crumb flavour. In many cases, the fermentation periods may

extend for up to 24 hours. In bulk-fermented dough, a significant contribu-

tion to flavour comes from the action of lactic acid bacteria (Wirtz, 2003)

which deliver distinctively acid flavour notes in the final product.

As you are relying on fermentation to modify the gluten network in the

dough, it will be very important for you to control both the time and the tem-

perature of fermentation. To achieve control of the latter, you will need to

work to a constant dough temperature and carry out the bulk fermentation

under temperature-controlled conditions; if you do not do this, then you must

expect variable bread quality.

If you do not wish to ferment the dough in bulk, then you may choose

from one of the alternative methods which ferment only part of the flour and

other dough ingredients for many hours before mixing them with the rest of

the ingredients to make the final dough. These processes are known by many

different and traditional names; such as sponge (and dough), flying ferments,

sourdough and polish (Calvel, 2003) and each contributes different attributes

to final product quality.

Choosing the ‘right’ flour will be very important to you as you are rely-

ing heavily on the flour proteins for gas retention.

References

Calvel, R., 2003. The Taste of Bread. Aspen Publishers, Inc, Gaithersburg, MA.

Wirtz, R.L., 2003. Improving the taste of bread. In: Cauvain, S.P. (Ed.), Bread Making:

Improving Quality, first ed. Woodhead Publishing Ltd, Cambridge, UK, pp. 467�486.






4.1.24 We make bread and rolls using a bulk fermentationprocess; can we use ascorbic acid (AA) to improve our breadquality?

AA is considered in chemical terms to be a reducing agent or anti-oxidant in

food systems. However, in breadmaking is commonly regarded as an ‘oxidis-

ing’ agent. This is because in the preparation of bread dough, the AA reacts

with oxygen from the air which is incorporated during dough mixing. The

reaction in dough converts the AA to a substance known as dehydro-ascorbic

acid (DHA) (in conjunction with the ascorbate enzyme present naturally in

wheat flour) and so can act as an oxidant by promoting the formation of dis-

ulphide bonds in the developing gluten network (Wieser, 2012).

The presence of oxygen in the dough is an integral part of the oxidation

process when AA is used. There is another important reaction involving oxy-

gen in the dough, and this is linked to yeast activity. During mixing and in

the early stages of dough processing, the yeast scavenges the oxygen mole-

cules which are present with the result that the environment in the dough

changes from being aerobic (i.e., with oxygen present) to anaerobic (i.e.,

without oxygen).

The yeast can continue working and generating carbon dioxide in the

anaerobic environment which has been created, but the AA can no longer be

converted to DHA. When this situation arises, the AA reverts to its usual

chemical function as a reducing agent and can reduce the strength of the

dough. In these circumstances, there will be a loss of dough gas retention

properties and in turn, a loss of bread volume. In bulk fermentation pro-

cesses, the environment in the dough will quickly become anaerobic, and

there is the potential for the AA to act as a reducing agent during the long

fermentation period which follows mixing.

The potential for using AA as an ‘improver’ (that is, to increase dough

gas retention) depends on the length of the bulk fermentation time that you

are using. If you are using short periods of time (say up to 2 hours), you are

likely to get some improvement in dough gas retention properties, but with

longer periods, you are likely to see the opposite. You should avoid using

AA in the sponge part of a sponge and dough process, unless you need the

reducing effect for some reason.

In practice, the levels of addition of AA for use in bulk fermentation should

be low and limited to no more than 15�20-ppm flour weight (0.15�0.20 g to

10 kg flour). Some millers supply flour treated with low levels of AA. You may

want to check if this is the case because adding more AA in the bakery could

well create problems for your bread quality as described above.

Reference

Wieser, H., 2012. The use of redox agents. In: Cauvain, S.P. (Ed.), Bread Making; Improving

Quality, second ed. Woodhead Publishing Ltd, Cambridge, UK, pp. 447�469.





4.1.25 We have had bread returned to us by the retail storethrough which it is sold. They are not satisfied with the quality.We have some pictures of the products concerned. This seems tobe a ‘one-off’ and we are at a loss to understand what has led tothe problem. Can you help us understand where the problemcame from?

Identifying the cause of ‘one-off’ problems can be very difficult. The best

place to start is to look at any production records that you may have for the

period in question. In particular, you should look at any process information

which might indicate changes in ingredient batch, recipe or deviations from

the normal process times. If there are no suitable records available, then you

will need to start the investigative process by recording what you see and

then work towards the likely cause of the problem.

Our first observation is that there is a clear problem with the shape of the

product and in particular the top which is not uniform in appearance

(Fig. 4.14). There are some dips in the surface which are also paler in colour

than the surrounding areas. The pale colour tells us that these parts of the

dough were not in contact with the lid on the pan for the whole of the baking

period; otherwise, they would have the same colour. What is does not tell us

is whether these pale areas are formed because the dough pulled away from

the pan and lid (collapse) or whether they expanded too late to reach the lid.

The outer edges of the loaf show that the dough had clearly filled the

pan at some stage. If expansion of the dough was late in the oven then we

would expect that the edges of the loaf would be the pale areas. So, we can

reasonably assume that the pale areas are associated with a collapsing back

of the dough.

The interior of the loaf show considerable variation in cell structure with

considerable compression at the base and the sides of the loaf (Fig. 4.15). In

contrast, the area in the centre towards the top is more open. This could be

FIGURE 4.14 Loaf external appearance.


because the lid was not heavy enough to cause compression under the top

crust. However, we have already concluded that in places the dough was not

in contact with the lid long enough to become as coloured as the rest of the

crust. This internal effect is also consistent with a collapse of the dough

early on in the baking process and an almost complete recovery of the shape

later due to the significant gas production potential in the centre of the

dough piece.

Taken together, these observations suggest that the problem is caused by

over-proof of the dough combined with a bumpy transfer between the prover

and the oven. It is also likely that the oven temperature was on the low side,

and this in effect gave the dough piece a second, short proof in the oven

which is why the piece was able to expand to mostly fill the pan. A check

on production and plant operation records would be able to verify whether

this was the case.

FIGURE 4.15 Loaf internal appearance.


4.1.26 We have noticed that loaves sometimes break only onone side of the pan but that the break is not formed consistentlyon one side. Can you explain why this is?

The process that you are asking about is often called ‘oven spring’ or ‘oven

break’ and is related to the ability of the dough to retain the rapid evolution

of carbon dioxide gas and steam in the first few minutes in the oven. The

break forms when the pressure created by the expansion of the centre of the

dough piece is sufficient to cause a break in the crust which has formed soon

after baking starts. At this time, the crust is still relatively soft and does not

have sufficient strength to hold back the expansion forces. Due to its relation

with dough gas retention, controlled oven spring is often seen as a desirable

characteristic in fermented bread products. The aim is to have controlled and

uniform expansion. In the case of pan breads, the ideal is to have a small but

uniform break along both sides of the loaf.

The nature and precise location of the oven break on a loaf depends on

many factors. The presence or absence of moisture in the oven atmosphere

has a profound effect on the oven break. A low relative humidity tends to

lead to the formation of ragged and uneven breaks though this is usually a

greater problem with oven-bottom or hearth breads (see Section 4.1.3) due to

the lack of shielding from a pan. Raising the level of humidity in the early

stages of baking through the deliberate introduction of steam is a common

practical way to control oven spring with open-top pan breads. Steam may

be introduced when baking lidded pan breads though its impact may be very

limited by the presence of the lid.

A common factor which can influence the formation and location of the

oven break is the delivery of heat to the dough piece. For example, if the

loaves are placed close to the sidewalls of the oven, they will be exposed to

greater radiant heat than other loaves more centrally placed. This causes the

crust to set quickly and lose its elasticity. In some cases, this may mean that

the oven break is on the side nearest the oven wall, whereas in other cases, it

will occur on the opposite side of the loaf. Much depends on the total

amount of heat and the rate at which it reaches the product. This will vary

with different ovens and be influenced by temperature settings and air flow

patterns in the oven, especially between pans. It will also be influenced by

the dimensions of the dough pieces, the strapping configuration of the pans

and their spatial layout in the oven chamber.

To get a uniform oven break, it is very important to ensure that the dough

is able to gently expand in the oven. Optimising the final proof of the dough

so that it has the appropriate rheological characteristics is an important factor

in achieving uniformity of expansion; as a ‘rule of thumb’ bakers aim for the

dough piece to achieve about 90% of the final bread volume in proof.


4.1.27 We are making a range of crusty breads using a smallbread plant. We appreciate the value of having an open cellstructure to encourage the formation and retention of the crust.However, from time to time, we have difficulty in achieving thedesired degree of openness in the structure. Can you help usidentify why this happens?

You are quite right in recognising the important link between the openness of

bread cell structure and the formation of a crisp crust. The openness of the

final structure depends on two key factors; the ability to create large gas cells

in the dough and their retention during dough processing, proving and baking.

When dough leaves the mixer, large numbers of small gas bubbles are trapped

in the gluten network. Carbon dioxide from yeast fermentation inflates these

small bubbles, and they grow larger. Later on, during the proving and baking

stages, the gas bubbles grow very large, begin to touch and coalesce (that is, join

together) to form even larger gas bubbles. It is these gas bubbles which eventu-

ally become the cell structure in your product. To help you appreciate the scales

involved the initial gas bubbles may range from 10 to 200 μm in size while the

cells in the baked crumb are typically 5�15 mm; that is, around 100 times larger.

A key process in the gas bubble expansion is the generation of sufficient

carbon dioxide gas in the processing time available. This will be affected by

the yeast level you are using, and the dough and processing temperatures and

times. Assuming you are not varying the time then a likely cause of variation

may well come from variations in dough temperature. You may be compen-

sating for these by adjusting final proof times, but often, it is the amount of

gassing that you get during the dough processing stages (particularly between

moulding stages) that makes the difference to the product structure.

Some of the creation of an open cell structure occurs in the mixer as some

mixers incorporate larger gas bubbles than others. After leaving the mixer, it

is best to divide the dough into individual pieces and limit any first moulding.

If you have created larger gas bubbles, then it is important to retain them dur-

ing processing, and this can only be done with gentle handling of the dough.

If you find that you cannot achieve the openness of cell structure that

you require, then you may want to lengthen the first or intermediate proof

time. If you do lengthen this time, then you should make sure the tempera-

ture of the dough pieces does not fall and that there is no opportunity for

skinning to occur. You may also need to slightly reduce your final proof

time to maintain a constant dough piece size entering the oven but no so

much as to end up with under-proved loaves as this may lead to other quality

problems, such as ragged breaks (see Section 4.1.3).

In summary, the key to getting a consistent cell structure in your final

product is to ensure that there are minimal variations in dough temperature

and to ensure that your moulding regime is preserving the larger gas bubbles.

Think of the larger gas bubbles as being eggs and that the objective of dough

processing is to carry them unbroken in the dough to the prover.


4.1.28 During the manufacture of bread and other fermentedproducts, we sometimes have small quantities of ‘leftover’ doughfrom a mixing, can we add these back to other mixings or reuseit in other ways?

With fermented products, it is advisable to be cautious in using rework. In

products such as circular biscuits which are cut from a sheeted dough, it is

common practice to use dough leftover from previous batches provided there

are no product safety or quality concerns. For fermented rework dough the

storage and reuse, in terms of time and temperature, quality and quantity

should be carefully controlled so that the introduction of quality defects is

avoided.

For fermented products, there are many factors of which to be aware.

Using one type of rework, e.g., white dough, with another type, e.g., whole-

meal dough, must be avoided as such use may be considered as contamina-

tion from safety and quality viewpoints. In addition, one type of dough

should only contain rework of the same type of dough as in many countries

the permitted ingredients in the manufacture of a particular type of bread are

limited by legislation.

Storing rework and using it at another time may result in products with

quality defects such as poor and irregular cell structure, loss of volume and dif-

ferences in external colour. If rework is stored for any significant length of

time, e.g., a few hours, doughs with higher temperatures may result in the

development of ‘off-odours’ or flavours in the final product. Such rework

should not be seen as a substitute for creating a ‘sponge and dough’ product or

enhancing flavour unless it has been kept under strictly controlled conditions.

In some cases, rework may be considered as an ‘ingredient’ with speci-

fied characteristics. It should be incorporated into the mixer to ensure uni-

form dispersion and optimum control and as a guide should be limited to no

more than 10% of flour weight for the new mix. Adding greater quantities

than this can result in the rework dough acting like a reducing agent with

quality defects such as irregular cell structure and poor slice appearance.

With stored rework, yeast activity leads to the continued evolution of car-

bon dioxide and the eventual depletion of sugars in the dough and loss of the

crust colour-forming components in the dough. There will also be changes in

the rheological properties of the gluten network in the dough which com-

monly contribute to loss of its gas retention ability. If fermented rework

must be used then its level of addition should be severely limited and it is

important to ensure thorough mixing with the ‘fresh’ ingredients. If using the

CBP the weight of this added rework should be excluded when calculating

the energy requirements for the mix.


4.1.29 Our total time for bread production from flourto baked loaf is set for about 6 hours. Currently, we use a bulkfermentation time of 4 hours and a final proof time of90 minutes. We find that with increased bread sales that we donot have enough proving capacity. If we were to shorten thefinal proof time what other changes would we have to make tomaintain our current bread quality?

Final proof has two important functions; one is to encourage the production of

carbon dioxide gas by the yeast and the other is allow some modification of

the rheological properties of the dough so that it will lose some of its elasticity.

This latter change is important as it allows for a more gradual expansion of the

dough in the oven and the delivery of a smooth and uniform oven bread.

Bread which is ‘under-proved’ is often characterised by a ragged or wild crust

break, sometimes referred to as a ‘flying top’ or ragged break (Fig. 4.16).

In view of the above comments, there will be a minimum final proof

time that you can use without compromising bread quality. You will need to

explore the options for yourself as this minimum time is affected by the

dough temperature and final proof conditions. As a guide, you could reduce

your final proof time to about 60 minutes and we would suggest that (pro-

vided you have the process space available) that you compensate by increas-

ing you bulk fermentation time to about 4.5 hours. This change should

maintain your existing bread quality without the need for recipe changes.

If you are not able to extend your bulk fermentation period, then you

would have to slightly increase the level of yeast that you are using to ensure

that you maintain dough volume at the end of proof. You may find that with

extra yeast that you need to cut back your bulk fermentation time slightly.

FIGURE 4.16 Flying top.


4.1.30 In breadmaking, what is the difference between asponge and a ferment and when would they be used? We havealso seen references to barms, can you tell us anything aboutthese as well?

Both sponges and ferments are based on the principle of initiating yeast

fermentation before the main bread dough mixing stage of breadmaking.

The most significant differences between the two is the length of time for

which they stand before being used and that the ferment will be of a much

softer consistency with less flour being used in the ferment recipe.

The basic recipe of a sponge comprises flour, water, salt and yeast and

after mixing the sponge is allowed to stand for several hours before it (or a

portion of it) is transferred to the mixer where the rest of the dough ingredi-

ents are added and dough preparation is completed (see example in Section

4.1.31). The ratio of water to flour in the sponge is similar to or slightly less

than that used in a standard dough. The yeast level in the sponge is usually

low as it will be fermenting for many hours, commonly 10�20. During the

fermentation period, the sponge will develop a distinctive acid flavour profile

which will be carried through to the final product. The sponge also contri-

butes to the development of the final dough. After final dough mixing, the

bulk dough is usually divided immediately for further processing.

A ferment is used in the ‘short ferment and dough breadmaking method’;

this is now a less common process than the sponge and dough. Typically, the

ferment will contain flour and water in at least equal parts, all of the yeast

but no salt. These ingredients are normally whisked or beaten together and

allowed to stand for a short period of time, typically 20�40 minutes, before

being mixed with the other ingredients. After final dough mixing, it is com-

mon to leave the dough in bulk for a short period before dividing it into unit

pieces for further processing. The ferment can be particularly useful if you

are using dried yeast that requires pre-hydration (see Section 2.6.7).

Barms are not often seen in use these days, if at all. They were based on

the use of distillers yeast from the maltings and were often seen in use in

some bakeries on the west of Scotland. The formulae and methods used were

complicated and relied on the preservation of a portion of barm for use in

subsequent batches. The process started with malt and water being mashed

together for several hours. A liquor was pressed from the mixture, flour stir-

red in and boiling water added to gelatinise the flour. The ‘scald’ as it was

called gradually cooled over 24 h and a portion of old barm from a previ-

ously prepared batch added. This mixture was then fermented for 3�4 days

before baking. Barms were normally prepared twice a week.


4.1.31 How would we prepare and use a spongewith the Chorleywood bread process (CBP)?

The preparation and use of a sponge with the CBP is not difficult. The common

use of a sponge is with no-time dough processes (i.e., the dough moves from

completion of mixing to the divider without delay). The only special facilities

that you will need would be the provision of space for storing the sponges.

To get consistent results, you should store the sponges under temperature-

controlled conditions and cover them to prevent dehydration and the formation

of a skin on the surface. It will be important to use the sponges in strict

rotation. Ideally, you would make one sponge for each dough and, that is,

the basis of the recipe given below. In practice, this may be difficult due to

space conditions, so you may have to make a larger sponge and use portions

for several successive doughs. If that is the case we suggest that the sponge

should not be used for more than 20�30 minutes of doughmaking to minimise

the risks of quality variations. In principle, these precautions are no different to

using a sponge with any other sponge and dough-type process.

There is no need to fully develop the sponge so you may use another

mixer for its preparation. You can use your CBP-type mixer for the sponge

preparation, but you need only mix for a short period of time; this will be

helpful in controlling the sponge temperature (see below).

The level of sponge that you prepare depends on the how much you wish

to change the crumb flavour; the larger the quantity of sponge used the stron-

ger the flavour profile. We suggest that you try a quarter sponge; that is, using

one quarter of the total flour weight to prepare the sponge as follows:

Sponge recipe and method

Ingredient Weight (kg)

Flour 12.50

Water 7.00

Yeast 0.10

Salt 1.25

Mix to clear dough with a final temperature of 20�C and ferment for 16 h.

Doughmaking

Add the sponge to the rest of the ingredients in the mixer, i.e., 3/4 of the

flour with appropriate water, salt, improver and yeast (the latter may be

reduced by about 5�6% of its original level).

Do not include the quantity of sponge in your energy calculation.

Further reading

Cauvain, S.P., Young, L.S., 2006. The Chorleywood Bread Process. Woodhead Publishing,

Cambridge, UK.




4.1.32 Our bread and buns prove to a satisfactory height inabout 50 minutes, but we get no additional lift from the productsin the oven. We have tried increasing its strength and using moreimprover, but whatever we do we see no oven spring.Do you have any ideas as to why we are getting no oven lift?

There are two processes which contribute to oven spring; gas production and

gas retention. By increasing the strength of the flour that you are using, you

should have improved the gas retention properties of your dough and the fact

that there was no improvement in oven spring strongly suggests that the

problem is with the gas production capabilities of the dough.

Initially, gas production in the dough relies on the ability of the yeast to

ferment the sugars which are present in the wheat flour to produce carbon

dioxide and alcohol (see Section 2.6.2). If there are added sugars the yeast

may use these; first the mono-saccharides (simple sugars) and later the di-

saccharides. There is also some maltose sugar being produced as the amylase

enzymes in the dough begin to break down the damaged wheat starch.

The metabolic processes of yeast in bread dough are complex and are

regulated by the osmotic pressure (see Section 11.12) across the walls of the

yeast cell. In part, this osmotic pressure is affected by the nature and concen-

tration of soluble ingredients in the recipe. In addition to the sugars already

mentioned, soluble ingredients in the dough which have an effect on yeast

activity include salt (sodium chloride) and preservatives such as calcium

propionate.

One of the complexities of the metabolic processes of yeast is that the

cells adjust their metabolism according to the food sources which are avail-

able in the dough. However, the transition from one food source to another

is not a straightforward relationship and at different times the metabolic pro-

cesses in the yeast slow down and gas production falls. After the yeast has

made the adjustment gas production will again increase. From the description

of your problem, it appears that the yeast strain that you are using is making

one of these transitions as the dough begins to reach the oven and so is not

able to provide the last burst of carbon dioxide gas which normally contri-

butes to oven spring.

Different strains of bakers’ yeast have different tolerances to sugar

(osmotolerance) and calcium propionate. They produce carbon dioxide gas at

different rates from other yeast strains in the dough and so may be more

suitable for your bread and bun production. You will need to consult with

your yeast supplier to find the most suitable strain of yeast for your particu-

lar recipe and processing conditions; once that you have the most appropriate

strain of yeast, we are sure that oven spring will be restored.


4.1.33 We are experiencing a problem with loaves baked inrack ovens since we bought new pans. As the enclosedphotograph shows, they are joining together above the pans. Theportions of the loaves that touch have no crust formation whichmakes them weak when they are depanned and handled. Howcan we prevent this from happening?

In the photograph, it is clear that the dough has risen well during the early

stages of baking and loaves in adjacent pans in the strap have touched

(Fig. 4.17). Consequently, these parts of the loaf did not form a solid crust

and had a pale, under-baked patch on the side. On the ends of the strap

where the dough has overflowed slightly, a normal crust was formed.

You indicated that you changed to new pans recently and now have four

small pans across the rack width where you had three previously. If bread

pans are strapped too closely together, then with a well-developed dough,

this ‘kissing’ of adjacent loaves will occur as they grow in the oven. This is

because the hot air in the oven cannot easily penetrate between the gaps

between individual pans in the strap, and in effect, you are prolonging the

final proof of the dough, albeit in the oven.

As general guidance the gap between pans of your strap should be

between 22 and 34 mm to allow adequate air circulation between straps in

the oven. The exact dimension between pans will depend on the efficiency

of the oven in circulating air through the gaps. Ovens which provide signifi-

cant air flow between the pans are usually based on the principle of forced

air convection. Air flow in fan-assisted rack ovens may not be as good at cir-

culating hot air as forced convection ovens.

FIGURE 4.17 Touching loaf from new straps of pans.


If the scaled weight of the dough piece deposited in the pans is too heavy,

then this may be a contributor to the problem. The scaling weights should

be checked for consistency. With the current deregulation of bread weights

in many parts of the world, it may be possible to slightly reduce the dough

scaling weight provided the finished baked weight is within the weight

specification for the product at point of sale.

Another option may be to reduce the gas retention properties of the

dough a little (e.g., by using a slightly weaker flour or slightly less improver)

provided the reductions do not compromise product quality (cell structure

and softness). It may also be possible to use less yeast in the recipe provided

the time to reach proof height is not too long and that oven spring is still evi-

dent in the baked loaf.


4.1.34 We wish to create a bolder shape and more open cellstructure with our crusty sticks and have recently increasedour dough development by mixing longer. Now, we experienceproblems with the products joining together in the oven. If weunder-prove the dough pieces, we have problems with raggedbread and poor shapes. Should we reduce our mixing time backto its original level?

This problem has similarities with that in Section 4.1.33. Our first response

is that you should not seek to solve your problem by under-proving the

dough pieces, indeed you own information suggests that this will only lead

to unacceptable product quality. We do not recommend that you go back to

your old mixer settings as this will only result in a loss of gas retention in

the dough because it will be less well developed. This will not help you

achieve the volume, boldness of shape and openness of cell structure that

you are seeking in the final product.

You have been scaling the dough pieces to give you a 400g baked weight

in the product, but the indented trays that you are using were designed for a

lower dough piece weight which would deliver a baked stick weight of 300g

or slightly less. Now that you have improved the gas retention properties of

the dough the extra expansion that you get in the early stages of baking

means that the cross-section of the stick is too large for the indent on the

tray, the pieces are not supported at their sides and so flow over the edges to

touch one another.

As you do not want to reduce your scaling weight to deliver a baked stick

weight of 300 g or less this leaves you with two possibilities; one is to only bake

three sticks per tray by placing dough pieces in alternate indents. This will

reduce your overall baking capacity and you may need to reduce your batch size

accordingly. The other solution would be to seek a tray design with only four

indents instead of five while retaining the tray width (Fig. 4.18). If you are going

to use this solution, then we also suggest that you seek a slightly deeper profile

for the indents so that you can be sure of retaining a bold shape to your product.


FIGURE 4.18 Alternative crusty stick trays.


4.1.35 We are finding that the crumb of our bread is too softfor slicing. We also notice a tendency for the sides of the loavesto slightly collapse inwards. We do not think that conditions inour cooler have changed can you please advise us of what toinvestigate?

When bread leaves the oven the crust is firm, but the crumb is still rela-

tively soft. In the initial stages of cooling, the crumb begins to firm as the

amylose fraction of the wheat starch begins to retrograde (recrystallise). The

longer-term firming effect associated with bread staling is related to the ret-

rogradation of the amylopectin fraction on the starch. It is the initial

increase in firmness due to the amylose retrogradation which allows the

bread to be sliced mechanically. The length of time that the bread spends in

the cooler is usually linked with core loaf temperature at which the bread

can be sliced. Typical loaf core temperatures for bread slicing are in the

order 27�30�C.Of course, the ability to slice a loaf mechanically is also linked with

the crumb moisture content and the lower the moisture content of the

crumb the easier it will be to slice. However, bread softness is reduced

when the crumb moisture content is lower, so it is common practice to

limit as much as possible moisture losses during cooling. The sides of

loaves sometimes pull inwards if there has been excessive loss of water

from the loaf during cooling.

A number of ingredients which are used in the recipe also play a role in

determining the initial crumb softness. For example, the addition of fat is

said to improve crumb softness though with the low fat levels used in many

breads this effect is most likely to be associated with the accompanying

improvement in bread volume.

The addition of anti-staling agents can have an impact on the initial

crumb softness in addition to the longer-term anti-staling effects. In this con-

text, the addition of modified bacterial (maltogenic) amylases has become

popular in many bread types, and high levels of addition have been associ-

ated with excessively soft crumb at slicing.

The slight collapse inwards of the loaf sides also suggests that the level

of enzyme addition is too high in your recipe. Check that the flour Falling

Number is not too low and talk with your supplier about making a small

reduction in the level of enzyme addition in your improver.

Further reading


AG, Switzerland.




4.2 OTHER FERMENTED PRODUCTS

4.2.1 Can you suggest what steps could be taken to preventour round doughnuts shrinking or collapsing within a fewminutes of leaving the fryer?

The collapse of your doughnuts after they leave the fryer is associated with

the transition of the dough from a ‘foam’ to a ‘sponge’ (in the generic not

specific cakemaking sense). In foams, the gas bubbles or cells are separated

from one another by a stabilising film of one form or another, e.g., protein,

fat, emulsifier, whereas in a sponge, the cells are interconnected and gases

and liquids can readily pass through the matrix (see Fig. 4.19).

In the oven, most baked products undergo the transition from foam to

sponge and the gas contained within the individual cells diffuses out of the

product into the surrounding atmosphere. The transition occurs at different

parts of the dough piece at different times, depending on the heat transfer

rate from the surface to the centre of the piece. Before conversion, the pres-

sure inside the air bubbles is greater than that of the surrounding atmosphere,

and this contributes to inflation of the product. At the moment of conversion

from foam to sponge, there is an equalisation of the gas pressure inside the

foam with that in the surrounding atmosphere, and this is seen as a slight

shrinking of the volume of the baked product just before the end of baking.

The process in the doughnut fryer is essentially the same as that for dough in

the oven. In fact, the increased pressure inside the gas bubbles in the dough

foam contributes to what makes doughnuts float in the hot oil.

The addition of some ingredients can delay the conversion of the foam

to a sponge to a later time during the baking process. As sugar is almost

always present in doughnut formulations, it is important to appreciate the

role that it plays in the formation of doughnut structures. Sugar, in the form

of sucrose, delays the gelatinisation of the wheat starch, and subsequently,

the temperature at which the foam to sponge conversion is made. In some

formulations, the starch gelatinisation temperature can be raised so high that

in the centre of the product it may not even occur before frying is com-

pleted. As a consequence, some of the foam remains intact and as the tem-

perature within the cells falls so does the internal pressure. At some point,

the external pressure on the product becomes greater than the internal pres-

sure in the cells and the product shrinks. This is the collapse and wrinkling

of the product that you see.

FIGURE 4.19 Transition from foam to sponge.


It is well known that a mechanical shock delivered to many such products

can be used to eliminate this type of problem, so simply banging the trays as

you remove them from the fryer can reduce or even eliminate this problem.

However, this is not may not be easy to achieve in a commercial bakery, and

so to avoid the problem, you should look to reduce the sugar level in the

formulation or slightly reduce the ability of the dough to retain gas, being

careful not to lose overall product volume.

Further reading

BakeTran, 2012. A guide to doughnut technology. Chorleywood Bookshelf Monograph No. 2.

BakeTran, Witney, UK (www.baketran.com).



4.2.2 The fermented doughnuts we are making tend to be quitegreasy to eat. Can you advise on how we can reduce thisproblem?

During the frying process, the heat expands the air bubbles which are trapped

within the dough, carbon dioxide gas is evolved from the last of the yeast

activity and steam is given off. While all of this is taking place, the pressure

within the dough piece is greater than that of the surrounding atmosphere,

and this greater internal pressure prevents the absorption of oil. Once the

transition from foam in the dough to sponge is made (see Section 4.2.1), the

pressure within the dough becomes equal to that outside the dough, and it is

only after this point that oil can penetrate into the product.

In fact, much of the oil absorption that one sees with doughnuts occurs

after the product has left the fryer. In particular, any pools of oil which

remain of the draining wires in contact with the final product provide easy

access of the oil below the product surface. You should try to find a means

of shaking off as much excess oil as possible before leaving the doughnuts

to stand. In some cases, tapping or banging of the trays can be employed and

this may also help avoid problems of collapse and wrinkling (see Section

4.2.6).

Other means of reducing oil absorption in doughnuts include:

� Adding a low level of a cellulose-based material to the formulation (up

0.3% flour weight).

� Maximising the added water content of the dough as this will help to

increase the steam pressure during frying.

� Ensuring that the frying temperature of the oil does not fall too low.

Typically, it should be about 180�C. Too low an oil temperature reduces

the heat input and lengthens the time that the doughnut spends in the fat

after the foam has converted to a sponge, thereby increasing the time for

oil penetration.

Further reading

BakeTran, 2012. A guide to doughnut technology. Chorleywood Bookshelf Monograph No. 2.




4.2.3 We have recently been experiencing difficulties with theproduction of our bread rolls. The finished rolls have poorvolume with large holes in the crumb. Can you suggest measureswe might take to eliminate these faults?

Your problem with small volume may come from a number of sources, all

associated with a lack of gas retention in the dough. The specific volume

(volume per unit mass) of rolls is normally expected to be greater than that

of bread and so it is necessary to increase the gas retaining abilities of the

dough. You can achieve this in a number of ways including:

� Using a stronger flour. It is common practice to use a higher grade of

flour for rolls than bread.

� Raising the level of the improver that you are using. Often, bread improvers

are used at 1% flour weight, and this may be increased to 2% for rolls.

� Change to a more powerful improver, that is, one which will give

improved gas retention in the dough.

� Ensure that the dough is fully developed during the mixing cycle. This

may entail raising work input in the CBP or mixing longer with other

breadmaking systems (see Section 4.1.12).

� Raise the dough temperature to aid dough development. If excessive gas

production before moulding becomes a problem, simply reduce the yeast

level.

The holes that you observe are most likely to come from damage to the

gas bubble structure during moulding. There are a number of reasons why

this damage might occur including:

� The level of water in the dough being too low so that moulding pressures

have to be increased to achieve the required shape.

� The dough being insufficiently relaxed because the resting time between

moulding stages is too short.

� The dough temperature being too low giving a more viscous (stiff) dough

similar to having too low a water level.


4.2.4 We have been receiving complaints that our smallfermented products, such as rolls, teacakes and baps,are staling too quickly. Can you advise on how we can improvethe product softness?

There are several different ways in which you can improve the softness of

your products. They can be grouped under the headings of improving

volume, raising moisture content, using functional ingredients and

storage.

4.2.4.1 Improving volume

In general, larger-volume products will have a softer crumb. This is because

the resistance of the crumb to compression, whether by the fingers or in the

mouth, is reduced. You will need to ensure that the dough has been fully

developed before baking as this gives a degree of resilience to the crumb

which is important for the overall quality of the product. Rolls which show

no resiliency after compression while definitely appearing soft lack the che-

winess associated with fermented products. The better the dough develop-

ment and gas retention in the dough the larger the product volume. Better

dough development often comes from principles such as extending dough

mixing times (see Section 4.1.12) or increased energy input.

4.2.4.2 Raising moisture content

The higher the recipe water content in the dough, the higher the moisture

content in the final product will be for a fixed baking time and therefore

the softer it will be. You should look to maximise the water addition to

the dough, this will also help dough development. Try also to bake less

water out in the oven, the final moisture content is more affected by the

length of time that the product spends in the oven so there are advantages

to raising the baking temperature and reducing the baking time. Some of

the moisture from the crumb will inevitably migrate to the drier crust to

achieve equilibrium. Keeping the crust thin means that less water is needed

to achieve equilibrium (Cauvain and Young, 2008).

4.2.4.3 Using additives

There are a number of functional ingredients which may be used to improve

crumb softness including fat (mainly through improved gas retention), emul-

sifiers such as D-acetyltartric esters of mono-glycertides (DATA esters) and

sodium stearoly-2-lactates (SSL) (Cauvain, 2015). GMS forms complexes

with the starch and so has a true anti-staling effect in fermented products

(Cauvain, 2015).


Additions of enzyme active materials are also useful. For example, the

so-called maltogenic or intermediate thermal stability enzymes have a bene-

ficial anti-staling effect, whereas fungal alpha-amylase can be used to

increase product volume (Cauvain and Chamberlain, 1988). Lipase enzymes

are also known to have an antistaling effect as they split tri-glycerides in the

dough to form di- and mono-glycerides in situ.

4.2.4.4 Storage

It is important to wrap your products as quickly as possible after cooling in a

moisture impermeable film to minimise moisture losses. You should also be

careful where you store the products because bread staling proceeds faster as

the temperature falls (Cauvain, 2015), so avoid storage areas where the

ambient temperature falls below about 15�C.

References


AG, Switzerland.


J. Cereal Sci. Nov. 8, 239�248.

Cauvain, S.P., Young, L.S., 2008. Bakery Food Quality & Manufacture: Water Control and










4.2.5 Our fruit breads rise very slowly in the prover and fail torise any further in the oven. We make some unfruited productswith the same formulation and they are satisfactory in allrespects. Can you explain why?

As the problem is associated only with fruited products, then we must look to

the fruit for the cause. You appear to have a problem with both gas produc-

tion � the slow proof � and gas retention � the failure to rise in the oven.

Bakers’ yeast is a microorganism and as such its activity, that is, its abil-

ity to produce carbon dioxide gas, can be inhibited by a number of naturally

occurring materials. Dried fruits do contain such anti-microbial agents, this

is part of the reason that fruited cakes take longer to grow mould. Although

the fruit pieces are intact then the effect of these agents is small, but when

the fruit skins are broken, they are more able to exert their inhibitory effect.

The concentration of sugars in dried fruit is high and the breaking of the

fruit skins releases these into the aqueous phase of the dough where the

increased concentration also slows down gas production by the Bakers’ yeast.

To avoid these effects, we suggest that you examine the mixing process

and ensure that the fruit is added as late as possible consistent with achieving

a through blending of the fruit into the dough. This will minimise the break-

age of the fruit skins. You may also wish to examine the mixing speed and

mixing action that you are using for the fruit addition.

You may need to increase the water level that you are using to make the

dough for your fruited products. This is because the addition of the dry fruit

will absorb some of the dough water and produce a stiffer dough. This may lead

to difficulties with fruit dispersion and the inclination to mix longer than neces-

sary. If you can we suggest that you avoid the practice of making a plain dough,

taking off part for your plain products and then adding fruit to the remainder.

You will get much better results by making a dedicated fruited dough.

Ideally, the temperature of the fruit that you use should be the same as

that of your dough, otherwise, the fruit addition will give you a lower tem-

perature and lower yeast activity.

Some dried fruits may be treated with sulphur dioxide to help maintain

their quality for long periods of time. When the fruit is added to the dough

such pre-treatment may result in the formation of reducing agents which will

adversely affects dough gas retention. This will be seen as a lack of oven

spring though in severe cases, the effects may be seen in the prover as well.

If you suspect that this is the cause of your problem, we recommend that

you wash and drain the fruit before use, this normally solves the problem. If

you wash the fruit remember to adjust the added water level to compensate

for the wetter fruit.


4.2.6 Our fruited buns frequently collapse when they leavethe oven. We have tried baking them for longer but this does notcure the problem. Our fruited loaves made with the same doughdo not have the problem. Can you advise?

The cause of this problem is essentially the same as that described for the

doughnuts (see Section 4.2.1). Namely that, the transition of the dough from

a ‘foam’ to a ‘sponge’ (in the generic not specific cakemaking sense) is not

occurring in the oven and the gases within the individual bubbles or cells are

not diffusing out of the product into the surrounding atmosphere. During

cooling, the external pressure becomes greater than the pressure within the

intact bubbles and the product shrinks, collapses and the crust wrinkles. No

amount of extra baking will cure the problem. To avoid the problem, you

should look to reduce the sugar level in the formulation or reduce the ability

of the dough to retain gas.

It is well known that a mechanical shock delivered to many such products

can be used to eliminate the product, so simply banging the trays as you

remove them from the oven can reduce or even eliminate this problem. But

care should be taken to avoid personal injury or damage to equipment and

trays. If the mechanical shock is too violent, then it is possible to crack the

crust surface of the product as it lacks the necessary flexibility to withstand

the mechanical stresses.

You are less likely to see the problem with the dough baked in pans

because the standard procedure when you take the products out of the oven

in smaller bakeries is to give the pans a sharp knock to release the product

from the pan for cooling. This depanning action delivers the required

mechanical shock necessary for the disruption of the gas cells. In industrial

scale bakeries, automatic depanning may not help eliminate this problem.


4.2.7 We are making a fruited bun product and from time totime experience problems with the product flowing out duringproof and baking. Can you identify the cause and suggesta remedy?

There are a number of possible reasons for your product flowing during

proof and baking. They include the following:

� Too much water in the dough. This may come from incorrect levels of

addition or from the fruit if you have been soaking it.

� The presence of the reducing agent glutahione arising from the disruption

of yeast cell which have not been stored correctly (see Section 2.7.9).

� Too much humidity in the prover which causes solubilisation of the pro-

teins in the dough.

� Residual sulphur dioxide in the dried fruit (see Section 4.2.5).

As the problem is associated with a fruited product, we suggest that you

thoroughly wash and dry the fruit before using it. If the problem persists, then

you should look for a processing cause, such as excess humidity in the prover.


4.2.8 When we cut open bread rolls and hamburger bunswhich have been stored in the deep freeze for a period of time,we observe a white ring just inside the crust which has a hardeating character. Where does this problem come from?

The phenomenon that you have observed is commonly referred to as ‘freezer

burn’ and arises from the movement of water within and from the product

while still in the deep freeze. This type of problem was reported by Pence

et al. (1958) who examined the whitened areas of products exhibiting the

phenomenon and observed that they had a greater number of tiny voids asso-

ciated with starch granules. These voids where linked with ice crystals which

had sublimated from within the starch granules causing a greater opacity of

the crumb and the whitened appearance during frozen storage. The change in

the crumb texture from this effect also causes the crumb to have a harsh, dry

eating quality arising from the lower moisture content. However, the effect

does not come exclusively from the loss of moisture as the attempts to

restore the crumb properties are largely unsuccessful.

Even though, the product has been stored in a deep freeze running at

about 220�C not all of the aqueous phase in the product is ‘frozen.’ This

arises because of freeze�concentration effects and the presence of soluble

materials like salt and sugar. As water turns to ice crystals, the concentra-

tion of the remaining aqueous phase in the product increases, and its

‘freezing point’ becomes lower (Cauvain and Young, 2008). Eventually,

the concentration may become so low that the solution will not freeze

even at 220�C.Any increase in the product temperature during storage will enable some

of the ‘unfrozen’ water present to diffuse from the product into the surround-

ing atmosphere. This clearly happens with many frozen products, as it is not

common to find ‘snow’ or ice within the wrapping material. The longer the

product is held in the storage freezer, the greater is the accumulation of

snow as the product progressively dehydrates.

After the product has warmed in the storage freezer, any subsequent

refreezing will take place very slowly from the surface inwards. This creates

an interesting effect because the centre of the product often remains frozen;

the surface begins to freeze quite quickly while a few millimetres under the

surface freezes slowly. The end result is the formation of the white areas of

freezer burn which commonly reflect the outer shape of the product.

The problem can be minimised by paying attention to a few simple

‘housekeeping’ rules:

� Do not store the product for very long periods of time.

� Check the actual storage temperature over a period of running time. The

set temperature in the deep freeze is nominal, and the thermostat will

allow some degree of fluctuation around the set point.


� Ensure that your storage freezer is regularly serviced and have the condi-

tions of any automatic defrost cycles checked.

� As much as possible avoid actions which allow the freezer temperature to

rise excessively. For example, keep doors closed as much as possible and

minimise loading and unloading times as much as practically possible.

References

Cauvain, S.P., Young, L.S., 2008. Bakery Food Quality & Manufacture: Water Control and


Pence, J.W., Standridge, N.N., Black, D.R., Jones, F.T., 1958. White rings in frozen bread.








4.2.9 We are not a large bakery but are planning to part-bakeand freeze bread products for bake-off at some later time;what points should we be aware of?

The bake-off of frozen bread products gives bakers flexibility of supply to

their customers. However, in freezing and baking-off such products, it is

important that they lose as little moisture as possible to reduce the rate at

which the final baked product will firm (stale).

When cooling the products after their first baking, the core temperature

should be checked. A temperature of 30�C should be aimed for in order to

reduce the thermal shock that the products will experience when transferred

to the freezer. It takes some time for heat to be drawn out from the product

centre, whereas the surface will freeze very quickly. It is better to cool the

bread to ambient temperature in the bakery rather than put hot bread in

the freezer. Covering the products can help to reduce moisture losses but

ensure that you do not get condensation on the product as this will affect the

final crust quality.

You will get best results if you are able to use a blast freezer rather than

a chest-type freezer. The speed of the air movement in a blast freezer can

remove as much as 2�3% moisture from the product. To limit moisture

losses, keep the freezing times as short as possible. Product core tempera-

tures after freezing should be in the order of 210�C, but remember that pro-

ducts with different dimensions (particular diameter or thickness) will freeze

at different rates.

Consider collating racks before loading and unloading the freezer �i.e., fewer door openings � or fitting an ‘air’ curtain. Opening the blast

freezer door reduces its efficiency which means that the product takes lon-

ger to freeze and loses more moisture to the bakery atmosphere. Once the

products are frozen, you should get them into moisture-impermeable bags

and into a storage freezer as quickly as possible to avoid moisture losses.

The salt in the bread depresses the freezing point to around 24 to 26�Cand so once the temperature rises above this (for example, during packing)

the product begins to defrost. Partial defrosting and then refreezing results

in ‘freezer burn’; this shows as white patches in the crumb which are hard

to the touch and have a harsh mouthfeel (see Section 4.2.10). The physical

and chemical changes which have occurred in the crumb are not usually

reversible so you need to take care of your storage conditions if you are to

avoid this problem.

Another common problem with frozen bake-off product is that called

‘shelling’ in which the crust of the product detaches from the crumb

(Fig. 4.20). This phenomenon arises because the different moisture content

of the crust and crumb cause the two components to freeze and defrost at


different rates which strains the physical links between the two. The prob-

lem can occur at a number of stages of the bake-off process depending on

its severity.

� During frozen storage, especially if the product is stored for long periods

of time.

� On defrosting before second baking.

� After second baking.

With prolonged storage times, you may see a combination of shelling and

freezer burn.

In preparing the product for bake-off, check the core temperature on

defrosting in ambient conditions. Aim for a temperature of 25�C (just

defrosted). At bake-off consider using higher temperatures than for standard

baking with shorter bake times. Moisture loss during second bake depends

more on time than on temperature and so accurate timing of bake-off is

essential if the product is not to lose too much moisture. Bake-off products

will always stale faster than scratch products and excess loss of moisture

(either in the freezing or the baking off) will exacerbate this staling (Cauvain

and Young, 2008).

Reference

Cauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture and Quality; Water Control and


FIGURE 4.20 Shelling of frozen bake-off products.




4.2.10 When we reheat par-baked products we find that theyremain soft for only a short period of time, typically an hour orso, but they quickly go hard and become inedible. If we do notreheat them, we find that par-baked products can stay fresh forseveral days. What causes the change in the rate of firming?Is it the additional moisture lost on the second bake?

Your assumption is partly correct. Moisture will be lost from the products at

both baking stages, and it is more than likely that the sum of the two mois-

ture losses will exceed that of a single bake. The lower the moisture content

of the product, the firmer the crumb. However, to fully answer your question

we need to consider the process which cereal scientists call staling.

Bread crumb firmness increases during storage even when no moisture is

lost from the product. Schoch and French (1947) proposed the most com-

monly accepted model for bread staling. Their model for bread staling was

based on the changes in the two major fractions of the starch in wheat flour,

the amylose and the amylopectin, post-baking and during storage. Raw starch

granules in flour have an ordered or crystalline structure and during dough

mixing those which have been physically damaged during flour milling

become hydrated. In the dough entering oven the starch first swells as it

absorbs water and then later gelatinises as the temperature increases to

around 60�65�C. Gelatinisation disrupts the crystalline structure and the

amylose diffuses into the aqueous phase to form an insoluble gel which con-

tributes to a soft crumb structure. On leaving the oven the bread cools and

the amylose fraction quickly re-associates; this process gives bread crumb its

initial firmness. The other starch fraction, the amylopectin, takes much lon-

ger to re-associate, usually several days. It is this process which is responsi-

ble for crumb firming during prolonged storage and is the one most

commonly associated with bread staling.

If stale bread is reheated it is possible to reverse the amylopectin recrys-

tallisation process and soften the crumb. However, when the breads cool the

second time, there is a noticeable increase in the rate at which it goes firm;

what used to take days now takes only a few hours. This increased staling

rate is associated with the temperature that the product achieves during

reheating. It is essential to melt the entire amylopectin fraction in the product

which means that the centre crumb temperature should reach 65�C. If this

does not happen then a few un-melted crystals of amylopectin act as seed for

the recrystallisation process which proceeds much faster as a result. Many

users are cautious about re-heating bake-off products and are concerned to

avoid excess surface colour, consequently the crumb does not reach the criti-

cal temperature and re-firming rates can be rapid.

Reference

Schoch, T.J., French, D., 1947. Studies in bread staling. 1. Role of starch. Cereal Chem. 24, 231�249.




4.2.11 While reading about the manufacture of hamburgerbuns, we see references to the pH and TTA of the brew.What do these terms mean? When are they used andwhat is the purpose of controlling them?

In the manufacture of hamburger buns, it is a common practice to pre-ferment

part of the flour with water and yeast before adding the mixture to the

remaining ingredients for mixing into the final dough and processing into

buns. This pre-fermentation stage has a number of advantages including the

modification of the rheological properties of the final dough which assist

in improved processing and flow of the shapes in the pan. The other important

change which occurs as a result of the pre-fermentation stage is the develop-

ment of acidic flavour notes in the final product.

During pre-fermentation the acidity of the dough falls and so the pH (see

Section 10.1) of the brew falls. However, the measurement of pH alone does

not provide the necessary information on the formation of acids in the brew,

and it is common practice to measure the total titratable acidity (TTA). The

TTA test measures both the dissociated acids (which directly impact pH) and

the un-dissociated acids under specified conditions and provides relevant

information on the expected flavour profile in the final baked product.

In broad terms, the two properties are related in that the TTA of a brew

increases as its pH falls. However, one of the problems associated with using

pH as the sole predictor of the degree of fermentation in the brew is that

some of the ingredients that may be used in baking have a buffering effect in

the brew. The presence of buffering agents means that even though the

amounts of organic acids in the brew increase, the hydrogen ion concentra-

tion (pH) does not significantly decrease. In a number of parts of the world,

the mandatory or voluntary addition of calcium carbonate to wheat flour

introduces a significant buffering agent.

It is worth noting that changes in brew pH and TTA are not exclusively

controlled by bakers’ yeast fermentation. The presence of lactobacilli and

other less desirable microorganisms in the flour can make significant contri-

butions to the generation of organic acids. Regular cleaning out of the brew

tanks is essential. Unexpected changes in TTA in the brew can often be an

indicator of the presence of high levels of unwanted microorganisms can be

an important indicator of the need to clean out the brew system.

Further reading


AG, Switzerland.




4.2.12 We have problems with our retarded teacakes whichhave large holes underneath the top crust. We do not experiencethe same problem with scratch-made products. Why is this?

Even though you are not experiencing a problem with your scratch produc-

tion one of the possible causes of your problem may come from the shap-

ing processes. In particular, the pressure applied during the pinning

(sheeting) process may be causing some damage to the dough bubble

structure underneath the upper surface of the dough. The dough pieces

spend a long time in the retarder, and this extended period of gas produc-

tion may tend to exaggerate the problem that might be seen on some occa-

sions with scratch production.

Some of the causes of damage to the gas bubble structure in the dough

can come from the initial dough mixing and processing. For example, if the

dough is stiff (lacks water) or cold then pinning pressures need to be higher

to achieve the required shape and size. There is often a temptation to make

doughs for the retarder at a lower temperature than with scratch production

to help control or limit gas production before the product enters the retarder.

However, this is to the detriment of dough development and yields a dough

less able to withstand the stresses and strains applied during processing

(especially rounding and pinning). It is better to use lower yeast levels to

control gas production in the dough destined for the retarder rather than

lower dough temperatures.

The appearance of holes underneath the top crust of the retarded product

can also be made worse if any skinning of the dough piece has taken place

in the retarding stage. There is always some loss of moisture from the

dough piece surface during retarding, but if this is too great, the upper sur-

face of the piece loses flexibility. When the piece moves into the proof

cycle the increased evolution of carbon dioxide in the dough increases the

internal stresses within the piece. This may exploit any areas of weakness

such as those arising from moulder damage to the gluten network. As skin-

ning is less likely to occur with the scratch product the upper surface

remains more flexible and better able to cope with the internal stresses and

strains and perhaps explains why you do not see the problem with scratch-

made products.

Further reading


AG, Switzerland.




4.2.13 When we retard our rolls before proving and bakingwe sometimes see a dark mark on the base immediately afterbaking and cooling. We see similar problems with our retardeddoughnuts. Is this mould because we have left the productsto cool on the trays before wrapping? We use silicon paperto bake on, does this aggravate the problem?

It is unlikely that you problem is one associated with mould growth because

you observe it so soon after baking. It is most unlikely that mould colonies

would grow large enough to see in such a short time in spite of the high tem-

peratures of the baked product.

The dark spots are almost certainly caused by a chemical reaction

between the dough pieces and any source of iron they have come into con-

tact with. The most obvious source will be the baking sheets that you are

using to hold the products in the retarder. The close contact between the

base of the dough pieces and the iron tray ensures that the relative humidity

in the area of contact remains high. The dough is slightly acid, commonly

the pH is around 5.5, and this accelerates the reaction with the iron to form

iron compounds which are dark in colour. The chemical composition of these

compounds is similar those involved in the rusting processes associated with

iron in damp environments.

The reaction can be so strong that it is known to take place through the

silicon paper that you are using if placed on iron trays. You should avoid

using trays which are damaged, scratched or showing signs of rust. A better

alternative may be to change to using aluminium or coated trays. The dough-

nut wires that you are using may be tin-coated iron/steel and the coating

may have worn sufficiently in places to expose the underlying source of iron

for the chemical reaction to occur. You can get these re-tinned or change to

an alternative metal form.


4.2.14 We are retarding our roll and stick doughs overnight butfind that the products made baked from them are covered withmany small, white, almost translucent spots on the surface. Wedo not get the same problem with our scratch production usingthe same recipe. Can you give an explanation for theirappearance and advise on how to get rid of them?

The formation of small, white, almost translucent spots on the surface of

retarded products is not uncommon (see Fig. 4.21). The principle reasons for

the problem are associated with excess gas production in the retarding phase,

especially if the dough lacks good gas retention.

Gas production continues in dough after it enters the retarder. The rate of

gas produced being directly related to the temperature of the retarder, the

lower the retarder temperature the lower the rate of gas production. In fact,

the production of carbon dioxide gas has been shown to continue in dough

even when stored at 25�C in a retarder. The release of carbon dioxide gas

over the long storage period begins to inflate the small gas bubbles in the

dough. When viewed under a low power microscope the larger gas bubbles

held just underneath the top surface of the dough piece where white spots

form appear to have water droplets hanging under their upper surface. This

‘free’ water may act as a diluent for the colour-forming components which

normally contribute to crust colour and so on baking those particular bubbles

appear white against a darker background. There has yet to be a full explana-

tion for white spot formation on retarded products. However, the important

role of moisture is indicated by the fact that white spots cannot occur on

retarded products which have skinned.

FIGURE 4.21 White spots on retarded rolls.


Elimination of the white spots can be achieved in a number of different

ways including:

� Ensuring that the dough has good gas retention, e.g., correctly mixed and

choice of a suitable improver.

� By not using a low dough temperature. Even though it is tempting to use

a low dough temperature to control yeast activity, this action will reduce

dough development and therefore gas retention.

� By reducing yeast level to minimise gas production in the early stages of

retarding.

� By using as low a retarding temperature as possible without freezing the

dough piece.

� By avoiding delays between product make-up and loading the retarder.

Further reading


AG, Switzerland.




4.2.15 We have been experimenting with retarding fruited rollsand buns. We find that the smaller products are quitesatisfactory but loaves made using the same formulation andbaked in pans have ‘stains’ around the fruit pieces and a darkercrust colour than we would like. Can you please advise us onhow to cure these problems?

It is not unusual to see variations in quality when different forms of retarded

products are made with the same dough formulation. The differences arise

because it takes longer for the heat to be extracted from the centre of large

dough pieces than it does from smaller ones. In your case, the pan loaves

will cool and warm more slowly in the retarding and proof phases respec-

tively. A key stage is the retarding phase which is intended to considerably

slow down yeast activity in the dough so that it may be stored for extended

periods before later warming and baking.

In addition to yeast activity, there will be significant enzyme activity in

the dough. In particular, the amylase enzymes will be reacting with the dam-

aged starch in the flour and converting them to maltose. With the long stor-

age periods which characterise retarding, there is significant potential for

such activity. The maltose which is produced effectively increases the level

of sugars that are present in the dough when it reaches the oven and this

gives increased Maillard browning (see Section 4.1.14) which is the cause of

the darker crust colour that you see. To minimise the crust colour increase,

you should have the retarding temperature as low as possible, we suggest

temperatures around 24�C. The dough will not freeze because the presence

of salt and sugar depress the freezing point. You will have to start your

proofing phase a little earlier to allow for the slightly colder dough.

If the above suggestions do not work, then you may have to make your

buns loaves using a formula with a slightly lower sugar level. Another change

which takes place in your products is the gradual seepage of sugars from the

fruit into the surrounding dough. This occurs because the fruit and the dough

have different moisture contents and water activities; first, water moves from

the dough to the fruit pieces, then the sugars dissolve and the sugar solution

diffuses out of the fruit back into the surrounding dough. The sugars coming

out of the fruit are different from the sucrose that you have added and when

they are heated they go brown at lower temperatures � hence, the stains on

the side of the loaves where the heat inputs are greater.

This problem will be difficult to eliminate but again lowering the retard-

ing temperature will reduce the rates of moisture transfer and diffusion of

the sugar solution. Alternatively, you could wash the fruit to reduce its

sugar content, drain off the excess moisture and allow the fruit to dry before

using it.


4.2.16 We are retarding rolls in our retarder-prover and findthat they lean to one side and lose weight during storage.Can you advise us as to how to cure these problems?

All dough products lose some moisture during storage during retarding, and

this accounts for the loss in weight that you are experiencing. The weight loss

occurs because the relative humidity of the dough pieces (typically around

95%) is greater than that of the atmosphere in the retarder and there is evapo-

ration of moisture from the dough surface. To maintain a high relative humid-

ity in the retarder chamber, the evaporator coil surface is much larger than in

standard refrigerator. This reduces the likelihood of moisture in the retarder

chamber condensing out and forming ice on the cooling coils. Moisture which

condenses lowers the relative humidity of the chamber atmosphere and

increases the differential between the chamber air and the product so that the

latter will continue to lose moisture in an attempt to achieve equilibrium.

Moisture losses from retarded products can be reduced by lowering the

cold storage temperature. We would recommend that you reduce your retard-

ing temperature to below 0�C but keep it above 25�C, e.g., around 23�C,to minimise weight losses. You may find it necessary to give a slightly lon-

ger proof period to compensate for the slightly colder dough but the differ-

ence should only be a few minutes. Lower yeast levels also lead to lower

weight losses from the dough pieces, whatever the storage temperature used.

If you do decide to use lower yeast levels, then you will certainly need to

compensate by increasing proof times after retarding.

Another factor which contributes to weight losses is the movement of air

across the product. Commonly air velocities are low in retarders, and usually,

they are just sufficient to maintain uniformity of the chamber air tempera-

tures. High air velocities will lead to dehydration of the dough pieces though

once again this can be reduced using lower retarding temperatures and lower

yeast levels.

The problem that you have with dough pieces leaning is linked with the

weight losses that you are experiencing. If you look closely, you will notice

that the dough pieces lean towards the air inlet. As the air enters the chamber

and impinges on the dough piece, it drives off a little moisture from the first

surface that it encounters but drives off relatively little moisture from the

surfaces of the dough on the other side of the roll � just as we notice less

air movement when we stand in the lee of a hill on a windy day. The dehy-

drated surface loses its flexibility and cannot expand when carbon dioxide

gas is produced and even with the low levels generated in the retarder the

dough pieces expand in a lop-sided fashion; i.e., leaning towards the air inlet.

Once again lowering the retarding temperature should reduce this problem.

Further reading


AG, Switzerland.




4.2.17 We are producing a variety of finger rolls using whiteflour. The rolls must be soft eating and retain their softness forseveral days; to achieve this we are using a roll concentrate.To help us cope with fluctuations in demand we freeze aproportion of our production, but find that the defrostedproduct is very fragile and may even fall apart. Can you help usovercome this problem?

In addition to the fragility, you are experiencing the samples that you have

provided, we see that they all have a very coarse cell structure and a dull,

almost dark, crumb colour. The products were certainly very soft, but there

was no resilience to the crumb which had a pasty eating quality. A key factor

in delivering a soft and resilient crumb is the development of a fine and rela-

tively uniform cell structure in the product; from our observations on your

product this is not happening. A number of different factors will contribute

to dough development; they include the choice of flour, roll concentrate

(improver) and mixing conditions.

Your product range is based on white flour but includes several variations

with seeds and grains added. These will reduce and the gas retention proper-

ties of the dough; in effect, you are asking the flour you are using to ‘carry’

some inert materials. As a basic choice, you should use a flour with a protein

content of 12�12.5% (on a 14% moisture basis) with a low ash or grade col-

our figure (see Sections 2.2.1 and 2.2.2). The protein is the basic building

block of dough development and will contribute to the crumb resilience

which your products lack.

Having chosen a suitable flour, it is just as important to choose a

suitable mixing time for optimising the development of the gluten network.

It turns out that you are using a spiral mixer with a combination of 2 minutes

mixing on slow speed and 4 minutes in fast speed. You should increase the sec-

ond speed mixing stage to at least 8 and even 10 minutes. You can compensate

for the slightly higher dough temperature by using a lower water temperature.

From the information that you provided, it would be perfectly reasonable

to use a slightly higher dough temperature as this will increase the oxidation

potential of the AA in your roll concentrate. Currently, your dough tempera-

ture is only 22�24�C, you can certainly increase this to 26�28�C. If you

experience problems with excess gassing during processing slightly reduce

the level of yeast in your recipe.

If you optimise your choice of flour and dough mixing conditions, you

may find that you can reduce the level of roll concentrate that you use. The

components in the roll concentrate that make contributions to crumb softness

are the fat, emulsifiers and some of the enzymes present; currently, you are

relying on these to deliver a soft product, but you should see these as a

‘top-up’ to basic dough development not an alternative to it.


4.2.18 Can you tell us something about Chinese steamedbreads and their production? We make our standard breadsusing the Chorleywood bread process, would we be able to makethese products using this process?

Chinese steamed breads, or ‘man-t’ou,’ are known to have been eaten in China

for around 3000 years. They are a staple food of the wheat growing areas of

northern China but are consumed throughout the country, commonly warm at

breakfast though they are often available at all mealtimes. They are known in

many other countries throughout south-east Asia and increasingly further afield.

It derives its common name, steamed bread, from the characteristic

method of steaming (rather than baking) which produces a round, roll-sized

product with a smooth, white, thin crust. Externally the surface should be

free from blemishes. Internally, the products have a close cell structure,

bright crumb colour and a distinctly chewy eating character. The product is

mainly eaten plain though sweet and savoury fillings may be used. They are

eaten warm. The tradition is for the product to be freshly made, often using

overnight fermentation so that the product is ready for breakfast.

A common recipe and method for their traditional production is based on

a mixture of 100 parts of a low protein breadmaking flour, 0.5 parts yeast

and 50�55 parts water; there is no salt in the recipe. The dough is thor-

oughly mixed (commonly by hand) and fermented for 3�16 hours. The yeast

level may be adjusted to use less for the longer fermentation times. Should

the dough soften excessively during the fermentation time then more flour

may be added, the dough re-mixed and then allowed to stand for about

another 15 minutes before processing.

After fermentation the bulk dough is divided into 100�200 g pieces and

either moulded round or to a rough cylindrical shape. A short proof period of

about 15 minutes is given before transferring the pieces to the steamer where

they are steamed for 15�20 minutes suspended on wire mesh trays. The spe-

cific volume of the final product is modest, typically around 2.0 mL/g which

is much lower than that of UK pan breads (around 3.5 mL/g).

The application of the CBP to the production of Chinese steam bread has

been studied and found that it was possible. Cauvain and Young (2006) pub-

lished the following details:

Ingredient % Flour weight

Untreated flour 100

Compressed yeast 1

Water 60

Ascorbic acid 0.0075 (75 ppm flour weight)


� The dough was mixed at atmospheric pressure to a total of 11 Wh/kg

dough in the mixer.

� Final dough temperature 30 6 1�C� Scale at 100 or 200 g.

� Mould round

� No intermediate proof.

� Prove at 40�C and 85% relative humidity; 15 minutes for 100 g and

30 minutes for 200 g pieces.

� Steam for 15�20 minutes.

Some of the ‘conventional’ CBP recipe and processing parameters were

not suitable for the manufacture of Chinese steamed bread. One of the

reasons for these findings was probably related to the low product specific

volume that was expected. In summary, their key findings were as follows:

� The optimum flour protein was around 10% (on a 14% moisture basis);

higher protein flours tended to cause product collapse.

� High level of AA caused product collapse.

� The addition of fat caused small depressions on the product surface.

� Work inputs of less than 11 Wh/kg resulted in cavities under the top sur-

face of the product, while higher level caused product collapse.

� High cereal alpha-amylase caused dough handling problems and product

collapse.

In summary, their findings showed that Chinese steamed bread made by

the CBP required little by way of the addition of dough conditioners or bread

improvers to deliver the required product quality.

Most steamed bread products call for a white flour essentially free from

bran particles which would otherwise spoil the appearance of the crust.

However, not all steamed breads are based on white wheat flour; one varia-

tion is made using a proportion of buckwheat flour which yields a product

with a distinctive flavour and even more distinctive purple colour.

Reference


Cambridge, UK.




4.2.19 What is cinnamon twist bread and how couldwe make it?

The distinctive feature of cinnamon twist bread is that it prepared by spread-

ing a cinnamon-based filling onto a sheet of bread dough and then rolling

the dough up like a Swiss roll. The end result is a loaf which when cut open

has a ‘swirl’ of filling from the rolling process. We have traced a recipe and

method for this unusual product which you could use as a basis for some

trials.

Dough

Ingredient % Flour weight

Bread flour 100.0

Yeast 5.0

Water 55.0

Liquid whole egg 10.0

Honey 4.0

Salt 1.9

Skim milk powder 6.0

Sugar 6.0

Fat 10.0

Filling

Based on a dry mix of caster sugar and cinnamon in the ratios of 7:1.

Processing details

� Mix the dough and ferment for 1 hour at about 25�C.� Scale the bulk dough into units of 2�2.5 kg, mould round and rest for

about 10 minutes.

� Sheet the dough pieces to 10mm thickness, brush with butter or marga-

rine and sprinkle on the filling.

� Roll up the dough forming a long cylinder which can be cut into the

length required for your pan. We suggest that the finished weight should

be around 250�280 g.

� Prove for about 40 minutes. Avoid full or over-proof as the dough softens

and is liable to flow over the sides of the pans and lose its ‘loaf’ shape.

� Bake at about 190�C for 25�30 minutes. The high sugar content will

give a dark crust colour. If this is too dark you could cut back on the

added sugar though this may affect the sweetness of the product.


Chapter 5

Cakes, Sponges and Muffins

5.1 WHAT IS THE FLOUR-BATTER METHOD OFCAKEMAKING?

The flour-batter method of cakemaking is based on two separate stages of air

incorporation which are later combined before mixing is completed. It

involves splitting the flour into two portions, the first to be creamed with the

fats and the second portion to be mixed into the batter at a later stage. At the

same time as the flour and fat are being mixed, the eggs and sugar are

whisked together using a second machine to form a foam (similar to the pro-

duction of sponge cakes).

Typically, the fats are creamed with an equal weight (or slightly less) of

flour until a creamy mixture is obtained. About 400 g flour to 450 g fat

(14 oz flour to 1 lb fat) is recommended. The egg is whisked with its own

weight of sugar. This whisking need not be as thorough as for sponge cakes,

and aeration should not go too far or the cakes will be too large in volume

and have a friable crumb. About 5 or 6 minutes on second or fast speed

with a planetary mixer is usually adequate. There is a greater possibility of

getting a batter too light (low density) when using this method than when

making cakes by the sugar-batter method (see Section 5.2).

When the egg�sugar foam is ready, it is added to the flour and fat batter,

while the machine is running at a moderate speed. The foam may be added

in small portions � Usually in four or five parts, each portion being beaten

in before the next portion is added. Alternatively, it may be run in as a con-

tinuous stream. When both batters are mixed, any remaining flour and bak-

ing powder can be mixed in, either by hand or at the slowest machine speed.

For fruited cakes, the fruit is added when the flour is almost mixed in.

Any minor ingredients such as essences or colours should be added to the fat

and flour while beating. If milk is added, then this should be done at the

time of adding the second portion of flour. Where the weight of sugar is

greater than the weight of eggs, the extra sugar should be dissolved in the

milk along with colours and salt (if used). This gives a better distribution of

the colour throughout the cake batter.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00005-9

If glycerine is used in flour-batter cakes, this may be added to either the

sponge or to the flour batter, usually the latter before the two are mixed

together. When milk powder is used instead of liquid milk, the necessary

quantity of powder is added along with the second portion of flour, whereas

the necessary amount of moisture in the form of water is added and the bat-

ter is mixed as before.

This method enables the eggs to be added far more quickly and with far

less possibility for curdling of the batter. In the sugar-batter method, adding

the eggs too quickly can result in curdling (see Section 5.3). Another advan-

tage of the flour-batter method is that by semi-foaming the eggs with the

sugar, a more even texture is imparted to the cake. As most of the flour has

been creamed with the fats, there is relatively little of it to be amalgamated

at the critical moment in cakemaking after all the eggs are in, so the poten-

tial for toughening of the batter by overworking is reduced.

All of the ingredients should be at the same temperature before mixing

starts to ensure that a suitable temperature is achieved in the final cake bat-

ter, typically around 20�C.Part of the traditional rationale behind the flour-batter method was to

‘waterproof’ the flour by blending it with fat and so limiting the potential

development of gluten structure in the batter. In fact, the formulation of cake

batters and their viscosity mean that the development of gluten network such

as seen in bread dough, is unlikely.


5.2 WHAT IS THE SUGAR-BATTER METHOD OFCAKEMAKING?

With this cakemaking method, a batter is formed on the basis of an emulsion

of oil/fat in water with air bubbles trapped in the solid fat phase. The other

ingredients are dissolved or dispersed in the water phase. The fats and sugar

are creamed together until the mixture is light. Usually, this takes about 10

minutes but does depend on the temperature and creaming qualities of the fat

and the type of mixer used. You will not be able to achieve the desired result

using only liquid oil. Many commercial bakers mix the batter to a fixed

specific gravity (see Section 10.2). The liquid egg is then added in four or five

portions over a period of 5 to 7 minutes with creaming of the mixture between

additions to prevent the batter curdling. Egg, and the other ingredients, should

be at the correct temperature (typically, 21�C/70�F is considered optimum) as

this will also assist in avoiding curdling of the batter (see Section 5.3).

Once, all the eggs have been creamed in, the batter should have a

smooth, velvety look and texture. Flavouring can then be added followed by

sifted flour and all other powders and any additional milk or water. These

are gently mixed into the batter. Any fruit should be added when clearing

the batter (i.e., the last stages of mixing to ensure that there are no unmixed

ingredients remaining). It is not advisable to mix the fruit with the flour as

some flour may stick to the fruit and could cause the formation of larger

holes in the baked cake.

It is important in all cakemaking processes to have correct temperatures

and mixing conditions to ensure consistent product quality.

Cakes, Sponges and Muffins Chapter | 5 237

5.3 WHY DO OUR CAKE BATTERS MADE BY THE SUGAR-BATTER METHOD SOMETIMES HAVE A CURDLEDAPPEARANCE? AND DOES THIS AFFECT FINAL CAKEQUALITY?

Curdled batters are usually the fault of carelessness or haste during prepa-

ration of the ingredients or mixing. If all the ingredients in the batter are at

a similar temperature, they will blend to form a thick, smooth cream.

However, if the eggs are added too quickly causing the butter or solid fat

particles to separate from the water in the mixture, breaking down the

emulsion, the mixture will become curdled. It will also happen if the butter

or margarine, which contains water as well as fat, is used in a hard rather

than a soft condition. This problem may well be evident in the case of rich

recipes e.g., such as those formulation containing a high percentage of

eggs, particularly, if the eggs have low solids, or if poor quality frozen

eggs are used.

Care should be taken to get the batter and eggs at a suitable temperature,

and the eggs should be added slowly. Each portion of egg should be ade-

quately beaten in before the next quantity is added.

Batter can be prevented from curdling by:

1. Ensuring all ingredients is at the correct mixing temperature, typically

20�22�C (70�F).2. Adding a small quantity of flour at the first signs of curdling.

3. Using a high-ratio shortening containing an emulsifier.

If the recipe includes a high ratio of sugar and liquid to flour, it is essen-

tial that a high-ratio shortening, or an emulsifier in conjunction with plain

shortening, is used.

Generally, curdling will not significantly affect the final cake quality,

provided the recipe is properly balanced. This is because any water which

separates out during curdling is later reabsorbed when the flour is added.


5.4 WE ARE EXPERIENCING SOME VARIATION IN CAKEQUALITY, ESPECIALLY VOLUME. HOW IMPORTANT IS IT TOCONTROL THE TEMPERATURE OF OUR CAKE BATTERS?

Almost all of the processes which are critical to successful cake quality are

initiated in the mixing stages, so to maintain consistent batter and final cake

qualities, it is important to maintain a standard batter temperature.

Variations in cake batter temperatures will have significant impact on the

following processes:

� The rate at which the soluble ingredients, mainly the sugars will dissolve;

the lower the batter temperature, the longer it will take for the sugars to

dissolve. This can have a profound impact when using coarser grained

sugars such as the granulated form and can contribute to the formation of

white spots or speckles on the baked cake (see Section 5.19).

� The rate at which the starch in the flour will hydrate; the lower the batter

temperature the slower the starch will be to hydrate.

� The creaming and aeration properties of the fat; in general, the lower the

batter temperatures the poorer the creaming properties of the fat in

the sugar-batter method of cakemaking (see Section 5.2) and the lower the

likely aeration of the batter with all cakemaking methods. In the latter

case, the baked cakes may lack volume and have poor eating qualities.

However, the precise impact of temperature on fat performance depends

on the solid fat index profile which is determined by the mixture of oils

which make up the fat (see Section 2.3.1).

� The functions of emulsifiers used to aid batter aeration will be affected.

� The rate at which the baking powder components will react. All chemical

reactions proceed more slowly when the temperature falls or proceed

more rapidly when the temperature rises. Of all of the potential impacts

of variations in cake batter temperature the impact on baking powder

reactions is perhaps the most important one. Variations in the rate of

release of carbon dioxide from the baking powder reaction have direct

impacts on cake shape, volume and structure (see Section 2.6.9).

� The control of batter deposit weight will be more difficult to achieve

because of variations in batter density linked with fat and emulsifier per-

formance and baking powder reaction rates from batch to batch.

In summary, you can expect that variations in the temperature of the

batter that you produce will be associated with variations in cake shape,

volume, appearance and structure.


5.5 HOW DO WE CALCULATE THE LIKELY TEMPERATURE OFOUR CAKE BATTER AT THE END OF MIXING ANDWHATTEMPERATURE SHOULD WE AIM FOR?

The prediction of the batter temperature at the end of mixing is relatively

straightforward because the main inputs to the calculation come from the

temperatures of the ingredients. Cake and other batters have a relatively low

viscosity and their low resistance to mixing means that relatively little heat

is generated in the mixing process. There may some influence from the

ambient temperature and equipment temperatures, but this is usually con-

fined to times when there are extremes of temperature, e.g., on cold start-up.

To calculate the likely cake batter temperature, you need only prepare a

simple table of the ingredient contributions and calculate the weighted aver-

age. Due to the high level of water present in various forms in the formula-

tion, it is less important to take into account the specific heat capacity of the

various ingredients than would be the case with bread dough. The following

example will help to illustrate the process:

Ingredient Mass (kg) Temperature (�C) Mass 3 Temperature

Flour 100 25 2500

Fat 50 20 1000

Baking powder 2 25 50

Sugar 110 25 2750

Liquid egg 30 4 120

Water 75 15 1125

Total 367 7545

Batter temperature5sumðmass3 temperatureÞ

total mass5

7545

3675 20:6�C:

If you want to achieve a consistent batter temperature and want to com-

pensate for variations in ingredient temperature then we suggest that you

adjust the water temperature. This simply means substituting the temperature

of the water in the above table with an unknown, say T and then use the fol-

lowing calculation:

The required final batter temperature is 20�C. Thus,

3673 205 64201 ð753TÞ


where 6420 is the sum (mass 3 temperature) of ingredients without the

water contribution. Rearranging this gives

T5ð3673 20Þ2 6420

75

so T, the required water temperature 5 12.3�C.We would recommend that the final cake batter temperature in the region

is 18�24�C. Low batter temperatures may lead to curdling (separation) of the

batter (see Section 5.3), impaired performance of the fat and unduly delayed

release of carbon dioxide from the baking powder (see Section 2.6.9).

All flours exhibit a phenomenon known as ‘heat of hydration’ (Wheelock

and Lancaster, 1970); that is when flour and water are mixed together, there

is an increase in the temperature of the mix beyond the contribution of the

individual ingredients. The drier the flour the greater will be the heat of

hydration. Many heat-treated flours (see Section 2.2.17) have moisture con-

tents significantly below 14%, and this means that the heat of hydration can

be significant. The heat of hydration can be calculated according to the for-

mula provided by Wheelock and Lancaster and should be deducted from the

target batter temperature before undertaking the appropriate calculations. In

practice, the effects are relatively small and seldom account for an increase

in batter temperature of more than 1�2�C. However, even such relatively

small increases can have an effect on the rate of reaction (ROR) of the bak-

ing powder and should be taken into account to minimise the impact on final

product quality (Cauvain and Young, 2008).

References


Effects. Wiley-Blackwell, Oxford, UK.

Wheelock, T.D., Lancaster, E.B., 1970. Thermal properties of wheat flour. Starke 22, 44�48.






5.6 WE USE AN ALL-IN CAKEMAKING METHOD FOR THEMANUFACTURE OF OUR PLAIN CAKES. OCCASIONALLY, WEEXPERIENCE LOSS OF VOLUME AND THE TOP OF THE BAKEDPRODUCT BECOMES PEAKED RATHER THAN FLAT. IT HASBEEN SUGGESTED THAT WE ARE OVER-MIXING THE BATTERAND DEVELOPING THE GLUTEN IN THE FLOUR; IS THISCORRECT?

First, it is rather difficult to develop a gluten structure in cake batters of sim-

ilar strength to that seen in bread doughs. There are two main reasons for

this; one is related to the nature of cake formulations and the other to the vis-

cosity of the batter. Cake recipes typically contain high levels of sucrose and

other sugars which dissolve in the water present in the batter and limit the

availability for hydration of the gluten-forming proteins in the flour. Some

multi-stage cakemaking methods have evolved which attempt to further limit

the development of the gluten network by using the mixing of fat and flour

as a preliminary stage; the flour-batter method is one such method

(see Section 5.1).

The water levels in cake batter recipes with respect to the recipe flour

weight are significantly higher than that see with bread dough recipes; typi-

cally, the recipe water level will be equal to that of the flour weight in cakes,

whereas it seldom exceeds 70% in bread dough recipes. The high level of

recipe water significantly lowers the viscosity of the batter and reduces the

ability of mixing equipment to transfer energy to the batter. In breadmaking,

the significant resistance of the dough during mixing is essential for the

transfer of energy, and as the frictional forces are low in cake batters, it is

highly unlikely that a ‘developed’ gluten network is present. There is a wheat

protein network in the final batters, but it is unlikely that this plays a signifi-

cant role in creating your problem.

You are using an all-in cake batter mixing method, and it is perfectly fea-

sible to manufacture cake batters in this way. However, as all of the ingredi-

ents are present at the start of mixing, all of the reactions which are

associated with cakemaking will be initiated. In the context of your problem,

an important one is the generation of carbon dioxide gas from the baking

powder that you are using. As the gas is generated, the continued agitation

of the batter permits the escape of a proportion of the carbon dioxide during

the mixing process itself and the longer the mixing time the greater is the

potential for the loss of carbon dioxide gas.


In essence, a long mixing time is delivering a cake batter similar in con-

stituents to that containing low or reduced level of baking powder; if you

reduce the level of baking powder in a cake recipe, you will certainly get

low volume products and a peaked shape.

The obvious solution is to avoid over-mixing the batter and work with a

fixed mixing time. You will also need to ensure that you are not allowing the

final batter temperature to rise too high as this can also cause premature

release of carbon dioxide. Much as you should fix your mixing time, you

should fix your final batter temperature (see Section 5.4). If you continue to

have problems, then you may consider changing the composition of you bak-

ing powder to one with a lower ROR (see Section 2.6.9).


5.7 WHEN MAKING FRUIT CAKES, WE FIND THAT THEFRUIT SETTLES TO THE BOTTOM OF THE CAKE AFTERBAKING. WHY IS THIS? AND WHAT CAN WE DO ABOUT IT?

The settling or sinking of fruit in cakes is connected with the viscosity and

density of the batter during the early stages of baking. If the initial viscosity

decrease during baking is too great, the fruit, being of higher density than

the batter, will sink, whereas the latter is still in a semi-liquid state � rather

like a stone would sink in water. The denser or the larger the pieces of fruit,

e.g., whole cherries, the greater their potential for sinking in the batter.

To prevent the fruit, whether it be cherries, sultanas or other particulate

materials, e.g., chocolate chips, from sinking the batter viscosity in the early

stages of baking must be increased. There are various ways in which this

problem can be overcome, such as recipe changes, using high protein cake

flour, the additions of hydrocolloids such as cellulose gums, decreasing the

batter pH or processing changes, e.g., by adjusting baking conditions.

In high-ratio cake recipes, the batters are always more fluid than tradi-

tional types of batters by the end of mixing. However, the use of chlorinated

or heat-treated flours will give a more viscous batter than untreated flours

during baking. In such fruit cakes, it is common to add tartaric acid or some

other organic acid in excess of that found in baking powder. Lowering the

batter pH is probably the most effective remedy to your problem as the extra

acidity increases the contribution to batter viscosity of the proteins present in

the flour, egg and other raw materials. The levels of addition are small, typi-

cally, 0.2% to 0.3% tartaric acid based on flour weight is added.

Another remedy involves ensuring that the batter does not remain in a

fluid state for too long. In some cases, baking at a slightly higher tempera-

ture reduces the time that the batter viscosity is at its lowest. Reducing the

baking powder, particularly for larger units or slab cakes, will reduce the bat-

ter aeration during the slower baking conditions normally required for these

large sizes of cake and so keeps the batter more viscous for longer periods.

Eggs also have an effect on the viscosity of the batter. The addition of

too much egg can cause the batter density to become too low. Generally, fro-

zen egg once thawed is a more viscous product than freshly broken shell

egg. The addition of too much raising agent can have the same effect on

lowering batter density.

The fruit itself should not escape scrutiny. Washed but not properly dried

fruit will have a tendency to sink. The extra water associated with the fruit

will cause the batter to be less viscous and add to the potential for it to sink.

In more traditional cakemaking methods, it is often proposed that the dried

fruit can be dressed with the recipe flour (not extra flour) to coat it and help

prevent its downward movement by providing a ‘granular’ coating. The mix-

ture should be added at the end of mixing after the flour has been added to

the batter. This is not a very practical solution in commercial bakeries.


Older recipe books show that bakers have added a small quantity of

ground almonds to the mixing. During baking, this will have sufficient bind-

ing and swelling effect to counteract the force of gravity acting on the fruit.

However, this can add to the costs of the recipe and may cause other pro-

blems, e.g., in the safety of the product when marketing for people with nut

allergies. Additions of other starches, e.g., cornflour, should be avoided

because they have different gelatinisation characteristics to wheat starch and

may lower batter viscosity at the critical moment during baking.

Another cause of sinking fruit is using too weak a flour, that is, one with a

low protein content. Most flour suppliers will have a slightly higher protein trea-

ted flour (typically around 11�12%) which can be used for fruit cakemaking. If

you are making lower ratio cake recipes, then you can use a good quality bread

flour.


5.8 CAN WE FREEZE CAKE BATTERS AND WHAT HAPPENSTO THEM DURING STORAGE?

Cake batters can be frozen successfully and frozen cake batters may be pur-

chased to reduce the wastage that might occur with scratch production where

consumer demand is often less predictable. For those purchasing frozen cake

batters, the advantages include:

� No storage or handling of raw materials (apart from product decoration).

� No ingredient weighing or mixing on site.

� Specialist centralised production improving the chances of optimal prod-

uct quality.

� Improved ability to meet peak demands for a variety of cake products.

Cake batters can be frozen and stored for up about 2 or 3 months before

any substantial quality losses in quality of the final product are encountered.

Cake batters do not freeze until temperatures between 212 and 220�C(11 and 6�F). The temperature will vary depending upon the level of dis-

solved salts and sugars because their presence depresses the freezing point of

the free water in the batter. The high sugar concentration in most dried fruits

will further depress the freezing temperature of fruited cake batters. The

time taken to freeze the batter will be shorter at lower air temperatures and

higher air velocities in the freezer.

Care should be taken not to expose the frozen batter to temperatures

above its freezing point between production, distribution and storage as

unplanned thawing can lead to deformation of the batter in the container.

Some loss of volume will occur with cakes produced from batters which

have been deep frozen and stored at 220�C. This loss of volume will be progres-

sive with increasing storage time. A long storage time will also lead to a firmer

and less tender crumb in the baked product. However, with care, the product

should still have acceptable volume, crumb texture and taste when baked. The

crust of the cake may have a marbled appearance due to the batter drying out

during storage causing localised excess sugar at the surface of the cake.

The frozen batters should be removed from the deep freeze and can either

be given a short defrosting period, or baked immediately from frozen. The

defrosting method has no significant effect on cake quality though a slight

surface discolouration may occur when product is baked from frozen, but

this may not be a disadvantage if the cake is to be decorated. Baking condi-

tions should be as normal but if baking from frozen a longer baking time

may be required.

Further reading






5.9 WHY DO CAKES GO MOULDY?

Mould growth is the visible sign that the product has been contaminated

with mould spores in an environment suitable for their growth. Such spores

can be present in the batter but are usually killed in the baking process.

However, as there are many spores in the atmosphere, it is likely that mould

spores will settle upon the surfaces of baked cakes as soon as they leave the

oven, during cooling and packing, and if the conditions are favourable, they

will grow and thus spoil your products. All products will suffer some level

of contamination and are unlikely to be ‘mould-free’. However, the mould

spores are too small for us to see with the naked eye, and it is only when the

colonies have grown large enough for them to become visible that we con-

sider the product to be mouldy.

The moulds which grow on cakes need water and oxygen to thrive.

Ingredients in the cake can ‘lock up’ water so that it is no longer available

for use by the moulds. A measure of the amount of water held by the ingre-

dients is the equilibrium relative humidity, ERH. This is sometimes referred

to as the ‘water activity’. ERH is measured on a scale of 0% to 100%, water

activity on a scale 0 to 1.0. The higher the ERH the greater the potential for

mould growth will be. Cake products usually have an ERH in the range

75�85%. The ERH of a product is different from its moisture content, and

whilst the moisture content is a good indicator of the product’s eating char-

acteristics, it is the ERH which governs mould growth.

The rate at which the moulds grow is also dependent on the temperature

of storage and the level of initial contamination. In general terms, the higher

the storage temperature (up to around 33�C), the faster the mould growth

will be. For example, with an ERH of 86%, the cake would have a mould-

free shelf-life of about 10 days for a storage temperature of 21�C (70�F) andof about 6 days if stored at 27�C (80�F).

It is possible to measure the ERH of a cake product. Representative sam-

ples of the product are carefully prepared and can be measured using a water

activity meter. Alternatively, the product ERH can be calculated from rele-

vant recipe ingredient and baking data.

Some ingredients have the ability to hold on to water better than others.

For example, salt and glycerine are very effective and additions can prevent

some of the water in the recipe from being used by the moulds. Increasing

sugar content or reducing water content can also extend shelf-life provided

the eating characteristics desired are still maintained.


It is important to have as clean an atmosphere as possible postbaking to

reduce the potential for spore contamination. The following suggestions may

reduce such contamination:

1. After detinning allow products to cool without removing any lining

paper. All surfaces in contact with the cake should be clean, dry and free

from flour dust. Preferably cooling should not take place in the bakery

but in a temperature-controlled area.

2. If the product is to be cut or decorated ensure that all utensils used are

clean and dry and wrap immediately after further processing.

3. Store the product in a cool place before dispatch.

4. In larger bakeries, ‘clean room’ technologies can be effective at limiting

contamination of products before and during wrapping.

Further readingCauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture & Quality: Water Control and





5.10 IN THE LIGHT OF THE PREVIOUS QUESTION, WHY DOHEAVILY FRUITED CAKES GO MOULDY MORE SLOWLY? ANDARE THERE ANY SPECIAL CONDITIONS WE SHOULDOBSERVE WHILE MAKING CHRISTMAS PUDDINGS?

Vine fruits used in heavily fruited products, such as Christmas cakes and

puddings, Dundee cake etc., have natural mould-inhibiting properties. This is

partly as a result of the high natural sugars present in the fruit which lowers

the ERH of the product and so extends the shelf-life. Also there are traces of

natural preservatives in the fruit skins which while not changing the batter

ERH will improve the product mould-free shelf-life because they provide a

natural inhibitor for mould growth.

Care must be taken, however, with products like these that the cake or

pudding is cooled properly before packing to ensure that there is no localised

condensation on the surface of the product. Localised condensation provides

areas high in moisture and, while the overall ERH of the product may be

adequate to ensure the desired mould-free shelf-life, on these localised areas,

the relative humidity and moisture content can be high enough to allow

mould growth at a faster rate.

In Christmas-pudding production, the steaming process actually adds

moisture to the product rather than removes it as is the case with conven-

tional baking. An allowance must be made for this extra moisture in the final

product when determining its ERH and subsequent likely mould-free shelf-

life. Usually, Christmas puddings have an ERH below 80% and a moisture

content between 25% and 28%. On storage, the space in the container above

the pudding can become saturated (owing to the evaporation of moisture

from the product into the atmosphere in the pack). If the storage tempera-

tures fluctuate grossly, then moisture can condense and fall onto the product

surface either by spot condensation from the packaging film or on the sides

of the container. The local atmosphere then becomes favourable to mould

growth. If the pudding basins are not adequately filled with the pudding mix-

ture, water enters while they are still boiling and remains to a much greater

extent than if the basins/containers had been well filled and tightly sealed

before boiling. When the puddings are boiling, the water must not be

allowed to cease boiling because if the temperature falls, the puddings are

inclined to contract, and water might enter between the container and the

outside of the pudding. After steaming, the puddings should be cooled with

the top surfaces exposed to permit drying out without risk of condensation

and allowed to dry for 24�48 hours before packing.

Further readingCauvain, S.P., Young, L.S., 2008. Bakery Food Manufacture and Quality: Water Control and





5.11 UNEXPECTEDLY, WE ARE GETTING MOULD BETWEENOUR DECORATED CAKES AND THE BOARD ON WHICH THEYSIT. WHY SHOULD THIS HAPPEN?

Mould spores are always present in the atmosphere in a bakery, particularly

where there may be poor hygiene or an excess of flour dust. Moulds in flour

dust are usually destroyed during baking. The board itself may not be the

source of contamination though this cannot be discounted. The cake may have

picked up the mould spores postbaking, for example, from a surface in the bak-

ery on which there was flour dust. If the spores are picked up and the cake is

subsequently iced, they are sealed by placing the cake on the board. The humid

conditions which will be created in those circumstances provide the appropriate

conditions for the mould spores to germinate and develop mould colonies.

This problem only occurs with cakes of high ERH (equilibrium relative

humidity). Usually, there is a certain amount of air trapped between the

board and the cake surfaces. If the relative humidity (RH) of the localised

trapped air is below 75%, mould growth will not take place despite the initial

contamination. This can be achieved by painting the base of the cake with a

concentrated sugar solution (thus lowering the RH) before putting it on the

base board � the basis of the tradition of painting on a fruit puree onto the

surface of cakes. A practical, low cost solution is to raise a fondant to boiling

point and paint it over the base of the cake. The syrup is largely absorbed

and also helps to act as an adhesive to keep the cake in place on the board.

Eventually, moisture migration will take place between the cake crust

and crumb and the whole cake will come into equilibrium but for a long

time the desired localised reduction in ERH near the base is maintained

which limits mould growth.

Similarly, the top surface of a sponge, which may have become contami-

nated from mould spores in the atmosphere and which is subsequently iced,

can exhibit mould growth of this nature between the cake surface and the

coating.

It is very difficult to eliminate contamination of this type, but it can be

reduced by placing the cakes on a clean dust-free surface and covering them

with, for example, greaseproof paper prior to packing. The boards should be

stored in a dry place and protected from contamination by dust.






5.12 WE ARE EXPERIENCING MOULD GROWTH ON THESURFACE OF OUR ICED CHRISTMAS CAKES. THIS IS THEFIRST TIME WE HAVE HAD THIS PROBLEM AND CANNOTEXPLAIN WHY. CAN YOU?

Christmas and celebration cakes need to be stored with care to avoid mould

growth on their surface. This mould growth is caused by localised areas of

high moisture on the surface of the iced cake. These localised high moisture

areas can often form because the presence of undissolved sugar crystals in

the icing which makes it hygroscopic. If cakes are stored in a container

before they are completely cool, condensation can form on the surfaces of

the container or wrapping material and drop onto the cake forming areas of

high moisture which are good breeding grounds for mould. This type of cake

can be a particular problem because they are stored for long periods of time.

A good way to avoid this problem is to cool the cakes completely and

then to wrap them in greaseproof paper before place them in tins with a few

holes for ventilation. The tins should then be stored in a cool, dry place. The

cakes should not lose too much moisture during storage because the average

ERH will be low and this limits evaporative losses.


5.13 WE ARE EXPERIENCING A ‘MUSTY’, OFF-ODOURDEVELOPING IN OUR CAKES, EVEN THOUGH WE STORETHEM IN A DEEP FREEZE. CAN YOU ADVISE?

Due to their high sugar content cakes are susceptible to picking up both

moisture and odours from the surrounding atmosphere. Care should be taken

to keep the areas and surfaces of all containers clean and free from other

materials which might impart odours into the atmosphere. In the case of a

deep freeze, it is important to regularly flush out with clean water any stag-

nant water which might accumulate in the drip tray near the evaporator.

Such water provides a breeding ground for moulds and bacteria which can

produce odours that are readily absorbed by the cakes.


5.14 WE REGULARLY MEASURE THE WATER ACTIVITY OFTHE INDIVIDUAL COMPONENTS IN OUR COMPOSITE CAKEPRODUCTS AND TRY TO ADJUST THEM TO REDUCE THEDIFFERENTIAL BETWEEN THEM TO REDUCE MOISTUREMIGRATION. EVEN THOUGH WE DO THIS, WE ARE STILLHAVING PROBLEMS KEEPING THE CAKE MOIST DURINGSHELF-LIFE. CAN YOU GIVE US SOME ADVICE AS TO WHATWE MAY BE DOING WRONG?

In addition to balancing the water activities of the cake components, there

are other factors which encourage the migration of water to take into

account. First, you should check your packaging. Moisture lost through the

pack will create a moisture gradient in the pack which encourages moisture

migration in the product. Cardboard packaging has a low moisture content

(and low water activity) so moisture in the pack atmosphere can be

absorbed by the board and since it is relatively permeable, can easily pass

out to the atmosphere. As well as the permeability of the pack you should

check the integrity of the pack seals to see that no moisture is escaping via

this route.

Even when the pack is not losing moisture to the surrounding atmo-

sphere, moisture will migrate from the product into the pack atmosphere.

The mass of water which can be held in the pack atmosphere is controlled

by the saturated vapour pressure of the air (Cauvain and Young, 2008). This

is low at the typical temperatures used to store cake products, but the greater

the volume of air in the pack the greater will be the mass of water required

to achieve saturation. You may want to consider whether the pack size can

be reduced. Sometimes, it is better to over-wrap the cake product in a mois-

ture impermeable film before placing it in a box.

You should look closely at the formulation that you are using for your

cream filling. Currently, you are measuring the water activity of the filling,

but you should check that all of the sugars that you are using in the cream

formulation are in solution. If you are not getting all of the sugars into solu-

tion, then the crystalline material will increase the likelihood of moisture

migration from the cake. The presence of crystalline material is not mea-

sured with a water activity meter.

We suggest that you carry out a mass balance with composite products;

that is, you calculate the moistures and water activities of the different compo-

nents to see where the potential is for moisture migration, remembering to

take into account the volume of air in the pack. We also find it useful to draw

a diagram showing the likely movement of water in a composite cake system.






5.15 WHEN WE TAKE OUR CUP CAKES FROM THE OVEN,WE FIND THAT THE PAPER CASES THEY WERE BAKED IN FALLOFF. HOW DO WE AVOID THIS PROBLEM?

The tendency for cakes to shrink when baked is the most usual cause of paper

cases becoming detached. The shrinkage generally results from the recipe hav-

ing too high a liquid level or sugar level, especially if the water to sugar ratio

is not in balance. On cooling, the pressure of the steam formed and maintained

within the cake while in the oven is reduced and the cake shrinks under the

effects normal atmospheric pressure. As the cases are rigid, they hold their

shape, and the result is that the cake shrinks away from the case.

This same problem is sometimes found in pound cakes baked in metal

hoops or with paper bands, and in loaf cakes baked in cardboard containers.

The steam within the cake cannot readily escape from the sides as it does

from the surface and so the cake remains softer here. Under-baking or sweat-

ing during cooling can also contribute to the fault. Sometimes, these cakes

have an uncooked core inside near to the bottom of the cake.

The remedy is to reduce the liquids in the recipe or by increasing the pro-

portions of baking powder and sugars.


5.16 OUR SMALL CAKES OFTEN SHRINK EXCESSIVELYDURING COOLING. HOW CAN WE AVOID THIS?

All cakes shrink a little on cooling. However, excessive shrinking on cooling

occurs because the intact gas cells in the texture contract. During baking, the

gas cells forming the foam in the batter expand as they are filled with the steam

and gas produced by the raising agents. Due to the high quantity of sugars in

the batter, the gelatinisation temperature of the cake cell wall material is

delayed, and the structure does not ‘set’ until the temperature reaches about

80�C. The flexibility of the cell wall material allows the cells to expand until

they burst or perforate converting the foam to a sponge structure and allowing

the gases to permeate throughout the cake. This all happens at a microscopic

level. If this setting does not take place, even though the cake is considered

baked because it has achieved the necessary appearance and colour, then on

cooling the pressure inside each cell falls and under the weight of the cake and

atmospheric pressure the cells shrink. This causes the whole cake to shrink.

This problem can be remedied as follows:

1. Give the tins a substantial jolt as they leave the oven causing ant intact

cells to ‘burst’ and the pressures to equalise.

2. Increase the level of baking powder in the recipe or change to a slower

acting powder. This should help to breakdown the cell walls as the cake

sets during baking, so leaving the minimum number of intact cells in the

crumb.


5.17 OUR CAKE SHEETS TEND TO LACK VOLUME, AREUNEVEN IN SHAPE AND HAVE CORES IN THE CRUMB. CANYOU ADVISE?

Poor volume seen with very close grain and the development of seams or

cores in the crumb suggests inadequate chemical aeration in the batter. It

may be that the sodium bicarbonate was omitted or the wrong balance of

raising agents was used. Check that the sodium bicarbonate is included when

weighing up the other ingredients. Often preparing a composite baking pow-

der for general use or purchasing a ready-made baking powder will avoid

such errors in preparation. To improve the general quality of the cake sheet,

we suggest, as a trial, you increase the proportion of aerating agents to deter-

mine the level best suited to your recipe.

Cake sheets sometimes have an uneven surface giving problems with uni-

form volume. This unevenness can be the result of poor mixing and scraping

down of the batter during the mixing cycle. We suggest the following proce-

dure on adding the eggs should be followed:

1. Add half of the eggs over 1 minute. Scrape down.

2. Add remaining eggs over 1 minute. Scrape down.

3. Mix further for 3 minutes.

All mixing should be done on slow speed. Make sure that, on scraping

down that the job is done properly.

Have a look at your mixer and examine the gap between the beater and

the bottom of the bowl. This should be as small as possible to avoid areas of

under-mixed batter which may then find their way into the sheet when

deposited. If you think that the gap is too large you may need to replace

your beater or even your mixing bowl.


5.18 SOMETIMES, OUR UNIT CAKE HAS A POOR (COARSE)TEXTURE. HOW CAN WE IMPROVE IT?

Unit cakes are characterised by their uniform and fine texture (cell structure).

If the texture is coarse the addition of a suitable emulsifier can help rectify

the problem. The emulsifier will help to reduce the overall size of the gas

bubbles incorporated into the batter and improve their stability during bak-

ing. A number of emulsifier preparations are available. They come in gel

and powdered form, we suggest that you consult your ingredients supplier.

The powdered form is used in the formulation of dry cake mixes. A pro-

portion of such emulsifiers consists of a carrier, often skimmed milk or whey

powder. If this is the case then you should make allowance by reducing the

level of milk solids in the recipe; otherwise, the cake may be too brown due

to the Maillard reaction (see Section 4.1.14) and the presence of lactose in

the milk powder. You should have no such problems if you use a gel emulsi-

fier, but you will need to adjust the recipe water addition to compensate for

the inclusion of some water in the gel.

A suitable usage level for powdered emulsifier would be between 5 and

10% of flour weight; you should reduce the milk powder level by about half of

your normal level of addition in your recipe to avoid the potential for darkening.

In the case of a gel emulsifier, around 2.5% flour weight should be suitable.


5.19 WHAT ARE THE CAUSES OF THE SMALL, WHITESPECKLES WE SOMETIMES SEE ON THE CRUST OF OURCAKES?

White speckles on the crust of cakes are most commonly due to sugar which

has recrystallised during baking. They are sometimes referred to as ‘sugar

spots’. During the baking process, the reduction of moisture content particu-

larly on the crust can result in the sugar coming out of solution and forming

the spots on the surface.

Any changes in the recipe resulting in a reduction of moisture content or

excessive sugar, thereby increasing the ratio of sugar to water, may give rise

to sugar spot formation. For example, the change from butter or other fat

containing a proportion of water to a white fat containing no water can be

enough to precipitate the problem. Similar results may occur if any water

containing ingredients are replaced by forms containing no water.

Other factors which might cause sugar spotting on cakes include:

� Increased granularity of sugar which may prevent it dissolving properly

at the batter stage. As a precaution, the sugar can be dissolved in the

water added to the batch before mixing. This is easily done with when

using a flour-batter (see Section 5.1) or blending-mixing method. When a

sugar-batter mixing method (see Section 5.2) is employed, sugar in

excess of the weight of fat may be dissolved in the liquid portion before

addition. With all-in mixing methods, pre-dissolution of coarse sugar is

essential to avoid this problem.

� Baking at a lower than normal temperature or baking in an oven with too

low humidity may prove detrimental.

� Allowing the deposited batter to stand for too long a period in the bakery

before baking may cause surface drying and subsequent sugar spotting. If

using a travelling oven, a much shorter standing time is required because

of the hot air passing over the cakes at the entrance to the oven. In such

ovens, the problem can be overcome by applying, by hand or automati-

cally, an ‘atomised’ spay of water over the cakes while they are on the

oven sole and as they pass into the oven.

� In round cakes where a ring of batter (a sugar ring) may have overflowed

the wrapper and has tended to become loose, a slight reduction in scaling

weight or increasing the height of the paper band used would help to pre-

vent overflowing and hence the localised sugar spotting.


5.20 WE ARE GETTING AN ORANGE DISCOLORATION OFTHE CRUMB OF OUR FRUIT CAKES. CAN YOU OFFER ANEXPLANATION?

Fruits, for example, cherries, used in cakes may contain permitted colouring

dyes. Many such colours are soluble at different pHs (usually above pH 4.0).

When the discolouration occurs in the crumb surrounding the cherries it is

caused by the colour from the fruit ‘bleeding’ into the crumb.

If the cherries are added at a later stage in mixing, the discolouration will

be far less pronounced. If they are washed and drained before use and intro-

duced at a late stage, then the bleeding should cease.

In summary:

� Use good quality fruit in your products. Preferably use whole, unbroken

fruit.

� Where the problem occurs wash the fruit with water slightly acidified by

citric acid and drain thoroughly.

� Check with your supplier which dyes (and their solubility level) are used

in the fruit so that the problem can be avoided.


5.21 WHEN WE ADD FRESH FRUITS SUCH ASBLACKCURRANTS TO OUR CAKE BATTERS, WE SOMETIMESFIND THAT THEY FAIL TO KEEP THEIR COLOUR DURINGBAKING AND OFTEN DISCOLOUR THE BATTER ADJACENTTO THE FRUIT. CAN YOU OFFER AN EXPLANATION AND ASOLUTION TO THE PROBLEM?

This problem occurs because the natural colouring agents in the blackcur-

rants and many other fruits (see Section 5.23) are pH sensitive. This means

that they will change colour as the pH changes. For example, anthocyanin, a

major colouring component of blackcurrants and other red fruits, will change

in colour from red to pink to violet as the pH progressively increases. Blue

and violet colours are most likely to occur when the pH or 7.0 or above. To

overcome the problem, we suggest that you make the batter slightly more

acid by adding up to 0.3% tartaric acid based on flour weight. This should

maintain the basic colour of the fruit without adversely affecting other cake

qualities.

The leaking of the colour into the surrounding batter comes from damage

to the fruit skins during mixing and depositing. This is difficult to avoid but

you should keep the handling of fruit in the batter to a minimum. You may try

the addition of frozen fruits as this may help to avoid rupturing the fruit skin.

Blueberries have a tougher skin and so are less sensitive to mechanical han-

dling than blackcurrants. However, they are just as sensitive to pH changes.


5.22 WE ARE BAKING FRUIT CAKES USING SULTANAS ANDFIND THAT WHILE THE CENTRE OF THE CRUMB IS A NICEGOLDEN YELLOW AROUND THREE SIDES OF THE CUT FACEOF THE CAKE (THE BOTTOM AND THE TWO SIDES) THECOLOUR IS MUCH BROWNER AND DARKER IN COLOUR.CAN YOU HELP US IDENTIFY THE CAUSE OF THIS PROBLEM?

This type of discolouration is usually associated with the Maillard-type reac-

tions which take place in baking (see Section 4.1.14). These are the ones

which gives the brown colours of the crust. They are complicated reactions

influenced by a number of different factors (Arnoldi, 2004) which involve

sugars and proteins.

You should look first at your baking conditions. Low baking tempera-

tures and long baking times tend to increase the risk of caramelisation of

sugars, especially in large cake units. You might also want to look at the dis-

tribution of heat in the oven as the problem is exacerbated by having too

much bottom heat.

Some sources of sugars are more likely to cause browning of this type in

cakes. Your problem will be exacerbated if you have sources of reducing

sugars like golden syrup, glucose syrups, invert syrup or honey. These are

commonly used ingredients intended to contribute flavour and in some cases

to the retention of a moist eating character and longer mould-free shelf-life.

As a ‘rule of thumb’, you should limit the level of addition of such sugars

collectively to no more than 10% of the total weight of sugars in the recipe.

You can encounter similar problems if you are adding glycerol or sorbitol

to extend product shelf-life. For recipe balance purposes, you should con-

sider these to be sugars and include them in the 10% limitation.

One less than obvious source of reducing sugars is the fruit that you are

adding though if this is a problem then you will often see darker stains in

the crumb around the pieces of fruit. You could wash and drain the fruit and

see if this makes any difference to the problem. Be careful to check that the

increased moisture content of the fruit does not cause you problems by

raising the product water activity and shortening the mould-free shelf-life of

the product. This will be particularly important if you are cutting the slab

into smaller pieces and exposing the cut surface to view as this increases the

risks of mould contamination.

Finally, check that you are not using too much sodium bicarbonate in the

recipe as any residue will raise the cake pH and increase the extent of the

Maillard reactions.

Reference

Arnoldi, A., 2004. Factors affecting the Maillard reaction. In: Steele, R. (Ed.), Understanding

and Measuring the Shelf-life of Food. Woodhead Publishing Ltd, Cambridge, UK.




5.23 WE ARE USING NATURAL COLOURS IN OUR SLABCAKE BAKING AND FIND THAT WE GET VARIABLE RESULTS,NOT JUST FROM BATCH TO BATCH BUT SOMETIMESWITHIN A BATCH. CAN YOU SUGGEST ANY REASONSFOR THIS PROBLEM?

Being derived from natural materials colours can be subject to variations in

shade and intensity of the colour. This is usually well controlled by the sup-

plier. All colours are affected by the pH of the medium in which they are

used. Natural colours are especially sensitive to variations in batter pH, and

this can lead to problems when making additions of fresh fruits (see Section

5.21). If this was the source of your problem, we would only expect you to

see variations on a batch to batch basis as a reflection of the small variations

in batter pH which can occur in any manufacturing environment.

When used in baked products, natural colours are likely to suffer from

some instability during their storage. Commonly, this will be seen as a loss

of intensity of the colour, but usually, the overall storage time is too short

for cakes for any significant variations to come from this source.

The fact that you are getting variations between cakes manufactured

within a batch is unusual. Some natural colours are known to lose colour

intensity during baking so one possibility is that the variations in colour that

you see may reflect the degree of bake which a particular cake has received.

As you will appreciate, there are inevitably some variations in the degree of

bake within an oven.

Natural colours are particularly susceptible to the effects of exposure to

light. In particular, they tend to lose colour intensity with increasing expo-

sure. Yellow colours appear to be more likely affected than reds. Your cakes

are more likely to be affected by light if they are wrapped in clear film. This

is often the case in cake manufacture based on slab cakes as it allows the

consumer to see the product and its qualities.

We suggest that you look closely at how your cake samples have been

stored with respect to any light sources, whether natural or artificial. This

should include all of the times for which the cut surfaces of the cakes are

exposed to light sources, including standing times in the bakery while the

composite product is being assembled before wrapping.


5.24 WE ARE GETTING LARGE HOLES IN THE CRUMB OFOUR FRUITED SLAB CAKE BUT ARE NOT SURE WHY THIS ISHAPPENING. CAN YOU OFFER SOME ADVICE?

Large and unsightly holes in fruit cake can be caused by any of the following

reasons:

� If damp fruit is used, localised steam is formed around the fruit during

baking, especially near the centre of the individual berries where it is less

able to escape quickly. The top of the cake becomes baked and so the

localised steam is trapped and it produces holes in the crumb as the

pressure builds up. All fruit should be thoroughly dried after washing to

remedy this problem.

� Air may be entrapped during depositing or, while spreading the batter by

hand or with a wet palate knife, as part of the batter may be folded over.

� Low carbon dioxide levels, either because there is too little baking

powder or because the baking powder has reacted too quickly.

� Occasionally, over-mixing of the batter, especially when adding the fruit,

can cause this problem. In this case, the holes may run vertically or at an

angle rather than horizontally.


5.25 OUR SULTANA CAKES ARE COLLAPSING. WHAT CANWE DO TO REMEDY THIS PROBLEM?

Sultana cakes can tend to shrink or sink slightly at the top. This is sometimes

accompanied by a slightly open crumb cell structure (grain). This is often

caused when the batter has been over-aerated during mixing thus making the

specific density of the batter too high to support the denser fruit, particularly

nearer the centre.

This may be countered by increasing the amount of liquid in the recipe,

if the flour content is adequate, or by reducing either the sugar content or the

amount of aerating agent. The first and last of these actions usually brings

about an improvement. It is also preferable to have the egg content slightly

higher than the total fat content as egg proteins add strength to the cake

structure. Where milk is replacing eggs, a simple method for calculating the

baking powder requirement is to assume that 560 mL (1 pt) milk requires

28 g (1 oz) baking powder.


5.26 WHY DO CAKES SOMETIMES SINK IN THE MIDDLE?

Many of the faults, which occur in cakemaking, are a result of the ingredi-

ents in the recipe not being ‘balanced’ for the type, size and shape being

made. This balancing of ingredient ratios is important to ensure the correct

aeration and structure for the baked product (see chapter: Key Relationships

Between Ingredients, Recipes and Baked Product Qualities).

You did not specify whether the collapse occurs during baking or after

baking. This is an important clue as to why the problem is occurring.

In the case of the sunken top the following ingredient effects are

relevant:

� The sugar level may be too high. The late gelatinisation of the starch

means that the transition from foam to sponge does not occur before the

end of baking (see Section 4.2.1).

� The fat level may be too high.

� The baking powder level may be too high.

You may need to rebalance you recipe to eliminate this problem.

Other reasons why a cake might sink in its middle include

removing the cake from the oven before it is thoroughly baked. The centre

of a cake is the last portion to bake so that if the product is removed from

its source of heat when it is still fluid the crust will be unsupported and

the cake sinks.

If the cakes are knocked or moved about whilst they are baking and

before they have become properly set there could be a premature release of

gases which can cause the cakes to sink in the centre; this would often be

accompanied by a loss of volume.


5.27 WE ARE ENCOUNTERING AN INTERMITTENT FAULTWITH OUR ROUND HIGH-RATIO CAKES IN THAT A SHINYRING WITH PITTING IS SEEN ON THE CAKE SURFACE. WHATFACTORS ARE LIKELY TO GIVE RISE TO THIS FAULT?

This fault is caused by the batter viscosity being too low during the early

stages of baking. As the product is heated the viscosity of the batter helps to

trap the gases produced by the raising agents. If the batter is too fluid then

the structure which is not set allows gases to escape and these burst through

the forming crust leaving behind the pitted surface appearance.

The shine on the ring suggests that the sugar level in the recipe is too

high. High levels of sugar delay the gelatinisation of the starch and so keeps

the batter fluid for a longer in the oven.

An increase in viscosity can be achieved in any of the following ways:

� Reduce the water content of the batter.

� Increase the flour damaged starch. Damaged starch will hold more water

thus making the batter more viscous.

� Extend the mixing time but avoid over-mixing.

� Reduce the recipe sugar level.


5.28 OUR FRUITED CAKES ARE FINE TO EAT SOON AFTERPRODUCTION BUT TEND TO BECOME DRIER EATING AFTERA FEW DAYS; WHY IS THIS?

Fruited cakes are a multi-component product comprising two phases; the cake

crumb and the dried fruit. Even though the two components are in intimate con-

tact from mixing through to baked product, equilibration of moisture does not

necessarily occur. In many cases after baking, there is a significant difference in

cake crumb and fruit particle moisture content with the dried fruit continuing to

absorb moisture from the cake crumb. Experimental data (Cauvain and Young,

2008) has shown that up to four days may be required for equilibrium to be

achieved (see Fig. 5.1). This lack of moisture equilibrium is most likely to be

the reason for the dry eating cake crumb that you are observing.

One way to overcome your problem is to raise the moisture content of

your fruit by washing and draining it before use. However, note that this will

raise the overall moisture content of the cake and may decrease its mould-

free shelf-life.

There are several ways of preventing crumbling with fruit cakes:

� Use flour of medium strength (10�11% protein) instead of high-ratio

cake flour.

� The proportion of fat used should be less than the egg content by approx-

imately 10% (based on flour as 100%).

FIGURE 5.1 Effect of fruit on cake moisture during storage.


� Where the ratio of sugar to liquid is high, the cake the crumb tends to be

more fragile. For a fruit cake this ratio should be lower than 115% flour

weight.

� When the proportion of egg in the total liquid is low the cake structure is

weak and has a tendency to crumble on cutting. Egg should make up

about 50% of the total liquids to prevent this.

� Emulsifier additions should be kept to a minimum.

� Avoid high levels of raising agents as these can increase crumb fragility.

� Wash the fruit and dry well before use.

� Mixing must be controlled to ensure constant batter aeration and emulsi-

fication. Under-mixing and over-aeration of batters can cause a crumbly

end product.

� Batter depositing and baking should not be delayed after mixing.






5.29 WE HAVE SEEN THAT OUR CAKE QUALITY VARIESWHEN WE CHANGE FROM ONE TYPE OF OVEN TOANOTHER, EVEN WHEN THEY REGISTER THE SAMETEMPERATURE. WHY IS THIS?

Ovens, even those of the same make and model vary in their ability to

deliver heat to the product. The temperature settings seen on dials or displays

are indications of the actual air temperature rather than a measure of the heat

available for baking.

During baking heat is transferred to the product in one of three ways:

� Convection, the transfer of heat in fluids achieved by the colder fluid car-

rying away heat from a hotter surface which sets up convection currents.

� Conduction, the passage of heat through a medium, from hot to cool

regions, the heat being passed on from molecule to molecule, e.g., hot

pan to cooler bread dough.

� Radiation, the transfer of heat from hot surfaces without the need for a

transferring medium, e.g., the heat we receive from the sun.

Ovens used in bakeries use all three heat transfer mechanisms though the

balance between the three varies with oven type and design. For example, in

a deck oven conducted and radiant heat dominate while in a rack oven con-

vection and to a lesser extent radiation dominate.

The thermostat fitted to an oven senses and controls the temperature of

the oven by calling for more or less heat accordingly. Occasionally, this may

be at fault and may not be working accurately or may be controlling the tem-

perature at a point which does not coincide with the position of the cakes in

the oven. For specific temperature settings in your oven, it is advisable to

bake the products at several different temperatures to find the ideal settings

for your oven. You should try to make sure that the oven has a reasonably

similar load for each trial otherwise you will get variable results. Try adjust-

ing temperatures in 5�C steps, above and below your current settings, so as

to avoid making products which would not be acceptable for sale.

It would be wise to check that a consistent temperature is being delivered

for consecutive bakes in case you have a problem with burners or heating

elements. You may find that the oven is not fully recovering its heat load

between bakes of successive batches. If this is the case, you should consult

your equipment supplier. On the other hand, it may be that the time between

bakes is so long that ‘flash’ heat builds up in the oven. This is associated

with the radiant heating component in the oven and often leads to burning of


the product crust. As most products are baked to a particular colour and

shape, the temptation in these circumstances is to lower the oven temperature

for the next bake. You should avoid this if possible. If you are about to use

an oven which has been standing empty but heating for a period of time and

you suspect there may be problems with flash heat, we suggest that you inject

a burst of steam into the chamber and release it before loading the oven with

product. The evaporation of the water will remove some of the excess heat

and readily escapes when you open the oven door or damper. If you use the

latter, remember to close it again when you load the product into the oven;

otherwise, you could end up drying the product out unnecessarily.

Variations in oven humidity can also lead to variability for some pro-

ducts. For example, Swiss rolls benefit from humidity in the oven as the

water vapour keeps the crust moist and so aids the rolling process

postbaking.

Although your problem is associated with cakes, you might like to note

that the same rules will apply to almost all baked products.


5.30 HOW IMPORTANT IS THE TEMPERATURE OF CAKES ATTHE POINT OF WRAPPING?

Cakes can be wrapped at either high temperatures or completely cooled. In

either case, the important point is to ensure that no localised condensation

occurs on the surface of the product which might result in mould growth during

storage. The ERH of the product should remain at the level required to achieve

the desired mould-free shelf-life (see Section 5.9).

If a cake requires no filling, coating or other finishing after baking there

is no reason why it should not be wrapped direct from the oven at tempera-

tures around 88�93�C (190�200�F). Obviously, there may be some difficul-

ties involved in wrapping at these high temperatures, such as damage to a

fragile product and control of condensation as the product cools. Provided

the wrapping material is in reasonably close contact with the product, con-

densation which does occur soon disappears even when a moisture imperme-

able film is used.

Materials for wrapping at high temperatures should be chosen with care.

Material such as polyethylene would be unsuitable because, but most grades

of cellulose film do not appear adversely affected by hot wrapping.

If products are to be cooled then wrapped, care must be taken during the

cooling process. Rapid cooling can be achieved with suitably high air veloci-

ties. However, if drying out of the product is to be prevented, the relative

humidity in the cooler must be carefully controlled. The relative humidity

can be controlled only if the air temperature is closely regulated as relative

humidity changes rapidly with a small change in air temperature at a given

moisture vapour content.

If refrigeration is used both temperature and relative humidity can be

controlled satisfactorily with an air temperature of, say, 16�C (60�F) and

about 80�85% relative humidity. To prevent the product drying out, the rel-

ative humidity should be close to the equilibrium humidity of the product

(typically 80�85% for cakes) so that moisture is not encouraged to move

from the product. The high relative humidity in a refrigerated system means

that large cooling plates are required to prevent condensation of moisture

onto the cooling coils.

Without refrigeration, relative humidity can be controlled using water

spray type humidifiers. In this case, close control is more difficult especially

if the air temperature (around 21�C, 70�F) is subject to fluctuations.


The moisture loss from flour confectionery products during cooling may

be a critical factor in determining their mould-free shelf-life and eating quali-

ties. If controlled cooling conditions are used, it is possible that an increase

in the moisture content of the product could occur with a resulting reduction

in the shelf-life. It is advisable to make careful checks on moisture content

when setting up the cooling system and recipes may need adjustment to

decrease the ERH of the product.

Under controlled cooling conditions, it is important that any air blown

over the product is clean and thorough filtering of air drawn from outside is

desirable.

Cooling times are dependent on the size and thermal conductivity of the

product. It is pointless using high air velocities with large products, as cool-

ing time is controlled mainly by the time taken for heat to be conducted

from the centre of the product to the outside.






5.31 WHAT PRECAUTIONS SHOULD WE TAKE WHENFREEZING CAKE AND SPONGE PRODUCTS?

The greatest benefits to be gained from freezing cakes and sponges are the

delay of the staling process and avoidance of problems with mould-free

shelf-life. Provided the products are adequately protected against moisture

loss, you will preserve their freshness and limit moisture migration in com-

posite cake products.

Before freezing, the products should be cooled to ambient temperature

(typically 20�25�C, 70�77�F) to maintain the efficiency of the freezing

process. The most efficient and economical frozen storage temperature

is 220�C (25�F). However, cryogenic freezing systems using liquid nitrogen

or carbon dioxide have led to the use of much lower temperatures, 2171�C(2275�F) for liquid nitrogen and 2100�C (273�F) for liquid carbon dioxide.

In common blast freezers, fans operating in such equipment aid heat transfer

and air temperatures will typically be in the order of 230 to 235�C. Theproducts should spend as little time in the freezer as possible to reduce mois-

ture losses, but you should make sure that core product temperatures reach at

least 210�C before transferring them to frozen storage. The high levels of

sugars in cakes and sponges significantly depress their freezing point and

makes then susceptible to the effects of fluctuations in frozen storage

temperature.

It is advisable to use a specially produced moisture-proof film which has

increased flexibility and is resistant to cracking. Wrapping the products

before freezing will help reduce evaporative losses but does increase the

length of time taken for the product to become frozen.

Storage times for frozen products vary but can be many weeks at 220�C(25�F). Remember that if products are stacked in frozen storage, then the

temperature of the product may vary according to its position in the stack

and in some cases may be unacceptably high with subsequent defrosting.

The thawing time for frozen cakes and sponges depends on the unit size

and thawing conditions available. A 285 g (10 oz) sized plain slab cake can

take up to 6 hours standing at 21�C (70�F) before the internal temperature

reaches 21�C but such a cake would be eatable within 4 hours. If the same

cake was thawed at 38�C (100�F) an internal temperature of 21�C would

be reached within 1.75 hours. Dry eating products may occur if the thawing

rate is too slow resulting in excessive moisture losses.

Condensation can occur during thawing and depends largely on the thaw-

ing temperature, which controls the time during which the surface tempera-

ture of the product remains below the dew point of the atmosphere in the

packaging. The higher the thawing temperature, the more quickly is the con-

densation removed and the less likely it is to affect the product.


5.32 WHAT HAPPENS TO THE BATTER WHEN CAKES ENTERTHE OVEN, AND HOW CAN YOU TELL WHEN A CAKE ISBAKED?

Converting a fluid batter to the desired eating characteristics in the end prod-

uct is the result of getting both the temperature and timings correct during

baking. The ‘foam’ structure (discrete cells) of the batter is converted to a

‘sponge’ structure (interconnected cells) in the baked product. Baking is a

process of heat gain and moisture loss.

Even before the cake enters the oven, the condition of the oven is impor-

tant. Any buildup of ‘flash’ heat should be dissipated so that the cake

receives an even bake. Once the cake is in the oven, the heat starts to melt

the fats. This first occurs on the outside of the cake and gradually extends to

the inner portions. At the same time the air cells begin to expand and if rais-

ing agents are present carbon dioxide is released to inflate the cells. This

begins slowly at first from the outside and gradually extends to the interior

of the batter. The temperature of the cake continues to rise and some of the

starch granules are gelatinised while the cake is still in a molten state. The

cake continues to rise until the structure is set by the gelatinising starch and

the outside of the cake colours to give the required size and appearance. The

continued expansion of the cells along with the gelatinisation of the starch

causes the foam cells of the batter to become ruptured to form the intercon-

nected cells of the final structure.

If the cakes are small and the oven is hot, a skin forms quickly on the top

and rapidly colours as the moisture in the vicinity of the surface is converted

to steam leaving the sugary portion of the batter to reach a temperature where

the Maillard reactions occur (see Section 4.1.14) and the sugars caramelise.

Although this skin forms quickly, it will not have sufficient strength to prevent

the interior of cake expanding (especially where, there is a high proportion of

baking powder). The pressure eventually exceeds the strength of the top. The

top is the weakest portion of the cake as the sides and bottom are often sup-

ported by the tin or hoop. The batter forces its way through the forming crust

and a rounded or bold head is formed. This is small at first but grows as bak-

ing continues.

In larger cakes, the top skin takes longer to form, as in these cases, the

oven is cooler (to allow for a more even bake and to prevent the outside

being burnt before the inside is baked). Also the humidity in the oven is

higher (e.g., when the oven is full of products), and as larger cakes usually

contain a higher proportion of eggs than milk, they give up their moisture at

a lower rate. Eggs coagulate at the boiling point of water and retain a good

deal of the water that would otherwise have been driven off as steam. If the

recipe is correctly balanced, the bursting through the centre top is less

pronounced.


The temperature at which the structure is set depends on the sucrose con-

centration in the batter. The higher the sucrose concentration, the higher the

gelatinisation temperature is and the longer the batter will remain fluid dur-

ing baking. To test whether a cake is baked the centre surface is lightly

pressed. If the surface just springs back, it shows that the centre of the batter

(the last portion to set) is baked.

If the oven temperature is too low, aeration proceeds as usual, but the

cake is slower at drying and setting on the outside so that the top skin will

be longer in forming. The fluid batter will rise evenly all over the surface

and a flat-topped cake will result. Another manifestation of too low a tem-

perature in baking is a discoloured crumb, particularly in the lower portion

of the cake and the cake will also be dry eating. The long baking time at

lower temperatures encourages drying out of the cake. As the drying out con-

tinues, the sucrose concentration in the unset portions of the cake becomes

higher and will begin to caramelise. The coloured crust becomes thicker and

the longer the cake remains in the oven, the more the discoloration of the

crumb extends into the body of the cake. The upper part of the cake has

been in contact with the steam inside the oven and the damp atmosphere will

have kept the cake moist and, to some extent, will have prevented the devel-

opment of excessive dryness. The lower crumb however, not in contact with

the steam, becomes dry and then discoloured.

Deciding the temperature at which to bake one particular kind of cake is

complicated. The ingredients, their quality and quantity, and the size of the

cake along with the type of results expected all need to be considered. Some

‘rules of thumb’ for deciding on the baking temperature are as follows:

� The greater the difference between the proportion of flour to fats and

eggs used, the hotter the oven should be.

� The higher the proportion of fats, the cooler the oven should be.

� The larger size the cake, the lower the temperature should be.


5.33 WHAT ARE THE ADVANTAGES OF HAVING THE OVENFILLED WHEN BAKING SLAB OR OTHER CAKES?

The advantages of having an oven filled with product come from the humid-

ity and heat transfer. Once cakes are placed in the oven their temperature

rises and eventually the moisture in the product reaches boiling point and

steam is given off. If the oven is full of product, then the volume of steam

will be fairly large for a given volume of oven capacity. The humidity in the

oven will be high and will act on the surface of the cake keeping it moist.

As each cake is in close proximity to its neighbour, the side crusts will be

kept thin and pale in colour. The hardening or drying of the final crusts on

the top and sides will be delayed enabling the cake to reach full growth

before it is set.

If the crust has become set before full growth has been achieved, the

inside of the cake will burst through the prematurely formed crust and form

a break or crack across the slab. In some cases this break may be desired,

e.g., Muffins (see Sections 5.47 and 5.48). The atmosphere in the oven is

less humid and so the product crust sets and dries before the cake has risen

fully.

For slab cakes, a break on the surface is not desirable and so a full oven

is an aim with the oven door remaining closed for the whole baking period.

Where this is not possible, a humid atmosphere should be created in the

oven by placing tins of water in the oven with the product.


5.34 WHY DO WE ADD EXTRA ACID TO MAKE WHITE CAKEBATTERS?

If the sodium bicarbonate element of the raising agent is not completely neu-

tralised by the acid component then the excess bicarbonate will increase the

degree of degree of browning of the sugars during baking. This is because

Maillard browning (see Section 4.1.14) is encouraged at higher pHs. This

type of browning occurs with all types of cakes but because the crumb of

many cakes is tinted yellow either with egg yolks or egg colour the slight

degree of discolouration largely passes unnoticed. In the case of a white

cake where no egg yolk is present, the slightest discolouration would be

noticed. To prevent this therefore, additional acid � such as cream powder

or cream of tartar � is added to make sure that all the bicarbonate of soda is

neutralised.


5.35 WE HAVE BEEN MAKING A RANGE OF DIFFERENTCAKE SIZES USING THE SAME PLAIN BATTER AND GETVARYING QUALITY RESULTS IN TERMS OF THEIR SHAPE ANDAPPEARANCE DESPITE HAVING ADJUSTED THE BAKINGCONDITIONS. DO YOU HAVE ANY ADVICE?

Traditionally, bakers would change two aspects of their production if they used

the same batter for different size products. One of these would be to change the

baking conditions which is what you have done. Heat can only reach the centre

of the batter for each unit by being absorbed at the surface and then transferred

to the centre (see Section 5.32). In cake shapes which have a small surface area

(SA) relative to their depth or thickness, the oven baking conditions are adjusted

to allow the rate of heat penetration to be compatible with the various changes

which occur in cake baking.

As the batter is heated in the oven, carbon dioxide gas from the baking

powder present in the formulation is released. It is common practice to adjust

the level of baking powder according to the cake type. The bakers ‘rule of

thumb’ is that the level of baking powder is higher for small cake units and

lower for large cake units. Too much or too little baking powder for a given

product recipe can have an adverse impact on cake shape (see Section 5.39).

As a matter of interest we took three recipes for three common cake pro-

ducts � slab, loaf shape and cup cake � and calculated the ratio of surface area

(SA) to the thickness (T) of the batter deposit in the pan. Using this ratio, we

then plotted it against the traditional level of baking powder in the recipe with

the results shown in Fig. 5.2. The straight line should only be seen as a guide to

one principle that should be employed in adjusting baking powder levels in

cake recipes rather being indicative of an ‘absolute’ relationship.

FIGURE 5.2 Relationship between cake type and level of baking powder.


5.36 WE WOULD LIKE TO CHANGE THE PHYSICALDIMENSIONS OF SOME OUR CAKE PRODUCTS TO MAKEDIFFERENT SIZES AND SHAPES DO YOU HAVE ANY ADVICETHAT YOU CAN GIVE US AS TO HOW TO ADJUST THEBATTER DEPOSIT WEIGHTS FOR THE DIFFERENT PAN SIZES?

There is no simple formula which allows you to calculate batter deposit

weights for different dimensions of pan. At first sight this may seem

strange but in fact there is a perfectly reasonable explanation and it is

related to the transfer of heat into the product during baking. In the oven

heat is absorbed by the surface of the batter before being conducted from

the surface to the centre of the product. The rate at which the heat reaches

the centre depends in part on the distance from the batter surface to the

centre; in general terms the greater the distance from surface to centre the

longer it will take for the heat to travel the distance (for a given set of bak-

ing conditions). However, as cake batters have a low viscosity by compari-

son with most other unbaked products (e.g., dough and paste), there is

potential for convection currents to be set up in the batter in the early

stages of baking (Cauvain and Young, 2006). The potential for such con-

vection currents is greatest in products which the surface area is small rela-

tive to the depth (thickness) of the deposit.

For cakes, the practical implication of the different rates of heat transfer

are that the key changes in conversion from batter to cake, such as the gen-

eration of carbon dioxide from the baking powder and the transitions from

foam to sponge, play a major role in determining the final structure of the

baked product. Change the heat transfer rate and you can end up

compromising key product characteristics. Bakers have learnt to compen-

sate for these effects by adjusting baking conditions when changing product

dimensions.

The following table using the same batter formulation (except for level of

baking powder � See Section 5.35) illustrates the principles that we have

described above and may help you in making your decision on scaling

weights.


Pan shape Length/

diameter

(cm)

Breadth

(cm)

Depth

(cm)

Pan

volume

(cm3)

Deposit

weight (g)

Baking

temperature

(�C)

Rectangular 15 8.5 8 1020 300 185

Rectangular 45 75 2.5 8437 3500 205

Rectangular 45 75 5 16,875 8500 190

Square 15 15 5 1125 370 190

Round 13 3 398 250 190

Round 20 2.5 785 320 200

Reference






5.37 WE HAVE RECENTLY CHANGED THE ACID THAT WEUSE FOR OUR BAKING POWDER MIX AND HAVE ADJUSTEDTHE NEUTRALISING VALUE ACCORDINGLY. SUBSEQUENTLY,WE HAVE BEEN HAVING SOME PROBLEMS ACHIEVING THEVOLUME AND SHAPE THAT WE WANT WITH OUR SMALLCAKES. CAN YOU EXPLAIN WHY WE ARE HAVING THESEPROBLEMS?

The neutralising value refers the proportion of a given acid which is required

to completely neutralise (react) with a given amount of sodium bicarbonate;

this proportion varies according to the chemistry of the acid (see Section

2.6.8). In addition to having a different neutralising value, each acid has its

own ROR which indicates the rate at which it will react with sodium bicar-

bonate to produce carbon dioxide gas. In addition, some of the baking acids

and the sodium bicarbonate are available in different grades � commonly

due to different degrees of particle size � and this too affects the ROR

because the acid and alkali go into solution at different rates.

The ROR of a baking powder mixture and the timing of the release of

carbon dioxide are important contributors to cake volume and shape. If the

ROR is too rapid then much of the carbon dioxide will be released during

mixing, and the early stages of the baking process which tends to lead to the

cakes lacking volume and often having a shape which is peaked rather than

rounded. A similar problem can occur if the ROR of the acid is too slow and

the majority of the carbon dioxide is released when the structure of the cake

has begun to set.

A visual summary of the effect of the ROR of the baking powder on cake

shape is given in Fig. 5.3. To find out where you are on the shape spectrum

decide which cake outline best matches the product that you used to get and

which matches the shape of your current cake products, and this will tell you

whether your ROR has increased or decreased.

For example, if you used to get shape number 2 (from the left in Fig. 5.3)

but now get shape number 3, then the ROR of your baking powder has

increased. To move the cake shape in a particular direction, you may need to

choose an alternative baking acid. The ROR can normally be obtained from

your baking powder supplier.

SLOW FAST

FIGURE 5.3 Effect of rate of baking powder reaction on cake shape.


5.38 WHAT ARE THE FACTORS WHICH CONTROL THESHAPE AND APPEARANCE OF THE TOP OF A CAKE?

The main influences on the shape and appearance of the top surface of cakes

fall into three categories; the balance of liquids to sugars in the recipe, the

balance between mechanical and chemical aeration and the rate of heat trans-

fer during baking.

The concentration of the sucrose solution in cake recipes has a significant

effect on cakes shape (and other structural features). As the level of sugar in

a cake recipe increases, the temperature at which the wheat starch gelatinises

is raised, and the batter stays fluid for longer in the oven. At low recipe

sugar levels, cakes tend to have a rounded and slightly peaked profile but as

the level increases, the shape becomes progressively flatter (Fig. 5.4).

Continued increases in recipe sugar level lead to collapse of the structure so

that a dip appears in the surface of the cake.

The volume, structure and appearance of cakes depend on creating a gas

bubble structure in the batter which will be expanded by the release of car-

bon dioxide from the baking powder reaction. Achieving the right balance of

mechanical and chemical aeration is important for controlling shape. The

examples shown in Fig. 5.5 are based on cake recipes which have all been

mixed to the same batter density but with different levels of baking powder

in the starting recipe. This means that the batter with the lowest baking pow-

der level has the highest proportion of air incorporated into the batter while

that with the highest level of baking powder has the lowest level of air incor-

poration. This follows because there is some reaction of the baking powder

INCREASING LEVEL OF ADDITION

FIGURE 5.4 The effect of increasing sugar level on cake shape.

INCREASING LEVEL OF ADDITION

FIGURE 5.5 Effect of baking powder level on cake shape.


components in the initial mixing stages, and some of the carbon dioxide gas

produced at this time remains trapped in the batter. The illustration shows

that as the level of baking powder increases (for the same final batter den-

sity) that the cake shape becomes less domed and eventually with high level

of baking powder a dip appears in the surface.

The impact of high levels of baking powder is pronounced because a lot

of the carbon dioxide gas is released in the oven at a time when the wheat

starch is swelling and the cake structure is close to setting. The critical

nature of the mechanical to chemical aeration balance can also be seen when

the ROR of the baking powder in the recipe is changed. A slow (late) release

of the carbon dioxide commonly yields a product with a peaked shape, and

as the reaction rate increases, the cake shape gradually flattens (Fig. 5.3).

However, fast reacting baking powders also give peaked shape products.

This is because most of the carbon dioxide escapes while the batter is very

fluid and none is left for expansion at the starch swelling stage.

Rapid heat transfer rates in the oven (high temperature) tend to cause the

cake shape to become more peaked, as does a high top heat when baking in

a deck oven.


5.39 CURRENTLY, WE ADD ALCOHOL, IN THE FORM OFSPIRITS OR LIQUEURS, TO OUR CELEBRATION CAKES AFTERTHEY HAVE BEEN BAKED AND COOLED. WE LEAVE THEMFOR A FEW DAYS AFTER TREATING THEM, BUT THIS ISTAKING UP A LOT OF SPACE. WHAT ADVANTAGES/DISADVANTAGES WOULD THERE BE IF WE ADD THEALCOHOL TO THE BATTER BEFORE BAKING?

The boiling point of alcohol is around 78�C, so you might expect a major

proportion of any added before baking will be evaporated during the baking

process. There are few estimates as to how much of the alcohol added to a

cake batter is lost during baking and they vary from 50% to 90%. There is a

suggestion that the losses are lower with heavily fruited cakes of the type

that you are making and greater with lightly fruited or plain cakes. It appears

from the few data available that the traditional method of soaking the fruit in

spirit before mixing and baking has no impact on reducing the losses. We

might assume that the benefits of soaking in alcohol before baking are simi-

lar to those obtained by soaking the fruit in water; namely a reduction in the

moisture migration from the cake crumb to the fruit so that the former stays

more moist eating.

The decision on whether to add them before or after baking depends on

why you are adding the spirits or liqueur to your cakes. If you are using the

spirits or liqueur as part of the description of the product, then you must be

sure that you are following the appropriate guidelines and legal requirements.

The position regarding alcohol as an ‘ingredient’ is complicated, so you

should seek local advice on what is permitted and what is not. On the one

hand, you may be required to have sufficient spirit to ‘characterise’ the prod-

uct, whereas on the other, there may be restrictions as to whether the pre-

mises from which the products may be sold should have a licence to sell

alcohol.

Not all of the spirit or liqueur is alcohol, there are many other compo-

nents which go to characterise this type of product. Many of these compo-

nents have distinctive flavours and they are likely to be retained in the

product, even if the spirit is added before baking.

The anti-mould properties arising from using alcohol offer a significant

advantage if the spirits are added after baking since losses from evaporation

during storage will be relatively small.

On balance, it would appear that the greatest benefits to be gained from

adding spirits or liqueurs to celebration cakes will come from adding them after

baking rather than adding them to the mix. If nothing else, the levels of addi-

tion will be lower as you will not have to compensate for evaporative losses.


5.40 WHY DO SOME TRADITIONAL SPONGE CAKEMAKINGMETHODS SPECIFY A DELAY IN THE ADDITION OF THESODIUM BICARBONATE AND THE USE OF HOT WATER?WOULD THIS APPROACH HAVE ANY PRACTICALAPPLICATIONS TODAY?

The delayed-soda method of making sponge cake batters is mainly used as a

means of controlling the reaction of the baking powder components and the

release of the carbon dioxide gas which is generated by that reaction. The

different baking acids which may be used in the manufacture of cake batters

have different rates of reaction (see Section 2.6.9). If a so-called fast-acting

acid is used, then the evolution of carbon dioxide would occur early in the

batter mixing stage. Although the batter is being agitated, there is a potential

for that carbon dioxide to be lost to the atmosphere and not able to contrib-

ute to the expansion of the cake in the oven. By delaying the addition of the

sodium bicarbonate to later in the mixing process, the potential for losing

carbon dioxide is reduced. Using the delayed-soda method will not reduce

the potential for batter deaeration which can occur during the storage of the

batter if it is stirred, or when it is being pumped through pipework or when

it is being deposited before baking.

A practical consequence of using the delayed-soda method for mixing cake

batters is that the combined level of baking acid and bicarbonate might be

reduced. This could have advantages in the current climate of seeking to

reduce the level of sodium in the bakery foods (see Section 2.5.4).

Each baking acid after reaction with the sodium bicarbonate leaves

behind a distinctively tasting salt; not everyone likes the ‘phosphate’ after-

taste which is characteristic of many baking powders. More traditional bak-

ing acids, such as tartaric acid, tend to be fast-acting in combination with

sodium bicarbonate and by using the delayed-soda method you could change

to such acids and modify the flavour profile of your products (and also

reduce sodium levels in some cases).

The specification of hot water is to encourage the rapid dissolution of the

sodium bicarbonate. This was probably more relevant many years ago when

the particle size of sodium bicarbonate was typically coarser than that of

today. If you are using a finely divided form then you may find that you can

readily dissolve the sodium bicarbonate in water at around 20�C; this will

have the advantage of not affecting the final temperature of the cake batter.

Undissolved and unreacted particles of sodium bicarbonate often show as

dark brown or yellow spots on the crust or more often in the cake crumb.


5.41 WE HAVE BEEN EXPERIENCING PROBLEMS WITHCOLLAPSE OF OUR SPONGE SANDWICHES WHICH LEAVESTHE PRODUCT WITH A DEPRESSION FORMING ON THE TOPOF THE CAKE AND AN AREA OF COARSE CELL STRUCTURE INTHE CRUMB. WHAT CAUSES THIS PROBLEM?

The area of coarse cell structure that you have observed in your collapsed

sponge cake is often referred to as ‘core’ formation. Sometimes, this might

be observed in the crumb even though the top of the cake has not collapsed.

The primary cause of your problem is instability and premature coales-

cence of the air bubbles in the batter. When the sponge batter reaches the

oven and the gas bubbles begin to expand, it is important that they do not coa-

lesce until the right moment in the later part of the baking process. To remain

separate from one another, the stabilising film must stretch as the air bubbles

expand under the influence of heat and due to the carbon dioxide gas which is

diffusing into them as the result of the accelerating baking powder reaction. If

the stabilising material is not able to stretch sufficiently, then it ruptures allow-

ing adjacent gas bubbles to coalesce and form larger ones � The coarse com-

ponent of the cell structure. At the same time, the displaced stabilising

material will join with other materials to form areas devoid of air cells � the

thick cell wall material you see which also looks darker in colour.

Although there is only one primary cause, there are many contributing

factors. They include the following:

� The presence of traces of fat or oil in a non-emulsified sponge recipe.

Ensure that all traces of fat or oil are removed from the mixing bowl and

use hot or boiling water to wash the utensils clear of oil and fat traces.

� Too little emulsifier in an emulsified sponge recipe. Try increasing the

level to about 0.75% of the batter weight (see Section 2.5.6).

� Too much baking powder in the formulation (see Fig. 5.6). Reduce the

baking powder level and if the cake lacks volume increase the mixing

time to lower the batter relative density or increase the emulsifier level.

� Batter relative density too low, especially with low levels of emulsifier.

Although the batter may be stable at low temperatures, it is during the

baking that bubble stability is most important.

� The particle size of the flour being too large.


One factor which is known to contribute to this problem is the presence

of ‘anti-foaming’ agents such as silicones. Even levels as low as 2 ppm have

been shown to induce core formation in sponge cakes. The effective level

depends to some extent on the level of emulsifier present, but 5 ppm silicon

will destabilise most sponge cakes batters. Traces of silicone may come from

a number of different sources. In the past, we have encountered traces of sili-

con in the following sources:

� Barriers creams used for hands.

� Vegetable oil.

� Sugar.

� Flour, most likely from the wheat.

� Skimmed milk powder.

If you suspect that an ingredient may have become contaminated with sil-

icon, you should discuss the problem with your supplier.

FIGURE 5.6 Effect of baking powder level in sponges.


5.42 RECENTLY, WE HAVE BEEN EXPERIENCING PROBLEMSWITH OUR SPONGE SANDWICH CAKES ASSUME A PEAKEDSHAPE DURING BAKING. WE HAVE NOT CHANGEDINGREDIENTS OR RECIPE. CAN YOU SUGGEST WHY WE AREHAVING THIS PROBLEM?

The onset of this problem seems to be related to the baking conditions rather than

the ingredients or recipe. As far as the baking conditions are concerned, there can

be a number of different reasons why this problem should occur. Often the condi-

tion is caused by too rapid a heat transfer to the batter. In all baked products, heat

is transferred from the surface to the centre, and in the case of round products,

much of the heat transfer is along the radii from outer edges to centre. In the case

of around sponges, the surface area is large relative to its thickness so that a small

portion of batter in the centre is the last to bake and the considerable expansion

forces which are present exploit the radial effect and force the sponge to peak.

The most obvious sources of too rapid a rate of heat transfer are as follows:

� Too high a baking temperature in the oven; cake peaking is entirely

dependent on baking temperature and independent of baking time. The

solution is to lower the baking temperature, but you may have to also

increase the baking time to remove sufficient water from the product to

avoid problems with shortening product mould-free shelf-life.

� Excessive top heat, particularly in deck ovens. The high radiant heat com-

ponent in such cases acts like too high a baking temperature. In such cases,

the ‘baking temperature’ may appear to be satisfactory. If you cannot bal-

ance the heat components in your oven, steaming the chamber before you

are ready to bake is a good way of removing excess radiant heat.

� In the case of ovens which bake by forced air convection, too high an air

velocity can cause the product to peak. High air velocities increased

sponge cake peaking even when the temperature is ‘normal,’ especially if

the turbulence above the product is high.

Other possible reasons for the problem include the following:

� Over-treatment of the flour, either from excessive chlorine treatment (see

Section 2.2.18) or excessive heat treatment (see Section 2.2.17), if they

are used. In the case of the heat-treated flour, you might also expect that

the flour has a ‘burnt’ odour which may carry through to the product. If

you suspect that this may be the cause, we suggest you discuss the prob-

lem with your flour supplier.

� A lack of carbon dioxide gas because the baking powder level is too low or

because the ROR has been too fast and much of the carbon dioxide gas has

been lost before the batter reaches the oven (see Section 5.38). Changes in

heat transfer can also affect the rate of release of carbon dioxide.

� Insufficient mixing so that there are too few gas bubble nuclei is present

in the batter for carbon dioxide inflation.


5.43 WE ARE HAVING PROBLEMS WITH THE BOTTOMCRUST OF OUR SPONGE CAKE PRODUCTS BECOMINGDETACHED AFTER BAKING. WE ALSO NOTICE THAT THECORNERS OF THE PRODUCT BECOME ROUNDED AND THETEXTURE CLOSE. CAN YOU OFFER ANY EXPLANATION FORTHESE PROBLEMS?

Your problem comes from a lack of carbon dioxide in the formulation either

because you are adding too little baking powder or because too much has

been lost before the product reached the oven, or you are mixing the batter

for too long.

In most cakes but especially with sponges, getting a fine cell structure

and light texture in the baked product requires the evolution of baking pow-

der in the oven to inflate the air bubbles which have been incorporated dur-

ing mixing. Even though the air bubbles expand under the influence of heat

in the oven their degree of expansion is limited by Charles Law, i.e., to

1/273 of their volume for each 1�K (for practical purposes 1�K 5 1�C). Theevolution of carbon dioxide provides increases in gas volumes far in excess

of that obtained purely from the temperature effect.

As the sponge batter expands during heating its relative density changes

and this affects the heat transfer rate into the batter. Batters with high rela-

tive densities, i.e., low gas volumes, bake faster than those with low relative

densities, because the gases involved act like an insulating material. Thus the

more gas that is evolved during baking, the slower the heat transfer rate and

this leads to more uniform expansion of the batter.

Steam is also generated during the baking process. This requires that the

temperature in the product exceeds 100�C. The presence of dissolved sugars

raises the boiling point of the aqueous phase in sponge (Cauvain and Young,

2008), but the crust still sets fairly early in the baking process. The quantities

of steam which are progressively evolved from the batter as the heat pene-

trates to the centre buildup pressure under the top crust and detach it from

the rest of the product. There is also a buildup of steam at the angle of the

base of the pan and its side which prevents the batter flowing into that area.

The rounding of this area of the product is often referred to as ‘chamfering.’

The rate at which carbon dioxide gas is evolved depends on the ROR

between the acid component and the sodium bicarbonate (see Section 2.6.8).

This can be regulated either by changing the acid type or its particle size. In

the latter case larger particles are slower to react.


We suggest that you first investigate the effect of raising the level of the

baking powder that you are using. This usually solves the problem. If it per-

sists then you are most likely using an acid which is too fast-acting, and we

suggest that you change to a slower one, a rough guide for choosing a

suitable acid is:

� Fast-acting acids � Acid calcium phosphate (mono calcium phosphate),

tartaric acid and cream of tartar (potassium hydrogen tartrate).

� Slow-acting acids � Sodium acid pyrophosphate and sodium acid alu-

minium phosphate.

The baking powder reaction rate can also be controlled by using an acid

or sodium bicarbonate with a larger particle size, however, you must ensure

that unreacted components are not left behind in the baked product as this

can lead to flavour and colour problems.

If you mix the batter for too long, then the carbon dioxide gas which is

being evolved during the mixing process may escape from the batter rather

than diffusing into the air bubbles. Cauvain and Cyster (1996) showed that

this could happen even when using an apparently ‘slow’ acting acid like

sodium acid pyrophosphate.

References

Cauvain, S.P., Cyster, J.A., 1996. Sponge cake technology. CCFRA Review No. 2. Campden









5.44 WHEN MAKING SPONGE DROPS, WE FIND THAT THELAST ONES TO BE DEPOSITED ARE NOT AS GOOD AS THEFIRST ONES. WHY IS THIS?

Once a batter has been mixed, changes in its properties occur with standing

time. The nature of these changes varies according to the manner in which it

is treated and the length of time which elapses before it is deposited. The

main change is related to the stability of the air bubbles in the batter and the

evolution of carbon dioxide gas from the baking powder in the formulation.

Once mixing starts, the acid in the baking powder begins to dissolve and

react with the sodium bicarbonate that is present. The rate of the reaction

depends on the type and nature of the acid (see Section 2.6.8) and the tem-

perature of the batter. The reaction proceeds more rapidly at higher tempera-

tures whatever the acid being used. Sometime after the baking powder

reaction has begun, the carbon dioxide gas diffuses into the air bubbles in

the batter and they begin to inflate. Some may become so large that they can

rise in the batter and escape at its surface. The stabiliser in the batter (e.g.,

emulsifiers) helps prevent this from occurring.

As the batter standing time before depositing increases, more carbon

dioxide is evolved, and eventually, some of it can escape from the batter. If

too much of the carbon dioxide is lost the batter relative density begins to

increase, that is, the batter becomes less well aerated and the sponge drops

deposited from this portion will lose volume. The length of time which has

to elapse before this situation is reached depends on the particular baking

acid being used but can occur with all acids. The potential for ‘de-aeration’

of the batter increases if the batter is agitated or subjected to shear to any

significant degree. The longer that the batter stands the greater will be the

potential deaeration effect from any agitation.

We suggest that you examine the length of time that the batter stands and

see if this can be shortened. This may require the production of smaller

batches mixed more frequently. Avoid excessive agitation of the batter once

prepared, e.g., try to minimise the degree of scraping down of hoppers

because this incorporates ‘old’ batter which contains less gas. Alternatively,

consider using a slower acting acid in your baking powder.


5.45 FROM TIME TO TIME, WE EXPERIENCE PROBLEMSWITH SWISS ROLLS CRACKING ON ROLLING. CAN YOUHELP IDENTIFY THE CAUSES OF THE PROBLEM?

The two most important characteristics of a Swiss roll sheet are that, it

should have a uniform thickness after baking and should be sufficiently flexi-

ble to withstand the rolling process. Control of a number of different recipe

and process factors are therefore important if you are to avoid problems with

the rolls cracking. We suggest that you look closely at the following aspects.

The thickness of sheet after baking as both increases and decreases in

thickness may cause cracking. Thinner sheets are particularly prone to crack-

ing. Pay attention to any changes in sheet thickness which may have arisen

from changes in batter density, lower or higher, from changes in mixing

times or from different levels of air injection in continuous mixers.

As baking powder action makes a significant contribution to roll thick-

ness you may wish to examine the level that you use. The rate at which the

carbon dioxide is released varies according to the type of acid that is being

used (see Section 2.6.8) and you may wish to check that you are using the

same acid each time. There is some release of carbon dioxide gas while the

batter stands before depositing, so any significant variation in batter standing

time can have an effect on final product volume.

You should check your deposit weight control to ensure that there are no

significant variations. Remember that the deposit weight for a given unit

area with Swiss roll batter is low and so even small variations may have a

significant effect.

Avoid unnecessary drying of the roll during baking. This may come from

longer baking times, higher baking temperatures or higher air velocities in

some types of oven. Variations in batter formulation and aeration will also

have an effect on the final roll moisture content. Remember that a thinner

deposit will bake to a lower moisture for a given set of baking conditions.


5.46 WHAT ARE THE KEY ELEMENTS TO CONSIDER WHENMAKING CHOCOLATE CAKES WITH COCOA POWDER?

The use of the term ‘chocolate’ to describe a cake varies a little around the

world and is often regulated in some way. For example, in the United

Kingdom, chocolate can only be used as a cake descriptor if the final product

contains not less than 3% dry, non-fat cocoa solids. This is usually achieved

through the addition of cocoa powder and when calculating the level to use

in a recipe allowance must be made for variations in moisture (usually

around 5%) and fat (commonly between 10% and 20%).

The calculation is quite straightforward as shown by the following exam-

ple for the United Kingdom:

Cocoa powder contains 5% moisture and 15% fat

The required dry, nonfat solids are 3%

The mass of cake crumb after baking is 100 kg

The quantity required is given by 3 3 100/(100 2 5 2 15) 5 3.75 kg

It is wise to slightly increase the level of added cocoa powder so that any

variations in cocoa composition or cake moisture content are taken into

account. Thus in the above example, the level of cocoa powder could be

increased to 4 kg.

The addition of cocoa powder should be considered as ‘flour’ for the pur-

poses of recipe balance. It is common practice to add extra water along with

the cocoa powder. For the example given above, the addition of 2kg extra

water would be recommended. Without this extra water addition, the batter

would be very viscous and may become difficult to process in the normal

manner.

Even with the addition of extra water chocolate cakes tend to be drier

eating than the equivalent plain form. It helps to slightly increase added oil

or fat levels, or to add glycerol. There may also be some loss of volume in

chocolate sponge, this can usually be compensated for by slightly raising the

added emulsifier or baking powder levels.

Often chocolate batters may contain an excess of sodium bicarbonate to

yield alkaline cake which helps enhance the chocolate colour in the final

product.


5.47 WE HAVE BEEN MAKING CAKE MUFFINS AND FINDTHAT WHEN WE CUT THEM OPEN, THEY HAVE LARGEVERTICAL HOLES IN THE CRUMB. WHY IS THIS AND HOWDO WE ELIMINATE THEM?

The holes that you have seen are often referred to as ‘tunnel holes’ and run

vertically from the base of the muffin towards the peak top. As heat begins

to penetrate into the muffin batter the starch gel swells and begins to gelati-

nise. At this time, there is a significant increase in batter viscosity in the

outer areas of the deposit. Above these areas of high viscosity, the batter is

still relatively fluid and can expand upwards eventually bursting though the

top crust and causing the muffin to form a peaked shape.

The expansion comes from the evolution of steam and the generation of

carbon dioxide from the reaction of the baking powder components and their

thermal expansion. It appears that the tunnel holes first form in areas of the

batter where the batter is close to gelatinising and coalescence of the previ-

ous small gas bubbles is beginning to occur. These larger bubbles become

buoyant and try to rise towards the surface of the muffin. The pressure in

these large gas bubbles forces the batter apart as it starts to set and initiates

the formation of the base of the tunnel hole. The portions of batter which

have still to set offer less resistance to the expanding gases, and they travel

upwards forming the tunnel holes but as the heat continues to penetrate they

become trapped in the setting crumb (see Fig. 5.7).

As batter viscosity and gelatinisation are important in determining the devel-

opment of the tunnel holes, you could eliminate them by changing your recipe,

particularly by re-balancing your sugar to water ratio with an increase in the

level of water. However, these types of holes have become so characteristic of

muffins that eliminating them may affect consumers’ perceptions of your prod-

uct quality so proceed with caution. If you are going to re-balance your formula,

you may prefer to call the product by another name.

FIGURE 5.7 Tunnel holes in cake muffins.


5.48 WHY DO SOME OF OUR CAKE MUFFINS LEAN TO ONESIDE DURING BAKING?

Due to the combination of recipe, deposit weights and pan dimensions,

cake muffins tend to form a large bulbous head which slightly overflows

the sides of the supporting pan. Usually, the bulbous head is located more

or less symmetrically and centrally on the product. The last portion of the

batter to set during baking is about two-thirds of the way up the vertical

height in the pan. The expansion of this portion of the batter provides suf-

ficient force to encourage the formation of the bulbous head and break on

the top crust.

The control of heat input in oven is a key element in the delivery of a

uniform shape with cake products. All baked products receive heat at their

surfaces which is transmitted through to their centres. The rate of heat

transfer depends on many factors related to dough or batter density,

dimensions and oven conditions. Cake batters are less viscous than bread

or cookie doughs and as heat is slowly being conducted to the product

centre, it is possible for convection currents to form in the batter before it

sets. The magnitude of the convection currents depends on many factors;

including flour treatment (Cauvain and Young, 2006) and the dimensions

of the cake. Convection currents are more likely to occur in products

which are relatively thick by comparison with their SA s (e.g., loaf and

slab cakes).

When products are baking in the oven, it is important that there is suf-

ficient air movement around them to help with the uniform transfer of

heat. If the gaps between products or pans are too narrow, then the heat

flow can be reduced and the crust of the product will take longer to form

on that part of the product. In such cases, the expanding batter will tend

to move in the direction where the crust is weakest and yield a product

which leans (Fig. 5.8). We suggest that you look closely at the spacing of

your cake pans on your trays and the way in which they are placed in the

oven.


Reference



FIGURE 5.8 Leaning cake muffins.




5.49 WHAT IS BAUMKUCHEN AND HOW IS IT MADE?

Baumkuchen is a speciality cake much loved by Germans. It takes its name,

meaning tree or log cake, from the way the batter was originally deposited

and baked, layer by layer on a thin log which was rotated over an open

wood fire. It is said to have its origins with the ancient civilisations of the

Greeks and Romans. It is believed, the Romans brought the technique for

producing the Baumkucken as they conquered Northern Europe, and in

Germany, the techniques were practised and enhanced to give the modern

day Baumkucken.

A typical recipe is:

500g butter

500g sugar

1500g egg

500g flour

The recipe can be varied by adding other fillings such as ground nuts,

honey, marzipan and rum or brandy.

The method of baking is critical, and it is doubtful that it can be carried

out without special equipment. Normally, baking is carried out in a specially

constructed oven which is heated at the bottom with open gas jets. Above,

there is a revolving hardwood tapering roller or tube upon which is fastened

either a piece of cloth or, more usually, buttered greaseproof paper, which is

tied with thin string at regular intervals to assist in the adhesion of the batter

and subsequent removal of the baked cake.

The batter, which is similar to that used for Sandkucken (a traditional

plain cake from Northern Europe), is poured over the greased paper while

the roller is constantly revolving. To prevent large cakes from slipping off

the rollers, the latter are preheated and the first layers of cake are baked

more thoroughly than the following layers. As each layer is cooked, a further

layer is poured over until the desired thickness is obtained. Baking is accom-

plished by adjusting the heat source and/or the distance of the cake from that

source. The regulation of the flames during baking is very important and

experience is needed to get the best results.

To obtain the characteristic regular wavy appearance the rotating cake is

scraped with a large metal comb and finished with a specially shaped rod.

Using a broad palette knife the cake is then marked in rings where the pieces


of string hold the paper. Whilst still in the oven, the baked cake is decorated

with apricot puree which serves as a glaze. Other finishes such as fondant or

chocolate can be added afterwards. The roller is then removed and the entire

cake cut up into rings or used in an upright position as a speciality cake for

Easter or other festive occasion.

Sometimes, the cake is removed immediately from the roller and cut into

a variety of sections. (e.g., rings, wedges, slices). The crumb of the

Baumkucken is firmer and drier than that of other plain cakes.


Chapter 6

Biscuits, Cookies, Crackers andWafers

6.1 HOW IMPORTANT ARE THE DOUGH AND BATTERTEMPERATURES IN BISCUIT, COOKIE, CRACKER AND WAFERMAKING?

The temperature of biscuit doughs and batters is important in controlling a

number of the key chemical reactions and in influencing the processing of

the dough. The temperature requirements of biscuit and cookie doughs are

quite diverse, so we will discuss them under five different headings; semi-

sweet sheeted, short-dough rotary moulded, wire-cut and deposited, crackers

and other laminated biscuits and wafer batters.

Semi-sweet sheeted

A key requirement for the processing of semi-sweet biscuit doughs by

sheeting is to deliver a particular dough rheology in a consistent manner.

The dough rheological properties are strongly influenced by the flour proper-

ties and the development of the gluten structure in the dough during mixing.

A particular problem with semi-sweet sheeted doughs can be the tendency of

the cut pieces to shrink back after cutting or during baking giving misshapen

products. This problem is most commonly related to high levels of gluten

formation in the initial dough. In general, the warmer the dough the softer

will be its consistency and the more readily it will sheet. Warmer doughs

also tend to have less elasticity and so may better keep their shape after hav-

ing been cut from the sheet.

In some cases, in the manufacture of semi-sweet biscuit dough a reducing

agent (e.g., sodium metabisulphite, L-cysteine hydrochloride (see Section

2.2.7) or proteolytic enzymes may be added to help reduce the elasticity of

the dough. It is worth noting that the action of both reducing agents and

proteolytic enzymes will be temperature sensitive and that higher dough tem-

peratures will encourage greater chemical and biological activity. This is an

important consideration in the reuse of biscuit sheet trimmings as the higher

level of activity resulting from the combination of higher temperatures and

recycle times can cause considerable changes in dough rheological

properties.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00006-0

The low water levels used in making semi-sweet doughs means that there

is significant resistance by the dough during mixing, which in turn means

that there will be significant heat generated. The strong relationship between

energy transfer and temperature rise during dough mixing and its contribu-

tion to dough development is well-understood in the case of breadmaking

(Cauvain and Young, 2006a), but less in semi-sweet biscuit making though it

is recognised that significant temperature rises do occur during mixing.

Indeed, in some cases, the achievement of a final set dough temperature is

used to determine the final mixing point (Manley, 2000).

Short-dough rotary moulded

The higher levels of sugar and fat used in short-dough biscuits recipes

limit the formation of a gluten structure in the mixed dough (Cauvain and

Young, 2006b). The level and the choice of the type of fat being used in the

recipe plays a significant role in determining the consistency of the mixed

dough, the way in which it will process and the eating qualities of the baked

product. The melting profile and the final melting point of the fat play a

major role in determining the organoleptic acceptably of the baked biscuit.

High melting point fats (e.g., above 40�C) tend to yield biscuits with a

‘waxy’ mouthfeel, whereas low melting point fats tend to confer ‘oily’ char-

acteristics to the baked products.

The type of fat used has an impact on the mixing method employed for

the manufacture of short-dough biscuits. Commonly, the mixing process for

short doughs comprises two stages; the first one is often described as a

‘creaming’ stage in which the fat is mixed with the sugar and other ingredi-

ents before the flour is added, and this requires the fat to have the appropri-

ate melting profile to give good dispersion and aid with the incorporation of

air. Careful control of the dough temperature during mixing is required to

maintain the key roles of the fat in the recipe, and in the manufacture of

short-dough biscuits, final mix temperatures are much lower than with semi-

sweet biscuit doughs.

Wire-cut and deposited

Wire-cut cookie doughs are of a similar consistency to short-dough

biscuits, but often the recipes will contain particulate inclusions such as

chocolate chips and nuts. The considerations with respect to the impor-

tance of dough temperatures are similar to those for short-dough

biscuits.

Deposited biscuits are similar to cake batters, so the control of batter

temperature is important for the control of gas production by the baking

powder and the batter viscosity. The batter temperatures used will be lower

than those used in the manufacture of wafers because there is no yeast

present.

Crackers and other laminated biscuits

Many cracker formulations contain yeast and use periods of fermentation

(see Section 6.19) followed by lamination of the dough to achieve their


characteristic crisp and flaky structures. There are a number of variations on

the fermentation system including sponge and dough, straight dough and

continuous fermentation systems. In all cases control of the dough, tempera-

ture is very important to optimise the contribution by the yeast to gas

production.

In cracker-making processes which employ long fermentation times, there

is the potential for significant flavour development. The added yeast will

contribute to the final flavour profile but equally important will be the contri-

bution from the naturally occurring lactobacilli and other microogansims. In

some cases, a specific culture of lactobacilli may be added at the start of

mixing to achieve a specific flavour profile. The temperature used in the fer-

mentation processes associated with cracker production may be varied to

encourage a particular flavour profile.

Wafer batters

In the preparation of wafer batters, the temperature will play an important

role in determining the viscosity of the batter which in turn will impact on

its flow properties although it is being pumped through the processing equip-

ment and its behaviour at depositing. It is important that the batter flows

readily onto the wafer plates and will quickly spread to fill the whole of the

plate as it enters the oven to get a complete wafer sheet. Low temperatures

yield batters with high viscosity and the deposit weight may have to be

increased to ensure that a complete wafer is formed. High deposit weights

tend to result in wafers with a harder texture after baking because they are

denser.

The aeration of wafer batters is a most important aspect in production.

Some wafer batter formulations may contain yeast and be given a short

period of fermentation before depositing. Thus, temperature control is

required to achieve consistent results. The more common method of aerating

wafer batters is through the addition of sodium or ammonium carbonates or

a combination of both. Neither of these chemicals is particularly affected by

variations in batter temperature over the typical range in a bakery as most of

their reaction occurs when the batter is deposited onto the wafer plates for

baking and the temperature is much higher.

One reaction that is affected by batter temperature is that of the cereal

alpha-amylase present in the flour. The amylase acts on the damaged starch

granules and reduces the viscosity of the batter by breaking down the starch

and releasing the water that is had been holding. It is common for wafer

batters to stand for a period of time before depositing, so any variations in

batter temperature can have a profound impact of batter viscosity. High batter

temperatures should be avoided to reduce the potential for amylase activity.

Temperature ranges

Some typical temperature ranges for different groups of biscuit products

are given in the following table.

Biscuits, Cookies, Crackers and Wafers Chapter | 6 301

Product Temperature range for

dough or batter (�C)

Wafers 22�32

Semi-sweet sheeted 40�46

Short-dough rotary moulded 18�22

Wire-cut and deposited 16�24

Crackers and other laminated biscuits 30�38

References

Cauvain, S.P., Young, L.S., 2006a. The Chorleywood Bread Process. Woodhead Publishing Ltd.,

Cambridge, UK.

Cauvain, S.P., Young, L.S., 2006b. Baked Products: Science, Technology and Practice.











6.2 WHAT IS ‘VOL’ AND WHAT IS ITS FUNCTION INBISCUITS DOUGHS?

Vol is a baker’s term which is applied to ammonium carbonate. It is used as

an aerating agent and does not require the addition of an acid to evolve car-

bon dioxide. It also differs from other aerating agents, in that, it evolves

almost no gas in the cold and decomposes under the influence of heat to

yield three gases; ammonia, carbon dioxide and water vapour (steam).

The evolution of ammonia restricts the use of vol. Ammonia is readily

soluble in the liquid phase of doughs, pastes and batters and will remain

in the product if sufficient water remains after baking. This is the

case with cakes where the use of vol will leave an unpleasant ammonia

taste and smell. In biscuits, however, the degree of heat input required to

drive off almost all of the water from the dough ensures that the majority

of the ammonia is also driven off so that the effect on taste and flavour is

not detectable.

There are a number of reasons why vol has been used in the baking

industry, including:

� The volume yield of gases is considerable for a given weight of material.

� The complete decomposition and the absence of an aerating acid means

that there are no salts left in the product which may yield

unacceptable flavours.

� The minimal release of gas in the cold permits the mixing large batches

of dough and extended processing times without significant change in

paste density or loss of aeration before baking.


6.3 A BATCH OF OUR BISCUITS CONTAINING OATMEALHAS DEVELOPED A ‘SOAPY’ AFTER-TASTE WHICH MAKESTHEM UNPALATABLE. WHY IS THIS?

The soapy taste that you observe is almost certainly the result of lipase

enzyme activity in either the dough before baking or in the baked product

during storage, possibly through post-baking contamination.

Oats are prone to this problem due to the high level of lipase enzyme

activity which is naturally present. Lipase splits fats into fatty acids which

react with the sodium bicarbonate to yield the soapy flavour. The most com-

mon way of avoiding this problem is to only use oat products in which the

lipase activities have been eliminated. This is achieved by steaming the oats,

and you should specify this to your supplier. Steaming should not have any

adverse effects on the functionality of the oats which is limited in biscuit

making.

You should also examine your dough mixing and processing to ensure

that there has been no incorporation of scraps of old dough or ones which

have become heavily contaminated with microorganisms which also have the

potential for considerable lipase activity.

As commented above, the lipase activity can have a microbial origin and

so could also come from post-baking contamination. In normal circum-

stances, the water activity of an oatmeal biscuit is too low to support micro-

bial activity due to its low moisture content. However, if there has been any

condensation on the surface of the biscuit, then the water activity might have

become high enough to initiate the necessary microbial activity. You should

consider whether there has been any opportunities for warming and cooling

which may lead to condensation in the pack.

Oat-based products may also develop off-odours and bitter tastes due to

oxidative rancidity. In the case, the low water activity in the product

encourages the problem, along with exposure to light and traces of cer-

tain metals, e.g., iron and copper. Oxidative rancidity is normally a

lengthy process taking many weeks or months to manifest. The inclusion

of a suitable antioxidant in the fat is usually helpful in avoiding this

problem.


6.4 FROM TIME TO TIME, WE HAVE NOTICED A WHITEDISCOLOURATION ON THE SURFACE OF OUR ALL-BUTTERSHORTBREAD. CAN YOU EXPLAIN WHY THIS OCCURS?

The discolouration that you have observed is the phenomenon commonly

referred to as ‘fat bloom’. It is the formation of small crystals of fat on the

surface of the biscuit and occurs mainly as the result of temperature cycling

during storage, that is periods of warmth and cold such as may occur in

un-heated locations subject to the effects of ambient temperature fluctuation.

Fat crystals may exist in a number of different forms (see Section 2.3.1).

As their size may as small as 5 μm, only agglomerates of fat crystals can be

seen with the naked eye. The formation of crystal agglomerates is encour-

aged by rapid cooling, such as might be experienced when the products are

quickly chilled after baking. Similar conditions may occur if a warm product

is placed into a chilled environment. A similar problem may be seen with

chocolates which have become too warm in periods of hot weather and then

placed in a refrigerator to cool.

To minimise the problem, you should examine your cooling technique

and try to cool more slowly, or eliminate forced air cooling. Also consider

whether you can pack in a warmer environment. You should record

the typical storage temperature history of the product, looking for any

fluctuating periods of warmth and cold and eliminate, or at least minimise

these.

If none of these considerations are relevant, you might tackle the problem

by introducing a small portion (say about 5%) of a low melting point butter-

fat fraction or oil into the product. This will help to reduce the tendency for

the fat to recrystallise.


6.5 WE PRODUCE BISCUIT-CONTAINING POWDEREDFRUCTOSE WHICH WE CREAM WITH THE FAT AND SUCROSEBEFORE ADDING THE OTHER INGREDIENTS. RECENTLY, WEHAVE SEEN THE APPEARANCE OF BROWN SPOTS ON THEPRODUCT. DO YOU KNOW WHAT CAUSES THIS EFFECT?

The most likely cause of your problem is associated with the creaming of the

fat and the sugars. It is likely that some of the fructose that you are adding

has become so coated with fat that it cannot dissolve in the limited amount

of water that is available in a typical biscuit dough. This leads to excessive

browning during baking.

To avoid the problem, you could dissolve the powdered fructose in the

dough water before mixing. Alternatively, you could change to a fructose syrup,

remembering to re-balance the sugar solids and water content of the recipe.

Similar brown or dark spots may arise if you are using very large crystals

of sucrose which do not dissolve completely and lead to the problem some-

times described as ‘sugar burn’.

Dark spots may also originate from undissolved aerating acids in the mix.

For example, acid calcium phosphate is sparingly soluble and can hydrolyse

on the surface of baked goods to give free phosphoric acid. The acid can car-

bonise carbohydrates during baking giving rise to dark spots where the phos-

phate is concentrated. Often, the problem is alleviated by changing to a finer

form of the acid concerned so that there is better dispersion. Should the dark

spots still form they are usually too small to be detected by eye.


6.6 HOW DO BISCUITS AND CRACKERS GET BROKENDURING STORAGE, EVEN IF THEY ARE NOT DISTURBED?CAN WE STOP THIS FROM HAPPENING?

The problem you describe is the one commonly referred to as ‘checking’ and

is related to the uneven distribution of moisture in the baked biscuit or

cracker. It was first studied and the reasons for the problem reported by

Dunn and Bailey (1928).

After leaving the oven, the moisture remaining in biscuits and crackers

is unevenly distributed; in particular, the edges and upper and lower sur-

faces have a much lower moisture content than the centre. During storage,

the moisture migrates from the higher moisture content centre to the drier

areas to achieve equilibrium. This movement of moisture sets up a series of

stresses and strains in the product which, because the product is inflexible,

can be of sufficient force to crack the surface. In some severe cases, the

biscuit may completely break into a number of smaller pieces. The cracks

develop along weaknesses in the product structure, many of which are

microscopic in size.

The best means of avoiding this problem is to assure a minimum of

moisture gradient in the baked product. This commonly means baking at

lower temperatures for longer times. Alternatively, you can introduce

immediate post-baking drying using radio-frequency or microwave heating.

Ideally, the moisture differential between surface and centre should be less

than 1% and average biscuit moisture contents in the order of 2�3%. It is

possible for biscuits to absorb moisture from the atmosphere if they are not

packed correctly, but this usually leads to softening of the biscuit rather

than checking.

Dunn and Bailey (1928) suggested that part of the crystalline sucrose be

replaced with invert sugar syrup. Other suggestions have been using a lower

protein flour and smaller average particle size, though such changes may not

be suitable for cracker production where the protein plays an important role

in delivering the relevant dough rheology and formation of the layered struc-

ture. Micka (1939) suggested that raising the pH to around 7.0 was useful in

reducing checking, and he considered that careful use of rework was

necessary.

References

Dunn, J.A., Bailey, C.H., 1928. Factors affecting checking in biscuits. Cereal Chemistry 5,

395�430.

Micka, J., 1939. Study of checking and pH in cracker and biscuit product. Cereal Chemistry 16,

752�764.








6.7 WE ARE MAKING A GINGER CRUNCH COOKIE, BUTFIND THAT WE EXPERIENCE VARIATIONS SIZE. CANYOU ADVISE?

Variations in biscuit size often come from variations in flow during the bak-

ing process. The three main ingredients which control flow are sugar, ammo-

nium bicarbonate and flour protein level.

If you want to increase flow then you can:

� Increase sugar or glucose syrup level.

� Increase ammonium bicarbonate (vol) level.

� Use a flour with a higher protein content.

If you wish to decrease flow, then you should use lower levels of the

above ingredients.

As you are experiencing variations in flow, then you should check the

weights of the three key ingredients to make sure that they are being deliv-

ered consistently. If there is no problem with the weights being delivered,

then you should look to the flour qualities.


6.8 WHEN MAKING GINGER NUTS, WE FIND THAT WE DONOT ALWAYS GET THE DEGREE OF CRACKING THAT WEWOULD LIKE. WHY IS THIS?

The cracks which form on ginger nuts are mostly related to the level and bal-

ance of sugar types being used. You should try increasing the level of coarse

sugar or reduce the level of fine sugar in the recipe.

The oven humidity can also affect crack formation and an increase may

be of some help, especially if you can introduce the humidity into the first

section of a multi-section oven, the products may exhibit poor cracking

because they are flowing too much (see Section 6.7).


6.9 WE ARE TRYING TO MAKE SOFT-EATING COOKIES ANDARE HAVING A DEGREE OF SUCCESS WITH THE RECIPE THATWE ARE USING. THE PRODUCTS ARE NOT EXPECTED TOHAVE A LONG SHELF-LIFE, BUT WE FIND THAT THEY AREGOING HARD TOO QUICKLY. CAN YOU SUGGEST ANYWAYS OF EXTENDING THE PERIOD OF TIME THAT THECOOKIES WILL STAY SOFT EATING?

Soft-eating cookies are usually baked to higher moisture contents than many

types of biscuits and cookies; moisture contents may range from 6 to 12%

compared with less than 5% with more traditional biscuit forms. This higher

moisture content helps to confer some of the softer eating character that you

are seeking.

To help get and keep the higher moisture content, you may need to make

slightly thicker cookies than you are used to. This approach will mean that

more moisture is retained in the centre of the product and help with the soft-

ness and chewiness of the cookie. There will be a moisture gradient in the

baked cookie with the upper and bottom crusts and the edges having lower

moisture contents than the centre. Gradually during storage, you will find

that the moisture from the centre of the cookie will migrate to the regions of

lower moisture content with some loss of the soft-eating character, but they

will have a softer texture than standard cookies.

The rate at which this moisture equilibration occurs depends on a number

of factors but is especially affected by the moisture-permeability of the pack

that you are using. To reduce moisture losses and so retain the soft-eating

character that you are seeking you should use a wrapper with a low moisture

vapour transition rate (see Section 11.7) which limits moisture losses. You

should also check the integrity of the pack seals as moisture can readily pass

out of the pack through any small gaps.

In the oven, it is generally recognised that part of the sugar when

heated dissolves in the recipe water and melts to form an amorphous glass

(a super-cooled liquid). This sugar glass contributes to cookie flow and

significantly affects the final cookie eating character. With the loss of

moisture during baking, the level of water available for keeping the

sucrose in solution is lowered. As the cookies cool on leaving the oven,

some of the sucroses that is present will recrystallise which contribute to

the hardness of their eating character. If more moisture is lost during stor-

age, more sugar will recrystallise and the eating character will further

harden; it is for this reason that it is important to restrict the moisture

losses during storage.

In some biscuit products, the moisture gradient between the centre and

the crust regions can lead to problems of checking or the spontaneous break-

ing of biscuits (see Section 6.6). Checking is more commonly a problem


with biscuit products which are low in fat and sugar, e.g., semi-sweet and

cracker types (Cauvain and Young, 2008). You should not experience any

problems with checking, nevertheless, you should watch out for any signs of

the problem; for example, an increase in the crumbliness of your products.

If you are including any nuts, chocolate chips or pieces of fruit in your

cookies, they provide discontinuities or points of weakness in your products

which can be exploited by the strains which arise because of moisture

migration within the cookie. Dried fruit pieces can also be a problem as

they may absorb water from the moister areas of the cookie and so may

increase the likelihood for sugar recrystallisation.

One of the ways you can help keep the cookie soft is to replace part of

the crystalline sucrose (sugar) with non-sucrose sugar syrup. This

replacement will reduce the likelihood of the sucrose recrystallisation during

storage. Sugar syrups which may be used include glucose syrups and

high-fructose corn syrup. You will need to carry out a few trials to find an

appropriate level of replacement. Remember to adjust the water level in your

recipe to allow for the water present in the sugar syrup (typically around

18�20%). High levels of glucose syrup may lead to excessive browning in

plain cookies, with chocolate cookies this should be less of a problem. You

may also notice a slight change in sweetness.

Reference






6.10 WE ASSEMBLE A SELECTION PACK OF BISCUITS ANDCOOKIES, ONE OF WHICH IS A RECTANGULAR PRODUCTCOATED ON THE TOP WITH ICING. WHEN THE PACK ISOPENED AFTER SOMETIME THIS COATED BISCUIT HAS A‘BOWED’ SHAPE, THE BASE IS SOFT EATING BUT THE ICINGREMAINS HARD. CAN YOU SUGGEST REASONS FOR THESECHANGES?

As you know, biscuits are very low moisture, baked products and this contri-

butes to their hard eating character. As they have a low moisture and low

water activity, they are susceptible to absorbing moisture from the atmo-

sphere, and this makes them soft eating. This particular biscuit has obviously

absorbed moisture and as well as becoming soft eating has begun to expand.

It is not unusual for biscuits to expand when they absorb moisture; the

degree of expansion is very small and often goes unnoticed. However, in this

case, the icing on top of the biscuit has remained hard and not significantly

changed its dimensions, and the overall effect is for product to assume the

slightly bowed shape that you see. It may be the case that many of the differ-

ent biscuit types in the pack have been affected to some degree or another.

It is interesting that the icing has not been affected by the available mois-

ture. Icings are usually quite likely to absorb moisture and go sticky, espe-

cially if there is a lot of crystalline material present. In this case, it would

appear that your icing formulation and preparation has minimised the poten-

tial for the icing to absorb water.

The moisture which has caused this problem may come from a number

of sources. There are at least three possibilities to consider:

1. That the biscuits have been stored in a damp atmosphere. If the products

are in a box then the lid may not be properly fitted, if they are over-

wrapped then the seal may not be secure. Of course, once the biscuits

have been sold, then you have no control over the conditions under which

they are stored.

2. The volume of air in the pack around the biscuits can be quite large, and

if they were packed in a damp environment, then there could be the

opportunity for moisture migration from the enclosed air into the pro-

ducts during subsequent storage.

3. A strong possibility is that the moisture which has caused this problem

comes from other products in the pack. This would be the case if any of

the other biscuits have relatively high moisture content fillings, e.g., fig

rolls (fig Newtons). If you want to include such products in the pack,

then you may have to over-wrap these separately in a moisture imperme-

able film before they are placed in the pack. If you do not want to do

this, then you will have to change the selection of biscuits that you put in

the pack.


6.11 WE ARE EXPERIENCING DARK BROWN SPECKS ON THESURFACE OF OUR PLAIN SHEETED BISCUITS. WE HAVE BEENUSING THE SAME RECIPE FOR A NUMBER OF YEARSWITHOUT A PROBLEM. CAN YOU IDENTIFY THE CAUSE OFTHE SPECKS AND SUGGEST A REMEDY?

We have examined your recipe and cannot see any particular problem with

the ratios of the ingredients that you have been using. However, the cause

of the problem is clearly associated with one ingredient in particular �namely the sodium bicarbonate that you are adding. The specks are based

on particles of undissolved and unreacted sodium bicarbonate which on

heating in the oven turn dark brown in colour. Incomplete reaction of

the sodium bicarbonate may also lead to a yellowish colour in the biscuit

crumb because of the alkaline conditions and the potential for a soapy

taste.

It is most likely that the grade of sodium bicarbonate that you are using

has changed. There are at least three or four different grades which may be

used in food production. The finesses of the grade will dictate how quickly

the sodium bicarbonate dissolves and thus how quickly it reacts with any

acid materials to produce carbon dioxide gas. There is clearly a balance to

be achieved; very fine grades will react faster and may release the carbon

dioxide gas too early in the manufacturing process which will result in loss

of lift in the biscuits. Using a coarser grade of sodium bicarbonate will delay

the gassing reaction but may lead to the problems that you are experiencing.

Commonly, the sodium bicarbonate for biscuit making should have a particle

size less than 0.06 mm.

The problem is likely to be exacerbated by the low water levels that are

used in biscuit doughs. If there is no alternative to use the coarser grade of

sodium bicarbonate, then you may have to change the mixing procedure and

move to what is often called ‘delayed soda addition’. In this case, you should

mix your dough as usual but hold back a small quantity of water and the

sodium bicarbonate. The bicarbonate should be dissolved in the water that

you have held back and only added to the dough at the very end of mixing.

It is important not to mix the dough for too long after the addition of bicar-

bonate and water because the bicarbonate is now in solution and so is able to

react with the acids in the recipe.

If you have long resting or processing times after dough mixing, then the

delayed soda approach will not be helpful due to the risk of losing too much

carbon dioxide gas before baking, and so you have no alternative but to

change to a finer grade of sodium bicarbonate.


6.12 WE ARE HAVING SOME PROBLEMS WITH PACKINGOUR ROTARY MOULDED BISCUIT LINES. WHEN WE MEASURETHE THICKNESS OF THE BISCUITS, WE HAVE NOTICED THATSOME ARE THICKER THAN OTHERS. CAN YOU SUGGEST ANYREASONS WHY WE SHOULD BE GETTING SUCH VARIATIONS?

Close examination of the samples that you provided showed that the main

problem is not that the biscuits vary in thickness, but that many of the indi-

vidual biscuits are in fact ‘wedge-shaped’; i.e., one edge of the biscuit is

thicker than the opposing edge. As the biscuits are not necessarily uniformly

orientated at the time of packing, this is what is giving rise to your problem.

First of all, you need to establish if the wedging is uniform across the oven

band. You can do this simply by removing a complete row of biscuits from

across the band retaining their individual orientation with respect to the direc-

tion of travel along the plant. From this action, you can establish the ‘leading

edge’ for future trials. Next, you stack the whole row of biscuits one on top of

one another (with the same leading edge orientation) and see which way the

stack tilts; this will tell you if the wedging lies in one particular direction. In

some cases, the occurrence of wedging may be more complicated, and you

may have to measure the two thicknesses (leading and trailing edges) for each

biscuit. If you are seeing variations in the direction of wedging across the

band, you should confirm this by collecting several rows of biscuits to check

the orientation of individual lanes. The pattern of wedging that you see in the

products leaving the oven is indicative of the pattern in the dough pieces leav-

ing the rotary moulder. Once you have established this pattern, it can be used

to check progress in eliminating the problem.

There are a number of potential reasons for the occurrence of wedging;

they include the following:

� Running the extraction and moulding rolls at different speeds.

� High levels of water leading to a softer dough which is more likely to

allow extrusion of the dough through the front or rear of the moulds (i.e.,

formation of tails).

� High levels of syrup in your recipe. Remember if you are using high

levels of syrup you should compensate for any water that might be pres-

ent in the ingredient.

� High levels of fat leading to softer dough.

� Using a low melting point (low solid index) fat which increases the soft-

ness of the dough.

� Higher final dough temperatures which lead to a softening of the dough

because less of the added fat will be solid.

� Changes in sugar particle size, either finer or coarser (see Section 2.4.1)

You should also look closely at your extraction roller to make sure it is not

worn, especially if the problem is only associated with a few lanes of biscuits.


6.13 WE ARE HAVING INTERMITTENT PROBLEMS WITHSHRINKAGE OF OUR SEMI-SWEET BISCUITS AFTER THEYHAVE BEEN CUT OUT FROM THE DOUGH SHEET. HOW CANWE STOP THIS FROM HAPPENING?

Shrinkage can be a relatively common problem with semi-sweet biscuits

due to the degree of gluten formation that occurs in such doughs during

mixing. The problem is exacerbated by the unidirectional nature of the

sheeting and cutting process which align the stresses in the dough in one

particular direction. The sheeting stages transfer some energy to the bis-

cuit dough, and this adds to the development of the gluten network that is

already present. To reduce or eliminate the problem, you will need to

look closely at your ingredients and recipe, mixing and processing

conditions.

Among the possible reasons for the intermittent nature of the problem

are:

� Variations in flour quality with respect to both protein content and pro-

tein quality. Although the flour may be within specification, you should

look closely at the data to see if the problems are associated with times

when the properties are closer to the limits of the specification.

� Variations in the weights of key ingredients to the mixer. You should

check each of these carefully for consistency of delivery.

� Variations in dough temperature exmixer. These may be within your

specification but is the problem associated with one end of the

acceptable range? You may have to adjust the range or the mid-point or

to move the dough to a less sensitive position.

� Variations in standing time before processing. Delays after mixing can

lead to variations in dough consistency as the water is absorbed by the

different ingredient and recipe components and as the dough temperature

changes.

� Any trimmings which are recycled should be carefully controlled in terms

of weight of addition and condition. In the case of the latter variations, in

age and temperature can have a significant impact on dough rheology.

� Check the plant speeds. A common cause of variations is running the

plant at different speeds.

� You should look closely at those points immediately after sheeting where

the dough is taken away on conveyors. A common practice is to allow a

degree of ‘relaxation’ in the sheet by building-in a small, hanging-loop in

the run of the dough sheet. This releases a little of the tension which has

built-up in the dough as it passes through the sheeting rolls; the length of

time that the dough sheet spends under reduced tension is short, but it

can have a significant impact, especially after the last of the sheeting

rolls and before cutting.


� Another option is use a cross-pinning roller which runs at right angles to

the direction of paste travel, and this will help reduce the unidirection

nature of the sheeting process.

FIGURE 6.1 Surface cracking on high-sugar cookies.


6.14 WE ARE EXPERIENCING BLISTERING ON THE SURFACEOF OUR SEMI-SWEET BISCUITS AND SOMETIMES SEECAVITIES UNDER THE TOP CRUST AND LITTLE HOLLOWS ONTHE BOTTOM. CAN YOU IDENTIFY POSSIBLE THE POSSIBLECAUSE OF THE PROBLEM AND SUGGEST A SOLUTION?

You may be experiencing two slightly different problems with your products

though baking conditions are implicated in both cases. The blistering proba-

bly comes from a lack of humidity at the feed end of the oven. To obtain a

smooth surface appearance, the humidity in the first two or three zones of

the oven needs to be high. The humidity in the early stages of biscuit baking

comes mainly from moisture evaporated from the biscuit dough pieces them-

selves. Commonly, humidity is regulated by the extraction dampers fitted to

the oven, and to maintain a high initial humidity, these need to be fully

closed for the first one or two zones. If this does not have the desired effect,

you may need to consider the introduction of extra humidity via the steam

jets. You may find that by increasing the oven humidity that the biscuit stack

height falls slightly; if this is the case and the change is unacceptable, you

may want to consider compensating by slightly increasing the biscuit aera-

tion levels.

The cavities and hollow bottoms that you sometime observe are created

by steam trapped during baking. Hollow bottoms can be a particular problem

if you are baking on solid trays or oven bands. Changing to wire mesh

should help eliminate this problem. Hollows underneath are also known to

be related to using a sugar with a coarse grain.

With respect to the cavities underneath, the top crust we suggest that you

investigate the docking pin arrangements associated with your products. The

docking holes should go right through the dough piece to ensure the ready

release of steam. You may find that this also helps with the problem of hol-

low bottoms.

9.910

10.110.210.310.410.510.610.710.8

0 2 4 6 8 10 12 14 16 18 20Fat solids (%)

Wei

ght (

g)

FIGURE 6.2 Impact of fat solids on cookie piece weight.


Cavities under the top crust may also be associated with the aerating

agents that you are using. Larger particles of ammonium bicarbonate (vol)

will release significant quantities of gas in the oven, essentially blowing the

dough piece apart. Check that the particle size of your supply of vol has not

increased or dissolve the vol in water before adding it to the dough during

mixing. For more information on using vol in biscuits, see Section 6.2.


6.15 WE ARE MANUFACTURING SHORT-DOUGH BISCUITSUSING A ROTARY MOULDER AND HAVE BEEN OFFERED ANALTERNATIVE SUPPLY OF SUGAR. WE NOTICE THAT THENEW SUGAR IS MORE GRANULAR THAN THE MATERIAL WEHAVE BEEN USING PREVIOUSLY; WOULD THIS HAVE ANYEFFECT ON BISCUIT QUALITY?

We suggest that you are cautious before switching to the alternative source

of sugar. The particle size (coarseness) of the sugar that you use will have

effects on a number of different dough and biscuit properties. You need to

bear in mind that the water levels typically used in short-dough biscuits are

such that not all of the sugar that you are adding will go into solution and

undissolved grains of sugars are likely to be present. The rate at which the

sugar particles will go into solution is affected by their particle size, with

coarse-grained sugars taking longer to get into solution in the available

water.

Water is lost during the biscuit baking process so that there is even less

water available to keep the sugar in solution when the product cools which

increases the potential for sugar recrystallisation. Once again the initial parti-

cle size of the sugar has a potential effect as coarser-grained sugars are more

likely to recrystallise as large sugar grains in the baked product.

Some of the likely impacts of sugar particle size include the following:

� The appearance of visible sugar crystals of the biscuit surface when using

coarse-grained sugars (though in some cases this may be seen as a posi-

tive product character).

� An increase in the grittiness of the biscuit eating character with the use

of coarse-grained sugars.

� Biscuit hardness tends to increase as sugar particle size increases.

� An increased tendency to the occurrence of hollow bases as the particle

size of the biscuits increases (see Section 2.4.1).

� Variations in biscuit flow with varying sugar particle size. This is a most

important change due to the impact on biscuit dimensions, including

stack height (thickness), which will affect the subsequent performance of

the biscuit wrapping equipment. Biscuit flow increases as the particle

size of the sugar decreases.

� Biscuit dough firmness increases when using coarser sugars, probably

because there is more water available for absorption by the flour.

� Dough piece and biscuit weights tend to increase when using coarser-

grained sugars.


6.16 IS IT POSSIBLE TO REDUCE THE LEVEL OF SUGAR INOUR BISCUIT AND COOKIE RECIPES WITHOUT AFFECTINGTHEIR QUALITY? WHAT WOULD BE THE ALTERNATIVES WECOULD USE TO SUCROSE?

Reductions in the sugar (sucrose) level in your biscuits and cookies will

have an immediate effect on dough handling and the final product quality.

This is because sucrose plays a number of important roles in the manufac-

ture of biscuits and cookies. In the dough, the effect on water activity is

part of the reason for the inhibition of gluten development during mixing.

In broad terms, the effect of reducing added sucrose levels would be like

changing a short-dough biscuit recipe to become more like that of semi-

sweet product. In practice, you may find it difficult to continue to rotary

mould reduced-sugar short doughs, and you may experience increased

shrinkage of the pieces after release from the mould and almost certainly

when the products are baked. In the baked product, sucrose makes impor-

tant contributions to product sweetness, crust colour, flow and shape in

cookies and the texture of the product, particularly the hardness and

crunchiness of the eat so there are quite a few consideration to take into

account.

The main features of the alternative sugars to sucrose are discussed in

Section 2.4.2. The crystalline nature of sucrose and its particle size (see

Section 2.4.1) are important in the creaming process which is typically part

of short-dough mixing. The sugar crystals aid the dispersion of fat through-

out the dough and contribute to some air incorporation. Liquid sugars will

not be able to make the same contribution as sucrose, though some of the

sugars which are powders can deliver some of the required functionality. To

some extent, product sweetness and colour can be adjusted using different

combinations of sugars, perhaps with a compensatory re-balancing with other

recipe ingredients, such as milk powders.

More difficult to replace will be impact that sucrose has on the formation

of the cookie structure and ultimately on its texture. Manley (2000) sum-

marised in diagrammatic form the changes taking place in biscuit dough

during baking. The baking time for biscuits is much shorter than that of com-

mon breads, but there is still time for a similar series of changes to occur;

namely expansion of the structure, loss of water and structure setting. In the

case of biscuits, the relatively low added water levels and short baking times

probably militate against a significant degree of starch gelatinisation in the

structure formation process so that reducing or changing sugar levels is not

likely to have the major impact that it does with cake batters though you can

still expect some changes in biscuit properties.

More important in the context of structure formation and texture for

biscuits and cookies is the formation of a super-saturated sugar solution in

the oven. The solubility of sucrose is high and increases dramatically as


the dough piece temperature increases. The formation of this super-

saturated sugar solution throughout the dough matrix contributes to the

expansion of biscuits and cookies in the oven, but as the structure begins

to become porous, the escaping gas leads to collapse of the structure to

yield (usually) a thin final product. Commonly, this collapse occurs in the

oven, depending on sugar level. In some biscuit and cookie types, the col-

lapse may not begin to occur until the product is cooling after it has left

the oven.

As well as contributing to the expansion of the product the super-

saturated sugar solution which is formed in the oven also permits consider-

able flow or spread, and this spread needs to be controlled to maintain final

product characteristics. As the product cools, the sugar solution solidifies

and becomes rigid, often forming a characteristically cracked surface (see

Fig. 6.1). The impact of the different sugar solubilities and their effect on

product flow will be an important factor to take into account when reformu-

lating for lower sucrose levels.

The crunchiness and crumbly eating character of many cookie products is

a direct result of the high levels of recipe sucrose, and reductions in sugar

levels will result in the loss of those eating characters and a harder texture.

In many high-sugar products, the recrystallisation of sugar on cooling results

in weak points in the cookie structure and contributes to the shortness of its

texture. Some of this effect comes from starting with a proportion of coarse

sucrose particles in the recipe, most alternative sugars and sugar replacers

are not available with the same range of crystalline forms as sucrose and so

are not able to make a similar contribution to texture.

Reference

Manley, D., 2000. Technology of Biscuits, Crackers and Cookies. Woodhead Publishing Ltd.,

Cambridge, UK.




6.17 WE WOULD LIKE TO REDUCE THE LEVEL OF FAT INOUR BISCUIT RECIPES. HOW CAN WE DO THIS?

A reduction of fat will lead to changes in processing requirements due to the

potential for greater gluten formation in the dough and an increased risk of

shrinkage during processing and baking. As the fat level in a biscuit recipe is

reduced, there is a progressive loss of product weight, see Fig. 6.2. The fat

also contributes to the shortness of the eating quality. There will also be an

increased risk of checking (see Section 6.6). In the manufacture of crackers,

the fat contributes to product lift as part of the ‘cracker dust’ which is lami-

nated into the product.

The most common way of enabling fat reduction in biscuit making is

through the addition of suitable emulsifiers. The most commonly used emul-

sifiers (see Section 2.7.6) for this purpose are diacetyl tartaric esters of

mono- and diglycerides of fatty acids, usually referred to as DATA esters or

Datem, sodium stearoyl-2-lactylate and lecithin.

The rates of emulsifier addition would be at about 1.5% of the fat weight

in the original recipe and this would allow for a reduction of around 20% of

the original fat level. For example, if the fat level was 16% or 16 g in 100 g

mix; the rate of addition of the emulsifier would be 0.24 g in 100 g mix and

the new fat level would then be 12.8 g. Obviously, when the ingredient per-

centages are adjusted back to a 100-g mix, the percentage of fat will not be

12.8% because the total ingredient weight is slightly less; the new percentage

fat level in 100-g mix would become 13.2%.

If you do encounter excessive shrinkage during processing, you can

consider the addition of a reducing agent like sodium metabisulphite of

L-cysteine hydrochloride (see Section 2.7.7) or the addition of proteolytic

enzymes.


6.18 WHAT ARE MAIN ISSUES THAT WE SHOULD BE AWAREOF IN THE MANUFACTURE OF SAVOURY PUFF BISCUITS?

The principles for manufacturing puff biscuits are similar to those for puff

pastry. The biscuits themselves may be plain, slightly sweetened or savoury.

The latter mainly use cheese to give the product flavour and in some cases a

cheese-based cream is used to make a sandwich snack product. Many of the

savoury forms of puff biscuits are small in size and served as snacks.

The basic structure is formed by creating layers of a suitable fat between

dough. The steam pressure created by the evaporation of water during baking

forces the dough layers apart to give the characteristic flaky structure (see

Section 7.1.1). The creation and control of the integrity of the fat and dough

layers is therefore an important part of the lift mechanism for puff biscuits.

In general, the degree of lift that gives satisfactory puff biscuits is slightly

less than you would seek in the manufacture of puff pastry. Typically,

around 96 fat layers are suitable for puff biscuits. Fewer layers yield thick

biscuits which are very flaky in character, whereas with greater numbers of

fat layers, the products become thin and lose flakiness because of the break-

down of the integrity of the fat and dough layers.

The level of laminating fat used in the recipe will tend to be lower than

in the manufacture of puff pastry. Typically, the level of laminating fat for

puff biscuits will be around 40% of the flour weight in the base dough.

Higher levels of laminating fat tend to yield biscuit products which show a

greater degree of shrinkage and which are very fragile.

A range of flours may be used in the manufacture of puff biscuits though

the tendency is to use stronger ones which are suitable for breadmaking.

Weaker flours may be used but they are better suited to manufacturing pro-

cesses with limited rest periods between the different sheeting and laminat-

ing stages. Weaker flours are also less tolerant to process interruptions.

Cheese, whey and milk powders may be added for flavour and colour in the

manufacture of puff biscuits. Cheese powders are high in fat and proteins and

tend to reduce the lift and flakiness of the final product. Cheese powders tend to

have a short shelf-life due to their high fat content and should be used with care

to avoid unwanted rancid flavours being carried through to the final products.

A common practice in the manufacture of savoury puff biscuits is to

spray the surface of the product with oil immediately after baking (Manley,

2000). This treatment gives the products a shiny surface and enhances its

colour. Spraying may also be used to add flavour. However, oil-based sprays

and flavours are susceptible to rancidity and so care is required in their use.

Reference






6.19 IS IT IMPORTANT TO USE A FERMENTATION PERIODIN THE MANUFACTURE OF CRACKERS? WHAT EFFECTS AREWE LIKELY TO SEE FROM VARIATIONS IN THEFERMENTATION TIME?

A function of the fermentation time in the manufacture of crackers is the

modification of the gluten network which has been formed in dough mixing;

in particular, to reduce its elasticity and increase its extensibility, it is easier

to machine the dough and to create the required laminated structure which

delivers a flaky texture in the finished product. During the fermentation

period, there is a small increase in dough acidity (lower pH) which not only

contributes to the rheological properties of the dough but also potentially to

baked cracker flavour and colour. During fermentation, there is considerable

enzymic activity from both the flour and yeast sources.

It is important to recognise that fermentation is not just a matter of time,

but it is also affected by temperature (fermentation increases as temperature

increases) and yeast level (higher yeast levels yield greater fermentation).

Thus, in practice, fermentation time is seldom considered as a single

variable.

Long fermentation times lead to considerable gassing activity by the

yeast and increased enzymic activity. The latter will be dominated by the

amylase activity on the damaged starch in the flour and by proteolytic activ-

ity on the flour proteins (gluten structure) both of which result in softening

of the dough with prolonged fermentation which makes it more difficult to

handle and process. This may result in the need for increased dusting flour

with some potential loss of cracker lift. Low dough pHs coming from

extended fermentation times may increase the likelihood of cracker

shrinkage.

The main impact of shortening dough fermentation times is that the

dough will be tougher (more resistant to deformation) and harder to machine.

Commonly, this leads to an increase in sheeting rolls pressures with the risk

of crushing layers and losing cracker lift and flakiness due to breaks in the

layering.

If you do want to reduce fermentation times, then you may find it helpful

to add a little extra water to the dough formulation to yield a softer, more

machinable dough or to add dough softening agents such as L-cysteine

hydrochloride (see Section 2.7.7) or proteolytic enzymes. You will need to

be cautious when using dough softening agents as there can be a progressive

build-up of their levels through the continued use of rework and eventually

the dough may become too soft for machining.


6.20 WE HAVE INSTALLED A NEW CUTTING ANDCREAMING MACHINE FOR THE PREPARATION OF OURSANDWICH WAFERS AND REFURBISHED THE PRODUCTIONAREA. WE HAVE FOUND THAT WE ARE NOW GETTINGINTERMITTENT PROBLEMS WITH THE WAFER SHEETSBREAKING UP ON CUTTING. CAN YOU OFFER ANEXPLANATION AS TO WHY THIS MIGHT BE HAPPENING?

The fragility of wafers is determined by a number of recipe and process

factors, but as you have not changed any of these during your refurbishment,

then we need to look more closely at how the wafer sheets are treated

after they leave the oven.

Immediately after baking wafer sheets have very low moisture contents,

commonly less than 2%. As they have such low moisture contents, they are

prone to picking-up moisture from the atmosphere. The rate and degree to

which they pick-up moisture will commonly be related to the relative humid-

ity of the atmosphere and the length of time to which the sheets are exposed

to that atmosphere. If you have any data on the relatively humidity of the

atmosphere in the cutting and preparation areas before and after the changes

were made that would be helpful in understanding, why you are now having

problems; especially if the relative humidity of the refurbished facility is

now lower, for example, because there is less air movement from the baking

areas than before or if you have installed better extraction facilities.

We suggest that you look closely at the moisture content of the wafer

sheets at cutting to see if this is lower than before. One of the problems with

wafer sheets is that the moisture distribution throughout the sheet coming

from the oven is not uniform, and some equilibration will occur as the sheets

are cooled and stored. Often wafer manufacturers allow a ‘conditioning’

period after baking and while the wafers are cold to allow for equilibration

of the moisture content throughout the sheet.

In some cases, the wafer conditioning process may be carried out in an

atmosphere with specific relative humidity control to adjust the moisture

content of the sheets to optimise the cutting process or even with the addition

of moisture by spraying the sheets with water. Such processes must be care-

fully controlled as high moisture content wafers (e.g., above 4%) have less

than satisfactory eating qualities.

We suggest that you look closely at the control of the wafer cooling and

storage conditions to ensure that they are uniform in terms of wafer tempera-

ture at the time of cutting and that any storage times are consistent.


6.21 OUR CHOCOLATE-COATED WAFER BISCUITS AREPRONE TO CRACKING. CAN YOU SUGGEST WHY THISHAPPENS AND HOW WE CAN AVOID THE PROBLEM?

The most likely cause of your problem is the absorption of water by the

wafer in the coated biscuit and its subsequent expansion. We suggest that

you look closely at the quality of your enrobing practices because any

uncoated areas or even pin-prick holes in the coating provide access points

for water from the atmosphere. The longer that the products are stored, the

greater the potential for the wafer biscuit to pick-up moisture and expand.

The moisture content of wafers is very low in order that they will have a

crisp eating quality. The equilibrium relative humidity of the wafer is also

very low and much lower than the relative humidity of most atmospheric

conditions in which the products will be kept. This means that the natural

driving force is for water from the atmosphere to condense on exposed wafer

surfaces where it will be absorbed and diffuse through the sheet. As the

moisture level rises, the wafer will begin to expand and exert so much pres-

sure on the inelastic chocolate coating that the latter will split. Barron (1977)

showed that for each 1% increase in moisture wafer sheets expanded by

between 0.33 and 0.42% of the original dimension.

The time taken for the cracks to become manifest will vary according to

the completeness of the coating and the initial wafer moisture content. The

relative humidity of the surrounding atmosphere will also affect the rate of

wafer expansion, the higher the relative humidity the greater the relative

humidity differential and the faster the transfer of moisture. One way to limit

this latter effect is to ensure that the wrapping of the final product is tight

around the product and so has a minimum volume of air around the product.

Unfortunately, many chocolate-coated wafer products are foil wrapped which

does little to limit the ingress of moisture. Ultimately, the solution to your

problem is to ensure completeness of your enrobed chocolate coating.

Reference

Barron, L.F., 1977. The expansion of wafer and its relation to the cracking of chocolate and

“bakers’ chocolate” coatings. J. Food Technol. 12, 73�84.





6.22 WE ARE EXPERIENCING INTERMITTENT PROBLEMSWITH GLUTEN FORMATION IN OUR WAFER BATTER. WHATCAUSES THIS PROBLEM?

Gluten development is undesirable in wafer batters because it can lead to

blockages in pipes or nozzles of batter distribution systems. In the latter

case, this can lead to uneven distribution of batter on the plates and the

incomplete formation of wafer sheets. To avoid this problem, it is common

practice to have filters in different parts of the line to remove any ‘gluten

balls’ which form.

Gluten formation depends of three main factors; the presence of protein

in the flour, the hydration of that protein from the addition of water and the

input of energy during mixing. In batter systems, the ratio of water to flour

solids is usually high enough to lower batter viscosity to such an extent that

gluten formation should not occur (Cauvain and Young, 2008). However,

wafer batters are often pumped and recirculated through holding tanks to

prevent separation of the solids while they are standing, and this may cause

shear in a number of areas of the pipework. Shear leads to work and subse-

quently increased gluten formation.

As the recirculation of wafer batters is a practical expedient, then you

will have to look to changes in ingredient specification or batter formulation

to alleviate the problem. Lowering the overall protein content of the flour

that is used is a most obvious way of reducing the potential for gluten forma-

tion. This may be achieved by using weaker or softer milling wheats.

Alternatively you could use a low protein, starch-rich fraction from an air-

classified or fractionated flour, typically, this would equate to particles in the

range 15 to 40 μm.

Alternatively, you could replace a portion of your standard flour with a

heat-treated flour such as might be used for cakemaking. Heat treatment

denatures the protein and restricts its gluten forming potential (see Section

2.2.17) but will affect water absorption and an increase in the water addition

will be necessary to maintain a standard batter viscosity. Other ways to

reduce gluten formation would be to replace a portion of the standard flour

with a chlorinated flour (see Section 2.2.18) in those parts of the world

where its use is permitted or with starch from wheat or some other

suitable source.

Be aware that lowering the protein content of the flour used in your batters

may have an adverse effect on the wafer strength, making them more fragile

and so more prone to physical damage, especially during cutting and creaming.

Reference






6.23 WHAT ARE SHREWSBURY BISCUITS AND HOW ARETHEY MADE?

Shrewsbury biscuits are one of several ‘old-style’ English biscuits that were

traditionally made by local bakers before the advent of large-scale biscuit

and cookie bakeries. Collectively, they would be referred to as

‘Confectioner’s biscuits’ and would be made on a relatively small-scale.

Many of the different terms for such biscuits have fallen out of use, and a

good number of Confectioner’s biscuits have evolved into the main biscuit

and cookie types familiar to us today. Many of the traditional recipes for

Confectioner’s biscuits tend to use butter as the fat and whole eggs as the

moistening agents, and many of the mixing processes are similar to those

used in cakemaking.

Shrewsbury is a medium-sized market town in the west midlands of

England, and its name probably became attached to a biscuit type that was

made in a local bakery in or near to the town.

The following recipe will make Shrewsbury biscuits:

Ingredient Parts by weight

Soft flour 100

Baking powder 1.25

Butter 50

Caster sugar 50

Whole eggs 15

Currants 20

Mix the butter and sugar until lightly aerated. Mix in the eggs, add the

flour and baking powder and mix to a clear dough (paste). If the fruited vari-

ety is required then add the currants towards the end of mixing.

Sheet the paste to about 5-mm thickness and cut out shapes with a 70-mm

diameter plain or fluted cutter. Bake on sheets at 200�210�C for 15�20

minutes and dredge the baked products with caster sugar while still hot.

There are quite a few examples of biscuits which have associations with

localities or towns. In England another example is Banbury biscuits which

have a similar recipe and make-up procedure, though in this case, the caster

sugar is applied before baking. Quite a few examples of such specialist bis-

cuits are associated with market towns in the United Kingdom, and this

almost certainly reveals their traditional origins and original points of sale.


6.24 WE FIND THAT OUR VIENNESE FINGERS GO SOFTVERY QUICKLY AFTER BAKING. HOW CAN WE PREVENT THISFROM HAPPENING?

When biscuits go soft after wrapping, it is usually because of moisture

uptake during storage. When a biscuit is wrapped in a well-sealed moisture-

impermeable film softening does not occur.

There are other possible explanations. These include the following:

� the presence of moisture in the filling which leads to moisture absorption

by the biscuit as a result of moisture movement from the filling;

� the presence of invert sugar in the recipe;

� under-baking of the biscuit originally so that more moisture remains in

the product;

� condensation on the internal surface of the packaging film.

Softening of the biscuit can be prevented by the use of a moisture-free fill-

ing such as a compound shortening or hardened palm kernel oil, instead of

margarine, which contains some moisture. Check that the recipe does not use

invert sugar syrup. Ensure that the biscuits are well dried out in baking and

that the biscuits are cooled adequately before packing. Especially, avoid trans-

ferring products to a cold atmosphere after packing as such changes in temper-

ature can result in condensation on the inside of the wrapper.



Chapter 7

Pastries

7.1 LAMINATED PASTRIES

7.1.1 What causes puff pastry to rise during baking?

Most of the lift in puff pastry comes from the water held in the dough layers

which when converted to steam in the oven, becomes trapped in the melting

fat between the dough layers (see Fig. 7.1). The pressure, which is generated

by the trapped steam, forces the dough layers apart. The thickness of the

dough layers changes little during baking and makes no significant contribu-

tion to pastry lift.

Expansion of the paste can only occur if the dough layers are sepa-

rate and discrete from the fat layers. Any strong bridges between the

dough layers, such as may be caused when adjacent layers are crushed

together in sheeting, restrict the rise that can be obtained. However, if

no crushing occurs, then the baked pastry may be so flaky that it falls

apart after baking.

Most of the expansion of puff pastry occurs in the first half of the baking

time, but we need to drive off more water before the pastry is set firm

enough to stand without collapsing (Cauvain and Young, 2008).

In the context of creating lift in laminated products, the characteristics

of the fat, particularly its melting profile (see Section 2.3.1), are very impor-

tant. If the fat has a low final melting point, then the lift will be limited.

However, although a high melting point may be desirable from the point of

view of lift, there may be undesirable eating qualities in the form of palate

cling. Equally, the laminating fat must remain plastic enough to deform dur-

ing sheeting but remain as an integral layer between the dough layers;

breaks in the fat layers will allow the ready loss of steam during baking and

limit pastry lift.

Damage to the dough layers during processing must also be avoided to

optimise lift; breaks in the dough layers provide weak points through

which the steam can readily escape and limit lift. Docking, the practice of

pricking a pattern of holes in the dough sheet to control lift, must be

carried out with care; too heavily a docked product will lose lift through



http://dx.doi.org/10.1016/B978-0-08-100765-5.00007-2

the escape of steam, whereas too lightly a docked product will have

uneven lift and large blisters may form.

Reference



Further reading

Cauvain, S.P., 2001. The production of laminated products. CCFRA Review No. 25.

CampdenBRI, Chipping Campden, UK.

FIGURE 7.1 Mechanism for puff pastry lift.






7.1.2 We are experiencing a problem with our puff pastrywhich fails to lift and shows no sign of layering on baking. Whyis this?

The layered structure in puff pastry relies on the formation of discrete and

separated layers of fat and dough. The mechanism by which puff pastry rises

relies on this separation as described above (see Section 7.1.1) and any num-

ber of ingredient, recipe or processing changes may cause the problem.

We suggest that you examine the following:

� The solid fat content of the fat that you are using as fats with low con-

tents are can result in poor lift.

� The number of laminations which you are giving the paste. Too many

laminations cause the fat layers to rupture and allow the broken dough

layers to stick together and reduce lift.

� The application of any docking mechanisms because excess pressure or

large numbers of docking holes can pins dough layers together and

restrict expansion.

� Your oven temperature, as higher temperatures encourage lift. You

should bake at around 230�C.

You can increase pastry lift by using a stronger flour provided that suffi-

cient rest is given to achieve the optimum dough rheology during processing

and before baking. Low levels of an oxidising agent, e.g., ascorbic acid, may

help but you should note the comments on pastry shrinkage (see Sections

7.1.9 and 7.1.13).

Pastries Chapter | 7 333

7.1.3 Why do we get a less regular lift in our puff pastry whenwe use the Scotch method compared with the English or French?

The so-called Scotch method of producing puff pastry differs fundamentally

from the English or French in that the laminating fat is added at the dough

making stage rather than later in the process. To achieve this, the laminating

fat is usually cut into small cubes, with sides of about 20 mm, and added to

the mixing bowl along with the other ingredients. After mixing, the paste

will be sheeted and laminated in a similar manner to paste prepared by either

of the two other methods.

Under a microscope, you would see that the distribution of laminating fat

between dough layers was less structured in paste made with the Scotch than

with the English or French methods. This is hardly surprising because we

would expect that the initial mixing of dough ingredients and laminating fat

would effectively prevent the formation of separate and discrete dough and

fat layers.

Variations in pastry lift with the Scotch method are common due to the

lack of uniformity in the paste, and the overall pastry lift will be less than

might be obtained with the English or French methods. Due to the variation

in pastry lift, it is not common practice to use Scotch method paste for pro-

ducts like vol-au-vent rings or other shape sensitive products. Scotch method

paste does find use in products such as savoury or sweet pie crust where a

flaky eating character but restricted lift is required of the paste. Often the

number of laminations given to Scotch method paste will be increased

beyond that seen with English or French methods to help distribute the fat

lumps as evenly as possible within the paste structure and so avoid large

voids and blisters in the paste.

A benefit of using the Scotch method is that because discrete dough

layers are not a feature of the method long paste relaxation times between

sheeting and folding operations can be avoided, so it provides a more rapid

means of making puff pastry products.


7.1.4 What are the purposes of the resting periods in themanufacture of laminated products?

The rheology of the base dough is very important to the formation of the dis-

crete dough and fat layers in the manufacture of laminated products. The

successive sheeting and lamination stages during manufacture continue to

change the dough rheology due to the work that is imparted, especially by

the sheeting rolls. The overall effect of the work is to increase the dough

elasticity and to reduce its extensibility, and this may lead to tearing or

breakdown of the individual dough layers. The holes which form in the

dough sheet provide a ready escape route for the steam generated during

baking and this restricts the pastry lift that can be obtained.

If a dough is left to rest after mixing or some other form of work, its rhe-

ological character changes with time. In particular, its character becomes

less elastic and more extensible and the effects of subsequent sheeting are

less severe. Thus, a key role for the resting period is to modify the dough

rheology so as to preserve intact the separation of dough and fat layers so

important to the formation of laminated product structure.

The degree of change in dough rheology is influenced by temperature

and varies with different flours. Strong flours, that is ones high in protein

or with strongly elastic glutens, require longer periods of relaxation than

weaker ones to achieve the necessary rheological changes for optimum

product quality. This change in rheological properties with resting time

is linked with the natural reducing agents (glutathione) and enzymic

activities in the flour.

The data in Fig. 7.2 compare the rheology of two flours, one strong and

one weak, and examines the changes in dough resistance to deformation

which occur with resting time. In the case of the stronger flour, some resting

time is required for the dough to achieve the optimum zone and it remains

there for the full resting period. The weak flour on the other hand is immedi-

ately in the optimum zone but rapidly passes through it. These observations

allow us to conclude that weak flours are more suited to rapid processing

methods but will not be tolerant to plant delays.


FIGURE 7.2 Effect of relaxation time on dough deformation resistance with two flours.

7.1.5 We have been experiencing some problems with excessiveshrinking of our puff pastry products. Can you advise as to whatthe likely causes might be?

Some shrinkage of puff pastry during baking is inevitable though it can be

minimised. It is also important to recognise that in most cases puff pastry lift

and shrinkage are linked with greater lift often leading to greater shrinkage

and vice versa.

Causes of excessive shrinkage may come from a number of recipe and

processing sources, including:

� The flour is too strong for the processing methods being used. Strong

flours require longer resting periods than weak flours in order for

the dough rheology to become optimised for sheeting and laminating (see

Section 7.1.4).

� Oxidants, such as ascorbic acid, may be present in the flour or dough

formulation.

� The pH of the dough is too low due to the addition of acidic materials


� The sugar level, if present, is too high.

� The level of recycled trimmings in the paste is too high. This is espe-

cially the case if the trimmings are added at the sheeting stage rather

than in the mixer.

� Insufficient relaxation of the paste during the processing stages whatever

the flour strength. This often applies to the stage after cutting out and

before the product enters the oven.

Shrinkage may be overcome to some degree through the addition of a

reducing agent, such as sodium metabisulphite, L-cysteine hydrochloride or a

proteolytic enzyme. However, as such materials remain relatively active in

the paste, the effect in recycled trimmings may lead to excessive softening

of the paste. We recommend that you try to reduce shrinkage by other means

before considering the addition of such materials.


7.1.6 Why are acids sometimes added to puff pastry?

The acidification of doughs was commonly seen as a means to ‘strengthen’

the flour gluten, making it more pliable and extensible, which, in turn,

would lead to extra pastry lift. Although it is certainly true that puff pastry

lift is increased by the addition of a suitable food-grade acid, there is also

a tendency for pastry shrinkage to increase (see Fig. 7.3). With high levels

of acid addition, shape-critical products (e.g., vol-au-vent rings) may

expand excessively and non-uniformly in the oven and may even topple

over during baking.

The optimum level of acid addition varies according to the type of

acid and the flour being used. Variations in pastry shrinkage from the

addition of a given level of acid to a range of flours are usually greater

than variations in pastry lift. The reasons for the variations are not

clear but are most likely to come from variations in the natural buffering

effects of different flours (i.e., variations in paste pH) and the rheology of

the gluten.

Where possible, greater pastry lift should be sought through other

means (see Section 7.1.2) rather than through the addition of an acid to the

dough.

FIGURE 7.3 Effects of pH on puff pastry lift.


7.1.7 What is the best way to reuse puff pastry trimmings? Atpresent, we are feeding them back into the sheeting stages

The production of trimmings in the manufacture of pastry products is inevi-

table; they mostly come from trimming the paste sheets during processing. It

is common practice on automatic plants to gather them at various processing

points and feed them back during the sheeting stages, though in some cases,

they may be added directly into the mixer to be incorporated with fresh

ingredients. Puff pastry trimmings are often used as a means of incorporating

fat into the base dough.

To make the best use of trimmings there are a number of important fac-

tors to consider. They include the following:

Age and condition

All pastes contain microflora which are capable of changing the pH of

the trimmings and contributing to spoilage and the generation of off-odours

and flavours. Such reactions are time and temperature dependent and so it is

best to have a standard length of time in which the trimmings are used and a

fixed storage temperature under which they are held. If the trimmings are

gathered automatically on your plant, then the time will typically be too

short for any significant effects. If you are keeping the trimmings for any

length of time, then the lower paste pH that you get contributes to pastry

shrinkage. The growth of microflora in trimmings may also lead to disco-

louration of the subsequent paste. In the case of Danish pastry and croissant,

the presence of bakers’ yeast in the dough will also influence the effects of

trimmings on product quality.

Temperature

Storing trimmings at reduced temperatures before use is a useful way of

maintaining lower paste temperatures for processing. If you choose to do

this, you should ensure that the temperature in a given batch of trimmings is

as uniform as possible; for example, by spreading them out on sheets rather

than holding them in tubs for chilling. You may also need to ensure that they

do not unduly dry out.

Level of addition

Bakers often see the re-incorporation of trimmings as a financial issue.

However, in many cases, they should be seen an ‘ingredient’ as their condi-

tion can have direct impacts on the quality of the paste during processing

and the baked product. In some cases, the ‘standard’ paste product cannot be

made without trimmings being present, and it may be necessary to produce a

paste at the start of a production run to act as though they were trimmings.

This is especially true if the trimmings are kept for any length of time (the

pH effect) or held at reduced temperatures.


It is worth noting that the continued re-use of trimmings will lead to a pro-

gressive concentration of subcomponents in production, and this may have

unwanted effects, e.g., increasing concentration of paste relaxants which may

make the paste sticky. This is usually dealt with by incorporating a ‘break’

into the production cycle when any unused trimmings are sent to waste.

To use trimmings successfully we suggest the following guidelines:

� Recycle trimmings by adding them to the mixer rather than trying to add

them at the sheeting stage. Addition at the mixing stage ensures their uni-

form dispersion and should avoid problems with uneven layering and

shrinkage.

� Keep all trimmings at refrigerated temperatures (4�C) until required for

use to minimise microbial activity.

� Allow a reasonable length of time for the trimmings to warm before

re-use to avoid adversely affecting dough or paste temperatures.

� Every 3 or 4 days stop using trimmings to avoid excessive build-up of

microbial activity in the paste.


7.1.8 We are experiencing problem with the discolouration ofunbaked puff paste stored under refrigerated conditions. Sometimesblack spots appear on the surface. Can you explain why this happensand advise on how to avoid it?

The discolouration and dark spots that you see comes from enzyme-assisted

oxidation of the polyphenols naturally present in the flour. These polyphe-

nols are associated with the bran particles that come through from the mill-

ing process for white flour. The greater the level of bran present in the flour,

the greater will be the potential number of black spots and the larger the

bran particle size the larger would be the spot.

Although enzymic activity is reduced as the storage temperature is

lowered, there is still sufficient activity even at refrigerated tempera-

tures for the problem to be manifest because of the long storage time

involved. One possible way in which to avoid the problem would be

to lower the storage temperature even further, perhaps even low

enough to freeze the paste. However, while using this approach, you

will have to ensure that the paste is sufficiently defrosted for subse-

quent processing.

Other means of minimising the problem include the following:

� Excluding oxygen such as by storing the paste in gas-tight film.

� Adding ascorbic acid, though this may adversely affect pastry lift and

shrinkage (see Section 7.1.5).

� Adding citric acid at low levels, i.e., up to 0.2% flour weight, but this too

may adversely affect pastry lift and shrinkage, and flavour (see Section

7.1.6).

The easiest and most reliable solution is to change to a white flour with a

lower level of bran present (e.g., lower grade colour figure or lower ash, see

Section 2.1.1).

The addition of low levels (5�15 ppm) of glucose oxidase is

claimed to prevent the formation of spots and general discolouration

of fermented and non-fermented doughs after freezing and thawing

(Unilever, 1992).

Reference

Unilever, N.L., 1992. Improved doughs, European Patent Application 0 469 654.


7.1.9 We have been experiencing considerable variability inprocessing our short and puff paste products; sometimes,we have problems with paste shrinkage and on other occasionswe get stickiness. We have checked our weighing systems andcan find no problems with ingredients additions. We have noclimatic temperature control in the factory or ingredient storagefacilities, are these likely to significant contributors to theproblems?

Producing and using pastes at consistent temperatures is very important in

ensuring consistent processing and optimum final product quality. Ideally, you

should be controlling ingredient and environment temperatures along with the

delivery of a consistent paste temperature exmixer. To advise you on the best

way to eliminate your problem we need to consider the various influences.

Ingredient temperatures

Flour and fat are the main ingredients to concern us. As your flour is

stored in non-insulated silos, you must expect the temperature of this ingredi-

ent to vary with changes in climatic conditions. The common way of coping

with such variations is to adjust the temperature of the water added to the

mix (see Section 7.2.3). Remember that water levels are low in pastes by

comparison with those used in bread dough, so the cooling potential of the

recipe water is lower. You need to make sure that you have an adequate sup-

ply of chilled water and often you may need to resort to the addition of ice

or an ice�water mix. In colder periods, you may need to provide heated

water.

Relatively high levels of fat are added to the base dough of pastry pro-

ducts so variations in fat temperature will contribute to variations in paste

temperature. It is best to keep the fat at a constant temperature and only try

to adjust paste temperatures ex-mixer using water at the appropriate tempera-

ture. The functional properties of fats are related to their ‘temperature histo-

ries’, and it is best not to subject them to too many warm and cold cycles.

Ideally, you should hold your fat at a similar temperature to your processing

environment or slightly lower than your ideal paste temperature exmixer.

If you are using rework added to the mixer, then you should ensure that

this is at a constant temperature. If it comes from a chilled environment, then

you should make sure that the temperature throughout the batch is uniform.

Processing temperatures

Ideally, you should have a constant processing temperature. This is par-

ticularly important if you have long rest periods or are using fats which are

particularly temperature sensitive. You will find that pastry lift is directly

related to paste processing temperature for a wide range of laminating fats

(see Fig. 7.4).


In the manufacture of laminated products, variations in paste temperature

can directly affect the integrity of the layers. Higher processing temperatures

often result in breakdown of the layering as the laminating fat ‘oils’. In such

cases, the paste becomes sticky and is usually compensated for through the

increased use of dusting flour on the plant or by lowering the added water

level both of which introduce other problems.

Low paste temperatures make the dough firmer and more difficult to

sheet. Commonly, this means that extra sheeting pressure is applied during

processing which can then lead to breakdown of the layering of the lami-

nations. Most laminating fats will lose some of their plasticity at lower

temperatures, and this can lead to loss of layer integrity and subsequent

pastry lift.

0

0.5

1

1.5

2

2.5

3

3.5

4

A B C DLaminating fat type

Pas

try s

peci

fic h

eigh

t (m

m/g

past

e)

12

19

FIGURE 7.4 Effect of processing at temperatures of 12�C and 19�C on puff pastry lift.


7.1.10 Why should croissant and Danish pastry doughs begiven less lamination than puff pastry?

A key difference between puff pastry and Danish pastries and croissant is

the presence of bakers’ yeast in the latter two products. The yeast plays a

significant part in the aeration of the paste during proof and baking but also

disrupts the integrity of the dough and fat layers in the paste. To counteract

this disruption of the dough layers and retain a degree of flakiness in the eat-

ing quality of the product, it is necessary to keep the dough and fat layers

thicker than would be normal with puff pastry. Optimum lamination for puff

pastry is typically achieved with about 100 to 130 theoretical fat layers,

while the optimum for Danish pastry and croissant lies between 18 and 32.

The aerating effect of yeast places a significant strain on the gluten net-

work in the dough during proof. Higher yeast levels and longer proof times

are likely to cause greater rupturing. It is important to ensure that the gluten

network in the dough has good extensibility; otherwise, the baked products

will lack volume and definition. This may require an increase in the strength

of the flour used.

Further reading


AG, Switzerland.




7.1.11 What is the optimum level of fat to use in theproduction of puff pastry?

The level of fat that is used in the manufacture of puff pastry depends on a

number factors including the degree of lift and flakiness of eat that you

are seeking in the baked product. Puff pastry and other laminated products

are characterised by the formation of a relatively thin dough sheet, part of

which is covered with fat and subjected to a series of folding and further

sheeting steps with the objective of forming alternate and discrete layers

of fat and dough.

Traditionally, there are three types of puff pastry characterised by the

level of laminating fat used in the formulation. They are commonly desig-

nated as full, three-quarter and half puff in which the laminating fat is used

at an equal weight to the flour, 3/4 and 1/2, respectively. The level of lami-

nating fat has a direct effect on the thickness of the fat layer in the laminated

paste and thus a direct impact of the degree of separation of the dough

layers. The higher the level of laminating fat, the greater the pastry lift but

also the greater the pastry shrinkage. With an increase in laminating fat

levels, the baked pastries become more tender eating.

There is no absolute optimum level of fat for use in the manufacture of

puff pastry, the choice depends on a number of different criteria which may be

required in the final product, such as lift, eating quality and flavour. The level

of laminating fat is also linked with the number of laminations (folds or turns)

given to the paste. In general, the lower the laminating fat level the lower will

be the number of laminations required to achieve maximum lift or optimum

quality; typically, the optimum quality with half paste is achieved with 128 the-

oretical fat layers while with full paste the optimum was achieved with 256.

The base dough may also have a small addition of fat (5%) which confers

a more tender eating quality to the baked product but does decrease pastry

lift. Due to the latter effect, we recommend that you avoid using levels of

added dough fat greater than 10% of the flour weight.

Similar effects of changing fat levels may be observed in the production

of Danish pastry and croissant though the numbers of laminations are fewer

than with puff pastry, and the maximum laminating fat level lies around

65% of the flour weight.

Further reading

Cauvain, S.P., 2001. The production of laminated products. CCFRA Review No. 25.

CampdenBRI, Chipping Campden, UK.




7.1.12 We would like to reduce the level of fat that we use tomake our puff pastry but would like to retain pastry lift. Can youprovide us with some guidance as to how we might achieve ourobjectives?

As you know, the laminating fat plays a major role in delivering lift in

puff pastry and other laminated products. As soon as you reduce the

ratio of laminating fat to base dough, you will experience some loss of

lift. However, there is some potential for making other changes to your

recipe and process which may be of help. You have not provided any

specific recipe or production details so we can only provide you with

general guidance.

The first point to make is that the potential for reducing fat levels

depends on the ratio of fat to base dough and the number of laminations that

you are giving the paste during processing. The general pattern is that for

any ratio of laminating fat to base pastry lift increases to reach a maximum

before falling as the number of laminations increases. The loss of lift comes

from the crushing and loss of integrity of the dough layers in the paste.

Depending on the ratio of laminating fat to base dough and the number of

laminations that you are giving then, it may be possible to use less with

fewer laminations to maintain pastry lift.

You could investigate using a stronger flour to maintain the integrity of

the dough layers, but if you do then you may need to lengthen the resting

times that you are using during processing. This may be difficult on a plant

with a fixed throughput. With stronger flours, you may find that increasing

the mixing time has some positive benefit on pastry lift. This is akin to using

more energy on the mixing of bread dough. Commonly, pastry dough is less

developed than bread dough but extending the mixing time well beyond that

normally considered appropriate, e.g., from 2 to 5 and even 10 minutes, can

produce a more extensible gluten network which retains the integrity of the

dough layers in the paste during sheeting. If you do lengthen the mixing

time to such an extent, then you may need to use crushed ice to help you

control the final base dough temperature.

As noted in Section 7.1.9, you may find that you can adjust the proces-

sing temperature to a lower value and still maintain lift. Any potential ben-

efit from this type of change will be influenced by the type of laminating

fat that you are using; for example, see Fig. 7.7 which illustrates the effect

of processing temperature when using butter. Lowering the processing

temperature increases dough resistance to deformation and so again you

may need to adjust paste resting times to avoid problems with product

shaping.

The addition of trimmings tends to reduce pastry lift, especially if they

are being folded-into the paste during sheeting. There are two options, you

could reduce the overall level of trimmings that you add or you could


change to mixing the trimmings into the base dough. Adding the trim-

mings at the mixer roughly reduces their negative impact on pastry lift by

about 50%.

A number of fat reduction and fat replacement technologies have been

summarised by Wickramarachchi et al. (2015).

Reference

Wickramarachchi, K.S., Sissons, M.J., Cauvain, S.P., 2015. Puff pastry trends in fat reduction:

an update. Int. J. Food Sci. Technol. 50, 1065�1075.





7.1.13 We are experiencing distortion of our pastry shapes. Wehave measured the shrinkage but find that it is not even. Wehave also noticed that the laminated products are experiencingsome variation in product lift. What might be the causes of theseproblems?

There are quite a few causes of pastry shrinkage (see Section 7.1.5) which

include using a flour which has too high a protein content and over-mixing

the paste which yields excessive gluten formation in the paste or base dough

for laminated pastries. Often paste shrinkage can be minimised by making

resting periods longer (see Section 7.1.4). If this is not possible on an

automatic production line, you can consider adding a paste relaxant such as

L-cysteine hydrochloride.

You describe the problem as being uneven shrinkage which suggests

that it is not an ingredient or mixing problem but more likely to be

related to paste processing. Check that resting times are being controlled

and that you are not experiencing undue production stoppages. If such

issues are not the cause of the unevenness in product shrinkage, then you

will need to look more closely at your paste sheeting and product cutting

methods.

You should examine the way that you are using paste trimmings. If you

are feeding them in during sheeting, you should make sure that they are

being uniformly distributed across the paste sheet. If you are adding them

back at the mixing stage, then they should be recycled at regular time inter-

vals and in regular proportions to your virgin paste, and ideally, they should

be at a consistent temperature.

When sheeting short pastes, the forces are all aligned in one direction

along the length of travel down the plant which aligns the gluten network in

a particular direction, and when different shapes are cut from the sheet, the

paste elasticity can cause distorted shrinkage especially with round or com-

plex shapes. The most common way of reducing this problem is to employ a

cross-pinning roller; this is a small wheel which moves rapidly backwards

and forwards at right angles to the direction of the paste sheet just before the

cutter and its action helps even out the stresses in the sheet. If you have one

make sure that it is doing its correct job, if you do not have one then you

may want to fit one.

The process of laminating paste will even out some the stresses referred

to above though employing a cross-pinner before cutting the shapes is still a

good idea. However, there is a more fundamental processing problem for

you to consider, namely that after the paste has been folded and is then

resheeted a characteristic ‘w-shaped’ pattern is formed in the paste (see

Fig. 7.5). This occurs in many plants due to the characteristic ‘lapping’

motion while the paste is still moving down the plant. The spread of the ‘w’


depends on the number of laminations that you are giving the paste with

respect to the speed of the plant.

At edges of the laminated paste, there can be tendency for the laminat-

ing fat to be expressed from within the layers when they are sheeted, and if

more laminations are carried out, it becomes redistributed in the subsequent

layering. Thus, in some parts of the paste sheet, there are small variations

in the dough to fat ratios, and this contributes to variations in lift and

shrinkage. The extent of the variation can be assessed by sampling products

across the sheet width and extending along the band to cover at least one

full ‘w’ formed of the sheet (e.g., as shown by the shaded section in

Fig. 7.5).

To reduce the variation, you will need to reduce the length of each ‘w’ so

that they spread over a shorter distance, and this usually requires the plant

speed to be slowed down; such a change may not be possible as it will

reduce the plant throughput. Alternatively, you may find that a change in the

number of laminations that you give the paste will reduce the degree of

variability that you are experiencing. Commonly, lift and shrinkage go hand-

in-hand so that a reduction in the number of layers may give you less shrink-

age; you will need to carry out some trials to see if the loss of lift is

acceptable to you.

Direction oftravel onplant

Direction ofpastry lappingtravel on plant

FIGURE 7.5 Typical processing pattern on laminated pastes.


7.1.14 We are looking to start production of croissant.In my travels, I have seen many variations on products whichare called croissant. Why are there so many different formsand how are they made?

An essential feature of the products that we call croissant is that they are

made from a laminated dough, that is, one which comprises alternate

layers of a fermented dough and a suitable fat. Most people consider

the origins of the product to be in central Europe and a number of

legends suggest that are associated with conflicts between the western

world and the Turkish empire of the Middle Ages. One story suggests

that they were a special bread to celebrate the role that bakers played in

saving Vienna from attack � the traditional crescent shape being a sym-

bol associated with the invaders.

The primary shape of the croissant which is thick in the middle and thin

at the ends comes from rolling a triangular shaped piece of dough cut-out

from a thinly sheeted laminated paste. Whatever the true origins of croissant,

it does appear that the first shapes were in the form of a crescent with the

two thin ends curved inwardly towards one another. The main regional varia-

tions to this shape include forms in which the two ‘horns’ are stretched to

join together to form a ring (common in Spain) and others where the crois-

sant is not curved and remains straight (common in Germany). Another vari-

ation which is often considered to be very important is related to the

definition of the ‘shoulders’ formed on the piece after rolling the paste trian-

gle; in some cases they should be prominent while in other they should not.

In addition to variations in shape, we now commonly see variations in size.

Many baked products have changed in form since their first introduction

as they have evolved to meets consumer needs and marketing strategies. For

example, in its ‘classic’ form, the croissant should have a very flaky texture

which can often leave a mass of crumbs behind when it is eaten. This does

not suit all tastes and new forms have evolved in which the flakiness of the

product has been reduced and begun to assume a more ‘bun-like’ texture.

We leave it to you to decide which form of croissant you wish to make.

However, whatever your choice the characteristics of croissant are controlled by

a few key recipe and process features. In summary, the following are the features:

� The quality characteristics of the flour.

� The mixing of the base dough.

� The quality characteristics of the laminating fat.

� Yeast level in the base dough.

� The ratio of laminating fat to base dough.

� The numbers of fat layers created during lamination.

� Roll gap settings during sheeting.

� Resting periods between lamination and sheeting stages.


� Paste processing temperature.

� The triangle size of the unit croissant.

� Recycling paste trimmings.

� Prover conditions.

There are also some significant interactions which need to be considered

in the successful manufacture of croissant.

The quality characteristics of the flour

In general, strong flours are needed for croissant production, but it is

important to form an extensible not elastic gluten to avoid problems during

the sheeting and lamination stages. Using stronger flours will commonly

mean that longer resting periods are required between individual sheeting

and laminating stages.

The mixing of the base dough

The common practice is to ‘under-develop’ the base dough by compari-

son with bread production. This is said to allow for the extra development

which occurs when the dough and paste are sheeted, and it is true that the

pressure of the sheeting rolls does transfer some energy to the dough.

However, it is the rheological character of the base dough leaving the mixer

that is most important if a uniform and cohesive sheet is to be formed.

Under-development during mixing does not automatically deliver the appro-

priate dough rheology.

The quality characteristics of the laminating fat

The laminating fat will be extruded onto the base dough before the initial

folding stages (in small bakeries it may be applied as sheets), and it is impor-

tant that the fat is plastic enough to form as complete an initial layer as pos-

sible to help with lift in baking (see Section 2.3.1). Butter is a popular fat

used in the manufacture of croissant but its melting point is low, and this

makes it difficult to use without refrigeration of the paste during production


Yeast level in the base dough

The level of yeast in the base dough will depend on a number of other recipe

and process factors, e.g., processing and final proof temperatures. The produc-

tion of carbon dioxide gas by the yeast in the base dough will disrupt the layered

structure of the product, especially during proof, and this can reduce lift.

The ratio of laminating fat to base dough

In the manufacture of croissant, the ratio of laminating fat to base dough

has less impact on pastry lift than would be the case with puff pastry. This is

because of the disrupting effect of the yeast activity. The level of laminating

fat will have a significant effect on the eating quality of the product and its

flavour, especially if butter is used as the laminating fat.


The numbers of fat layers created during lamination

As a general rule relatively few fat layers are created in croissant, typi-

cally 18�32 (see Section 7.1.10). This is in contrast to puff pastry produc-

tion where the numbers will be two or three times greater. Once again, it is

the disrupting effect of the yeast activity that has to be taken into account so

the aim is to try and keep the fat and dough layers intact to gain lift and con-

tribute to the flaky eating character of the final product.

Roll gap settings during sheeting

A key aim during sheeting is to avoid breaking up the fat layers in the paste

as this will allow the ready escape of steam from the base dough and restrict lift

in the oven. The roll gap settings which are used are strongly influenced by the

rheological character of the base dough and the need to achieve a particular

width ready for the laminating (folding) stage which follows sheeting.

Resting periods between lamination and sheeting stages

Resting periods are helpful in adjusting the rheological character of the

paste. Longer periods help the paste to relax and make it easier to sheet; eas-

ier sheeting leads to less damage of the dough and fat layers and makes it

easier to achieve the required sheet widths for further processing. However,

longer processing times permit greater yeast activity and so a balance must

be struck between the two requirements.

Paste processing temperature

The control of paste processing temperature is important in retaining the

integrity of the fat layers; too low and the fat will be brittle, too high and the

fat will readily turn to oil. Lower processing temperatures help limit yeast

activity before final proof.

The triangle size of the unit croissant

The dimensions of the triangle are important in determining the final

appearance of the croissant. We suggest that you try rolling a few different

shaped triangles and see which one you prefer.

Recycling paste trimmings

There will always be some trimmings from the paste sheet during

production. You can re-use these by adding them to the mixer, but you

must control their level and age in order not to introduce unwanted product

variation (see Section 7.1.7).

Prover conditions

Your chosen proof temperature should be lower than used with bread to

avoid oiling of the fat and loss of lift. Prover temperatures in the range

30�32�C are usually suitable with a humidity of 70�80%.


7.1.15 We wish to make croissant with the moulded endsjoining to form a circle but find that they open up during baking.Can you suggest how we can overcome this problem?

During sheeting and processing, the rheology of the paste changes due to the

work that is done on the laminated dough; it tends to become more elastic

and less extensible in character. The relaxation periods which commonly fol-

low sheeting and laminating allow the paste to ‘relax’, that is, become less

elastic and more extensible. In a simple shape, such as a vol-au-vent ring or

a square, the elastic component of paste rheology manifests itself as an

eccentricity of shape, i.e., one side or radius shrinks more than the other.

Thus it is not uncommon for a round vol-au-vent ring to become oval or a

square shape to become rectangular.

In more complicated shapes, such as croissant, others changes may be

observed when the dough is too elastic and these may include the opening-

out of the circular shape. Increased paste elasticity may be overcome in a

number of different ways including the following:

� Higher water levels in the base dough.

� A weaker flour.

� Longer resting periods after sheeting and lamination, especially if strong

flours are used.

� A suitable resting period after the formation of the circle and before the

croissant enters the oven. This usually occurs in the prover.

The complicated shape of a croissant and the manner in which it is cut

from the paste sheet can play a very important role in controlling shape.

Towards the end of processing, much of the roller action on the paste is in

one direction, that is, in the direction of travel on the plant. The triangular

shape which is required for croissant before it is rolled up may be cut either

in the direction of travel or at right angles to it (see Fig. 7.6). In the latter

case, the stresses within the curled piece can often lead to the problem you

describe. If you cannot change the direction of the cut, we recommend that

you employ a cross-pining roller, that is, one which moves are right angles

to the travel of the plant to even out the stresses.


FIGURE 7.6 Effect of direction of cutting on croissant quality.


7.1.16 We have been trying to freeze fully proved croissant forlater bake-off. Can you identify the important criteria for theirsuccessful production?

There is significant interest in freezing fermented and proved dough pieces

with the intention that the pieces are removed from the freezer and trans-

ferred straight to the oven for baking. This would make the product very

convenient to use in a range of bake-off environments. However, there are

some significant technical challenges to overcome.

As is well-known, yeast cells die during freezing and subsequent storage.

This means that when the dough pieces are removed from the oven there is

no further potential carbon dioxide gas production from the yeast. In addi-

tion, during storage, the carbon dioxide gas that has already been evolved in

the proof phase gradually leaks out of the dough. In the prover, the carbon

dioxide gas diffuses into the nitrogen gas bubbles trapped in the dough, but

during freezing and storage, the diffusion process is reversed, and in some

cases, this leads to collapse of the dough structure.

The freezing of proved laminated pastries is more successful than that

achieved with bread doughs. This is because the mechanism by which crois-

sant and Danish doughs expand does not rely exclusively on the release of

carbon dioxide gas but is more closely related to the pressure of steam gener-

ated during baking which is trapped between the dough layers of the paste.

In broad terms, this means that frozen proved laminated products still have

the potential to expand and yield products of relatively ‘normal’ appearance.

The most important criteria for frozen proved laminated doughs are

essentially the same as those which would apply to the product when freshly

produced. The only exception may be that the pieces are not fully proved

before being transferred to the freezer as a small degree of proof may still

occur in the dough pieces in their initial phase of freezing. As a general prin-

cipal if the recipe and process will make a good fresh product, it will make

an acceptable one if frozen. There tends to be a small loss of product quality

with freezing.

It is important to ensure that the dough pieces are quickly frozen and

once frozen are not allowed to defrost and be refrozen. This can be a very

damaging process and is more damaging than would be the case with

unproved frozen dough. Care should also be taken to limit moisture losses at

any stage during freezing and storage. The products should be stored in

moisture impermeably film, and if they are wrapped in bulk, e.g., in boxes, it

may be necessary to over-wrap the bulk container.

Bulk wrapping of products is possible but be careful to avoid having

large numbers of dough pieces in a box or too many boxes stacked on top of

one another. The increased pressure on frozen dough pieces at the bottom of

a stack can cause then to defrost and become deformed in shape.


7.1.17 We are making puff pastry, Danish pastries and croissantusing all butter and often have problems with the processingof the pastes and feel that we do not get the best of qualityfrom the final products. What are the best processing temperaturesand conditions when using butter with such products?

Butter has a positive marketing image due to its ‘natural’ associations and is

a popular fat to use in pastry making. The melting profile of butter makes it

a particularly pleasing fat for incorporating into pastry products, but unfortu-

nately, it is not the easiest of fats to use in processing.

Butter has a relatively low melting point (see Section 2.3.7) and a

tendency to ‘oil’ during pastry processing creating problems with sheet-

ing. To overcome this particular problem, you will need to ensure that the

dough temperature after mixing and the paste processing temperatures are

kept as low as possible. This may mean you will have to air-condition the

pastry processing area. The data illustrated in Fig. 7.7 show how impor-

tant the effect of paste processing temperature can be on the lift of all-

butter pastries. It is equally important that the processing temperature is

not too low because butter lacks plasticity at lower temperatures and the

integrity of the layering in the pastry will be lost with subsequent loss of

lift.

The low melting point of butter also creates problems for proving

Danish pastries and croissant so you will find it an advantage to restrict the

temperature in the final prover to around 30�C with a relative humidity of

60�75%. These conditions will help avoid flow and loss of boldness and

shape.

0

0.5

1

1.5

2

2.5

3

21

Pas

try

spec

ific

heig

ht(m

m/g

pas

te)

FIGURE 7.7 Effect of processing at temperatures of 19�C and 12�C on puff pastry lift when

using butter.


7.2 SHORTCRUST PASTRY

7.2.1 What characteristics should we specify for the flour thatwe should use for making savoury and sweet short pastes forunbaked chilled and frozen shells and scratch-baked products?

Usually, the specification for short pastry flours is not very comprehensive

because there is no need for significant gluten formation in the paste and

recipe water levels are much lower than would be used in breadmaking and

the manufacture of laminated products. The general view is that soft wheat

flours with a moisture content of around 14% and a protein content of

8�10% are suited to the manufacture of both savoury and sweet paste

products.

It is probably advisable to avoid flours with low Falling Numbers

since they are high in cereal alpha-amylase. This is because it is common

practice to recycle paste trimmings in product and the trimmings may be

stored for some time before being used. During the storage period, the

alpha-amylase will act on the starch in the flour causing the paste to

soften and become sticky. This may later cause problems during paste

processing.

We note that you are making unbaked paste products which you sub-

sequently chill or freeze for a period before they are baked. Because you

are making such products, you should specify that the flour has a low ash

(see Section 2.2.1) or grade colour figure (see Section 2.2.2). The need

for an ash specification is not related to the colour of the baked pastries

but to the potential for enzyme-assisted oxidation of the polyphenols nat-

urally occurring in wheat bran (see Section 7.1.8). During refrigerated

storage, the oxidation reaction can cause the bran particles to become

dark brown or black in colour. The larger the size of the bran particles,

the more evident the dark spots will appear. If the bran is finely divided,

then the paste may assume a grey, almost dirty appearance. The oxida-

tion reaction will continue as long as the products are held in refrigerated

storage.

The same problem can occur with both savoury and sweet pastes and

can also be a problem with puff pastry stored under refrigerated conditions

(see Sections 7.1.8 and 7.2.7).


7.2.2 Why is the hot water method preferred for the productionof savoury pastry but not for sweetened pastry?

The use of hot or boiling water in the production of the savoury paste is

known to increase the crispness of resulting paste during storage, see

Fig. 7.8. The reasons why this should be are not entirely clear. Adding the

boiling water to the flour may cause limited gelatinisation of the starch

which is present, but there is no direct evidence that this contributes to the

formation of a crisper paste. The high temperature may inhibit the activity of

the amylases in the flour and reduce any potential effect on the gelatinising

starch. As many savoury pie pastes will stand for a period of time after mix-

ing or blocking, the limitation of any enzymic activity may be very

important.

The high temperature resulting from the addition of the hot water will

melt the solid fat in the mix. This may aid its dispersion into the microscopic

voids which are created during mixing. These voids carry through to the

baked product and provide a route for water to move through as it migrates

from the filling to the surrounding pastry. If the voids are filled with fat,

then there is less opportunity for the movement of water as shown by the

observation that the base paste of pies does not soften during storage (see

Section 7.2.10).

If the hot water method is used in sweetened pastry production, it tends

to produce a soft and sticky paste which will be difficult to block because

the dissolved sugars form a syrup in the paste.

FIGURE 7.8 Comparison of the effect of hot and cold pastry making methods on pastry

crispness during storage.


7.2.3 What method should we use to calculate the watertemperature to deliver a consistent final savoury short pastetemperature at the end of mixing?

Most paste preparation methods are designed to minimise energy transfer dur-

ing mixing. Nevertheless, we recommend that you do take into account any

temperature gain that might be experienced as a result of the mixing cycle.

First, you should make a number of pastes in which you record the main

ingredient temperatures � Flour, fat (not laminating fat), water and sugar, if

used � And the final paste temperatures that were achieved for your given

mixing time. You may already have such data in your records and you could

use these.

Next, calculate the ingredient contributions by summing the individual

contributions of weight and temperature multiplied by their specific heat

capacity. For example:

100 kg flour at 20�C5 2000 3 0.4

30 kg fat at 20�C5 600 3 0.7

30 kg water at 10�C5 300 3 1.0

Total heat input5 2900

Total heat input/total mass5 2900/160

Which gives an expected base paste temperature of 18.1�CActual paste temperature was 20.5�CThus temperature rise was 2.4�C

The approximate water temperature for future mixes could then be calcu-

lated using the following formula:

Total mass ingredients3 ðrequired paste temperature�temperature riseÞ � ðHeat input from flour and fatÞ

Mass of water

There will be small errors in the last calculation because the specific heat

capacities of the ingredients used are not taken into account, but as the varia-

tions in ingredient masses will be very small for a given recipe, the calcula-

tion method still has practical value.

If you are making laminated pastries then the choice of the final mixed

base paste temperature should be matched with that of the laminating fat for

ease of processing. This approach will also optimise the integrity of the fat

and dough layers after lamination. If the base paste and the laminating fat

temperatures are not matched, there will be transfer of some heat from the

warmer to the colder component but unless you are using long resting times

the practical effect will be small.


7.2.4 We are manufacturing savoury short pastry productswhich are blocked out to shape and lids by sheeting a pastewith the same formulation. We wish to increase our productionrate and are considering reducing or eliminating the rest periodsin the production sequence. Can you advise us on their functionand any consequences that we may face if we change them?

Rest periods are used in the manufacture of pastry products at different

points in the production sequence. Their primary function is to allow for the

modification of the rheological properties of the paste so that its subsequent

behaviour is optimised and the required final product characteristics are

achieved. The rheological properties of the paste are largely determined by

the degree of gluten development that occurs in the mixing and machining of

the paste. Following mixing and machining the rheological properties of the

paste change with resting time; the longer the resting time, the greater the

rheological change (the rate of change will also be influenced by the temper-

ature at which the paste is resting). Commonly, the rheological changes are

referred to as ‘relaxation’ of the paste.

Savoury short pastry products typically have less gluten development than

puff paste and resting periods tend to be relatively short after mixing as it is

easier to obtain the required shape and reduce the risk of shrinkage when

forming (blocking) of the pastry shape. The resting period may apply to the

bulk paste before dividing or the individual units (billets) after dividing.

If you are going to reduce the resting period, then you may need to mod-

ify the paste rheology in some other way; such as the addition of a paste

‘relaxant’. The most common paste relaxant is L-cysteine hydrochloride

which acts on the protein network and reduces the strength of gluten forma-

tion in the paste which in turn, reduces the need for resting periods.

Proteolytic enzymes may be used but these tend to be less effective.

Caution should be exercised when using a paste relaxant in a production

environment which yields high levels of paste trimmings. As the paste trim-

mings will be reused in subsequent mixings, there is a gradual build-up of

the level of the relaxant as production continues and a point may be reached

at which problems with paste stickiness may be experienced.

An alternative way of reducing paste resting times may be through the addi-

tion of extra water to the paste at the initial mixing stage. The extent to which

this can be practised will depend on the capabilities of the plant to operate with

a softer paste. If you take this approach, then you may also have to consider a

small reduction in mixing time as higher initial water levels tend to lead to

greater potential for gluten formation in the mixer for a given mix time.

One function of resting periods not always appreciated relates to the tem-

perature of the paste, especially in the production of pie pastry where the use

of hot water is practised. In this case, part of the rheological change in the

paste comes from the cooling of the paste after mixing.


7.2.5 From time to time, we experience problemswith the sheeting of our short paste, in particular it cracks orfails to remain cohesive. Can you suggest why this happens?

Significant gluten formation in short pastry doughs is not normally consid-

ered necessary. Traditional multi-stage methods for the mixing of short paste

were evolved to try and minimise the potential for gluten formation by

‘waterproofing’ the flour proteins with fat. Although the degree of gluten

formation required in the manufacture of short pastry is considerably less

than is required in breadmaking, some is desirable so that the paste units or

sheets remain intact during the forming and sheeting processes, otherwise

cracks may form on the surface of the paste. In extreme cases, the crack may

extend through the paste sheet causing it to break into two separate pieces.

Too much gluten formation in short pastry commonly leads to problems

associated with shrinkage during sheeting, blocking, forming and during bak-

ing. Getting the balance between too little � lack of cohesion � and

too much � excessive shrinkage � requires careful control of recipe and

mixing conditions.

As might be expected, the level of water used in the recipe plays a major

role in determining the rheological properties of the final paste (Cauvain and

Young, 2008). Too little and the paste will not form a cohesive sheet, too

much and the paste will be too soft to process. The final paste rheology is

also affected by the added fat level and to a degree fat and water are inter-

changeable in their effect on paste firmness, more fat gives a softer paste

which can be offset by reducing the added water level. However, fat and

water have completely opposite effects of gluten formation with fat inhibit-

ing gluten formation and water promoting it. In addition to ingredient effects,

the final rheology is also strongly influenced by the paste temperature; with

higher temperatures yielding softer and more easily machined pastes. It is

important to work to a consistent final paste temperature.

The cracking of short pastry is more influenced by the length of the mix-

ing time than the mixing method used. Short pastes mixed on a high speed

mixer tend to be more friable and prone to cracking because of the short

mixing times employed. We suggest that you first investigate the effects of

increasing mixing time. You may notice a small increase in paste tempera-

ture which can be readily compensated for lowering the water temperature.

If you still have the problem when you have optimised mixing time, then we

suggest you try raising the added water level.

Reference






7.2.6 We are producing unbaked meat pies but find that theshort pastry lid cracks on freezing. The cracks become largerwhen the product thaws out and during baking the filling mayboil out leaving an unsightly blemish on the surface.Why is this and what can we do about it?

In the freezer, the fat in the unbaked pastry contracts by about 10% in vol-

ume, whereas the aqueous phase in the paste expands by about the same

amount. This differential in expansion causes stresses to build-up in the paste

which may exploit any microscopic weaknesses that are present turning them

into visible cracks. The movement of air across the unbaked product during

the freezing operation removes a small amount of moisture from the surface

until ice is formed. This drying out of the paste also exacerbates the problem.

The level of gluten formation in short pastry is relatively modest com-

pared with that developed in puff paste or bread doughs. This means that the

gluten lacks any significant degree of extensibility and so during sheeting or

blocking there is a tendency for the gluten network in the paste to become

ruptured, if not visibly then certainly at the microscopic level. The cracks

which are formed are most obvious on the lid because they are readily visi-

ble but almost certainly occur in other parts of the product. In addition, the

lid is exposed to air movement and potential dehydration.

In addition to being extensible, the gluten network should not be elastic

as this increases the stress on the paste. Increased elasticity is most likely to

come from over-mixing of the paste.

There are a number of possible practical remedies for the problem. They

included:

� The use of a higher protein content flour.

� Increasing the paste water content.

� Reducing the fat content.

� Keep paste mixing times to a minimum consistent with forming an homo-

geneous paste.

� Blast freeze the pies as quickly as possible and try to minimise moisture

losses during storage.

� Keep the proportion of trimmings in the lid pastry to a minimum.

Incorporate trimmings into the base paste during mixing whenever possible.

With some products where the paste fits tightly around the filling, for

example sausage rolls and Cornish pasties, there may be some advantage in

lowering the filling moisture content to reduce the degree of physical expan-

sion which may occur.


7.2.7 Some of the short pastry cases that we make forrestaurants to fill and serve have been returned to us as being‘mouldy’ on the base. We were surprised as we thought that thewater activity of the shells was too low to support mould growth,and when we examined the bottom of the pastries, we can seethat there is a discolouration but we do not think that it ismould. Can you identify what has caused the discolourationand how to eliminate it?

We can confirm that the problem is not related to mould growth even though

the discolouration has a similar appearance to mould colonies (see Fig. 7.9).

Almost certainly, the problem is related to a chemical reaction between the

pastry base and the pans in which they are held before baking. The paste

will be slightly acid and this accelerates a reaction between the paste and a

source of iron to form iron compounds (similar to rust) which turn dark

when the pastry is baked-off.

You are storing the unbaked pastry pieces in a refrigerator overnight

before they are baked and such discolorations are sometimes seen with

retarded dough pieces (see Section 4.2.13). It is a little surprising that you

have had this problem as the moisture content of the pastry base will be

somewhat lower than that of dough but it may that there was some condensa-

tion on the pastry bases when they were transferred to refrigerated storage

and this may have encouraged the reaction.

The most obvious course of action would be to make and bake the pastry

bases without refrigerating them. If this is not possible, you should look at

the condition of your pans and discard any which are scratched or damaged.

Alternatively, you could block the pastries into foil cases which are placed

in the pans.

FIGURE 7.9 Dark marks on the base of refrigerated pastry shells.


7.2.8 We are having problems with the custard tarts that wemake. The pastry shell is very pale coloured, but if we increasethe baking time, we find that the custard filling is not verystable and shrinks away from the case during storage. If we raisethe baking temperature, the custard filling boils and breaksdown during storage. Can you give us any advice on how to get abetter pastry colour without causing problems with the filling?Sometimes the baked custard has a watery appearance.

Too much heat input during baking increases the loss of water from the cus-

tard causing it to shrink away from the pastry case and crack. During stor-

age, the low water activity of the egg gel allows more water to escape and it

will continue to shrink and, as illustrated in Fig. 7.10, cracks may appear on

the surface. It is always difficult to find the best comprise of baking time

and temperature in the manufacture egg custards to yield the required pastry

colour without compromising the filling qualities. Rather than trying to col-

our your pastry by changing baking conditions you could substitute a portion

of the sucrose in the paste recipe with dextrose; this is a reducing sugar and

will colour more readily than sucrose. If you have no dextrose then you can

use a glucose syrup, remembering to make allowance for the water in the

glucose syrup. Dextrose and glucose syrup are less sweet than sucrose

(weight for weight), but as you are only replacing a portion of the sucrose,

you may not notice the difference in flavour.

The formation of a stable gel in the filling of baked custards depends on

achieving the correct conditions during baking. It is important to prevent the

temperature of the filling going too high. The stability of the gel depends on

the ability of the egg proteins (the albumen), and any starches or stabilisers

present in the formulation to hold the water within their structures. Your

samples are just beginning to show a breakdown of the gel which is often

referred to as synerisis (see Section 11.1).

Under the influence of sufficient heat, the egg proteins will coagulate,

and in doing so, their spatial configuration changes in a way which

reduces their ability to hold large quantities of water within the three-

FIGURE 7.10 Cracks on the surface of custard tarts.


dimensional protein structure formed during mixing. As this water is ‘lost’

from the coagulated protein structure, it needs to be taken up by the

other custard components otherwise it will be released from the gel. The

quantity of the released water which will be mopped up by the other com-

ponents will be limited.

Most commonly, this problem arises from baking the product for too

long. The long baking time allows a greater input of heat into the filling and

raises its temperature far higher than that of the coagulation temperature of

the albumen. You should reduce the baking time. You may have to raise the

baking temperature to ensure that paste is fully baked. Raising the baking

temperature will have less effect on raising the filling temperature than

prolonging the baking time.

A common sign that the filling is boiling is that the top of the custard

will be rounded in the oven. If adjusting the baking conditions does not cure

this part of your problem then you will have to consider raising the egg or

stabiliser level in the filling formulation.


7.2.9 We have been receiving complaints from customersthat that our short pastry which we use for meat pie productshas an unpleasant eating character which they describeas ‘waxy’. The comments are most often related to the basepastry in the pies. Why is this?

The sensory characteristic that you describe is directly related to the type

and properties of the fat that you are using. The crispness of the pie paste

that you are making and its retention throughout life is of prime importance

in delivering a product which consumers consider to be appropriate � soft

and soggy pastry is most often associated with ‘staling’ in pastry terms.

All bakery fats are a mixture of oil and solid fat fractions (see Section

2.3.1). In pastry making, one of the ways in which pie pastry crispness is

maintained is by using a fat with a high melting point fraction. However, if

the melting point of the fat is above that of the temperature in the human

mouth, then it does not ‘melt in the mouth’ and leaves behind a waxy sensa-

tion which is most often referred to as ‘palate cling’. The problem is also

linked with the proportion of the fat component with the high melting point,

the greater the proportion of the high melting fat fraction the greater the sen-

sation of palate cling. This particular problem is often seen with animal fats

which are more popular in meat pie production due to their contribution to

product flavour and with hydrogenated fats.

When the unbaked product enters the oven, the fat component begins to

melt and becomes oil. Ultimately, all of the solid fat fractions will become

liquid. Under the influence of gravity, some of the liquid fat drains into the

base pastry and fills up the small voids that are present in the paste from

mixing and processing. In addition to fat from within the paste, there will be

a significant contribution from the fat in the meat fillings that you are using.

As the fat comes from an animal source, then it will have a high melting

point. The combination of the two drainage processes increases the propor-

tion of fat which is present in the base paste and so makes the problems of

palate cling more noticeable in that area of the pie.

As you are unlikely to be able to make a suitable meat filling with a low

melting point fat, we suggest that you change to a lower melting point fat in

the preparation of your short paste which should help reduce the problem.


7.2.10 Why does our pork pie pastry go soft during storageand what can we do to make our pastry crisper?

The softening of pork pie pastry (and the pastry of many other composite pro-

ducts) arises because of the migration of water from the moist filling to the

dry pastry. The driving force for this migration is the difference in the com-

ponent water activities. Cauvain and Young (2008) give typical water activi-

ties for savoury pie components as pastry 0.24, jelly 0.99 and filling 0.98.

Key factors which influence the rate at which water moves between com-

ponents in savoury pies and the rate at which the pastry softens include the

following:

� The storage temperature; the lower the temperature the slower the rate of

moisture migration.

� The absolute difference in water activities between the components; the

greater the difference the faster the initial rate of moisture migration.

Fat also migrates during the manufacture of pies but most of this occurs

in the oven when the all of the solid fat has turned to oil and is therefore

mobile (see Sections 2.3.1 and 2.3.2). At ambient or lower temperatures, the

solid component of the fat cannot move within the pastry matrix. In the past,

part of the softening of pie pastry has been attributed to fat migration, but if

this occurs, it is a minor contributor to pastry softening. In fact, the migra-

tion of oil into the base pastry under the influence of gravity in the oven

probably contributes to keeping the base pastry from softening. The oil fills

many of the microscopic voids formed in manufacture in the base paste and

probably acts as a waterproofing agent so preventing the ingress of signifi-

cant quantities of water.

As discussed above, the main cause of lack of pastry crispness is associ-

ated with the movement of water from the moist filling to the drier pastry.

The most common way to reduce this problem is to manipulate component

water activities to reduce the water activity differential. However, in the case

of savoury pastry, reformulation of filling and pastry tends to be a limited

option as they can significantly affect key product characteristics so other

means of maintaining pastry crispness must be sought.

One way of achieving a crisper pastry during its storage life is to increase

the initial crispness of the pastry on day of manufacture so that even though

the product will soften at the same rate the crispness at any given storage time

will be greater than the standard.

In summary, the opportunities for improving pastry crispness are:

� Lower the temperature to slow down the rate of moisture migration.

� Reduce the absolute difference in water activities between the components.

� Use the hot paste method which gives an initially crisper pastry.


� Increase the protein content of the flour used in the manufacture of the

paste.

� Cool the pies thoroughly before adding the jelly.

� Consider not using jelly in the pie filling.

Reference






7.2.11 We are having difficulty in blocking out savoury piepaste in foils, there is a tendency for the dough to stick to thedie block causing the base of the foil case to become misshapen.We do not have the same problems with our sweetened paste,can you explain why?

The problem is most likely to be associated with the temperature of the die

block that you are using. In particular, you are more likely to experience the

problem when the die block temperature is low, for example, at the begin-

ning of the production run or on cold mornings if the bakery is not tempera-

ture controlled. You should also look to the consistency of your paste

temperature after mixing and consider the impact of any resting time which

may cause the past to cool.

Soft pastes will exacerbate the problem so you will find an advantage in

restricting the added water or fat levels, or both. The addition of sugar

without changing the water level increases the solids to liquid ratio in the

recipe, and it competes for water with the flour components; the net result

is often that you have a firmer dough than would be the case in the absence

of recipe sugar.


7.2.12 Why do our baked pastries and quiches have smallindents in the base which project upwards and are pale incolour? They are baked in individual foils.

This problem has a similar cause to that described for fermented products in

pans (see Section 4.1.1). Namely that steam is trapped between the pastry

and the foil case during baking and as it cannot immediately escape then

pressure builds up in some areas and forces the pastry upwards. As

the pastry has not coloured, it is likely that this event has occurred early in

the baking process.

In the case of the pastry, the pressures encountered in the blocking pro-

cess itself helps to create the impermeable seal which is necessary for the

steam to remain trapped. It may be that some of the indent is created as the

die withdraws, though even hand-blocked products have been known to

show this particular problem.

The most obvious solution to your problem is to use foils with small per-

forations in the base. However, you should look closely at the location of the

holes which should be at the lowest point of the foil, or if the foil concerned

has more than one low point then holes should present in each of the low

areas. Even though the holes are small in size, typically less than 1 mm, the

pressure generated by the hot gases will still allow the steam to diffuse out

through them.

If the problem persists, you should look at your baking conditions. The

problem is always exacerbated by baking at high temperatures for short

times and with high bottom heat. If you suspect that this is the case, then try

reducing the temperature and increasing the baking time. Allowing the pastry

case to rest after blocking and before filling and baking can also reduce the

problem.


7.2.13 How can we make the sweet pastry that we use withour apple pies crisper eating?

The cause of sweetened short pastry softening is the same as that dis-

cussed for savoury pastry (see Section 7.2.10), namely that it arises

because of movement of moisture from the moist filling to the drier,

lower water activity pastry. In contrast to the situation in a savoury prod-

uct, there are many more ways to extend the crispness of sweetened pas-

try products due to the greater potential for recipe reformulation.

Potential ways of keeping your pastry crisper include the following:

� Lowering the storage temperature for the baked products.

� Reducing the differential in water activity between the pastry and filling

through reformulation. This can include the addition of sugar to the pas-

try or filling, or the addition of humectants such as glycerol to the filling.

� Omit or reduce baking powder from the pastry formulation to reduce pas-

try porosity.

� Ensure that any stabiliser in the filling has had sufficient time to become

effective. Some stabilisers may require several hours after having been

blended into the filling before they achieve optimum control over water

activity.

Another possibility is to include a barrier between the pastry and the

filling. Any such barrier must be edible and should not significantly

change the product character. Cauvain (1995) provided some examples of

suitable moisture barriers (see Fig. 7.11):

� A protein solution � Egg albumen sprayed onto the pastry before

depositing the filling.

FIGURE 7.11 Effect of barrier on short pastry crispness.


� A gum solution � Carboxy methyl cellulose sprayed on the pastry before

depositing the filling.

� A rice paper disc placed on the pastry before depositing the filling.

Reference

Cauvain, S.P., 1995. Putting pastry under the microscope. Baking Industry Europe, 68�69.

Further reading








7.2.14 How do we avoid ‘boil-out’ of our pie fillings?

The boiling-out of pie fillings is most readily controlled by adjusting the

baking conditions you are using. Commonly, products are baked to a desired

colour; the rate at which we achieve the required colour depends to a large

extent on the choice of baking temperature. Boil-out of the filling, however,

will depend mostly on the length of the baking time; the longer the product

spends in the oven the higher the filling temperature will become and the

greater the chances of boil-out. We suggest that you consider increasing the

oven temperature and shorten the baking time.

If the crust colour of sweetened pastry becomes too dark, then you may

need to reduce the level of sugar that you are using in the recipe. If you are

using glucose or another reducing sugar, you may need to replace part or all

of it with sucrose to limit the degree of browning.

Alternatively, consider lowering the water activity of the filling by adjust-

ing the soluble solids of the filling formulation. The level of soluble solids in

pie fillings controls the boiling point of the liquid in the filling, the higher

the soluble solids content the higher the boiling point (Cauvain and Young,

2008). You can therefore raise the boiling point by increasing the level of

soluble solids. In the case of sweet fillings, this may be through the addition

of extra sugars. To avoid the filling becoming too sweet, then you can use

glucose rather than sucrose, as the former is less sweet on a weight for

weight basis. Remember that if you use a glucose syrup then you must bal-

ance the water addition to compensate for that present in the syrup otherwise

the filling water activity may not fall.

Reference






7.2.15 We wish to reuse pastry trimmings but find thatsometimes we experience a ‘soapy’ taste in the final product.Can you suggest a cause for the flavour and how best to reusethe trimmings to avoid this and any other potential problems?

The ‘soapy’ taste undoubtedly comes from the trimmings that you have been

re-using. Soap is formed when some of the fat in the paste splits into glycerol

and fatty acids, the latter combine with any alkaline material present to form

soap. The fat splitting will be caused by microorganisms which are present in

and on the trimmings. Contamination of the paste during processing is difficult

to avoid because the microorganisms concerned will be in the bakery atmo-

sphere, coming from external and internal sources. You should keep the trim-

mings as free from contamination as possible, especially sweeping clear any

dusting flour which you may have used during their processing.

As the problem is linked with microbial contamination, you can expect

that the problem becomes more prevalent when the bakery temperature is

higher than usual. Usually, you can control the growth of microorganisms

present in the trimmings using low temperatures. We suggest that you trans-

fer any trimmings at regular intervals into refrigerated storage, around 4�Cand try to use them within 24 hours of production. It is helpful to store the

trimmings in thin sheets rather in a than large bulk because it will take some

time for the centre of a large mass of trimmings to cool and during that

period microbial activity may be sufficient to initiate an adverse reaction.

We recommend that you add the trimmings at the mixing stage to ensure

that they are uniformly distributed throughout the paste sheet when it is pro-

cessed. You should either allow the trimmings to warm before adding them

to the mixer or compensate for the lower paste temperature by raising the

added water temperature. Establish a production schedule which allows the

trimmings to be used in strict rotation, otherwise you may still encounter

problems. Limit the storage time of trimmings to about 24 hours.

Periodically, say every 3 to 4 days, it is advisable to have a break in produc-

tion which allows you to start with virgin paste to avoid progressively

increasing the level of microbial activity in the paste.


Chapter 8

Other Bakery Products

8.1 WHAT ARE THE MOST IMPORTANT FACTORS WHICHCONTROL THE VOLUME OF CHOUX PASTE PRODUCTS?

When choux paste is being baked any air that has been beaten into the paste

will expand and the water will be converted to steam. The expanded air and

steam try to escape but to a large extent are prevented from doing so because

both are trapped and retained by the gluten matrix and un-coagulated film of

egg albumen. The egg albumen (protein) is extensible and will be inflated

and distended by the internal pressures of the gases � air and steam.

Expansion of the paste only ceases when the egg albumen coagulates,

and both it and the gluten film lose their extensibility and gas-holding

powers. Egg albumen coagulates at high temperatures and loses its extensi-

bility, so the temperature of the paste at which the eggs are added is an

important factor in getting maximum volume. The presence of strong films

of un-coagulated egg protein in the paste when it goes into the oven is of the

utmost importance for the achievement of good volume in the baked product.

If the eggs are added to the paste before it has been allowed to cool ade-

quately, the fluidity of the eggs is quickly lost and the penalty is lower vol-

ume. Pastes can be left to cool to 24�41�C (75�106�F) naturally, by stirring

with the beaters of the machine or by being spread out onto a cold clean slab

or table-top. An economic advantage of cold paste is that it requires the addi-

tion of less egg and will still give a good volume product.

The consistency of the paste for choux pastry is another of the critical

factors in controlling the volume of choux products. It also plays a prominent

role in the appearance of the product. Ideally, the paste should be as soft as

possible but without causing the resultant pastry case to be of poor shape.

If the paste is too stiff when making eclairs, they become unattractive in

appearance and exhibit harsh surface cracks and breaks. If the paste is too

soft, they need more baking to dry them out; otherwise, they will collapse

on being taken from the oven. Even if they are adequately dried out to pre-

vent them from collapsing, they will have a lower volume and look

squashed in appearance. When the consistency is correct, they are beau-

tifully rounded, and have no harsh breaks, bursts or cracks to detract from

their appearance.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00008-4

For cream bun shells, the more they crack and burst the better the product

appears. To obtain this cracked shape the paste can be made a little softer

than for eclairs. Again however if the paste is made too soft the buns will be

of poor shape and can collapse. So although it is a good plan to make choux

paste slightly softer when making cream buns, the difference is only slight

and must not be over-done. When baking choux buns, it is essential to create

steam under sufficient pressure to aerate or inflate them as fully as possible

before the coagulation of the proteins and before surface drying or crust for-

mation occurs. This is achieved by baking the paste in a comparatively hot

oven, 227�C (440�F), so that steam pressure is built up rapidly to expand the

paste and to hold it in that condition until the coagulation of the proteins and

the crust formation.

Frozen and spray dried egg as well as liquid eggs are regularly used in

the production of choux pastry. Care must be taken when using spray dried

egg that the egg has not been kept too long as in storage egg proteins are

degraded through the activity of bacteria. Frozen eggs should be defrosted

before use. Some adjustment in recipes may be required when using frozen

egg as there may have been some change in egg viscosity as a result of the

freezing/thawing operation.


8.2 WHY ARE CREAM BUNS BAKED UNDER COVERS ANDECLAIRS ARE NOT?

A higher volume is usually required for cream bun than eclair shells. To

achieve this high volume, the surface of the bun should remain moist for as

long as possible in the baking process. When the buns are placed in the

oven, the heat gradually begins to expand the air beaten into the paste and to

generate steam from the moisture in the product. If the buns were baked in a

dry heat, the outer crust would soon set and prevent the paste from expand-

ing to the extent required. If the atmosphere surrounding the products is kept

moist, then the outer crust remains soft and pliable allowing expansion to

continue as long as there is expansive force left in the paste. When no more

moisture remains in the buns to be converted to steam, the crust of the bun

dries and becomes set.

A humid atmosphere surrounding the buns during baking can be achieved

in two ways. First, the cream buns can be baked under covers or tins to keep

the moisture generated near to the product. Second, filling the oven to full

capacity will obviate the need for covers as the oven itself then acts as a

steam-tight environment for the products. In larger bakeries, steam may be

introduced into the oven to raise the atmospheric humidity.

Eclairs are not required to expand as much as cream buns and there is

no need to bake these under tins. To help keep a regular baton shape, the

outer crust is formed after initial expansion has taken place and further

growth is restricted.

Other Bakery Products Chapter | 8 377

8.3 OUR CHOUX BUNS COLLAPSE DURING BAKING. CANYOU SUGGEST WHY THIS HAPPENS?

It is important when baking choux products that the oven temperature

is sufficiently high to impart heat quickly at the start of baking.

Consequently, a rapid recovery of the baking temperature after the product

has been loaded into the oven is vital. If the temperature controls are set

too low, then the recovery rate is low resulting in shrinkage or collapse of

the products. If the steam damper is partly or totally open the problem is

exacerbated. The best results are obtained when the steam damper is

closed (no loss of heat) and the baking temperature is set as near 232�C(450�F) as possible.


8.4 WE ARE GETTING A GREY�GREEN COLOURATIONTO OUR CHOUX BUNS. CAN YOU EXPLAIN WHY THISSHOULD HAPPEN?

The grey�green discolouration is associated with the formation of fer-

rous sulphide in the batter. If you examine the internal surface of your

buns, you may see small black specks. It is most likely that these will

give a positive reaction when tested for iron. The iron has probably

come from the surface of your mixing bowl that is being abraded by the

beater or from the surface of the container used to boil the roux. The for-

mation of ferrous sulphide is accelerated by prolonged heating or by

heating at a high temperature, such as that typically used for the produc-

tion of choux buns.

The discolouration in your choux buns is similar to the grey�green col-

our which sometimes forms on the surface of an egg yolk after the egg has

been boiled for too long a period or allowed to cool slowly. The reaction is

caused by the iron in the yolk combining with hydrogen sulphide from the

white of the egg.

When making choux buns it is advisable to:

1. Use stainless steel utensils.

2. Ensure that the container used to mix the roux is not corroded and that

the mixing utensil does not abrade the surface of the container.

3. Ensure that the roux is well cooled before beating in the egg. If

cooling is normally done by mixing on a machine, ensure that the

mixing tool does not abrade the surface of the bowl. If cooling is

achieved by allowing the roux to lie in a metal container, ensure

that it is not in contact with iron which may be exposed in a worn

tinned bowl.

4. Bake at as high a temperature, and for as short a period, consistent with

the choux shells being adequately baked.


8.5 WHY IS POWDERED AMMONIUM CARBONATE OR‘VOL’ ADDED TO CHOUX PASTE?

Powdered ammonium carbonate, or ‘vol’ as it is commonly known, is

entirely different from other baking powders used in baking. When heated,

the whole of the material turns into three gases � ammonia, carbon dioxide

and water vapour � and no residue remains in the product in the form of a

salt. Not all the gases escape with the result that a smell of ammonia remains

after the products are withdrawn from the oven. This is because ammonia is

extremely soluble in water. No action takes place until the products are

heated. Vol should be stored in an airtight container to maximise its subse-

quent effectiveness.

When added to choux paste in small quantities, it helps to improve the

volume, especially in the case of cream buns as these are required to be

extremely light in character and to have the greatest possible volume. It is

not always necessary to add ‘vol’ to choux paste to obtain good volume if

the choux products are correctly made. Neither is it necessary to add ‘vol’

when making eclair cases as there is a tendency for the paste to ‘blow’ too

much, thus spoiling the shape of the eclairs.


8.6 WE WISH TO MAKE A LARGE BATCH OF ECLAIR CASESAND STORE THEM FOR A FEW DAYS BEFORE FILLING ANDICING THEM. CAN YOU ADVISE ON THE BEST WAY TO KEEPTHEM TO PRESERVE THEIR QUALITY?

Making large quantities of eclairs for storage before finishing has to be

undertaken with care as the characteristics of the product do not lend them-

selves to storage for long periods, except under carefully controlled condi-

tions. There are two potential quality losses during storage; they are the loss

or gain of moisture. Both can adversely affect the eating character of the

final product.

Eclair cases are expected to be dry and crisp eating but not hard. Initially

after baking, the cases should be quite firm. The moisture content at the cen-

tre of the case may often be higher than that at the surface. It is therefore

important to minimise further moisture losses from the product surface dur-

ing cooling; otherwise, the moisture gradient from the inside to outside of

the case would be increased and may cause the case to crack and in extreme

cases, fall apart. If baking is extended too long, then the cases may become

too hard eating.

The cases should be allowed to cool thoroughly before being stored in a

closed container or room. Condensation should be avoided as this will cause

softening of the products. As they have a low moisture content, eclair cases

are prone to absorbing moisture from the atmosphere and so should be stored

at a low relative humidity or in airtight containers.


8.7 WE STAND OUR FINISHED CHOUX BUNS ON U-SHAPEDCARDBOARD ANDWRAP THEM IN A CELLULOSE-BASED FILM.RECENTLY, WE HAVE OBSERVED THE GROWTH OF MOULDCOLONIES ON THE PRODUCTS. WHY IS THIS?

In general choux products with fillings are susceptible to mould growth,

and if the products are wrapped, the danger of mould is increased because

of the greater degree of moisture which is maintained around the choux

buns by the cellulose wrapper. The cardboard on which you hold the pro-

ducts will absorb water from the product because of moisture migration

and the influence of gravity on some of the moisture. It is important that

good hygiene practices are observed not only in the production process but

also in the storage of both the U-shaped cardboard and the cellulose wrap-

ping film. Both cardboard and wrapping film should be stored covered in a

clean dry place.

From the hygiene point of view, the surface of the choux products

should be cool and dry before filling and coating. They should be kept

covered whilst cooling and drying-off to prevent mould spores settling

on them. If the goods are cut to insert the filling, keep the cutting knife

free from mould spores by regularly wiping with either a 12% acetic acid

solution diluted in water (for stainless steel knives only) or industrial

(not household) methylated spirits diluted in an equal quantity of water

or hydrogen peroxide. Care should be taken when handling acetic acid or

hydrogen peroxide. Where products are filled by injection through a noz-

zle, then the nozzle should be cleaned at regular intervals with solutions

similar to those mentioned above. The products should be handled as lit-

tle as possible to minimise contamination. Clean and wash benches and

trays that are to be used.

Use of a semi-moisture-proof cellulose film will allow more moisture to

‘escape’ from the atmosphere surrounding the product and keep the humidity

within the packing material at a lower level. Waxed or coated card will pre-

vent moisture from being absorbed into the cardboard and supplying a source

of water for mould growth.


8.8 OUR SCONES ARE MADE FROM FROZEN DOUGH BUTFREQUENTLY LACK VOLUME. WE ALSO FIND THAT THECRUMB COLOUR IS RATHER BROWN. CAN YOU OFFERSUGGESTIONS TO IMPROVE OUR PRODUCT QUALITY?

Scones depend on chemical raising agents for their volume. Once the raising

agents come into contact with water, the chemical reaction to produce carbon

dioxide begins. In the production of a frozen scone dough, some of this aera-

tion capacity will be lost as the reactions start, and this will lead to a loss of

volume in the baked product. To overcome this loss of aeration, a change to

a slower acting acid will help, e.g., sodium acid pyrophosphate or sodium

acid aluminium phosphate. The level of baking powder should be about 5%

on flour weight.

Alternatively, you could try using an encapsulated form of sodium bicar-

bonate or the baking acid. The encapsulation is usually with fat which delays

the production of most of the carbon dioxide gas until the product enters the

oven and the fat melts.

Baking powder may deteriorate under storage. It should always be stored

under dry conditions. If this is not feasible, then the acid and the bicarbonate

should be stored separately.

To overcome the rather brown crumb colour, we suggest you replace any

invert sugar with sucrose. The Maillard reaction is less in sucrose than with

invert sugar and so the crumb colour should improve.

In terms of quality improvements, increasing the fat level in the recipe to

20% on flour weight will produce a richer product. The use of butter instead

of shortening will improve the flavour but you will need to compensate for

the water in the butter.


8.9 SOME OF OUR SCONES HAVE A COARSE BREAK ATTHE SIDE AND AN OPEN CRUMB CELL STRUCTURE BUT THERESULTS ARE NOT CONSISTENT. CAN YOU PLEASE SUGGESTSTEPS WE MIGHT TAKE TO OBTAIN A BETTER AND MORECONSISTENT PRODUCT QUALITY?

A coarse break at the side of the scone indicates that more gluten formation

was achieved during mixing than is normally required for scones. The scone

dough should be cleared, i.e., all the ingredients should be thoroughly

blended, but you must be careful not to over-mix.

The level of baking powder should be sufficient to achieve aeration dur-

ing baking. Using cold water during mixing will minimise the baking powder

reaction before baking and also help restrict gluten formation.

It is possible that the problem could be associated with variations in

recovery times and baking conditions. A recovery period of 15�20 min after

pinning and cutting and before baking is helpful as it allows the dough to

relax and aerate slightly (early release of carbon dioxide from the baking

powder reaction) before baking. However, to minimise skin formation, the

dough pieces should be placed in a relatively cool (less than 20�C), moist

area (or covered) during the recovery period.

Small individual scones should be baked in a fairly hot oven, 240�C, andwe suggest that you check that your oven temperature controls are perform-

ing satisfactorily.


8.10 WE WISH TO EXTEND THE SHELF-LIFE OF OURSCONES. HOW CAN WE DO THIS?

The staling of scones can be reduced in any of the following ways:

� Wrapping scones in a moisture proof film will reduce moisture loss and

give a softer eat but will not prevent inherent staling.

� Scones can be frozen, but there is usually a loss in quality associated

with this process; in particular, the products may become crumbly on

defrosting.

� If freezing is not an option, then including a suitable emulsifier (e.g., a

high monoglyceride type of glycerol monostearate in emulsion or paste

form) will keep the crumb softer. Proprietary ready-to-use products are

available. Replacing the fat present with a high-ratio shortening or

increasing the proportion of fat in the recipe may also be beneficial.� Adding a humectant may help to retain moisture. We suggest replacing

part of the sugar in the recipe with invert sugar, though higher levels of

the latter may lead to excessive browning of the crumb. Glycerine may

also be added, but again high levels may lead to darkening of the crumb.


8.11 THE SURFACE OF OUR SCONES IS COVERED WITHSPECKLES OF A YELLOWISH-BROWN COLOUR. WE ARE USINGGDL AS THE ACID COMPONENT IN THE BAKING POWDER.CAN YOU SUGGEST WHY WE HAVE THIS PROBLEM?

The discolouration is probably due to unreacted bicarbonate in the scone mix-

ture. Often small brown specks in doughs can be attributed to undissolved

particles of sodium bicarbonate. In this case, the problem can be solved by

using a finer particle size (sieve of aperture size 0.06 mm). Alternatively, rest-

ing the dough for at least 40 minutes allows the bicarbonate to dissolve and

ensures that the speckles do not occur. If glucona-delta-lactone is the neutra-

lising acid, it requires time to hydrolyse to gluconic acid. Giving a longer

resting time before the scones are baked may resolve the problem.


8.12 WHY SHOULD PARTICULAR CARE BE TAKEN WHENWASHING SCONES WITH EGG WASH TO ENSURE THATNONE RUNS DOWN THE SIDES OF THE PIECES OF DOUGH?

After rolling and cutting out scone dough into round or finger shapes, the

surface of the scone is commonly washed with egg to obtain a glossy, rich

brown skin on baking which makes them so attractive. If the egg wash is

allowed to run or dribble down the sides of dough pieces, their baked appear-

ance is spoiled.

When the scones are baked, the egg on the side walls will coagulate long

before the baking powder inside the scone has evolved all of its carbon diox-

ide. This coagulated egg will form a more or less un-yielding band uniting

the top skin with the bottom edge of the scone and will prevent that side

from rising to its full height. The gas produced by the reaction of the baking

powder must cause expansion in some direction or other and will take the

line of least resistance. This will often cause the opposite side of the scone

to rise even higher than otherwise would have been the case. The end result

is that the scone rises unevenly and where the egg ran down the sides, it will

be spoiled by a yellow streak running from top to bottom, instead of the

sides presenting an unbroken, smooth, white colour.

The problem is usually avoided by paying attention to detail, for exam-

ple, avoid getting too much wash on the brush, using too large a brush, if

brushes are used. Having too concentrated an egg wash can cause problems

with brushing and spraying.


8.13 WE ARE FREEZING A RANGE OF UNBAKED,CHEMICALLY AERATED PRODUCTS INCLUDING SCONESAND CAKE BATTERS AND NOW WANT TO INCLUDE SOMEVARIATIONS USING FRESH FRUITS. WE HAVE CARRIED OUTA NUMBER OF TRIALS AND HAVE A RANGE OF ISSUESWHICH ARE MOSTLY RELATED TO THE FRAGILITY OF THEFRUIT. CAN YOU PROVIDE SOME ADVICE?

You have clearly recognised the main problem with using fresh fruits in that

the skins of most of them tend to be susceptible to mechanical damage, and

this can lead to the ‘bleeding’ of the contents into the dough or batter. On

defrosting and baking, a commonly observed problem is the presence of disco-

loured streaks in the baked crumb. The colour of these streaks varies according

to the fruit being added and the pH of the dough or batter (see Section 10.1

for an explanation of the pH scale). There are many naturally occurring col-

ours in fruits which can contribute to the colour change and it can occur in

many different situations (for examples, see Sections 5.21 and 5.23).

Some of the problems with the fragility of the skin are manifest at the

dough and batter mixing stage. You should try to delay the addition of

fruits as late as possible in the mixing process and use as low a speed as

is possible to disperse the fruits. It is possible to obtain some fruits

already frozen, and this makes the product more robust (provided you do

not let them defrost). However, you should still try to add these products

as late as possible during mixing and also get them into the freezer as

quickly as possible.

In your case, the problem is exacerbated by the freezing and thawing

process that you are employing. Fresh fruits are high in moisture, often

around 60�70% or higher. As the unbaked products begin to freeze, ice

crystals begin to form within the cells of the fruit matrix. As the tempera-

ture continues to fall, the crystals can grow very large and begin to punc-

ture the fruit skins. In the frozen state, not much change takes place, but

when the products are defrosted, the ice crystals melt and leave holes in

the walls of the fruits and the cell contents begin to leak out. You are not

re-mixing the dough or batter and so you might expect that the problems

would be limited. Indeed, they are but what tends to happen is that the

crumb immediately around the fruits pieces is affected, and you often

get discoloured rings or patches; this can be just as undesirable as disco-

loured streaks.

To reduce the problems, you should look at your freezing operation. In

general, rapid freezing favours the formation of smaller ice crystals, and this

can contribute to a reduction in the damage to the skins of the fruit.

However, you need to remember that it takes some time for the cold front in

a deep freeze to travel to the centre of products, so it is not simply a case of


lowering the temperature of the freezer. You will need to check the time that

it takes for the core of the products to be frozen because the potential for ice

crystal growth is greater in the product core.

It may be that you will need to turn to using a blast freezer rather than a

static one. In the blast freezer, the movement of the air across the product

speeds up the freezing process and will help in the reduction of the ice crys-

tal size in the fruits. However, there are other issues to consider with blast

freezing, and one of these is that the air movement can remove some of the

product moisture (1�2%), so you will need to check that this does not

adversely affect the final product when baked and eaten.

In theory, if you could stop the fruit pieces from freezing, then you would

prevent the formation of ice crystals and in turn, would eliminate damage to

the skins. Such processes are often referred to as ‘cryo-protection’ and are

often based on the infusion of materials like glycerol (glycerine). By way of

an example as to how this might work, to lower the freezing point by about

20�C (e.g., to keep the material un-frozen at 220�C, a typical frozen storage

temperature), you would a need a concentration of about 50% glycerol/50%

water, and this would need to be infused into the fruit. A potential problem

could be the change in product flavour.


8.14 WE HAVE BEEN ASKED TO IMPROVE THE SENSORYQUALITIES OF OUR SCONES AND HAVE BEEN ABLE TO DOTHIS BY A NUMBER OF RECIPE CHANGES. ALTHOUGH THESECHANGES HAVE BEEN LARGELY SATISFACTORY FOR OURPLAIN SCONES THE FRUITED VARIETIES, WE MAKE STIL TENDTO BE TOO DRY EATING. DO YOU HAVE ANY SUGGESTIONSAS TO HOW WE CAN MAKE THEM MORE MOIST EATING?

A common problem with fruited baked products is that the crumb of the

products tends to become dry eating with extended shelf-life (see Section

5.28). This problem is most commonly associated with the migration of

moisture from the crumb to the dried fruit inclusions. Typically, the mois-

ture content of the dried fruits are less than 20% to restrict the potential

for microbial growth during their storage; this is a little lower than the

moisture content of your plain scones, but the sugar content of the dried

fruits is very high, often around 60%. This combination of lower moisture

and higher sugar in the fruit pieces means that the natural movement of

water is from the crumb of the scone to the fruit pieces. Some of this

moisture migration will occur during the baking process, but a significant

proportion will occur during storage. This moisture migration phenomenon

explains why the problem is not readily observed with the fresh scones but

becomes increasingly apparent during their storage. In the case of the

scones that you make with pieces of candied fruits, the problem is even

greater because the fruit pieces have even higher sugar contents.

The most usual way to improve the eating quality of fruited products in these

circumstances is by soaking the fruit pieces for a short period of time to raise

their moisture contents (Cauvain and Young, 2008). When the excess moisture

is drained away, some of the sugar which had been present will be lost, and this

double change will reduce the driving force for moisture migration.

However, raising the moisture content of the dried fruit pieces is not

without its potential problems.

1. The skins of the soaked fruit become more fragile, so there is a tendency

for them to break during mixing leading to dark steaks in the crumb.

2. The overall moisture content of the scone and its equilibrium relative

humidity (ERH) can increase which increases the susceptibility of the

wrapped product to mould growth. You will need to check this carefully.

Reference






8.15 WE MAKE AND BAKE SCONES ON A DAILY BASIS.RECENTLY, WE PLACED THEM UNBAKED IN A REFRIGERATORBUT THE BAKED QUALITY WAS POOR. WE USED A RETARDERINSTEAD BUT WE STILL FIND THAT THE PRODUCTS WERESMALL IN VOLUME. IS IT POSSIBLE TO RETARD UNBAKEDSCONES AND STILL PRODUCE AN ACCEPTABLE PRODUCT?

A retarder is always a better option than a refrigerator for storing unbaked items.

This is because the surface area of the cooling fins in the retarder is much greater

than in a refrigerator which helps maintain a high relative humidity and moisture

in the unbaked product. As a ‘rule of thumb’, you should keep unbaked products

in a retarder at as low a temperature as you can achieve without freezing

the product. In practice temperatures, around 23�C are quite suitable.

However, your problem is to do with the loss of carbon dioxide from the

dough. Even at refrigerated temperatures, there is progressive reaction of

the baking powder components and with virtually no gluten network in scone

dough the carbon dioxide gas generated is free to escape to the atmosphere.

This is why your products are losing volume when you bake them off.

The rate at which the carbon dioxide gas is lost depends on the rate of reac-

tion of the baking powder (see Section 5.37). Even if you are using the slower

acting baking acids, long storage times will allow for significant reaction and

loss of carbon dioxide gas. You may find that by increasing the level of baking

powder you can restore some of the product volume on bake-off, but the higher

levels of residual salts will change the flavour profile of the baked product.

An alternative would be to switch to using a micro-encapsulated baking

acid or sodium bicarbonate. The coating delays the reaction of the baking pow-

der components, so it should help delay much of the gas production until the

bake-off period. An example of such an approach is illustrated in Fig. 8.1; note

you cannot expect to use the encapsulated material for your fresh scone produc-

tion. There are a number of commercially encapsulated products available.

2

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

0 10 20 30 40 50Retarding time (h)

Sp

ecif

ic v

olu

me (

ml/

g)

Standard bicarbonate Encapsulated bicarbonate

FIGURE 8.1 Comparison of carbon dioxide evolution in scones during refrigerated storage.


8.16 I AM HAVING DIFFICULTY WITH ROYAL ICINGWHICH WILL NOT HARDEN ADEQUATELY.CAN YOU ADVISE?

To obtain hard Royal icing, there are several points which you should address.

� The mixing bowl in which the egg whites are beaten should be completely

free from grease. Even small traces of grease will affect the aeration of the

egg albumen. If the icing has not received adequate aeration, it will have

difficulty in setting well. However, it is important to whisk at a slow speed

as faster speeds tend to result in large bubbles in the icing. For the same

reason, it is advisable to mix with the bowl about half full before beating.

When the icing is applied, it should be worked lightly on the surface of the

cake to break down any large bubbles which may still be there.

� Glycerine, which is sometimes added to prevent the icing becoming

‘flinty,’ should be kept to a minimum as an excess will prevent the icing

from setting.

� If making the icing for ‘run out’ work, it should be thinned with egg

white and not water as this too will prevent the icing from setting.

� The cake should be kept in a dry atmosphere to allow the icing to set and

should also be stored in a dry atmosphere; otherwise, the icing will soften

as it absorbs moisture from the atmosphere.

� If the Royal icing is to be applied to a cake covered with almond paste, it

is best to allow a crust to form on the paste overnight in a well-

ventilated, warm, dry area. In such cases, two coats of Royal icing are

normally adequate with the first coat being light and of normal piping

consistency and being allowed to dry overnight. The second coat may be

slightly softer to give a smoother finish. If the paste has a tendency to

oil, or if there is insufficient time to allow two coats to be applied, hot

fondant may be used to seal the surface of the paste.

� For a quick setting icing the moisture content should be low. A low glu-

cose content will avoid the uptake of moisture and a gum or stabilising

material should be included.

Further reading

Bent, A.J., 1997. The Technology of Cakemaking, sixth ed., Blackie Academic & Professional,

London, UK.




8.17 I HAVE HEARD THAT OFF-ODOURS CAN BE CAUSEDBY THE ICING USED FOR CAKE DECORATIONS.IS THIS TRUE?

The icing itself should not cause off-odours. However, the varnish used on

cake decorations can sometimes transfer odours to the icing. A preventative

action would be to ‘air’ the decorations for a period of time before they are

required so that any smell of varnish may disperse.


8.18 AFTER 2 DAYS OUR ROYAL ICING TENDS TO TURNYELLOW. CAN THIS DISCOLOURATION BE PREVENTED?

There are many causes of discolouration in royal icing. Some are listed below:

1. Royal icing made with inferior types of albumen substitutes or weak

albumen solutions will slowly discolour on ageing and become slightly

yellow. Using good quality, ingredients should prevent the problem.

2. The use of poor quality icing sugars produces a poor colour in the icing.

3. If the icing is allowed to stand in a metal mixing bowl for too long or the

palate knife is left in the icing for a long period of time discolouration

will occur, changing the white to a creamy colour. This can be because

of reactions involving iron particles from the equipment.

4. In some cases, ready-prepared marzipans are highly coloured by the man-

ufacturer. This colour can be absorbed by the moisture in the royal icing

causing it to change colour. To avoid this, after coating the cake with

marzipan, brush it over with boiling apricot puree or a thin coating of

fondant which has been heated to a higher temperature than would nor-

mally be used for coating purposes. These coatings act as a seal limiting

colour transfer.

5. If marzipan or almond pastes are worked excessively during their prepa-

ration, they will become oily. This change may also occur if the atmo-

spheric temperature in the work and storage areas are higher than normal.

Ensuring that the work and storage areas are reasonably cool and the

marzipan is not over-worked can prevent oils being released. In addition,

to minimise the transfer of oily stains, the surface of the marzipan could

be coated with a boiled apricot puree.

6. Very slow drying of the royal icing can cause discolouration.

7. Excessive quantities of glycerine can cause a creamy colour to form.


8.19 WE ARE RECEIVING COMPLAINTS OF OPAQUE SPOTSON OUR FUDGE ICING. CAN YOU SUGGEST A REMEDY?

Spots on fudge icing are the result of recrystallisation of the sugar. The sugar

graining is caused by insufficient mixing or by over-heating or by loss of

moisture from the icing to the cake or atmosphere.

To avoid moisture transfer, the cake should be brushed over with the

boiling puree before icing. Adding glycerine to the icing at a rate of 0.5%

will help keep the fudge icing soft and lowers the ERH of the icing bring-

ing it nearer to the ERH of the cake which will also help reduce moisture

migration.


8.20 AFTER STORING OUR COATED PRODUCTSOVERNIGHT, WE FIND THAT CRACKS FORM IN FONDANTCOATING. CAN YOU SUGGEST WAYS TO OVERCOMETHIS PROBLEM?

Many faults encountered with fondant are associated with one or more of the

following:

� The ERH of the components of the product.

� The degree of moisture permeability of any wrapping material.

� The glucose content of the fondant.

Fondants can remain soft or become hard depending on the formulation

and process used for their manufacture. Surface problems with fondant such

as white spots, streaks or stickiness also have some of their roots in the for-

mulation and processing, and others in the storage conditions and compo-

nents on which they sit.

Cracks that appear on the surface of fondant are a result of the fondant

drying out and hardening. A glucose syrup level below 12% total weight

leads to very rapid hardening and so a level between 12 and 14% is

recommended. Inclusion of 5 to 10% hard fat such as hardened palm ker-

nel oil or a high-ratio fat containing an emulsifier can be used to prevent

hardening.

The reverse of the problem with hardening is that of the fondant becom-

ing sticky. The cause of this is the hygroscopic nature of the fondant. When

stored in a humid atmosphere or surrounded with packaging film of low per-

meability or moisture vapour transpiration rate (see Section 11.7), the ERH

of the fondant, being very much lower than its surrounding atmosphere and

the presence of undissolved sugar crystals, causes uptake of moisture. This

results in the fondant becoming sticky. Storage of fondant products in a

refrigerated cabinet, which may have a relatively high humidity when filled

with other goods could accentuate the problem. Thawing of frozen products

in high humidity conditions can also cause the problem.

In products where the fondant topping sits on a pastry product which is

cream filled (e.g., chocolate eclair), moisture moves from the cream (with

high ERH), through the pastry casing to the fondant topping (low ERH) and

forms a thin film of water between the topping and the pastry case. Any jolt

during transportation of the product can cause the fondant to slip off the

product (the thin film of water acts like a lubricant). In this case, the problem

is alleviated if the ERHs within the components are brought closer together.

Further reading






8.21 WE MAKE SUGAR PASTE SHAPES AND STORE THEMIN PLASTIC CONTAINERS FOR LATER USE. IN A FEW DAYS,THE SHAPES SOFTEN AND ARE INCLINED TO DROOP.CAN YOU SUGGEST HOW WE MIGHT OVERCOMETHIS PROBLEM?

If your containers are not sealed, then the sugar shapes can take up moisture

from the atmosphere. Generally, the relative humidity of the atmosphere

indoors is in the range 40�70%, so sugar paste shapes with a low ERH will

absorb atmospheric moisture. You should try to minimise the headspace in

the container used to store the shapes which will limit the mass of water

available for absorption by the paste.

It is possible that the formulation of the sugar paste contains too much

humectant for your requirements, and we suggest that you reduce the propor-

tion until the ERH is in the range 75�78%.


8.22 WE WOULD LIKE TO STORE OUR HEAVILY FRUITEDWEDDING CAKES AFTER COATING WITH MARZIPANFOR SOME TIME BEFORE WE ICE THEM BUT FIND THATTHE MARZIPAN HARDENS. WHY IS THIS AND HOW CANWE ACHIEVE OUR AIMS?

Heavily fruited wedding cakes contain many ingredients which are good at

holding onto the moisture and collectively cause the cake to have a low

water activity value. Marzipan has a higher moisture content, and its ingredi-

ents are not so powerful at holding onto the moisture and so has a higher

ERH. Consequently, moisture will move from the marzipan into the cake

thus causing the marzipan to dry and harden.

The addition of some glucose, which as well as helping to reduce sugar

(sucrose) crystal size, acts as a humectant and thus helps to prevent moisture

loss should overcome the problem. We would suggest that you use either

stock syrup (boil 1kg sugar, 1L water, 250g glucose, allowing it to cool

before use), or a mixture of 50% glucose, 50% water, rather than water

alone, for softening purposes.


8.23 WE ARE NOT GETTING THE QUALITY OF FINISHTHAT WE WOULD LIKE FROM THE FONDANT WE AREUSING, OFTEN THE FINISHED PRODUCTS LACK GLOSS.CAN YOU GIVE US SOME TIPS ON HOW TO IMPROVEOUR USE OF THE FONDANT?

The lack of a gloss finish with your fondant suggests that you are over-

heating it when preparing it for use. The temperature to which fondant is

heated before use is very important; to get a gloss, you should only heat the

fondant to about 38�C. Over-heating the fondant results in the formation of

larger crystals when it cools, and these do not reflect the light so well �hence the product looks dull. To get the best results, you should heat the

product carefully to the required temperature with continuous stirring.

If the product is too thick to work with, then you should adjust the con-

sistency with a stock or ‘simple’ syrup (see below for the formulation). Once

the fondant has reached the required temperature, hold it at that temperature

using a water bath and avoid fluctuations in temperature as much as possible.

Keep the fondant pot covered when not in use and scrape down any crystals

which may form above the fondant bulk. Avoid letting a skin form on the

top of the fondant bulk.

Try to heat only sufficient fondant for your particular needs in a day

and avoid having large quantities of fondant scraps. Although it is perfectly

possible to re-use these, they do contribute to the dullness of the finish. If

you do have a large quantity of scraps, try to find an alternative use for

them, such as incorporation into fillings and creams where the appearance

of the finish is less critical.

Always use a stock syrup to adjust the consistency of the fondant, never

use water alone. The syrup should be added a little at a time with stirring to

ensure full dispersion. Try to avoid making the syrup too runny and having

to add fresh fondant stocks.

The formulation for typical stock syrup is as follows:

Parts

Sugar 100

Water 83

Glucose 17

Cream of tartar 0.15 (optional)

The glucose is used to limit the recrystallisation in the syrup. Bring the mix-

ture to the boil and remove any scum which forms as this will contain impurities

which may encourage recrystallisation. Cool the syrup, strain to remove any

sugar crystals which may form and store in covered containers ready for use.


8.24 WE BAKE OUR MERINGUES ON ALUMINIUM SHEETSAND ARE HAVING PROBLEMS WITH THE MERINGUESBECOMING DISCOLOURED. CAN YOU OFFER ANYADVICE ON HOW TO ELIMINATE THIS PROBLEM?

Aluminium baking sheets would not be expected to cause meringues to

become discoloured unless the sheets were particularly dirty and the disco-

louration was on the surface.

If the discolouration is internal, then the cause could be because of

baking the meringue at too high a temperature or for too long. If the brown

discolouration is overall, this could be because of using fresh or frozen

albumen. Reconstituted dried albumen is less likely to cause this problem as

any reducing sugar present is removed before drying.


8.25 WHEN MAKING ITALIAN MERINGUESWHY IS THE BOILING SUGAR WATER ADDED SLOWLY?

One of the effects of adding boiling sugar water to the beaten egg whites is

that the air which has been trapped by the albumen is heated and expands, so

that the volume of the meringue foam increases considerably. If the sugar is

added very quickly, the albumen would almost immediately coagulate. In

this condition, it is much less elastic and any expansion causes the air cell

walls to break and release their contents. Thus, the meringue would become

heavier rather than lighter.

Adding the sugar solution as a gradual stream whilst still whipping, the

temperature of the mixture is slowly increased. Expansion takes place and

the meringue becomes lighter. Further when hot sugar solution is added, the

temperature increases, and by the time all the sugar is added, it will become

sufficiently high to coagulate the thin films of expanded albumen. Each cell

will be filled to capacity with expanded air.

The meringue should stand well without loss of aeration for prolonged peri-

ods. This explains why Italian meringue may be used for making buttercreams.

After mixing the meringue and the butter, there should be little breakdown of

the air cells as each is coated with a delicate skin of coagulated albumen.

Cold meringue, on the other hand, readily breaks down in buttercream

because the un-cooked, and therefore un-coagulated, albumen chains are eas-

ily shortened by contact with the butterfat. The cells break open, release their

trapped air, and the buttercream loses its lightness and bulk. Marshmallow, a

gelatinous form of Italian meringue, is often blended with buttercream. Due

to the structure of the marshmallow, the volume is retained when added to

the buttercream, just as is the case with Italian meringue.


8.26 WE ARE EXPERIENCING CRACKING OF OURMERINGUE SHELLS DURING BAKING. WHY IS THIS?

When the sugar concentration in the albumen mix increases from 2:1 to 3:1,

there is an increased tendency for meringue shells to crack during baking. If

baking is carried out for short periods of time at high temperatures, the prob-

lem is accentuated because the albumen on the surface coagulates earlier

than in the centre. Being hard and inflexible, it cannot move with the pres-

sure created by the still expanding centre and so the surface cracks.

The vapour pressure of the sugar solution decreases as the strength of the

solution increases. This means that as the sugar concentration increases,

moisture will evaporate more slowly during drying or baking and will con-

tribute to the problem.

Reducing the sugar concentration to 1 kg to 400 mL albumen should

help. Reducing the baking temperature will also have a beneficial effect.


8.27 WE ARE HAVING PROBLEMS WITH SOFTENING OFCOFFEE MERINGUES IN WHICH WE USE COFFEE POWDERAS THE FLAVOURING. IS THIS THE CAUSE OF THE PROBLEM?

Adding coffee powder or coffee essence to the recipe does not usually cause

meringues to soften provided they are baked thoroughly. Meringues are nor-

mally baked at about 116�C (240�F) for 3 hours to ensure that they are

completely dried out. To ensure that the meringues are completely dried out

during baking, it is advisable to bake the meringues in a dry atmosphere

with the oven dampers left open.

The meringues should be cooled completely before packaging and stored

in a warm dry atmosphere. If you do not have such storage conditions avail-

able, they should be packed in either moisture impermeable bags or sealed

containers. Meringues are very high in sugar and consequently are hygro-

scopic (i.e., they easily absorb moisture from the surrounding atmosphere). If

left in a humid atmosphere, they will soon become sticky to touch and even-

tually will become soft. In wet weather where the atmosphere is more moist

than usual, the meringues should not be left exposed.


8.28 ON SOME OCCASIONS, OUR ALMONDMACAROONSEXHIBIT VERY COARSE CRACKS ON THE SURFACE INSTEADOFTHE FINE CRACKSWE ARE SEEKING. WE HAVE NOT BEEN ABLETO TRACE THE CAUSE, CAN YOUHELP?

Coarse cracks can be caused either by the deposited macaroons forming a

skin before baking or by insufficient humidity during the initial stages of

baking. If a skin has formed, then the surface is no longer porous enough to

allow the ready escape of moisture vapour during baking. Instead pressure

builds up inside the macaroon causing the skin to eventually form a coarse

crack. To avoid this problem, do not leave the product standing in a warm,

dry atmosphere and bake them off as soon as possible after depositing.

Most products containing high percentages of sugar should be baked in a

cooler oven or they burn rapidly. Sugar caramelises at high temperatures and

becomes hard. In the case of macaroons, the oven should be cool enough to

allow the product to ‘grow’ by the expansion of the air cells beaten into the paste

and to flow out to the correct size before the albumen of the egg whites is coagu-

lated or set. It is also important that the product should not become too darkly

coloured. A hot oven would not only burn the products but causes rapid coagula-

tion of the albumen and prevents full growth taking place so that the final pro-

ducts would be of small in volume and have a poor shape with coarse cracks.


8.29 WHAT ARE STOTTY CAKES AND HOW ARETHEY PRODUCED?

Stotty cakes (stotties) are a traditional Tyneside (north-east region of

England) delicacy prepared from a bread-like dough enriched with fat and

sugar. A close relation is the bread cake which is found in Yorkshire. Both

products are strictly not cakes in that they are not prepared from a dough.

A typical recipe is as follows:

% Flour weight

Flour 100

Salt 2

Lard 5

Sugar 1

Yeast 5

Milk powder 2

Water, approx. 57

The dough is scaled at about 340 g (12 oz) then rounded and flattened to

a disc. The dough pieces are baked either between two metal sheets or baked

on the oven sole and turned halfway through baking. Very occasionally,

Stotty cakes may contain fruit.


8.30 WHY DOES OUR WHIPPED CREAM COLLAPSEON STANDING?

During the whipping of cream, the movement of the wires of the whisk

through the fluid draw in small bubbles of air. Fat chains in the cream form

at the interface of the air bubble and the aqueous phase where they stabilise

the bubbles and prevent them from rising and escaping from the cream after

mixing. In the stable foam which is formed, the liquid of the aqueous phase

is effectively trapped in the spaces between the stabilised air bubbles. On

standing, the bubbles in the cream become unstable and they collapse. In

doing so, the liquid previously held in the spaces between the bubbles now

escapes and usually drains under the influence of gravity. The rate at which

the cream will collapse depends on the many factors which affect the stabil-

ity of the foam. As the main stabilising agent is the fat present, there needs

to be a minimum of 40% butterfat to produce a stable foam structure.

The amount of stabilising material present limits the maximum amount

of air that can be beaten into the cream. This is because the stabiliser must

be located at the bubble surface. The greater the quantity of air incorporated

into the batter the larger the surface area that needs to be stabilised. With

ever increasing quantities of air being incorporated, a point is reached when

the stabiliser cannot stretch any further and the cream density stops falling.

Too much air in the cream will make it unstable and more likely to col-

lapse with small changes in storage conditions, e.g., a small increase in tem-

perature can cause the air to expand and increase the surface area that must

be covered by the stabiliser. The aeration of cream may be expressed as rela-

tive density or specific gravity (see Section 10.2). It is also common to see

cream aeration expressed as ‘over-run.’ This is the reciprocal of density

expressed as a percentage (thus a relative density of 0.77 5 130% over-

run).

Careful control of cream temperature before during and after whipping

needs to be taken. Before whipping, ensure that the cream temperature is

3�5�C (38�40�F). If, for any reason the cream temperature is above this,

then chill it in a refrigerator until its temperature has fallen to this level to

increase the proportion of solid fat. During warm weather in particular, rinse

out the bowl and beater with cold or chilled water, or preferably place in a

refrigerator for some time before use.

Whisk the cream on a medium speed until it starts to thicken, then finish

whisking on high speed. During warm weather, the cream should be whisked

in as short a period as possible to minimise the time it is exposed to the high

atmospheric temperature. Aim to have the whisked cream at a maximum

temperature of 10�C (50�F) at the end of whisking. After whipping, the bulk

of the cream should be stored in a refrigerator at 3�5�C (38�40�F), andafter depositing, the cream temperature should not be allowed to exceed

10�C (50�F). Above this temperature, the cream will start to collapse.


If attention to the cream temperature control is not enough to overcome

the problem, then we suggest increasing the butterfat content to about 42%.

If your supplier is unable to provide this, you could blend six parts by weight

of whipping cream containing 40% butterfat with two parts by weight of

double cream containing 48% butterfat. It is not uncommon to experience

whipping problems with fresh cream arising from changes in the diet of the

cows. In the United Kingdom, the so-called ‘spring flush’ problem with diary

cream arises when the cows move from winter feed to spring grass and the

composition of the fats in the cream may change.

If you continue to have problems, then you may consider the addition of

a suitable cream stabilisers such as:

� Sodium alginate

� Sodium carboxymethyl cellulose

� Methyl ethyl cellulose

� Guar gum

� Locust bean gum

� Xanthan gum

� Carrageenan

� Gelatine


8.31 RECENTLY, WE EXPERIENCED A PROBLEM WITH AFISHY TAINT IN A BATCH OF BUTTERCREAM. CAN YOUSUGGEST WHY?

Detection of taints varies from consumer to consumer and may be present in

all or only part of the buttercream. Such off-flavours are not usually caused

by microbial spoilage but rather by a chemical reaction. Due to its high fat

content, buttercream is often susceptible to such problems.

A fishy taint in butter is probably because of the action of peroxides on

the choline derived from the lecithin present in the butter. Both copper and

iron can catalyse the development of this taint by accelerating peroxide for-

mation and promoting the reaction of peroxides with the lecithin. The pres-

ence of as little as 1 ppm of copper can produce a fishy flavour in butter

within 3 days. However, the off-flavour caused by the iron is not ‘fishy.’

As only traces of copper are needed to accelerate a taint in buttercream,

care should be taken that products containing butter or other fats do not

come into contact with copper or copper-containing materials such as brass

fittings, phosphor-bronze bearings or copper utensils.


8.32 WE ARE EXPERIENCING SEEPAGE OF OUR JAM IN OURFROZEN FRESH CREAM GATEAU WHEN THEY ARE THAWED;CAN WE AVOID THIS?

Seepage of this nature is caused by the formation of surface water through

syneresis (see Section 11.1) within the cream and jam as a result of the crys-

tallisation or aggregation of polymers. It is commonly found with products

which undergo freezing and then thawing. Surface water forms because of the

breakdown of the cream foam. In the case of jam seepage, the jam is basi-

cally a coloured sugar solution containing fruit and the colour is unlikely to

be held fast. Once a coloured solution has formed, it can diffuse into the

cream.

The problem is sometimes encountered where frozen products are par-

tially thawed and then frozen again as might be experienced with refrigerated

transport. Any temperature cycling impairs cream stability, and as a conse-

quence, the jam spreads out. If the temperature cycling in transport reaches

above 25�C (23�F), then the seepage is more likely to occur. We would not

expect to see such temperature changes in a well-managed and monitored

distribution chain, except for some boxes on the outside of stacks or pallets.

The cardboard sealed box and the air between it and the gateau do present a

reasonable barrier to heat transfer. In addition, a stack of frozen gateau

should behave as a reasonable cold sink.

The solution to the problem is to avoid periods of intermediate defrosting.

Where such periods do occur, the temperature which the gateau reach should

be kept as low as possible.

Further reading

Cauvain, S., Young, L., 2008. Bakery Food Manufacture and Quality: Water Control and Effect,

second ed. Wiley-Blackwell, Oxford, UK.




8.33 WE HAVE RECENTLY BEEN EXPERIENCING ‘WEEPING’FROM OUR NON-DAIRY CREAM FORMULATION.THIS SHOWS ITSELF AS A ‘SOGGY’ LAYER WHERE THE CREAMIS IN CONTACT WITH THE CAKE. CAN YOU PLEASE ADVISEON HOW TO CURE THE PROBLEM?

To solve your particular problem, we first have to decide its origins. There

are three possibilities; fat, moisture migration or both.

Fat migration can occur when the oil fraction of the cream filling is too

large because it does not remain trapped within the cream structure and sinks

into the cake layer below under the influence of gravity. To decide the oil to

solid fat ratio, you will have to consider a number of factors including:

� The product storage temperature, the higher the storage temperature the

higher the solid fat index needs to be.

� The eating qualities of the cream, the softer the eating character the

greater the liquid oil fraction will have to be.

Fat migration is not particularly influenced by storage humidity but is

affected by storage temperature (see Fig. 8.2); the higher the storage temper-

ature, the greater the proportion of a given fat that is liquid and so the greater

the risk of seepage. Fat seepage is also affected by the degree to which the

cream has been aerated with seepage being greater as the cream specific vol-

ume increase. You may wish to limit your cream specific volume or reduce

your overall fat content. To reduce fat separation, you may find some advan-

tage in adding a suitable emulsifier to the cream formulation, e.g., lecithin or

glycerol monostearate, or a stabiliser like gelatine.

FIGURE 8.2 Fat and moisture seepage in nondairy cream cakes.


Moisture migration occurs when the water activity of the cream is not in

equilibrium with that of the cake. The causes and cures for moisture migration

have been reviewed by Cauvain and Young (2008). Your problem is associ-

ated with moisture migration by diffusion, that is, where two materials are in

direct contact with unequal water activities the moisture moves from the wet-

ter to the drier component. The main solution to the problem of moisture

migration is to balance the component water activities and reduce the driving

force for change. This will require a reformulation of cream, cake or both.

You should have the component water activities measured and reformulate to

reduce any differential. Adjusting salt or sugar levels can be advantageous, or

additions of glycerol may be used. Placing a moisture-proof barrier between

the two components is possible but difficult given the porous nature of cakes.

Moisture migration is also strongly influenced by the storage temperature,

with migration being reduced as the storage is lowered. Unlike fat migration,

moisture migration is affected by storage humidity with migration moving at

a faster rate when there is a greater difference between the component and

storage humidities.

Reference






8.34 HOW CAN WE PREVENT OUR APPLE PIE FILLINGGOING MOULDY WITHIN A FEW DAYS WITHOUTCHANGING THE FILLING RECIPE?

If you do not want to alter the eating quality of the apple pie filling the easi-

est course of action is to add a preservative. For example, adding 150ppm

potassium sorbate (on a weight basis) to the filling should extend its mould-

free shelf-life to 7 or 8 days. However, for small batches of about 3.5 kg, the

quantity of sorbate involved is only about 0.53 g. The easiest way of adding

such a small quantity of preservative would be for you to make up a bulk

mix of sugar and potassium sorbate. For a recipe with 0.5kg sugar per 3.5 kg

batch of filling, each 0.5 kg of sugar in the bulk mix should contain 0.53g

sorbate. Thus, if you make up 12.5 kg (28 lb) of bulk mix, it should contain

13 g (0.5 oz) of potassium sorbate. It is essential that you mix the sugar and

the sorbate very thoroughly, for example by mixing at low speed for at least

0.5 hour. You could then weigh off appropriate portions of the mix for each

fresh batch of filling.


8.35 IN SOME OF OUR APPLE PIES, WE FIND THAT THEFILLING HAS TURNED BLUE. WHY SHOULD THIS HAPPEN?

The blue discolouration in your apple pie filling is probably caused by a nat-

ural pigment. Natural pigments from blackcurrants, black grape skins and

some flowers such as dahlias, lobelias and Michaelmas daisies contain antho-

cyanins. The most probable explanation of the coloration on your apple pie

filling is that it has come from utensils or machinery that had previously

been used for blackcurrant filling. If the same utensils are being employed

for both types of filling, we suggest that you ensure complete removal of

any traces of blackcurrant before the apple is applied.

Apples can turn pink if too high a temperature is used during baking. The

pink discolouration is because of the hydrolysis of leucoanthocyanins present in

the cell tissue of the apple. These normally colourless substances are closely

related to the natural red or purple colours (anthocyanins) of fruits. The changes

in the leucoanthocyanins to the coloured forms are accelerated by acidity, and

more acid apple varieties appear to discolour more readily on heating.

To avoid discolouration in this case, prepare a sugar/water/starch gel and

allow it to cool before blending in the solid pack apples. It is inadvisable to

add any extra acid to the filling. Sometimes, the addition of ascorbic acid to

the apple pieces can limit this problem, not because it changes the pH but

because it acts as an anti-oxidant.


8.36 CAN YOU SUGGEST A SOLUTION TO THE PROBLEMOF SHRINKAGE IN OUR APPLE PIE FILLING?

The main problem with shrinkage of apple pie fillings arises through the

loss of water, either during baking or subsequent storage. In some cases,

this will be because the ERH of the filling is too high and you may need

to lower it by adding some more sugar, or other suitable soluble material,

e.g., dextrose.

The other possible reason for the problem arises from the physical

breakdown of the fruit, ‘pulping,’ which results in loss of filling volume.

Bramley apples are generally considered to be the most satisfactory type

of apple for baking purposes. It is possible, however, that well-matured

fruit which has undergone canning may not be able to withstand baking

as well as less mature fruit would in a relatively ‘fresh’ condition. You

may wish to try using fresh apple which has been preserved in ascorbic

acid or brine.

Alternatively, it has been reported that apples retain their shape better if

they are soaked for half an hour in a solution of calcium lactate prior to bak-

ing. A solution made from 50g (2 oz) calcium lactate in 2 L (4 pt) of water

should be sufficient to treat 9kg (20 lb) apples. You may find it worthwhile

to carry out a trial using canned apples.


8.37 WHY HAVE OUR CRUMPETS LOST THEIRCHARACTERISTIC SURFACE HOLES?

The characteristic appearance of crumpets is that the upper surface is cov-

ered with many small holes. These holes are formed when the crumpet batter

is deposited onto the hot plate and carbon dioxide which is dissolved in the

batter is quickly driven out of solution. The evolution of the carbon dioxide

leaves behind vertical holes (tunnel-like) as the gas pushes though the setting

batter. Crumpets which lack the characteristic holes on the top surface are

commonly described as being ‘blind.’

The phenomenon is most commonly caused by draughts blowing

across the hot plate and cooling the surface of the crumpets as they are

baking. The problem may also be caused by excess grease on the inside

of the rings into which the individual portions of batter are deposited or

on the hot-plate itself. Blind crumpets are also associated with too heavy

a deposit weight.

If you take steps to reduce draughts and control greasing and still have

the problem then you may find it helpful to have a minimum fermentation

time of 1 h before depositing the batter to make sure that the batter is well

aerated. During depositing, you need to avoid degassing of the batter as

much as possible.

Sometimes, moving to a weaker flour, about 10.5% protein, can be useful

in allowing will allowing more of the carbon dioxide gas to escape during

baking on the hot plate. It is helpful to limit gluten formation in the batter

and so mixing should be as short as possible. Recirculation of crumpet bat-

ters can contribute to the formation of gluten as the batter is subjected to

shear in the pipework. It is important to maintain viscosity of the batter as

this helps the formation of the holes on the hot plate.

This may be difficult with lower protein flours but the replacement of

part of the flour with a chlorinated (see Section 2.2.18) or heat-treated flour

(see Section 2.2.17) may be helpful. Both the chlorinated and heat-treated

flours will absorb more water than a non-treated flour and so raise batter vis-

cosity. The aim would be to slow down the vertical movement of the carbon

dioxide gas as it is driven out of solution on the hot plate.


8.38 WHY IS A SMALL AMOUNT OF BICARBONATE OFSODA ADDED TO PIKELET BATTERS JUST BEFORE BAKING?

The pikelet batter is similar in formulation to that of crumpets and their pro-

duction is based on the mix which is fermented by yeast and has typically

remained for an hour and a half to 2 hours before it is ready to be baked on

the hot plate. Before baking begins, a little bicarbonate of soda is moistened

in a drop of water and stirred into the batter. If the whole batch of pikelet

batter could be baked at once, there would be no need to add the bicarbonate

of soda, but often we need to bake the batter in a number of smaller batches

which extends the time for which the batter must remain aerated.

While standing, the batter continues to ferment and progresses towards

sourness with increasing acidity being developed. Eventually, the batter would

be unusable. The bicarbonate of soda prevents this acidity by reacting with the

acids formed during fermentation and helps the batter remain neutral.

Only a very small quantity of bicarbonate of soda is needed. If used at

too high a level, you may get an excessively yellow the colour in the baked

pikelets.


8.39 THE CHOCOLATE COATING ON OUR MARSHMALLOWTEACAKES CRACKS DURING STORAGE. CAN YOU OFFERAN EXPLANATION AND SOLUTION TO THE PROBLEM?

The cause of this problem is easy to explain but rather more difficult to

eradicate. A marshmallow teacake is a composite product made up of a

biscuit base, marshmallow topping and chocolate coating. Each of these

components has a different ERH. Moisture will move from one compo-

nent to another driven mainly by the relative differences in water activity

between components.

Biscuits have a low ERH and will readily absorb moisture from the

atmosphere and become soft. When marshmallow is deposited onto the bis-

cuit moisture from the, higher ERH mallow will move to the biscuit and as

a result the biscuit expands or swells (Cauvain and Young, 2008). This nor-

mally occurs after the chocolate coating has dried, and the overall effect is

to crack the chocolate coating which is not extensible enough to take up the

increase in size.

To overcome this cracking:

� The biscuit must not be allowed to absorb moisture from the mallow.

You could try spraying the surface of the biscuit when cool with melted

fat which places a moisture barrier between the biscuit and the mallow.

� Ideally, the biscuit should have an ERH similar to that of the mallow.

This can be achieved increasing the ERH of the biscuit or by decreasing

the ERH of the mallow by modifications to the formulations. Spraying

the biscuit shortly after baking with water, using a fine nozzle, or storage

in a moist atmosphere for about 12 hours before depositing and enrobing

should increase the ERH of the biscuit. For the marshmallow, replacing

some of the sugar by glucose will decrease its ERH and enable it to hold

onto its moisture. Using one of these remedies or a combination the

moisture migration from mallow to biscuit should be reduced.

Reference






8.40 WHAT CAUSES THE WHITE BLOOM WHICHSOMETIMES OCCURS ON CHOCOLATE COATINGS?

White bloom on chocolate coatings is the result of temperature cycling in

preparation (the tempering � the heating and cooling regime used to stabilise

cocoa butterfat crystals of the chocolate before coating) and storage which

causes deposits of small fat crystals on the surface of the coating.

The types of chocolate used in a coating have a bearing on the coating’s

susceptibility to bloom. For example:

� Bakers’ chocolate is very stable to fat bloom under storage conditions

varying from 13 to 27�C (55�F to 80�F).� Couverture needs tempering and care should be taken to minimise inclu-

sion of air during stirring as this can produce small bubbles which con-

tribute to fat bloom formation.� Fat bloom occurs more quickly on plain than on milk couverture, particu-

larly at high storage temperatures and also when alternating between high

and low storage temperatures. Cooling couverture rapidly to temperatures

lower than 13�18�C (55�F to 65�F) makes it less susceptible to bloom

on subsequent storage than cooling slowly to 21�C (70�F) (especially if

the storage temperature is relatively high).

Surplus chocolate that has bloomed can be re-tempered to produce satis-

factory results.


8.41 THE BAKERS’ CHOCOLATE COATING WE USE HASRECENTLY TENDED TO FLAKE OFF OUR ECLAIRS.CAN YOU IDENTIFY A LIKELY CAUSE OF THE PROBLEM?

All chocolate coatings should be correctly tempered to avoid problems.

Generally, bakers’ compound chocolate should first be heated to 54�C(130�F) for plain or 52�C (125�F) for milk and then allowed to cool to

coating consistency. The necessary temperatures are about 41�43�C(105�110�F) for plain and 38�41�C (100�105�F) for milk.

If the chocolate is not maintained at a constant temperature, there may be

variations in the speed of setting. Very rapid setting, perhaps because cooling

has occurred in a low temperature environment (e.g., draughts), may cause

shrinkage and subsequent flaking after coating.

If the shells are coated on the base, rather than the top, excessive grease

on the baking sheet which makes the eclair base oily may be contributing to

the fault. The presence of moisture on the surface of the shell before coating

could also cause lack of adhesion.


8.42 WHAT IS GANACHE?

Ganache is the name given to a blend of chocolate and cream. To prepare it,

1kg grated couverture is placed in a stainless steel bowl. Over this is poured

1 L boiling, fresh cream and the mixture is stirred. The heat of the boiling

cream melts the couverture and the two amalgamate to form a smooth paste.

This should be stirred occasionally until it is cool.

Ganache takes many forms and is used in many ways. As cream is

expensive, various methods of reducing costs can be adopted but in all

cases may reduce the quality of the product. For example, cream can be

replaced by non-dairy cream, by milk or by water containing a little mar-

garine or butter. The couverture may be replaced with cheaper bakery

chocolate.

Milk ganache can be made by using milk chocolate instead of plain cou-

verture and this type of material is excellent when blended with an equal

quantity of buttercream flavoured with kirsch, for making fillings for conti-

nental types of gateaux and torte.


8.43 WHAT ARE STAFFORDSHIRE OATCAKES AND HOWARE THEY MADE?

Staffordshire is a region (county) in the midlands of England and the oat-

cake in question is a regional product. The Staffordshire oatcake should

not be confused with the Scottish Oatcake which is a biscuit (cookie).

Both products use oatmeal as one of their essential ingredients, but the

final products are very different. The Staffordshire oatcake appears to

date from the 19th century when they were baked on a hot plate over an

open fire.

There are a number of variations on the recipe but a typical one is as

follows:

Ingredient Parts by weight

Water 100

Strong flour 30

Fine oatmeal 13

Salt 1.0

Skimmed milk powder 1.0

Yeast 0.3

Bicarbonate of soda 0.3

As shown by the recipe above, the oatcakes are made from a very

fluid batter. Blend the dry ingredients, except for the yeast and the bicar-

bonate of soda. Disperse the yeast in about two-thirds of the water mass,

add the mixture to the dry ingredients and mix to a lump-free, smooth

batter (about 5�6 minutes at a medium speed on a planetary-type mixer).

Cover the batter and leave to ferment at about 20�C in a draught-free

area for 1.5 h.At the end of the fermentation period dissolve the bicarbonate of soda in

the remaining water, add to the fermented batter and mix thoroughly.

Deposit 9�10 g of batter per oatcake onto a greased hot plate at about

225�C and bake for about 1.5 minutes on one side, turn the oatcake over and

complete baking with about another 1.5 minutes. The final product should be

covered to keep soft until ready for use.

The final product may be eaten hot or cold. They may have savoury (typ-

ically cheese) or sweet (typically jam) fillings spread on them before being

rolled up like a Swiss roll or folded like a wrap for serving. The products are

best eaten within a short period of time after preparation.

As with all hot-plate goods, Staffordshire oatcakes have a high water

activity and stringent hygiene precautions should be observed in their prepa-

ration, storage and use.


8.44 WHAT ARE FARLS AND HOW ARE THEY MADE?

Farls are a traditional chemically aerated or soda-bread originating from Ireland.

They are made in two main forms; white and wheaten, the latter being based on

a brown flour (a blend of white flour and bran) which was traditionally referred

to as ‘wheatmeal’ to distinguish it from wholemeal (the term wheatmeal is now

largely redundant in the United Kingdom and elsewhere).

Traditional recipes would be as follows:

Wheaten farl (based on 100 parts brown flour)

Brown flour 100.0

Salt 1.7

Malt flour 2.3

Baking powder 6.8

Fat 18.0

Sugar 13.6

Bran 4.5

White flour 36.0

Milk 90.0

Mix to a clear dough. You adjust the milk to give a smooth, easily han-

dled dough. Scale units at 1 kg, mould round, flatten slightly with a rolling

pin and cut into four quarters. Brush the top with water and sprinkle on

some brown flour. Bake at around 230�C for 15 minutes.

White farls (based on 100 parts of white flour)

Flour 100.0

Baking powder 3.1

Salt 1.6

Malt flour 2.0

Fat 4.2

Milk 70.0

Process as for wheaten farls.

Some recipes suggest the addition of a small level of yeast, around four

parts to boost volume. Buttermilk may be used to replace milk if a more dis-

tinctive flavoured product is required.


8.45 THE EDGES OF OUR SODA FARLS BECOME GUMMYA COUPLE OF DAYS AFTER BAKING. WHAT IS THE CAUSEOF THIS QUALITY DEFECT?

A dark gummy seam on the side of farls is generally caused by inadequate

baking. This could be due to:

1. The temperature of the hot plate being a little higher than normal, caus-

ing the farls to be ready for turning sooner than they should be and the

farl being removed from the hot-plate slightly sooner than usual to pre-

vent the surface being scorched. This would mean that the centre is

inadequately baked and tends to collapse during cooling, producing the

dark seams.

2. It is possible that if the centre of the farl never reached a temperature

high enough to inactivate the amylase enzymes in the flour. The latter

may still be active in the baked product though it is unlikely that this is

the cause of the fault unless you have bacterial amylase present. You

should check the Falling Number (see Section 2.2.10) of your flours and

avoid ones with low Falling Numbers (high alpha-amylase).

3. The water absorbing capacity of the flour may have increased, requiring

the inclusion of more water at dough mixing. In this case, the product

may need slightly longer and cooler baking conditions than normal to

drive off the additional water.


8.46 WE WANT TO ADD FRESHLY BAKED DEEP-PANPIZZA TO THE PRODUCT RANGE THAT WE SELL THROUGHOUR BAKERY SHOP. WE DO NOT WANT TO MAKE SMALLQUANTITIES OF DOUGH THROUGHOUT THE DAY FORTHEIR MANUFACTURE, BUT WHEN WE TRY TO WORK WITHA LARGER BULK OF DOUGH, WE FIND THAT THEVARIATION IN QUALITY IS TOO GREAT, EVEN WHEN WEREFRIGERATE THE DOUGH IN OUR RETARDER. WHATWOULD BE A SUITABLE WAY FOR US TO MAKE THE BASES?

One way of spreading your pizza production throughout the day is to make a

larger dough which you split up after mixing and process into pizza base

shapes ready for proof. You will need to have a reasonable number of pans

available. Preferably, these should be ones which you can stack one inside

another, but if you do not have this type available, then you can use a series in

thin metal or plastic sheets which are placed on top of one set pans to allow

you stack others on top. The method that we are going to suggest requires you

to have access to both a prover and a retarder (though not at the same time)

and you will need to be able to fit the production into your existing production

plan or to be able to modify it to accommodate the new production.

After you have prepared the bases and loaded them into the pans, you

should put them into the prover; we suggest that you use temperatures in the

region of 25�35�C and certainly no higher. Depending on your yeast level,

you will need to give the dough pieces 1�2-h proof and it is important to

maintain a reasonable humidity level, say around 70%. You can stack the

pans for proof if you wish though it is not critical at this stage, it all depends

on how much space that you have available.

After the bases have been proved, they should transferred to the retarder

for cooling and storage. The retarder temperature should be in the range 23�Cto 13�C, and you should stack the pans on top of one another to keep the

humidity high enough to prevent skinning. When you need bases for baking you

simply take a base from the retarder, spread on the tomato sauce add the topping

and transfer to the oven for baking. The proved pizza bases cool quickly in

the retarder because they are thin and the cool temperature in the retarder

limits any further gas production but the method gives you ready proved pizza

bases which can be turned into the baked product in a few minutes.

As you are using metal pans, you need to make sure that they remain in

good condition to avoid any problems with the dough reacting with the metal

(see Section 4.2.13) though probably the retarded storage time is too short for

this to be an issue. You may find it helpful to have some small holes in the

base of your pans to allow trapped steam to escape and avoid blisters and hol-

lows on the base (see Section 4.1.1).


8.47 WE FREEZE OUR UNBAKED PIZZA BASES IN ANITROGEN TUNNEL. ON DEFROSTING AND BAKING,WE GET BUBBLES FORMING ON THE TOP OF THE BASEACCOMPANIED WITH AN OPEN CRUMB CELL STRUCTURE.CAN YOU SUGGEST WAYS OF OVERCOMING THESEPROBLEMS?

It is important to ensure that the temperature in the nitrogen tunnel is not

allowed, at any time, to go below 230�C. Below 230�C, the integrity of

the yeast cells is broken releasing the glutothione and proteolytic

enzymes which weaken the strength of the protein films between the

small air bubbles in the dough. As the dough begins to expand, the weak-

ened gluten film rupture and adjacent gas bubbles coalesce to form large

ones. This is likely to be the origin of your open cell structure and the

bubbles that you observe.

After you have optimised the freezer conditions you can consider:

� Adding low levels of an emulsifier or fat to improve gas bubble stability.

� Minimising any dough resting time after mixing.

� Increasing the level of improver that you use in the recipe.

� Using a higher protein flour.


8.48 WHAT ARE THE KEY CHARACTERISTICS OF CAKEDOUGHNUTS AND HOW DO THEY DIFFER FROM OTHERTYPES OF DOUGHNUT?

The two main classes of doughnuts are those based on making a low viscosity

cake batter and a fermented dough. The cake doughnut is made by depositing

the batter directly into the hot oil for frying. The most common form of cake

doughnut is ring-shaped, and they are often topped with a coloured and

flavoured icing or glaze (see Fig. 8.3). The most common form of the fermen-

ted doughnut is ball or finger shape with a jam or jelly injected into the shape

and the outer surface dusted with fine sugar crystals.

In formulation terms, cake doughnuts tend to have a higher sugar level

than fermented forms and use baking powder as the sole aerating agent.

Overall cake doughnuts tend to be denser and have a less well-defined cellu-

lar structure than fermented doughnuts; the eating qualities are distinctly

‘cake-like’ with a less chewy eating character.

The choice of flour is important for the manufacture of cake doughnuts,

and it is common practice to use a lower protein flour than with fermented

doughnuts. Sometimes, a mixture of standard and modified flours may

be used. In the case of the modified flour, it may have a reduced particle

size (see Section 2.2.16) or some post-milling treatment; i.e., heat treatment

(see Section 2.2.17) or chlorination (see Section 2.2.18) in those parts of the

world in which its use as a flour-treatment agent are still permitted.

It is important to control the release of carbon dioxide gas by the baking

powder reaction in cake doughnuts. The generation of carbon dioxide is not only

part of the expansion mechanism but is also part of the means of controlling the

degree of fat absorption during frying. The pressure from the expanding gases

prevents the absorption of fat as long as the gas cells in the dough are intact (see

Section 4.2.1). If the carbon dioxide is released too soon during frying, the final

product lacks volume and has a dense and ‘fatty’ eating character. If the carbon

dioxide is released too late, then the product will often have a distorted shape.

Further reading

BakeTran, 2012. A guide to doughnut technology. Chorleywood Bookshelf Monograph No. 2,


FIGURE 8.3 Doughnut types: Left, fermented; right, cake.



8.49 WE HAVE BEEN PRODUCING A RANGE OF CAKEDOUGHNUTS WHICH ARE ICED WITH VARIOUSFLAVOURED COATINGS. TO COPE WITH PEAK DEMANDS,WE HAVE TAKEN TO FREEZING A QUANTITY OF THEPRODUCTS. WE HAVE OBSERVED THAT PROGRESSIVELYDURING STORAGE A CRYSTALLINE GROWTH APPEARS ONTHE PRODUCTS. WHEN THEY ARE DEFROSTED THE GROWTHDISAPPEARS. CAN YOU IDENTIFY WHY THIS HAPPENS?

The growths that you are describing are most likely to the formation of

sucrose hydrate on the surface of the icing (Cauvain and Young, 2008).

During the freezing of the iced doughnuts, freeze�concentration can occur

in the icing. The presence of a high level of sugars in the icings considerably

depresses the freezing point of the mixture of sugar and water. As the tem-

perature begins to fall some of the water in the icing forms ice crystal and is

no longer available to keep the sugars in solution, the concentration of the

remaining sugar solution is increased and the freezing point is further

depressed. This cycle of action continues until the temperature of the freezer

is reached.

In the icing, there are two processes taking place. One is crystal nucle-

ation and the second is crystalline growth or propagation. Nucleation is the

coming together of two or more sugar molecules in the appropriate arrange-

ment for crystal growth. However, for crystal growth to occur, the sugar

molecules must be sufficiently mobile to aggregate. The freeze�concentra-

tion effect taking place in the icing probably means that there is a concen-

trated and unfrozen sugar solution even when the products are placed into

storage at 220�C and so the potential is there for crystal growth to occur.

First, we suggest that you look closely at your initial freezing and frozen

storage regimes. Try to make sure that the temperature to which you first

freeze your products is as close as possible to that at which they will be

later be stored. Keep transfer times between the initial and storage freezer

as short as possible and minimise any opportunities for moisture losses

before over-wrapping.

This type of problem is exacerbated by any periods of defrosting and

refreezing during storage because the rate at which the products will refreeze

in storage will be considerably lower than used initially for freezing the

product. A slow reduction in temperature favours crystal growth and the

retention of more water in the overall structure of the growth.

While the growths may disappear on defrosting it is not unusual to be left

with localised white spots, pitting and streaking on the icing surface. You

can try reformulating the icing by adding more glucose (see Section 8.16).


Reference



Further reading

BakeTran, 2012. A guide to doughnut technology. Chorleywood Bookshelf Monograph No. 2,






8.50 AFTER A SHORT PERIOD OF CHILLED STORAGE,WE OBSERVE CRATER-LIKE CRYSTALLINE FORMATIONSON OUR CHEESECAKE TOPPING. DO YOU KNOWWHY THIS OCCURS?

Crater-like crystal formations in fondant type toppings are consistent with

the formation of sucrose hydrate (Cauvain and Young, 2008). Localised

white spots or streaks are the result of the formation of sugar crystals larger

than those present in the mass of fondant. The presence of materials which

might cause the fondant to ‘seed’ and form sugar crystals which then grow

accentuates the problem.

Crystal growth can be retarded by increasing the level of glucose syrup in

the fondant. The inclusion of glucose syrup in the simple syrup form used for

thinning the fondant may prevent this seeding. A typical recipe for such syrup is:

Water 1.25 L 2 pt

Sugar 1.5 kg 3 lb

Glucose 250 g 8 oz

The ingredients are brought to the boil and allowed to cool before use.

Care should be taken that the fondant is tempered correctly and not

overheated (i.e., not above 43�C) during preparation. Preparation tanks

should be inspected to check that a crust of hardened fondant has not

formed round the rim as this can act as a source of seed crystals for sugar

crystallisation. Similarly, any superfluous icing sugar or other material can

cause the fondant to ‘seed’ and form sugar crystals. Minimising moisture

loss from the product can also alleviate the problem by preventing the loca-

lised sugar concentration reaching the point where recrystallisation is likely

to occur.

You need to be careful when recycling scraps of icing back into the mix

as these will have dried out and act as another source of seed crystals. It is

natural to want to recycle icing scraps, but these should be done frequently

during a production run rather than retaining them until the end of a run for

use in the next batch of icing.

Pitting, graining and even bubbles and blisters on the surface of iced

toppings can sometimes be seen, and they are caused by the multiplication

of osmophilic yeasts which are capable of fermenting the icing and generat-

ing carbon dioxide gas; the latter is the source of the bubbles and blister.

From a hygiene viewpoint, cleaning all surfaces that come into contact

with such coatings, including all vessels used to hold or transport them, the


bain-marie, all working surfaces, small containers and utensils, can mini-

mise the uptake of spoilage organisms and materials which might cause

seeding later. Once again the recycling of left over materials is used is

often the source of such problems because viable yeast cells may remain in

the product.

Reference






8.51 WEWANT TO EXTEND THE MOULD-FREE SHELF-LIFE OFOUR FLOUR TORTILLA (FIG. 8.4) BUTWHENWE TRY THEDOUGHMORE ACIDWE HAVE PROCESSING PROBLEMS. WHATOPTIONS COULDWE CONSIDER FOR ACHIEVING OUR AIM?

Acidifying the dough is sufficient for inhibiting the development of rope

(see Section 4.1.4) and is a common way to extend mould-free shelf-life,

especially when there are preservatives present in the recipe. The magni-

tude of the combined effect depends on the particular pairing used. The

combination of potassium sorbate and an acid is more effective as an anti-

mould agent than using calcium propionate and acid. Usually, you would

use potassium sorbate as an anti-mould preservative in the manufacture of

cakes but not in fermented products because of the inhibiting effect that it

has on yeast activity. As your products are powder-raised, then it is per-

fectly possible to use potassium sorbate.

Lowering the pH of the dough has an effect on its rheological proper-

ties and this is the reason for some of your processing problems. At low

pHs, the elasticity of the dough often increases and this can make shaping

more difficult. One way around this problem would be to use an encapsu-

lated acid which has no significant effect in dough mixing and processing.

Fat is normally used as the encapsulating agent, and in the oven, the

fat will melt releasing the acid. In this form, the acid is still effective at

lowering the final product pH, so you still get the combined benefit of pre-

servative and low pH.

Another way of lengthening the product mould-free shelf-life is by lower-

ing the water activity of the product. Once again, the combination of lower

water activity and potassium sorbate is more effective than either approach

on its own. Another way to lower the water activity would be by adding

glycerol or some other polyol (see chapter: What are polyols and how are

they used in baking?).

FIGURE 8.4 Flour tortilla.


8.52 WHAT ARE THE ORIGINS OF PAPPADAMS?

Pappadams are like extra-large crisps and are an accompaniment for Asian

foods (Fig. 8.5). Alternative names are papadams, puppodums, appalan and

papad. Papads are roughly round, the dimensions varying according to where

the papad is manufactured. Most fall within the following dimensions:

Diameter � 10 to 18 cm; thickness � 0.5 mm to 1.5 mm; weight � 4 to 24 g.

A typical papad is about 16 cm in diameter, 1 mm thick and weighs about

15 g. The colour of the papad depends on the type and quality of flour and

other ingredients used. The colour can be yellowish white to yellowish brown.

Papads are eaten with any type of meal or as a snack. One or two per

meal per person is usual but as with many foods it depends on personal taste.

Papads are eaten after frying for a few seconds in oil, or grilling or micro-

waving. When fried in oil they expand by about 30�40%. After the heating

process, the papad becomes crisp and brittle.

A basic recipe is:

� 100 parts blackgram flour

� 45 parts water (variable)

� 8 parts salt

� 1 part sodium carbonate or 1.0�1.5 parts sodium bicarbonate

The flour is obtained by milling a pulse (bean) known as Phaseolus

mungo or more commonly as blackgram. Each pod contains between 5 and

15 oblong-shaped seeds, 3 to 4-mm long and 2 to 3-mm wide. The pods are

dried under the sun, the seeds taken out, their husks removed and the bean

FIGURE 8.5 Flat breads (top right, pappadams; left, kebab bread; bottom right, chapattis).


milled. Other types of flour are sometimes mixed with the blackgram flour

to produce different varieties of papads.

The carbonate additions are essential as they improve the colour of the

dried papad, prevent formation of brown patches during frying and mellow

the ‘pulsy’ flavour of the blackgram. Salt is added to give flavour, improve

the rolling properties of the dough and increase expansion during frying.

Papads may be spiced by adding chilli, white pepper, black pepper, garlic or

jira as desired.

The dough is made by an all-in method (the carbonates being dissolved

in some water). When made, the dough is tough and sticky. It is rested for

approximately 30 min, then divided into small balls about 4�6-cm diameter

and 18�20 g in weight. The balls are then rolled out into thin circular discs

of about 1-mm thickness and 15�17-cm diameter. Oil or corn flour is used

as an aid during rolling.

Traditionally, the rolled out papad is dried under the sun to reduce the

moisture content to 14�15%. The papads are then ready for use. For storage,

which should not be for long, the papads can be put in airtight containers or

sealed in moisture impermeable film.


8.53 WHAT IS KEBAB BREAD?

Kebab bread is the western European name for the Middle Eastern bread

known as pitta or khubz (Fig. 8.5). This type of bread has been popularised

by Greek-Cypriot restaurants who serve the bread with shishkebabs.

The following recipe and method has been found suitable in commercial

practice.

kg

Flour 100

Yeast 0.7

Salt 2.5

Water (fairly soft dough) 57

The flour used is white, untreated, unbleached and low in protein. The

dough is mixed on a low speed mixer for about 20 min to a dough tempera-

ture 27�28�C. After 45 min the dough is scaled into 150 g (5 oz) pieces,

moulded round, rested for 10 min and then pinned to give a thin flat oval

shape about 24�25-cm long and about 11-cm wide. The oval dough is

proved between cloths for 10 min and then baked on the sole of an oven at

316�C (600�F) for about 5 min.

Following baking, the pittas must be cooled for about 10 min, after which

they can be stacked up. The breads may be put into polythene bags once

they are cool enough to keep them soft and flexible. They can be reheated

under a warm grill before serving.

It is essential to use untreated flour as treated bread flour yields pittas

with large surface blisters and an uneven distribution of crumb between top

and bottom surfaces.


8.54 WHAT IS BALADY BREAD?

Balady bread is an Egyptian bread product based on a sour dough or starter

system. The starter dough is used to provide flavour rather than for leavening

purposes. The bread is round, flat, puffs up during baking and is easily sepa-

rated into two layers. The flour blend normally used for this product is

25�30% strong flour of 72% extraction and 75�70% Egyptian flour of 82%

extraction.

Recipe for starter

� 11 kg old dough

� 100 kg flour

� 50 kg water

Compressed yeast may be added in cooler weather. The starter dough is

fermented for at least 3 hours. The fermentation period may be longer,

depending on how soon the starter is required for use.

Recipe for simple straight dough

� 100 kg flour

� 75 L water

� 0.5�0.7 kg salt

� 5�15 kg starter dough

The ingredients are mixed for 20�25 min to produce a slack dough (not

fully developed) which is then immediately scaled into 180g dough pieces.

The dough pieces are moulded into round shapes, placed on trays and sprin-

kled with bran. Intermediate proof lasts for 15 min. The dough pieces are

then flattened into pancake shapes 20 cm in diameter and 1.5cm thick and

left to ferment for 1 hour.

After fermentation, the excess bran is shaken off and the dough pieces

are transferred into a hearth oven using a peel. Baking lasts for 1.5 min at

temperature of 450�600�C (842�1112�F). The crust forms rapidly and after

about 1 min baking steam develops in the dough. At this point, the dough

rises very rapidly.

Immediately after baking, the bread is about 12 cm in height, and as it

cools, the centre sinks to a height of 4�6 cm. The finished product has a

firm crust with a very soft moist interior. The crumb may be split and filled

with beans or cheese.


8.55 HOW ARE CHAPATTIS MADE?

Chapattis are a baked product related to bread and originate in Asia, where

they are eaten with almost every main meal. Traditionally, chapattis are

made fresh for each meal and are roughly round in shape (see Fig. 8.5), with

a diameter ranging from 12 to 18 cm and thickness varying from 1 to 3 mm.

A great deal of variation in size and formulation occurs depending on per-

sonal preference.

Typical recipe

Flour 1 kg

Water 650 to 750 g

Wheat flour is used to make chapattis. The extraction rate can be anything

between 75 and 100%. The dough is made by mixing flour and water, with

salt and fat added according to personal taste. The recipe does not contain

yeast. The dough, which is fairly firm, is rested for up to 30 min before being

scaled into portions weighing 30�85 g. These are rounded into balls. A fur-

ther rest is desirable before rolling the balls into thin discs 1�3-mm thick.

The rolled out chapattis are cooked on both sides using a hot plate at a

temperature of 233�260�C (450�500�F). Cooking time will depend on the

thickness and continues until the chapattis start to blister on both sides and

the colour is just turning brown. This stage takes approximately 0�5 min

for each side. Chapattis may be eaten after this stage has been reached or

they may receive a second baking called ‘puffing.’ In the puffing process,

which takes just a few seconds, a chapatti is placed under a grill or over a

red-hot fire and it immediately puffs up into a ball. As soon as it has puffed,

it must be taken away from the grill or fire as it will burn. At this stage, the

chapatti is composed of two layers of skins with a space between. Puffing

is rarely carried out on chapattis which are more than 2 mm thick as they

do not puff well.

After puffing, the chapattis collapse back to the original shape, and they

should be stacked one on top of the other to avoid drying out. To prevent

them sticking together, the surface of the chapatti is greased with butter, a

practice which has the added advantage of making them soft and imparting a

buttery flavour. The final chapattis will vary in colour according to the type

and extraction rate of flour used, but almost all will have brown blisters,

some of them slightly burnt. If chapattis are stored after cooking for more

than a few hours, they tend to stick together and lose their attractive eating

characteristics. Stale chapattis can be improved by re-heating but they do not

regain their original quality.


8.56 WHAT ARE CORN (MAIZE) TORTILLAS? ANDHOW ARE THEY MADE?

The corn (maize) tortilla is a non-fermented product made from maize flour,

and is the basis for many traditional Mexican dishes. They are made on hot-

plate goods and have a simple recipe.

Whole maize flour 100

Water 33

Limea (calcium hydroxide) 0.1

aThe lime must be suitable for use in food and comply with local food legislation.

This recipe uses whole maize flour which has been passed through a US

40-mesh sieve (screen size 0.016 in). The tortilla dough, known as masa, is

formed into individual circular dough pieces about 15cm diameter and 2mm

thick and cooked on a hot plate until both surface is slightly browned.

Tortillas can be eaten alone like bread, or fried with a cheese topping

(nachos). A popular form is the taco. After frying the tortilla can be filled

with meat, tomato, cheese, olives, peppers and sauce. Alternatively the torti-

lla may be softened in oil or sauce, rolled round a meat or cheese filling and

baked to produce an enchilada.


8.57 WHAT IS TRENCHER BREAD AND HOW WAS IT USED?

It is believed that trencher bread was first mentioned in 15th century books

on etiquette (David, 1977) though its origins are likely to be much earlier

than the references suggest. Trenchers were essentially coarse slices of bread,

from loaves typically 4 days old, used instead of a plate at a medieval meal.

After the trencher had served its purpose as a plate and had been saturated

by the sauces and juices of the meal laid upon it, it was eaten by the servant,

cut up for the poor or given to the dogs.

Trencher bread was made from coarsely milled flour which probably

comprised some wholemeal (wheat) flour mixed with some whole barley

or rye flour. The wholemeal flour may have been sieved to remove the

fine white flour which would be used in the making of manchet bread.

Manchet bread was the finest and whitest variety and only eaten by the

nobility in the Medieval period. The coarse flour was made up into large,

flat, round dense loaves which were probably baked in an oven, though

occasionally, they were baked on a hot plate. The loaf was probably turned

halfway through baking to give two flat, firm crusts and an even layer of

crumb.

The trencher loaves were stored for 4 days and then prepared by the ser-

vant using a special knife for the purpose. (The upper crust was destined to

be the nobleman’s plate and may well be the origins of the phrase ‘upper

crust’.) It is believed that the top and bottom crusts were removed, along

with the side crusts leaving a square, crustless loaf about 2 to 3-cm high.

This ‘loaf’ was then made into one or two square plates on which a serving

of meat could be placed. In later periods the trencher bread was replaced by

wooden or pewter platters.

A recipe and method for trencher bread

g/Mix lb/Sack

Wholemeal flour 1120 186.5

Whole barley flour 560 93.5

Salt 24 4

Yeast 12 2

Water 1140 mL 190

Mix the dough on twin arm low speed mixer for about 20 minutes and

then ferment in bulk for half an hour. Scale dough pieces to 1.8 kg (4 lb),


mould into a ball, rest for 10 minutes and pin out to discs 267 mm (10.5 in)

in diameter. Place dough on greased baking sheets, prove for about 50 min

and bake for 45 min in an oven at 204�C (400�F). Once cool wrap the loaf

in a tea towel and store for 4 days. On the fourth day, cut the loaf in the cor-

rect way to give one or more trenchers.

Reference

David, E., 1977. English Bread and Yeast Cookery. Allen Lane Penguin Books Ltd, London,

UK.




8.58 WHAT IS THE PRODUCT KNOWN AS A GRANT LOAF?

The Grant wholemeal loaf is one recommended by Doris Grant (1944).

Grant had taught household readers to mix and bake wholemeal bread by an

easy method with no kneading and only one fermentation step (rising). The

Grant loaf is not one intended for commercial production but rather for

home baking. The following is the method and procedure suggested by

Grant:

� 3.5lb English stone-ground, wholemeal flour

� 2 pt 4 oz of water at blood heat (or slightly less)

� 1oz sea-salt, Maldon salt or ordinary salt

� 1oz sugar, preferably Barbados muscovado cane sugar

� 1oz yeast (or up to 4 oz)

The production method was as follows:

� Mix the salt with the flour in a large basin and warm it (make

lukewarm � not hot) on the oven top or above a low gas flame, so that the

yeast will work quicker.

� Crumble the yeast into a pudding basin, add the sugar and a quarter pint

of lukewarm water.

� Leave for 10 minutes to froth up; then stir to dissolve sugar.

� Pour this yeasty liquid into the basin of warm flour. Add the rest of the

warm water, and do so gradually in case all the water is not required.

� Stir the whole with a wooden spoon until the flour is evenly wetted, then

mix well by hand for 2 minutes.

� The resulting dough should be wet enough to be slippery, but not too wet.

� Grease three 2pt tins inside and warm them well. Turn the dough into the

warmed tins, put them about two feet above a low gas flame (or in the

oven while the oven is warming up), cover with a cloth and leave for

about 20 min to rise by about one-third. Bake in an oven at 205�C(400�F) for 45�60 min.

Grant considered that ‘real’ bread should be made from wholewheat

grown on naturally fertilised soil and freshly stone-ground (c.f. organic). She

identified the most important production points as being:

� To warm the flour and the baking tins

� To froth up the yeast separately

� To make the dough wet enough to be slippery

� To remember that wholewheat dough must not be kneaded and only

requires a few minutes to mix.


David (1977) gives a metric recipe as:

Wholemeal flour 1.6 kg

Water 1.25 L

Salt 30 g

Sugar 30 g

Yeast 30 g (or up to 120 g for extra food value)

Margarine or butter (optional) 60 g

Tin size: Three by 1 kg tins.

Baking temperature � 205�C.We have tried out the method using 500 g wholemeal flour to 0.5-L water

with mixing for 5 minutes with a household mixer. The resultant bread was

coarse structured with fragile crumb but perfectly acceptable for home-made

bread.

References

David, E., 1977. English Bread and Yeast Cookery. Allen Lane Penguin Books Ltd, London,

UK.

Grant, D., 1944. Your Daily Bread. Faber & Faber, UK.






Chapter 9

Processes and Equipment

9.1 I SEE MANY REFERENCES TO ‘NO-TIME’DOUGHMAKING METHODS. WHAT DOES THIS TERMMEAN AND WHAT IS ITS RELEVANCE?

The terms ‘no-time’ dough (NTD) or no-time doughmaking processes cover

a wide range of options of ingredient, recipe and mixing combinations in the

manufacture of bread and fermented products. Essentially, the term refers to

the principle that the bulk dough is transferred after mixing to be divided

without any significant or deliberate fermentation or resting period.

Breadmaking processes which employ a deliberate fermentation phase

between mixing and dividing are usually collectively referred to as bulk fer-

mentation processes, long fermentation processes (LFP), sponge and dough

or processes involving floor time.

The practical advantages of using a NTD are associated with space

saving � there are no large bowls of dough standing for long periods of time

in the bakery; improved process control � no risk of fermenting doughs being

taken out of sequence with subsequent negative effects on final product quality

and in the case of plant breakdown, no over-fermenting dough to deal with.

In addition with NTDs, there are none of the fermentation losses associated

with LFPs which may run to 2�3% of the starting raw materials as a result of

the prolonged fermentation.

To achieve the required development of the dough for processing into

bread, it is common to add functional ingredients with NTDs. The most com-

mon ingredient added is ascorbic acid, though enzymes of various types,

emulsifiers, fats and reducing agents may be used at different levels of

addition.

Often recipe water levels will be higher with NTDs than with LFPs so as

to adjust dough consistency for dividing and moulding. This extra water is

required to compensate for the lack of dough softening which occurs as the

result of enzymic action over the extended process times associated with

LFPs. Another important change is the addition of extra yeast by comparison

with LFPs. This is to compensate for the intrinsically lower gas levels in the

dough at the time of dividing and ensure that final proof times are not unduly

extended by comparison with LFPs.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00009-6

The flavour profile of breads made of NTDs will be different from that

of LFPs due to the lack of an extended bulk fermentation stage and is more

affected by levels of recipe ingredients such as salt, sugar, malt products and

inclusions. NTDs are suitable for all types of bread and fermented products

and can be used in both large and small bakeries. Due to their convenience

and their potential for good process control, NTDs in their forms probably

account for the greatest proportion of bread and fermented products manu-

factured around the world. The versatility of NTDs means that they can be

used with a wide range of mixing and dough processing equipment.

Further reading


AG, Switzerland.




9.2 WE ARE CONSIDERING THE PURCHASE OF A NEWMIXER FOR THE MANUFACTURE OF OUR BREAD USINGA NO-TIME DOUGH PROCESS. THERE ARE TWO TYPES OFMIXER WHICH SEEM TO BE APPROPRIATE FOR OUR PLANTPRODUCTION NEEDS, THE SPIRAL-TYPE AND THE CBP-COMPATIBLE TYPE, BUT BEFORE MAKING OUR DECISION,WE NEED TO UNDERSTAND ANY ISSUES WITH RESPECTTO DOUGH PROCESSING AND FINAL BREAD QUALITY.CAN YOU PLEASE ADVISE US?

The first point to make is that both mixer types are perfectly suitable for

making bread using a NTD process. In many ways, your choice will be dic-

tated by the type of bread that you wish to make and the final characteristics

that your products should have. We have listed below the main technical

issues that you should consider in making your choice.

Plant capacity and mixing times

Clearly it is important to ensure that you can provide sufficient dough to

run efficiently with minimal gaps between batches when the products reach

the oven. It is usually a relatively simple calculation to determine the batch

size capability of the mixer. You will also need to consider the mix cycle

time; that this, the length of time from the start of ingredient delivery to the

mixer and delivery of the mixed dough to the divider. The mix cycle time will

include the actual dough mixing time along with all of the loading and transfer

times required. In general, for reasons discussed below, the actual mixing time

(not the mix cycle time) for spiral-type mixers is longer than that for

Chorleywood bread process (CBP) compatible mixers; typical mixing times

would be 8�14 minutes for the spiral (see Section 4.1.12) and 3�5 minutes

for the CBP. These times may vary but it is worth noting that optimum mixing

times for CBP doughs are quoted as 2�5 minutes (Cauvain and Young, 2006).

Energy input and dough development

During the mixing cycle energy is transferred to the dough by the mechani-

cal action of the impeller. This energy is an important part of the development

of a gluten structure in the dough with the appropriate rheological and gas

retention properties; in general, the greater the energy input the greater the

dough development and the greater the gas retention properties of the dough

(see Section 9.3) though the precise effects of increasing the level of energy

input to the dough will vary according to flour quality (Cauvain, 2015).

The total level of energy transferred to the dough during mixing depends

to a significant degree on the length of the mixing time; the longer the mix-

ing time, the greater the total energy transferred. However, it has been

known for some time (Cauvain and Young, 2006; Cauvain, 2015) that the

‘rate’ at which energy is transferred to the dough also has an impact; in

Processes and Equipment Chapter | 9 445

general, the faster the mixing speed the faster the rate of energy transfer and

the greater the improvement in dough gas retention for a given set of ingredi-

ents and dough recipe. CBP-compatible mixers exploit this effect by running

at a higher speed than many spiral-type mixers which explains, in part, why

optimum mixing times are shorter with CBP-type mixers.

The rate of energy transfer to the dough during mixing also depends on

the physical geometry of the mixing bowl and the impeller blades that are

used. In the case of spiral-type mixers, the introduction of a static bar or a

twin spiral arrangement may be used to increase the rate of energy transfer

to the dough and shorten mixing times. In the case of the latter form of spiral

mixer, you could argue that this is the equivalent of a CBP-type mixer but

there are other considerations to be taken into account (see section: Dough

temperature control).

Dough temperature control

There is a direct relationship between the input of energy to the dough

during mixing and its final temperature; the higher the total energy input, the

higher the final dough temperature for a given recipe and batch size. In

dough mixing, the most common way to control the final dough temperature

is through the adjustment of the initial water temperature (Cauvain and

Young, 2008). It is common practice to have a sufficient supply of chilled

water available in the bakery for dough mixing to help with the control of

the final dough temperature and in some cases ice or ice-slush may be added

at the start of mixing (see Section 4.1.11).

Typical final temperatures for CBP-type dough will be in the order of

28�32�C while those for spiral mixed dough would be 24�28�C.Traditionally, spiral mixed dough tends to have a lower final temperature

because usually less energy is transferred during mixing. CBP-type dough

tends to have a higher final dough temperature not only because of the high-

er energy input but because the increased dough development yields a dough

with rheological characteristics which allow it to be readily processed on the

dough make-up plant at the higher temperature.

Dough gas bubble structure and product cell structure

The creation of the gas bubble structure in dough depends on the entrain-

ment and sub-division of air during dough mixing (Cauvain, 2015). Many fac-

tors influence the gas bubble population (i.e., the numbers and sizes of gas

bubbles) in the mixed dough. The initial gas bubble structure in the mixed

dough is a major contributing factor to the final product cell structure. It is sig-

nificantly affected by the mixer type. This is an important issue as with NTDs,

there is no significant opportunity during processing to significantly modify

the gas bubble population to reduce its average size. In practice, when the

dough leaves the mixer the main change for the gas bubbles is to increase in

size. Thus if a fine and uniform cell structure is required in the final product


essentially it must be created in the mixer. As gas bubbles grow after leaving

the mixer, it is easier to create a coarser cell structure in the final product.

The measurement of gas bubble populations in mixed dough has shown

that spiral mixed dough has a higher average bubble size and a wider range of

sizes than typically seen with CBP-type mixers (Cauvain et al., 1999). As the

initial gas bubble population is a major determinant of final product cell struc-

ture, this means that spiral mixed dough tends to yield final products with a

greater average cell size with a wider range of sizes; in practical terms the cell

structure of bread from spiral mixed dough will have a coarser and less even

structure than those from CBP-type mixers (but see the following section).

The modification of product cell structure

The preceding comments on the creation of gas bubble populations and

product cell structures are important in understanding one of the key principles

of the CBP, namely the control of product cell structure through the modifica-

tion of the mixer headspace pressure (Cauvain and Young, 2006; Cauvain,

2015). Spiral-type mixers do not commonly have a facility for controlling the

mixer headspace pressure as the mixer bowl is mostly open to the atmosphere.

The bowl of the true CBP-compatible mixer can be isolated from the sur-

rounding atmosphere by means of lowering a close-fitting lid. Historically

(Cauvain and Young, 2006), the atmospheric pressure in the mixing bowl

was reduced below that of atmospheric pressure to create a finer and more

uniform cell structure in the bread (with accompanying advantages for crumb

softness). Later, developments of the CBP-compatible mixer (Cauvain and

Young, 2006: Cauvain, 2015) include the facility to have pressures above or

below atmospheric and, most importantly, to change from one pressure to

another during the mixing cycle. This development enables the creation of

different gas bubble populations in the dough and therefore different cell

structures in the final product. In practice, this means that the same mixer

can be used to create the fine and uniform cell structure required for sand-

wich bread or the coarse open structure required for French bread types sim-

ply through the manipulation of mixer headspace pressure. There are no

spiral mixers available at the time of writing with this capability.

References


AG, Switzerland.


Cambridge, UK.



Cauvain, S.P., Whitworth, M.B., Alava, J.M., 1999. The evolution of bubble structure in bread

doughs and its effect on bread structure. In: Campbell, G.M., Webb, C., Pandiella, S.S.,

Niranjan, K. (Eds.), Bubbles in Food. American Association of Cereal Chemists, St. Paul,

MN, pp. 85�88.













9.3 CAN YOU EXPLAIN THE ROLE ENERGYIN THE CHORLEYWOOD BREAD PROCESS?

The transfer of mechanical energy to the dough during mixing with the CBP

is an essential component in the development of a dough with specific rheo-

logical properties and the necessary gas retention to produce a loaf of opti-

mum volume and crumb cell structure (Cauvain and Young, 2006). When

first introduced, the ‘optimum’ work input level for the CBP was reported as

11 Wh/kg dough in the mixer for the range of flours that were available in

the 1960s, but later, work has shown that the optimum total work input var-

ies with the type of flour being used, see Fig. 9.1 (Cauvain, 2015). There are

a number of reasons for this change which include the development of new

wheat varieties and the change in the oxidant system since 1960 (the original

work was carried out when potassium bromate was a permitted oxidant).

The role of energy in the CBP has still to be fully explained despite the

fact that the process has been around for 50 years. It is very likely that

the high energy inputs are capable of mechanically breaking the disulphide

FIGURE 9.1 Effect of work input: (A) 5: (B) 8; and (C) 11 Wh/kg dough.


(sSsSs) bonds holding the original protein configurations. In this way,

mechanical energy can be likened to the effects of natural (enzymic) or

chemical reduction. This may explain in part why the addition of a chemical

reducing agent like L-cysteine hydrochloride is considered to reduce the

energy required for dough development.

Chamberlain (1998) � one of the co-inventors of the CBP � considered

that only about 5% of the available energy was required to break the disul-

phide bonds. A significant part of the energy input during CBP dough mix-

ing will be taken up with the mixing of the ingredients and breaking weaker

bonds. In breaking the disulphide bonds energy may well play a role in open-

ing potential sites for oxidation. The CBP may therefore be considered as a

redox-type process, that is, a combination of mechanical reduction and chem-

ical oxidation in contrast to classical chemical reduction and oxidation.

As we consider the role of energy in the CBP, we must recognise that a

fundamental difference between CBP-compatible and other mixer types is

the rate at which energy is delivered. You can increase the total energy

imparted to doughs by lengthening the mixing time but the effect on bread

quality is not as good as if the same total energy is delivered at a faster rate.

In the original CBP, the delivery of energy was needed within 2 to 5 minutes

of mixing and the same premise holds true today, even when flours which

require more than the original 11 Wh/kg are used. To meet the required

energy delivery within the specified times, it is necessary to mix faster which

in turn, requires a more substantial motor being fitted to the mixer.

In addition to noting the rate effect, we should also recognise that the

input of energy to the dough is manifest as a significant temperature rise and

that the provision of suitable quantities of chilled water are required. It may

even be necessary to employ a cooling jacket of some from so that final

dough temperatures can be maintained at acceptable levels, typically around

30�C (Cauvain and Young, 2006).

References


AG, Switzerland.


Cambridge, UK.

Chamberlain, N., 1998. Dough formation and development.. In: Brown, J. (Ed.), The Master

Bakers Book of Breadmaking, second ed. Turret-Wheatland Ltd, Rickmansworth, UK,

pp. 47�57.










9.4 WE ARE LOOKING TO BUY A NEW FINAL MOULDERFOR OUR BREAD BAKERY. CAN YOU ADVISE US ON THE KEYFEATURES WHICH SHOULD LOOK FOR AND HOW THEYMIGHT IMPACT ON FINAL BREAD QUALITY?

The main function of the final moulder is to change the shape of the individual

dough pieces to fit the product concept and deliver them in the appropriate

form for final proof. As there are many different sizes and shapes of bread

products, there is no single moulder able to meet the requirements of all them.

A typical bread dough moulder will comprise a chute feeding the pieces

into a series of rollers (2�4 in number). Typically, the pieces entering the

rollers will have a round shape and the sheeting process by the rolls will

yield a flattened elliptical shape on exit. Immediately on leaving the rollers,

the leading edge of the dough ‘pancake’ is lifted by a chain and the dough

piece is rolled up like a Swiss roll before being carried underneath a final

moulding or pressure board. The gap between the board and the moving belt

of the moulder is adjusted to yield the desired shape. Side guide bars may be

fitted under the moulding board to help deliver a cylindrical shaped dough

piece (a most common shape for bread products).

The behaviour of the dough piece depends in part on the doughmaking

process which has been used. Dough which has undergone a period of bulk

fermentation has a low density with large pockets of gas trapped in the glu-

ten structure. Such dough pieces passing through the sheeting rolls will

become de-gassed, and this action can contribute to making the cell structure

of the final product finer and more uniform, though not to the same degree

as would be seen with doughs prepared by a NTD process.

In some dough types, e.g., baguette and ciabatta, the large gas pockets are

an integral feature of the final product and so de-gassing of the dough is not

advisable. Instead the moulding action will be designed to aid the retention of

the large gas bubbles though mechanical moulding is never likely to deliver

the same final product cell structure that can be achieved with hand moulding.

Modern NTDs have relatively low levels of gas in them and so the

de-gassing function of the sheeting rollers has limited value. Such doughs

also have a different rheological character and respond quite differently to

heavy pressures during final moulding. In many cases the pressures can lead

to damage of the gas bubble structure in the dough which in turn leads to

quality problems in the final product (see Sections 4.1.6 and 4.1.7). Such

quality losses are less likely to occur with longer moulding boards.

As a general rule, fine cell structure in bread is obtained by sheeting

thinly and using just enough pressure under the moulding board to achieve

the required shape. This sheeting is best achieved gradually in moulders with

a greater numbers of rolls.

Further reading


AG, Switzerland.




9.5 WHY IS A BREAD DOUGH PIECE COILED AFTERSHEETING? DOES THE NUMBER COILS ACHIEVED HAVE ANYIMPACT ON BREAD QUALITY?

The rationale for coiling a dough piece is closely connected with the process

of sheeting dough and the traditional use of a period of bulk fermentation

after mixing to ‘develop’ the dough ready for dividing and processing as

unit shapes.

The density of dough at the end of its bulk fermentation period is very

low and as much as 70% of the dough volume may comprise gas bubbles, a

mixture of mostly nitrogen and carbon dioxide, of various sizes (Cauvain,

2012). Some of the gas bubbles may be very large in size (several cm) and if

they are retained in the dough piece when it enters the prover these bubbles

commonly lead to the formation of unwanted holes in the crumb of many

types of pan breads (although they may be acceptable in baguette and ciabat-

ta). Such large gas bubbles can readily be expelled from the dough piece by

flattening them by hand or by pinning the dough. An alternative was to pass

the dough backwards and forwards through the sheeting rolls of a pastry

brake and gradually eliminate the large bubbles by bursting them. A similar

process to the latter was achieved by passing the dough through a series of

pairs of rolls one set mounted above another, and this is the basis of the

most common form of bread dough moulders. The expression of the large

gas bubbles from the dough piece is an important contributor to the forma-

tion of a fine and uniform cell structure in the baked product which in turn,

is an important contributor to bread crumb softness and brightness; both are

seen as desirable characteristics in white and many other bread types.

The formation of a round dough piece after dividing is a common prac-

tice, even if hand moulding is undertaken. When such dough pieces are

passed through sheeting rolls, they form an elliptical shape which is then

coiled (rolled like a Swiss roll) to form a crude cylindrical shape for final

processing (Cauvain, 2015). The number of coils that are achieved when cre-

ating the cylinder depends mainly on the length of the ellipse and is deter-

mined to a large extent by the design of the sheeting head of the final

moulder and the speed at which the dough piece passes through it. The

weight and positioning of the curling chain to catch the leading edge of the

flattened dough also has an important part to play in forming the coil.

The process of sheeting a moving round dough piece between rollers

will always result in an elliptical shape on exit from the rollers. This is

because the rollers grip the leading edge of the dough piece as it falls under

the influence of gravity into the roll gap. As the dough piece leaves the final

set of rollers a moving belt carries the piece forward, the net result is that

there is a stretching of the dough as it passes through the set of rollers; the

degree of stretching depends on the equipment design. A consequence of

forming and elliptical shape is that distribution of dough in the coil which is


formed is not uniform. If the coiled piece was cut longitudinally, then it

would be seen to comprise a series of wide and narrow layers (Cauvain,

2015) which has profound implications for the formation of the cell struc-

ture in the final product.

The general view is that sheeting thinly and the subsequent increase in

the numbers of coils that are achieved delivers a finer and more uniform

crumb cell structure in the baked product. However, it should be noted that

the volume of gas in NTD pieces reaching the final moulder is considerably

lower (typically ,20%) than that from bulk fermentation systems (typically

70%), and this implies that the impact of sheeting on the final cell structure

of the product will be less marked.

References

Cauvain, S.P., 2012. Breadmaking: an overview. In: Cauvain, S.P. (Ed.), Bread Making:

Improving Quality, second ed. Woodhead Publishing Ltd., Cambridge, UK, pp. 9�31.


AG, Switzerland.







9.6 WHAT IS THE FUNCTION OF FOUR-PIECINGOR CROSS-PANNING IN BREADMAKING?

Four-piecing (see Fig. 9.2) is a technique commonly used in the production

of sandwich style breads where a fine (small average cell size) and uniform

cell structure is required. In essence, it consists of moulding a dough piece

to a long cylindrical shape under the final moulding board and then cutting

the piece as it exits the board into four pieces of equal size or weight. The

four pieces are turned through 90� and gathered together before being

placed in the pan.

During sheeting some of the gas bubbles present in the dough are

elongated in the direction of the dough movement through the final

moulder. After curling the cells maintain their elongated shape because the

visco-elastic properties of dough and the curling process itself prevent

the bubbles from assuming a spherical shape. In single piece bread, the

cells formed from these bubbles are cut through their short sides in

the product and the cell walls cast a significant shadow, thus giving the

crumb a dull, grey colour.

In four-piecing turning the pieces through 90� means that the elongated

cells are cut through their long axis and the resultant shallow cells which

form in the loaf will cast less of a shadow when viewed under glancing light.

This means that the crumb from four-pieced bread will be seen as brighter

when viewed under similar lighting conditions to that of a single piece loaf.

In addition to the improvement in crumb appearance there is an improvement

in crumb softness and a small but helpful improvement in crumb resilience

when using four-piecing. The latter helps with the slicing and eating proper-

ties of such breads.

Although there is an improvement in cell uniformity within the indi-

vidual pieces, there can be greater slice to slice variation along the length

FIGURE 9.2 Four-piecing of bread doughs.


of the loaf with four-piecing. Cauvain and Young (2006) reviewed this

effect and provided cell size data to confirm that a ‘periodic’ structure

was created along the length of the loaf by four-piecing. This is espe-

cially true for the areas where two pieces meet and so it is important to

ensure that the four pieces are as equal as possible and uniformly placed

in the pan.

Eight-pieced loaves are known, though not common, and a similar tech-

nique is ‘cross panning’ or ‘cross graining’. Both techniques rely on the

reorientation of the cell structure in the dough to deliver similar benefits to

those described above.

Reference


Publishing Ltd, Oxford, UK.




9.7 WHAT IS PURPOSE OF THE ‘KNOCKING-BACK’ THEDOUGH WHEN USING A BULK FERMENTATION PROCESS TOMAKE BREAD?

In bulk fermentation breadmaking processes, the dough is left to ferment in

a suitable environment for a long period of time, often many hours. During

this fermentation period, the volume of the dough will increase greatly as the

yeast produces carbon dioxide gas which is largely retained in the dough;

approximately 70% of the dough volume at the end of 2 or 3 hours of fer-

mentation may be gas.

Knocking-back the dough is an operation commonly performed part-way

through the prescribed fermentation period, typically after half and usually

before three quarters of the prescribed period. However, some more tradi-

tional recommendations (Bennion and Stewart, 1930) are that knocking

back should be carried out in the early stages of bulk fermentation. In

small-scale production, the operation may well be carried out by and hand,

and this practice has given rise to an alternative description of the process �‘punching’ the dough. With larger bulk doughs, there is no reason why the

process cannot be carried out with a mixing machine though the mixing

time will usually be very short, commonly only a matter of a couple of min-

utes on slow speed.

A number of different reasons are given for carrying out a knock-back

and it very likely that they all have some validity. They include the

following:

� To even-out temperature variations in the bulk of the dough. � There is

no doubt that when a bulk dough stands for long periods of time that the

surface of the dough will cool, in part as the result of surface evaporation

and the sides in contact with the dough bowl may also be at a different

temperature depending on the bakery environment.

� To reduce the risk of the dough skinning from surface evaporation �Excessive skinning of the dough can lead to significant product quality

problems when the drier material is distributed throughout the dough at

the time of dividing.

� To reinvigorate the yeast by eliminating ‘waste’ products � In this case,

the waste product is alcohol, high levels of which can have an inhibitory

effect on yeast activity.

One potential benefit of knocking back the dough not commonly dis-

cussed is the contribution that the energy of this ‘re-mixing’ may make to

dough development. During fermentation, the gluten network becomes

stretched as the dough expands and re-mixing (as this is really what the

knock-back is) transfers some energy to the dough (even by hand) and


encourages the formation of a stronger gluten network, that is one capable of

retaining more carbon dioxide gas during proving and baking. It is interest-

ing to note that Bennion and Stewart (1930) recommend that ‘a bun dough

should be knocked back every 20 minutes if a bun of good bulk (volume)

and silk-like texture is required.’

Reference

Bennion, E.B., Stewart, J., 1930. Cake Manufacture and Small Goods Production. Leonard Hill

Limited, London, UK.




9.8 WE HAVE TWO BREAD LINES RUNNING SIDE-BY-SIDEWITH THE SAME EQUIPMENT BOUGHT AT DIFFERENT TIMES.WE ARE USING THE CBP AND DO NOT QUITE GET THE SAMEVOLUME AND CELL STRUCTURE WHEN MAKING THE SAMEPAN BREAD PRODUCT. WE COMPENSATE BY ADJUSTINGYEAST AND IMPROVER LEVEL BUT DO NOT GET THE SAMECRUMB CELL STRUCTURE. CAN YOU HELP US UNDERSTANDWHAT IS HAPPENING?

The operation of the CBP is almost unique in that the crumb structure can

be manipulated by adjusting the mixer headspace pressure to create differ-

ent structures. In your case, you are seeking a fine and uniform cell struc-

ture in your sandwich bread products, and it is with these products in

particular that you are noticing a difference. With the mixers on both

plants, you are applying a partial vacuum, the application of which is

delayed until part-way through the mixing to encourage the initial oxida-

tion of the dough by ascorbic acid before moving to deliver the required

dough to the divider.

The same types of mixers were purchased at separate times. Initially, you

did not use one of them with partial vacuum even though the mixer had the

capability. Close inspection of the equipment revealed that the two pressure

gauges which were fitted to the mixer were of different types so that when

they were regulated to the same dial setting they were in fact delivering dif-

ferent pressures in the mixing chamber. One dial reads down from 0 to 30vof vacuum and the other reads up from 0 to 30v of pressure. You have been

setting both mixers at 20v.These are old readings and it will be easier if we convert them to more

modern units � bars; in essence atmospheric pressure is 1 bar. In the case

of the dial reading ‘vacuum’, your setting is actually around 0.33 bar,

whereas with the dial reading ‘pressure’, it is around 0.67 bar. At 0.33 bar,

we would expect you to lose oxidation and have potential problems with

coarseness of crumb cell structure (see Section 4.1.9). If you adjust the

‘vacuum’ dial to 10v (0.33 bar), you should more closely match bread

quality.

It was also interesting to record that you were using different water

levels between the two plants. This apparently was in response to the

apparently different consistencies of the dough leaving the two mixers.

This was not surprising since the level of gas which remained in the two

doughs ex-mixer would be different and this would give rise to the per-

ceived differences in dough consistency. Once the vacuum levels had been

set to comparable levels, the recipe water levels in the dough became

comparable.


Authors’ note: There can be confusion over pressure units when talking

about partial vacuum because of the common use of atmospheric pressure as

a standard. One bar is defined as 105 N/m2 (nearly equal to 1 atm, i.e.,

760 mm or 30v mercury). Atmospheric pressures do vary with environmental

conditions and height above sea level. The above problem was for a bakery

at sea level.

Further reading


Cambridge, UK.




9.9 WE HAVE BOTH SPIRAL AND TWIN-ARM TYPE MIXERSAND WOULD LIKE TO PRODUCE A FINER CELL STRUCTUREWITH OUR SANDWICH BREADS; CAN YOU SUGGEST WAYSIN WHICH WE MIGHT ACHIEVE THIS AIM?

Much of the final structure of bread is delivered by the mixer, primarily the

design of the mixing tools and the mixing action. During the dough mixing

process, small air bubbles are trapped in the developing gluten network.

The numbers and sizes of those air bubbles are mostly determined by the

mixing actions with some input from ingredients like fat and emulsifiers

(which tend to reduce the average size of the air bubbles). The mixing

bowls of spiral and twin-arm type mixers are usually open to the atmo-

sphere, so there is no opportunity to adjust the initial gas bubble population

in the dough by changing pressures as is the case in the CBP (Cauvain and

Young, 2006).

During and immediately after dough mixing, there is a gradual change in

the composition of the gases in the bubbles trapped in the dough. Initially,

the bubbles trapped in the dough contain a mixture of nitrogen and oxygen

but the latter is scavenged by the added yeast, as well as taking part in the

dough oxidation process. Eventually, only nitrogen gas remains in the

entrained air bubbles. As the yeast begins to produce carbon dioxide, it goes

first into solution in the dough liquor and then later it diffuses into the nitro-

gen gas bubbles and expansion of the dough begins.

The expansion processes in the dough are complex and are related to the

initial gas bubbles size but in summary what happens is that the larger gas

bubbles tend to expand to a proportionally greater extent than the small

ones. Essentially, the larger gas bubbles have a lower internal pressure and

the natural driving force is for carbon dioxide to diffuse into them.

Sometimes, this is at the expense of the smaller bubbles which grow more

slowly and in some case may cease to exist in the dough. As the gas bubbles

continue to expand in proof and the early stages of baking they grow large

enough to coalesce (join together), and it is these gas bubbles which form

the basis of the cell structure in the loaf.

The mixers that you are using tend to deliver an initially wide range of

gas bubble sizes which ultimately becomes a wide range of cell sizes in the

loaf, so that the cell structure tends to be considered ‘coarse’ by comparison

with the very fine cells structures that may be achieved with other types of

mixers (e.g., CBP-compatible � See Cauvain, 2015). There is little that you

can do in the mixer to change the situation so any improvements will have

to be introduced during dough processing.

One way of producing a finer cell structure is to ‘de-gas’ the dough. In

essence what you seek to do is eliminate the larger gas bubbles while retain-

ing the smaller ones. The de-gassing processes delivers a more uniform gas


bubble population which will expand more uniformly during proof and

deliver a more uniform (and usually finer) cell structure.

The easiest way to de-gas the dough is to allow it to have a short period

of fermentation in bulk (e.g., 1 hour) and to de-gas portions of the dough by

passing them back and forth a few times through a pastry brake, this will

eliminate the larger gas bubbles. After sheeting, allow a short period for the

dough to recover and then divide into units and process the dough as before.

The short period of rest after sheeting and before dividing is to allow the

dough to recover its extensibility and avoid structural damage in the subse-

quent moulding.

References


AG, Switzerland.

Cauvain, S.P., Young, L.S., 2006. The Chorleywood Bread Process. Woodhead Publishing Ltd.,

Cambridge, UK.






9.10 WE HAVE BEEN FREEZING SOME OF OUR BAKERYPRODUCTS TO HAVE PRODUCTS AVAILABLE IN TIMES OFPEAK DEMAND. WE NOTICE THAT THERE IS ‘SNOW’ OR ‘ICE’IN THE BAGS WHEN WE REMOVE THEM FROM THE FREEZER.CAN YOU TELL US WHY THIS HAPPENS AND HOW ITCAN BE AVOIDED?

Freezing products ready to meet peaks in customer demand is a common

practice. Bread and rolls if wrapped to prevent any moisture losses will keep

well in the frozen state. Bread products have a high moisture content and a

high water activity. Once frozen, such products should be stored below their

glass transition (Tg) temperature (see Section 11.6). Effectively, this is the

temperature at which all the soluble materials in the product become immo-

bile or frozen. It has been estimated that approximately 30% of the water in

bread remains unfrozen even at the usual storage temperature of 220�C. Inpart, this is because of freeze�concentration effects which means that in prac-

tice not all of the water in the product is actually immobile.

However, at typical freezer temperatures any evaporation of water from

the product will proceed very slowly. If the temperature of the frozen prod-

uct rises above its Tg some of the moisture present can evaporate and sub-

lime through the product to the surrounding atmosphere; in this case, the

inside of the bag in which it is packed. Once there, the water vapour freezes

into ice crystals and becomes visible as ‘snow’ on the product (see Fig. 9.3).

With the reduction, for health reasons, of salt levels in bread products, this

problem is likely to occur earlier in the products’ frozen life than previously.

This is because salt is a material which has the ability to ‘hold on to’ the

moisture in the product thus preventing its ‘escape’ as vapour.

If the problem occurs frequently, it would be wise to check that your

freezer is operating correctly (temperature at or below 220�C) and try to

minimise any opening and closing of its door and check its defrosting

cycle. It is also beneficial to remove product from frozen storage in strict

FIGURE 9.3 Ice crystals formed in bread pack.


rotation so that any one product does not spend longer than necessary in

frozen storage. In addition, care should be taken that any product which is

removed from the freezer is not left in a warm atmosphere as the localized

melting of the ice particles provide a good environment for eventual

mould growth.

The problem can be greater with cake products because the presence of

sugars in the recipe lowers the freeing point of the product even further than

that of breads. In some cases, the sugar concentration can be so high that the

cake is not frozen even at 220�C.


9.11 WE HAVE BEEN DEEP FREEZING BREAD PRODUCTSAND EXPERIENCE A NUMBER OF PROBLEMS WITHDIFFERENT PRODUCTS. WITH CRUSTY PRODUCTS,WE OBSERVE THAT THE CRUST FALLS OFF WHILE WITHSOME OTHER PRODUCTS WE FIND THAT LONGER PERIODSOF STORAGE LEAD TO THE FORMATION OF WHITE,TRANSLUCENT PATCHES IN THE CRUMB WHICH ARE VERYHARD EATING. ARE THE PROBLEMS RELATED TO THEPERFORMANCE OF OUR FREEZER?

The first of your problems is commonly referred to as ‘shelling’, that is the

loss of the crust from frozen bakery items which may occur during storage

but more commonly it manifests itself when the product is defrosted. Similar

problems may be observed with some part-baked, frozen products.

When all bread products leave the oven, the moisture content of the crust

region is much lower than that of the crumb. This differential in moisture

content is much greater in crusty products than with many other types of

bread, e.g., sandwich breads, and is an integral part of the character of the

product. The difference in moisture content between crust and crumb is

partly responsible for their differences in texture, with the low moisture crust

having a harder, more rigid character than the higher moisture content, soft

crumb. The difference in moisture content also means that the salt concentra-

tion is higher in the crust region than the centre crumb which will lower the

temperature at which ice forms in these regions.

The combination of different freezing points and structural architecture

means that the crust and crumb will expand and contract at different rates

and the stress that this places on the interface between the two regions may

become so great that they become separated from one another. This phenom-

enon will occur under almost any freezing condition so it is unlikely that

your freezer performance is directly to blame for the problem. You will have

to accept that you are unlikely to successfully freeze crusty products because

the only solution is to allow equilibration of moisture before freezing, but

then the product would not be crusty anyway!

Your second problem could well be related to your freezer performance

and is a phenomenon known as ‘freezer burn’ (Cauvain and Young, 2008).

It comes from the loss of water from different regions of your product dur-

ing frozen storage. It has been estimated that about 30% of the water in

bread remains unfrozen in bread, even at 220�C. This ‘free’ water may

leave the product and enter the freezer or pack atmosphere where it eventu-

ally shows as ‘frost’ (see Section 9.10). The hard, translucent patches that

you see are areas of crumb which have become dehydrated in the freezer.

The condition is exacerbated by any periods when the freezer has been

allowed to warm to temperatures above the freezing point of the product.


The higher temperatures accelerate moisture losses and the slow re-freezing

which follows also contributes to this particular problem. We suggest that

you look at your freezer performance and in particular any changes in con-

ditions during the defrost cycle. Also look closely at your operating proce-

dures and try to minimise the opening and closing of the freezer door. This

is a common cause of the problem because the cold air is lost and replaced

by warmer air which raises the temperature of the products nearest to the

door or lid.

Reference






9.12 WE HAVE SEEN REFERENCES TO THE MILTON KEYNESPROCESS BUT CAN FIND VERY LITTLE TECHNICALINFORMATION ON THE PROCESS. CAN YOU TELL ME WHATIT IS (WAS) AND HOW IT IS (WAS) USED?

There is relatively little technical literature which has been published on

the Milton Keynes process (MKP). Launched in 1995, it was a patented

process (Anon, 1995) based on the production of part-baked breads of many

different sizes, including pan breads, but differed from other part-baked

products of the time in that an extended ambient shelf-life of 5�12 days

before second baking was claimed. The process took its name from the

city in the United Kingdom in which the part-baked bread products were

manufactured (Grindley, 1996).

The process was evolved by a consortium of four companies; a retail

baker, a plant baker, a machinery manufacturer and a bread improver com-

pany (Bent, 2007). Pan breads were mixed using CBP-compatible mixers,

whereas oven bottom and French sticks were prepared with a spiral-type

mixer. The dough recipes were essentially the same as would be used with

CBP and NTD making with the addition of a suitable enzyme for retaining

crumb softness in the bread after bake-off. There were no special aspects of

dough processing. Steam was used in the initial bake and crust colouration

was kept to a minimum in the first bake.

Immediately after leaving the oven, the warm products in their pans or

on trays were transferred to be cooled under vacuum in a dedicated cooler.

Using this technique, cooling times were reduced for all product sizes.

After cooling and depanning, the products were sprayed with a preserva-

tive solution to help achieve the 5�12 days mould-free shelf-life claimed.

It was claimed that the preservative was volatilised during the second bak-

ing stage. Some in-store bakeries which employed the process were

equipped with a mini travelling oven for bake-off though rack and deck

ovens could be used.

It has been well understood for quite some time that bread staling is

reversed by a second bake (Cauvain, 2015) and that has always been an

underlying principle for all bake-off bread products. However, to fully

refresh the products, the core temperature must exceed 60�65�C and the rate

of staling after the second bake is considerably faster than after the initial

bake. In practice, this meant that consumers who were used to purchasing

baked products which took 3�4 days to become unacceptably firm were

faced with the MKP product which could take as little as 3�4 hours to reach

the same state unless the bake-off process had been carefully controlled and

full re-freshing had been achieved, this was often not the case in practice

when the MKP was rolled-out into many stores. As a consequence the level

of sales of bread products baked in the retail stores fell markedly and after

an initial fanfare of excitement the process slipped quietly into history.


References

Anon (1995). Manufacture of baked farinaceous foodstuffs, Patent WO 95/30333.

Bent, A.J., 2007. Speciality fermented goods. In: Cauvain, S.P., Young, L.S. (Eds.), Technology

of Breadmaking, second ed. Springer Science 1 Business Media, New York, NY,

pp. 245�274.


AG, Switzerland.

Grindley, E., 1996. Made in Milton Keynes. Bakers’ Review January, 16�17.














9.13 CAN YOU EXPLAIN THE PRINCIPLESOF VACUUM COOLING OF BAKED PRODUCTSAND ITS POTENTIAL APPLICATIONS?

The vacuum cooler comprises a sealable chamber in which the internal pres-

sure can be reduced to a level considerably lower than atmospheric pressure.

When the pressure inside a closed vessel is lowered and maintained below

atmospheric pressure, the temperature at which water boils is considerably

lowered. This is because a liquid boils when its saturated vapour pressure is

equal to the atmospheric pressure. For example, in the natural world water

boils at progressively lower temperatures as the height above sea-level

increases. The impact of reduced pressure on the boiling point of water can

be considerable; for example, if the pressure is reduced to half an atmosphere

(i.e., 0.5 bar) the boiling point falls from 100 to around 80�C.As evaporation losses play a major role in cooling baked products, hold-

ing the products at lower pressures to extract the latent heat considerably

reduces the cooling time required. For example, Cauvain (2015) compared

the core temperature of loaves cooled conventionally with those subjected to

vacuum cooling and showed that that the times taken to achieve a tempera-

ture of 25�C were about 100 and 10 minutes, respectively.

It should be noted that the vacuum cooling conditions will vary according

to the type of product being cooled. There are a number of different points to

consider. The first is that even though the temperature at which the water boils

has been considerably lowered, the rate at which moisture leaves the centre of

the product will be affected by the product dimensions. Heat (and moisture)

can only be lost from the surface of the baked product, and it will always take

longer for the evaporation front to reach the centre of the product. In practice,

this can mean a significant differential in moisture losses between the product

surface and its centre. For crusty bread products, this may be acceptable but

this will not be the case for pan breads. This effect may well have been one of

the contributing factors to the demise of the MKP (see Section 9.12).

Some bakery products can benefit the application of vacuum cooling.

This is especially true for products with ‘delicate’ structures which are diffi-

cult to handle at the end of the baking processes but are key to final product

quality; two examples are Panettoni and malt breads.

One of the claimed benefits for the application of vacuum cooling is that

the normal baking time can be reduced because of the contribution that vac-

uum cooling makes to the physical stability of the baked product structure.

This advantage may be negated by the likelihood that overall moisture losses

from vacuum cooled products may be higher than with conventional cooling.

Reference


AG, Switzerland.





Chapter 10

Testing Methods

10.1 WHAT IS MEANT BY HYDROGEN ION CONCENTRATIONAND HOW IS THE pH SCALE DETERMINED?

The term means just what it says, namely the concentration of hydrogen ions

that are present in a solution. It is a scientific method of referring to the

degree or intensity of acidity or alkalinity and is based on the fact that, in

solution, the molecules of some substances split up and disperse throughout

the liquid to a greater or lesser degree. The pH of a liquid tells not only

whether the liquid is acid or alkaline but also to what degree or extent.

The symbol pH stands for the ‘potential of hydrogen’. The word ‘ion’

means traveller, so that the hydrogen ion concentration refers to the degree

of dispersal of ions of hydrogen in a given solution. It also refers to the fact

that such hydrogen atoms are in an active condition and are charged with

positive electricity, commonly denoted as H1.

To understand this more, we must consider the state of affairs in pure

water. This is neither acid nor alkaline, but it has been calculated that in neu-

tral water one molecule in 10 million ionises or splits up and disperses as

one atom of hydrogen charged with positive electricity and one group of ele-

ments consisting of an atom of hydrogen and one of oxygen. This is known

as a hydroxyl group and is charged with negative electricity (OH2). There is

therefore complete neutrality, the positive charge on the hydrogen atom

exactly neutralising the negative charge of the hydroxyl group.

In pure water, being neutral, only one part in 10 million parts is in this

state of ionisation. Mathematically 1/10,000,000 can be expressed as 1027,

that is, 10 to the minus seventh power. Hence, in stating the pH of a neutral

liquid like pure water scientists write pH 7, omitting the minus sign as being

superfluous.

Let us now consider what happens when we have a liquid in which there

is a higher concentration of hydrogen ions such as is the case when an acid

is diluted with water. Here, there may be one part ionised hydrogen in a

million parts of the liquid. This can be expressed as 1/1,000,000, that is,

1026 and so is written pH 6. This shows that the liquid is acid in character,

but not very strongly so, for only one part in a million is actively acid or

capable of reacting as an acid.



http://dx.doi.org/10.1016/B978-0-08-100765-5.00010-2

The greater the intensity of the acid the greater the concentration of

hydrogen ions will be. The expressions pH 5, pH 4, pH 3, pH 2 and pH 1

mean, respectively, that one part in 100,000, 10,000, 1000, 100, and 10 are

in this condition. As the numeral beside the pH decreases, the intensity of

the acid present in the liquid increases (see Fig. 10.1).

In the case of neutral solutions, we still refer to the hydrogen ion con-

centration, but the dispersed atoms charged with positive electricity may

not necessarily be hydrogen. The groups of negatively charged elements,

however, neutralise these and alkaline reactions are recorded. For

example, in sodium hydroxide, a well-known alkali, the ionised molecule

will split up into one atom of sodium and one hydroxyl group. The former

carries a weak positive charge and the hydroxyl group a stronger negative

one, cancelling out the weak acid tendency and substituting stronger alka-

line tendencies. Thus stronger negative electrical charges can be recorded.

As the pH numeral increases so alkalinity increases, and whenever the

numeral is above seven the substance or solution of substances is alkaline.

The higher the figure above seven the greater the strength or intensity of

alkalinity will be.

Examples of the value of this information to the practical baker and

confectioner include:

� The development of rope in bread (see Section 4.1.4). Rope spores cannot

grow unless the dough or loaf is lacking in acidity. This degree of acidity

is known and provided the pH of the baked product lies between 5.4 and

5.5, rope cannot grow in dough or bread.

Concentration of H+ ion pH

1 g per litre 01 g per 10 litres 11 g per 100 litres 2

34

Acid increasing in multiples of 10 56

1 g per 10 million litres 789

Alkali increasing in multiples of 10 10111213

17 g OH per litre 14

FIGURE 10.1 pH scale.


� In the manufacture of high-ratio cherry cake, the low viscosity character

of the batter does not prevent the cherries from sinking during baking.

However, if an addition of tartaric acid is made to the batter to bring the

acidity to pH 5.4 or less, then the gluten of the flour is strengthened and

batter viscosity increases in the early stages of baking so that the cherries

remain suspended during baking (see Section 5.7). High protein, high-

ratio cake flour responds even more readily to the use of tartaric acid.

Testing Methods Chapter | 10 471

10.2 IN SOME TECHNICAL LITERATURE, THERE ISREFERENCE TO BATTER SPECIFIC GRAVITY OR RELATIVEDENSITY. WHAT IS THIS? HOW IS IT MEASURED?AND WHAT IS ITS RELEVANCE TO CAKE AND SPONGEMAKING? WHY IS THE VOLUME OF THE BAKED PRODUCTREFERRED TO IN TERMS OF SPECIFIC VOLUME?

It would seem logical to use the same unit of measurement for expressing

the mass concentration of unbaked batters and baked cake products.

However, when considering how this property is measured, it becomes

clearer why a large part of the industry continues to use the different

measures.

The density of a substance is its mass (weight) divided by its volume.

The amount of air occluded in a batter is monitored by measuring its cup

weight, that is, the weight of batter required to fill a cup of known volume.

As the same cup size or volume is used for the comparison, the cup weight

relates directly to specific gravity (now more commonly known as relative

density) and this figure is used in the bakery for process control purposes

without having to make any calculations. The lighter the cup and its contents

(i.e., the larger the volume of air in the batter), the lower the relative density.

Thus, batter relative density and batter specific gravity essentially mea-

sure the same property, the degree of aeration of the batter. Batter relative

density in cakemaking is most commonly related to product volume; usually,

the lower the batter relatively density, the larger the cake volume in a given

set of circumstances will be.

In contrast, baked products are monitored by measuring their volume,

and as this is an important physical characteristic related directly to spe-

cific volume, that is the volume of a known mass, so it is convenient to

use this term.

Thus, practical considerations lead to the continuing use of different units

in these circumstances for measuring mass concentration.


10.3 WHAT VALUE IS THERE IN MEASURING COLOUROF BAKERY PRODUCTS AND HOW CAN WE CARRY OUTTHE MEASUREMENTS?

The crust and crumb colours of bakery products are important properties and

provide important for the bakery with respect to ingredients and processing.

Crust colour is one of the immediate features of a bakery product that is

seen and recognised by consumers. In most cases, consumers will see ‘devia-

tions’ from the normal product crust colour as an indication that the product

concerned does not have the quality that they are seeking and so may reject

the product as unsuitable.

The formation of a particular crust colour is directly related to oven baking

conditions and the product formulation. Both are important due to their respec-

tive influence on the Maillard reactions (see Section 4.1.14) which are largely

responsible for the brown colour of the crust of most bakery products. The

Maillard reaction products also contribute to product flavour. The measure-

ment of crust colour is not only a useful indicator of variations from the prod-

uct norm but can also be used to aid diagnosis of those quality problems

which can change the colour.

Many of the ingredients used in the manufacture of bakery products

make a direct contribution to crumb colour. For example, the intrinsic colour

of the flour endosperm will affect bread colour as will the level of ash or

bran present in a white flour (see Section 2.2.1). In the case of crumb colour,

there is a complication arising from the cellular structure itself as different

cell sizes reflect light to different degrees, and this affects the human percep-

tion of crumb colour, especially when the crumb is viewed in glancing light.

This is an important consideration as this is comparable with the assessment

of product colour made by experts and consumers alike. However, it is sepa-

rate from the fundamental colour of the product.

There are a number of different ways in which colour can be assessed in

the bakery. It has become relatively common to measure the crust and crumb

colour of bakery products using various forms of colorimeter. The numerical

output of a colorimeter is related to standards developed by the Commission

Internationale de l’Eclairage and comprises a series of tristimulus (i.e., three)

values defined as XYZ which are also related to other defined colour spaces,

such as Yxy and L�a�b�. In simple terms, a colour space is a method for

expressing the colour of an object using numbers under carefully defined and

controlled conditions.

A number of different colour spaces have been developed over the years

hence the different notations that are encountered. However, the common

element to each colour space is that the colour of an object is defined by

three values. The different colour values are related mathematically, so it is

common for a given colorimeter to have the ability to deliver readings in all

of the standard notations.


One of the earliest ways of expressing colour was developed by an

American artist, A.H. Munsell, who devised a method of expressing

colour using a series of paper colour chips. He classified the colours

according to their hue, lightness and saturation. The principle of this

approach is illustrated by the so-called colour solid as shown in

Fig. 10.2 which has a spine of lightness values based on white to black.

A given colour (hue) around the circumference of the solid will become

more saturated (intense) the further the point is on a given radius from

the central spine.

The Munsell colour chip-based system remains available today and can

often be used for visually matching colours in many applications. For exam-

ple, for baked product crust colour using a limited number of ‘brown-

coloured’ chips. Visually, matching crumb colour with Munsell chips is

more difficult due to the effects of cell structure.

Further reading

Billmeyer, F.W., Saltzman, M., 1981. Principles of Color Technology, second ed. Wiley-

Interscience, New York, NY.

Hue

Ligh

tnes

s

Saturation

Black

White

FIGURE 10.2 Schematic of a ‘colour solid’.




10.4 HOW CAN WE MEASURE THE TEXTURE OF OUR BREADAND CAKES? CURRENTLY, WE USE A HAND SQUEEZE TESTFOR BREAD AND APPLY A ‘SCORE’ TO THE RESULTS

You can measure baked product texture using trained assessors or with

instrumentation. The latter has the advantage that the results are objective,

and they can be saved on a computer for quick retrieval and comparison

with other results. The values measured can be linked to a scoring system

when consumer panels have rated the product characteristics being

measured.

The most appropriate parameters for the texture of bread and cake pro-

ducts are firmness (compression of the crumb) and resilience (spring back

when pressed). These are the product attributes most commonly linked with

consumer perception of ‘freshness’ with bread and cake crumb. In the case

of bread and the consumer squeeze test, there is an expectation that bread

products are easily squeezed, but the product must also spring back after

compression. Spring back is less important with cake crumb but softness

remains a key property.

There are a number of different instruments capable of measuring crumb

softness and resilience. Texture analysers, e.g., Stable Micro Systems TA.

XT Plus Texture Analyser, are found in many research and quality testing

laboratories using different probes and fixtures according to the type of mea-

surement required (Cauvain, 2017).

There are a number of different methods which can be employed. One of

the common techniques for assessing baked product texture is known as

texture profile analysis (TPA) which employs a double compression of the

product crumb. The TPA profile of seven texture parameters was first estab-

lished by Szczesniak (1963) using sensory panels and related to objective

measurement (Bourne, 1978). The measurements made using TPA are

strongly correlated to the biting and chewing actions of consumers. Fig. 10.3

shows a typical curve from a TPA test on bread crumb. Although firmness is

the component most often measured in assessing texture, several other com-

ponents also contribute to overall texture. Crumb resilience can be deter-

mined by using relevant software with the appropriate instruments and

repeated compressions can be made on the same sample enabling sample

adhesiveness and cohesiveness to be measured.

When using instruments to assess product texture (or indeed if using sen-

sory assessment), it is important to take the measurement in the same loca-

tion of each sample to reduce the variations in readings (Cauvain, 1991).

The areas close to the crust should be avoided as they will have a dispropor-

tionately large effect on the test results because they will tend to be lower in

moisture content than the bulk of the product crumb. It is also the case that

many baked products, especially fermented products baked in pans, tend to

have an uneven density distribution throughout a slice cross-section; usually,

the crumb density is lower in the centre of the product than it is near to the


crust due to cell compression resulting from centre crumb expansion. Both

the product moisture content and the sample density impact on sensory and

objective texture measurements, and it is advisable to have the relevant data

when assessing the results of trials.

One instrument which mimics the squeeze test carried out by consumers

is the Bread V Squeeze Rig (Cauvain and Young, 2008; Cauvain, 2017).

It enables testing of packaged and un-packaged loaves. The rig allows

repeatable, scientific analysis of the freshness and appeal of bread. It consists

of ‘V’ shaped, rounded ‘fingers’, which are lowered onto the loaf and the

force required to compress the bread is measured. The lower the recorded

force and the higher the value of springiness, the fresher the loaf. This non-

destructive test offers simplicity in operation and speed of assessment as the

loaf requires no sample preparation and can be analysed within the packag-

ing. It enables the assessment of changes which occur in increased resistance

to compression (firming) and a loss of recovery when compressed, i.e.,

decreased springiness, as the loaf ages.

References

Bourne, M., 1978. Texture profile analysis. Food Technol. 32 (July), 62�66, 72.

Cauvain, S.P., 1991. Evaluating the texture of baked products. S. Afr. J. Food Sci. Nutr.

3 (Nov), 81�86.


and Applications, second ed. DEStech Publishing Inc, Lancaster, PA.



Szczesniak, A.S., 1963. Classification of textural characteristic. J. Food Sci. 28 (July�August),

385�389.

–1

0

1

2

3

4

5

6

7

0 5 10 15 20 25

Total travel of probe (mm)

Fo

rce

(N)

FIGURE 10.3 Typical texture profile analysis curve for bread crumb.















10.5 HOW CAN WE MEASURE BAKED PRODUCT SHAPEAND VOLUME?

There are a number of different methods which can be used to measure vol-

ume ranging from relatively simple objective methods to more sophisticated

instrumental methods. The choice of which method to use depends, in part,

on the type of product involved and the purpose for which the measurements

are required.

Simple but effective measurements can be made using measuring tapes or

calibrated rules to assess bread heights, lengths and breadths. From such

measurements, a crude assessment of bread volume can be made by sum-

ming the various measurements. In the case of pan bread, the width and

length dimensions will be fixed by the pan, so it may simply be sufficient to

record product height to assess variations in quality or the effects of ingredi-

ent or process changes.

The most common and long-established method used to measure bread

volume is the one referred to as ‘seed displacement’. In this technique, the

volume of a box of fixed dimensions is related to a given weight of seeds,

commonly rape seed though pearly barley may also be used. To assess the

volume of a loaf or other fermented product, a sample is placed in the box

with sufficient space between it and the walls of the box. Seed is then intro-

duced to fill the empty space surrounding the sample until it is full. Excess

seed is removed by scraping the upper surface level before taking out the sam-

ple being measured. The weight of the seed remaining in the box is recorded

and compared with the weight of seed required alone to fill the box. As the

bulk density of the seed is known, then an estimate of the product volume is

given. The equipment required for this type of measurement is relatively sim-

ple and can be effectively mechanised. A few commercial examples using this

technique exist but often the equipment is ‘home-made’ and related to the par-

ticular test bakery product which may be different from commercial products.

More recently, the measurements of baked products shape and volume

data is being measured using laser scanning with software that allows 2- and

3-D images of the product to be built up (Cauvain, 2017). Essentially, the

product profile is assembled by taking a series of very thin ‘slices’ though

the product and then integrating the various measurements to output such

characteristics as volume, height, breadth. These scanning devices have the

advantage of being non-contact and so potential problems with the crushing

of delicate products from the introduction of seeds is avoided. Sampling han-

dling is also kept to a minimum which is an advantage with delicate products

such as laminated pastries.

Bread and cake slice shape data may also be combined with the measure-

ment of internal features such as cell structure. One such instrument is

C-Cell (Cauvain, 2017) which provides 48 different shape and cell structure

measurements from slices of bread and cake.


Bread shape and volume data are usually gathered on samples which

have been removed from the line for assessment, but with the advent of line-

age analysis techniques, it is now possible to collect some of these data

online using laser scanners. Products shape and height data can be measured

online, and while for some product (e.g., lidded pan bread), the height data

can be related to product volume, a true measurement of loaf volume online

is not possible.

Reference


and Applications, second ed. DEStech Publications Inc, Lancaster, PA.




10.6 WHAT IS THE PHOSPHATASE TEST?

Phosphatase is an enzyme associated with animal, insect and microbial activity.

The phosphatase test is often used to establish whether or not an insect has

been baked in a product or entered after the product has left the oven. It is valid

for samples which have been stored for a long time. Even after several years’

storage, dead insects give a strong positive reaction.

The materials required are as follows:

Buffer solution

3.5-g anhydrous sodium carbonate (analytical grade) and 1.5-g sodium

bicarbonate (analytical grade) per litre. (The buffer may be stored for up to 3

months in a tightly stopped container of resistant glass.)

Substrate

Disodium para-nitrophenol phosphate.

Buffer substrate

Transfer 0.15 g of the substrate to a 100 mL measuring cylinder and

make up to 100 mL with the buffer solution. This solution should not be

stored for long periods, but may be kept refrigerated for a week.

Testing procedure

Rinse the insect or fragments with water and then crush with a glass

rod. After mixing the fragments with a few drops of water, transfer to a

test tube and make with rinsings with water to about 1 mL. Add 5 mL of

buffer substrate and, after mixing, incubate at 37�C. Simultaneously, incu-

bate a blank comprising 5 mL buffer substrate and 1 mL distilled water.

After 30 minutes, compare the colours of the tubes. Normally the pres-

ence of phosphatase is indicated by the production of a dark yellow colour

within 30 minutes. Weakly positive tubes may require longer for the full

colour to develop. A negative result suggests that the insect or fragments

had been heated.

The disadvantages of the test are as follows:

� The test virtually destroys the sample.

� Very small insects do not give a sufficiently strong reaction.

� False positive results may be given if the product sample is heavily con-

taminated with microorganisms, e.g., moulds.


10.7 WHAT IS THE BOHN’S SPOT TEST ANDWHAT IS IT USED FOR?

The Bohn’s spot test was developed for use with soda crackers and is

designed to test their alkalinity. The test is based on applying a chemical

indicator to a broken surface of the products; the colour of the spot which

shows indicates the pH of the product.

The reagent is phenol red indicator prepared by dissolving 0.02 g phenol

red in a small amount of ethyl alcohol and diluting the mixture to 100 mL

with distilled water; ready-made solutions may also be available.

A drop of distilled water is first placed on the surface of a freshly broken

surface of a cracker followed by a drop of the prepared indicator and the

colour change observed. The relationship between the colour and the pH of

the product is as follows:

Colour pH Range

Lemon yellow Below 7.0

Orange 7.1�7.4

Pink to red 7.5�7.7

Reddish purple 7.8�8.2

Purple Above 8.2

Other reagents which are colour sensitive can be prepared (or obtained)

to cover other ranges within the pH scale. Such tests can only be applied to

products which are not coloured. In addition to quickly revealing a product

pH, spot tests of this type can be used for identifying whether the compo-

nents of baking powders are fully reacted because unreacted baking powder

components will show as vividly coloured spots against the background

colour of the product matrix.

An alternative method for determining the cracker pH would be by using

a pH meter. Grind about 10 g of the products to a fine powder in a pestle

and mortar and suspend the ground material in 100 mL of distilled water,

leave for a few minutes before checking the pH with the meter.


Chapter 11

What?

11.1 WHAT IS THE MEANING OF THE TERM SYNERISISWHEN APPLIED TO BREAD?

Syneresis is the name given to a particular physical or colloidal change that

takes place in starch and other gels as they age. It is caused by crystallisation

or aggregation of polymers causing loss of water from the surface of compo-

nents. It is common with some starch gels, particularly those subjected to

freezing and thawing. The released water may evaporate to be absorbed by

other components by diffusion or vapour phase transfer, or may be lost from

the product/component causing it to dry out and shrink.

It is the change in starch crystallinity that brings about the staling of

bread that is a day or two old causing a sensory change equivalent to convey

the impression that the bread contains less moisture and therefore to have

lost its freshness. Bread may lose actual water during the process of staling,

but there are many other changes occurring at the same time which will

account for the dry-eating qualities of the bread (Cauvain, 2015). This

change in the condition of the starch is sometimes described as the ‘process

of syneresis’ and is affected by the temperature and humidity under which

the bread is kept.

If a loaf is kept for several days, there is bound to be a loss of water by

evaporation, but this water will not be lost regularly from the entire loaf.

The loss is greatest at the part which is nearest to the crust. It has been

shown that the loss of moisture from the centre of a loaf is exceedingly small

and at the end of 2 weeks the moisture in the centre of a loaf is almost same

as the beginning. It would mean that if the outside portion of the loaf was

cut off the interior would be almost as moist eating as a loaf a day old.

However, this is not the case in sensory terms. A loaf several days old will

be dry eating and stale equally throughout its whole structure. In fact, there

is a change in the method by which moisture is held in the loaf.

To illustrate this, prepare a stiff starch jelly which can be made and

allowed to stand for a day or two. The water will partially separate out and

will be seen on the surface whilst the gelatinised starch will seem to have

become more solid. We can presume that something similar will occur in

bread during storage. The starch will separate slightly from the water it was



http://dx.doi.org/10.1016/B978-0-08-100765-5.00011-4

holding at the outset and the particles of bread will become dense and more

insoluble, though apparently it does not mean that the small amount of water

that has separated out will be evaporated. The bread particles being denser

will be harder to mix with saliva in the mouth so that a sensation of dryness

and a difficulty in masticating the bread are experienced and make us think

that the bread is dry.

Another point affecting the condition of the starch is the temperature

at which the bread is stored. Bread stored at 4�C stales more rapidly than that

stored at room temperature or under frozen conditions. At a low temperature

of 25�C staling does not occur, though the act of freezing and thawing bread

us the equivalent of 24 hours storage at ambient (Pence and Standridge, 1955).

References


AG, Switzerland.

Pence, J.W., Standridge, N.N., 1955. Effect of storage temperature and freezing on the firming

of a commercial bread. Cereal Chem. 32, 519�526.







11.2 WHAT IS A SUPER-SATURATED SOLUTION?

Sugar is soluble in water. Water is therefore the solvent and sugar is the solute.

When a solvent is filled with the substance in solution so that it cannot dissolve

any more it is said to have formed a ‘saturated’ solution of that substance. To

illustrate the principle of super-saturation, start by dissolving as much sugar as

possible into some water in a beaker. After adding sugar and constantly stirring

the mixture for some time, you will find it impossible to dissolve any more

sugar. If you do add more, it will remain undissolved and sink to the bottom of

the beaker. If the contents of the beaker are now gently heated, the sugar at the

bottom will dissolve, and if more sugar is added to the mixture, it can also be

dissolved. This process can be continued until once again the water can dis-

solve no more sugar. Again the water is saturated with sugar. It is obvious that

the same amount of hot water has more sugar in solution than it could hold

when cold. If the solution is then allowed to cool without stirring to the same

temperature as the cold solution, the previously warmed solution will contain

more sucrose, it will actually be a cold ‘super-saturated’ solution.

If a quantity of water at boiling point in which is dissolved as much sugar

as it can hold is continued to be heated then as the solution boils water is

driven off but the amount of sugar remains the same. This results in a hot

super-saturated solution. The longer the solution is heated, the less water

remains and the greater the degree of super-saturation. This causes a rise in

temperature which continues to increase until not only is all the water driven

off but the sugar decomposes. At any stage between the production of a

super-saturation until caramelisation occurs, the solution is in a very

unstable condition.

It would be easy to understand how simple it would be to cause the sugar

to form again as crystals, and very little agitation, or merely the addition of a

single crystal of sugar will cause the whole of the sugar to crystallise out

again. This must be guarded against in the boiling of sugar and is also seen

in some icings as surface eruptions. To prevent the mass from graining

through the ebullition of boiling liquid, an acid (usually cream of tartar) is

added or an amorphous sugar, such as corn syrup, which effectively does the

work of preventing graining taking place until it is required to happen.

The formation of saturated and super-saturated solutions has particular

relevance to the baking of cakes, biscuit and cookies where they contribute

to structure formation, such as flow with cookies. The preparation of icings

and fondants relies on the careful cooling of a super-saturated solution and

the prevention of recrystallisation and the formation of graininess in the final

product.

What? Chapter | 11 483

11.3 I HAVE HEARD THE TERMS ‘GLYCAEMIC INDEX’ AND‘GLYCAEMIC LOAD’ USED WHEN DESCRIBING BAKERYPRODUCTS. WHAT ARE THEY AND WHAT IS THEDIFFERENCE?

Both terms are used to describe the way food is digested by the body. The

glycaemic index (GI) of a food measures its immediate effect on blood glu-

cose levels over a short period of time following ingestion of a food. It is the

blood glucose profile of 50 g of available carbohydrate in a test food com-

pared with 50 g of glucose. On the index, glucose is taken as 100 since it

causes the greatest and most rapid rise in blood glucose � all other foods are

rated in comparison to glucose.

GI is a measure of how quickly a particular food triggers a rise in blood

sugar level and the rate blood sugar level drops off. It is a physiological

measure of how fast, and to what extent, a carbohydrate food affects blood

glucose levels. The type of carbohydrate in a food influences blood sugar

levels.

GI has its limitations in that it can only be accurately measured from a

blood sample. It only measures the ‘available’ carbohydrate and ingredients

that reduce digestability such as resistant starches are not taken into account

as they are digested later in the lower intestine. Processing can change a

food’s GI value. Fat, protein and a lower pH in a food all reduce product GI.

The table below shows the GI categories that foods can be placed in (the

sugar glucose has a ranking of 100).

GI Rating

Low ,36

Medium 36�50

High .50

The glycaemic load (GL) of a food is an expression of how much impact

or power the food will have in affecting blood glucose levels. It is calculated

by taking the percentage of the food’s carbohydrate content per portion and

multiplying it by its GI value

GL5% carbohydrate per portion3GI

100

GL is thus a measure that incorporates both the quantity and quality of

the dietary carbohydrates consumed. For example, the GL of one slice of a

seeded loaf is only eight. In contrast, a slice of brown or white bread has a

GL of 16. This means that ordinary brown or white bread will spike blood

glucose levels (higher GL), and the seeded loaf will not (lower GL). In addi-

tion, the GL of a roll (equivalent to two slices of bread) is more than 20, and


that of a bagel (equivalent to three slices of bread) is more than 30. In simple

terms the GI indicates the extent to which a food will raise blood glucose

levels, whereas the GL is the ‘power’ or ‘push’ behind the GI.

A comparison of the GI and GL for some typical bakery foods is given

below.

Product Carbohydrate concentration GI GL (typical portion)

White bread 45 40

Wholemeal bread 47 50 ,70 (1 slice)

Crackers 60 80 ,5 (1 biscuit)

Shortbread biscuit 68 55 ,5 (1 biscuit)

Satiety is another term linked to GI; it is a measure of the time a food

gives us a feeling of ‘fullness’. A food which is high in carbohydrates with

low GI take longer to digest and so give the feeling of ‘fullness’ for a longer

period of time. The term has come to the fore more recently with the con-

cerns over obesity and the drive towards healthier eating. An index of

Satiety has been drawn up (Holt, 1998) and examples are given below (com-

pared with white bread with index of 100), but the credibility of this

approach has yet to achieve universal acceptance.

Product Satiety index (%)

Wholemeal bread 157Cake 65Cookies 120Croissant 47Crackers 127

Reference

Holt, S. (1998) Diabetes Interview, May, pp. 1, 12�14. www.mendosa.com/satiety.htm.


http://www.mendosa.com/satiety.htm

11.4 WHAT ARE PRO- AND PREBIOTICS AND HOW CANTHEY BE USED IN OUR BREAD PRODUCTS?

A probiotic is a living microorganism considered beneficial to the human body,

particularly in the functioning of the gut. These beneficial bacteria are found

naturally in various fermented foods, e.g., yoghurt, but do not survive heat and

so would be destroyed by the high temperatures employed in baking and so

have no significant role in the technological formulation of bakery products.

Prebiotics are non-digestible dietary fibres that provide a food source for

beneficial bacteria and enhance the benefits of probiotics. Bifidobacteria

(good bacteria) contribute to health by enabling the digestive system to pro-

duce short chain fatty acids that lower the pH in the digestive system. This

in turn helps to increase the absorption of the minerals calcium and magne-

sium in the body. The intestine contains 70�80% of the body’s immune cells

and about the same number of neurons as in the spinal cord. Prebiotic dietary

fibres are found naturally in plants and can, in some cases, be produced by

enzymatic conversion from sugar. They pass unaltered through the stomach

and are fermented by gut microflora and selectively stimulate the growth and

activities of bacteria. The high molecular weight sugars referred to as oligo-

saccharides dominate this category and they include fructooligosaccharides

(FOS), inulin, arabinogalactans and lactulose.

FOS and inulin are particularly favoured by lactobacilli and bifidobacter-

ia in the gut. Lactobacilli can convert sugars into lactic acid, inhibiting the

proliferation of certain harmful bacteria, while also lowering the pH of the

gut. Bifidobacteria convert dietary fibre to lactic acid.

Inulin and oligofructose are made from chicory root (good source) and

are also found in artichokes, leeks, onions and garlic. In their pure form they

have a clean taste and are hygroscopic (prevent water loss) and when used in

cereal bars help keep them soft-easting. They increase beneficial bifidobac-

tria in the colon by creating a barrier effect thus reducing the potential

impact of ‘bad’ bacteria such as salmonella and clostridia.

The use of prebiotics, such as inulin, in bread products has been part of a

growing market of health-promoting speciality products. They can be incor-

porated at low levels in bakery formulations. The structure and colour of the

product into which they are incorporated should be monitored.

If you are going to use prebiotic ingredients you should check that they are

approved for use in your geographical location. You should also check the

validity of any health claims that you make and whether they are permissible

for use in marketing and promoting any products containing prebiotics.

Further reading

Myers, S. (2006). The Functionality of Probiotics and Prebiotics: Bringing Life to Functional

Foods and Beverages. http://www.naturalproductsinsider.com/articles/06oct16feat02.html.


http://www.naturalproductsinsider.com/articles/06oct16feat02.html

11.5 CAN YOU PLEASE EXPLAIN THE DIFFERENCE BETWEENHYDRATION AND HYDROLYSIS? WHAT IS THEIR RELEVANCETO THE MANUFACTURE OF BAKED GOODS?

Hydration and hydrolysis refer to reactions which involve water. Hydration is

the addition of water to a substance, whereas hydrolysis indicates those chemical

changes in which water reacts with a substance to yield two or more products.

Hydration is the more familiar term in baking because it is a necessary

first step in the formation of doughs and batters. In breadmaking, the hydra-

tion of the flour proteins during mixing aids the formation of the disulphide

bonds which are an important element of dough development. Hydration of

the flour proteins also occurs in the manufacture of biscuits, cakes and pas-

tries, but in the case of these products, the development of a gluten network

is limited by recipe and process factors.

The processes of hydration and hydrolysis are best understood by consid-

ering the reactions between water and starch in baked products. When starch

is mixed with water the granules become hydrated; that is water penetrates

the granules and this is part of the process related to the water absorption

capacity of the flour (see Section 2.2.3). In wheat flour, it is the damaged

starch which are most rapidly hydrated, and they absorb about four times of

water that will be absorbed by the undamaged granules (Cauvain, 2015).

The hydration of starch leads to hydrolysis. However, for the hydrolysis to

occur with wheat starch, both alpha- and beta-amylase enzymes need to be

present. In most cases, both enzymes are present and so are able to catalyse the

hydrolysis reaction. The full hydrolysis reaction may be described as follows:

Starch1waterðin the presence of amylase enzymesÞyields glucose1 fructose

The above equation is a simplified version of a complex reaction which

takes place in the manufacture of baked products. The heat which is intro-

duced during baking inactivates the enzymes and overall process times are

too short for the full conversion of all of the starch to sugars. This is just as

well because starch is an important component in baked product structure,

even in bread with its extensive gluten network. A substantial part of the

starch is not hydrolysed, and in baked products, there are a series of sub-

stances which are intermediate between starch and sugars; most notable of

which are the dextrins which can give rise to problems with bread quality.

Reference


AG, Switzerland.




11.6 WHAT IS MEANT BY THE TERM ‘GLASS TRANSITIONTEMPERATURE’ AND WHAT IS ITS RELEVANCE TO BAKING?

In simple terms, the glass transition temperature refers to the temperature

below which a food will be stable, i.e., not change, when stored for long per-

iods of time. It is commonly referred to by the notation Tg. The glass transi-

tion temperature of a particular food is unique to that food and is directly

related to its composition. The stability of a food refers to both its physical,

chemical and microbial condition.

The concept of glass transition comes from polymer science. The compo-

sition of bakery foods is a mixture of complex polymers (e.g., the starch and

proteins). Above its Tg, a bakery food is considered to exist in a ‘rubbery’

state. The use of the word rubbery does not refer to the texture of a product

but indicates that it is unstable and likely to undergo change during storage;

the staling of bread is an obvious example as the product increases in firm-

ness even though there may be no loss in overall moisture during storage

(Cauvain, 2015). If the temperature at which the bread is stored is lowered a

point is eventually reached at which firming stops, this is the Tg for that

bread and the product is now said to be in a ‘glassy’ state. In the glassy state,

the product will have a very long shelf-life because the water in the product

is effectively immobilised in the product. Materials may have a number of

glassy states depending on how the glass has been formed (Roos, 2007). The

rate at which a bakery product cools to reach its Tg has a significant effect

on how the water molecules become immobilised in the product and this

how it will behave in storage.

Many bakery products are stored and consumed at temperatures at which

they exist in a rubbery state and this limits their microbial and sensory shelf-

lives. This knowledge of a product’s Tg and in particular how to manipulate

it through reformulation to achieve a more stable storage state has significant

practical implications for the development of bakery products.

One of the difficulties facing bakers is that the glass transition concept is

not easily applied in the practice of product reformulation. More readily

applied is the measurement or calculation of water activity [or equilibrium

relative humidity (ERH)], and it is this property that finds most practical use

in baking (Cauvain and Young, 2008).

References

Cauvain, S., 2015. Technology of Breadmaking, third ed. Springer Publishing International,

Switzerland.



Roos, Y.R., 2007. Water activity and glass transition. In: Barbosa-Canovas, G.V., Fontana Jr., A.J.,

Schmidt, S.J., Labuza, T.P. (Eds.), Water Activity in Foods: Fundamentals and Applications.

Blackwell Publishing, Oxford, UK, pp. 29�48.










11.7 WHAT DOES THE TERM MVTR MEAN WHEN APPLIEDTO PACKAGING, AND WHAT IS THE RELEVANCE TO BAKEDPRODUCTS?

MVTR stands for moisture vapour transpiration rate, and when applied to

packaging material, it is a measure of the rate at which moisture passes

through a wrapping material. In metric units, it is a measure of the grams of

moisture which would pass through 1 square metre of packaging material per

24 hours at a temperature of 38�C in an atmosphere of 90% relative humid-

ity. In the USA, a similar term water vapour transpiration rate is used and

is expressed in grams per 100 square inches per 24 hours at 100�Fwith 90% relative humidity. For example, a 25μm gauge basic coextruded

polypropylene film might have a MVTR of 5 g/m2/24 hours at 38�C.Moisture- impermeable films would have a zero MVTR.

Packaging is used for baked products to preserve optimum product qual-

ity and prevent contamination by microorganisms or other means, to protect

them from physical damage and to make them attractive and to deliver ingre-

dient, nutritional and other information to consumers.

When purchasing packaging materials for baked products, the baker has

to decide whether it is advantageous or not to the product for moisture to

pass out through the wrapping film or whether the packaging needs to pre-

vent moisture escaping or entering the pack. In the case of biscuits, using a

moisture-impermeable wrapper is about restricting the risk of moisture

being absorbed from the atmosphere by the product which could result in

softening of the product texture rather than retention of its crunchy-eating

character. The consumer would perceive this softening as a staling of the

product.

The permeability of packaging materials can affect moisture migration in

the product by affecting the relative humidity of the atmosphere surrounding

the product (Cauvain and Young, 2008). Packaging materials with low

MVTR create high relative humidities in the pack atmosphere, and this

means that an equilibrium can be reached between product and atmosphere.

The impact on product quality will depend on factors like the ERH of the

product since products with low ERHs lose water less readily.

Packaging films can be used to keep the product’s key attributes for a

longer period as the type used influences the rate of moisture movement

both within and from the product, and therefore the product freshness. An

example is bread packaged in a moisture-impermeable film, the product

reaches equilibrium fairly quickly, with the crust softening but with little

loss of moisture from the product overall. This situation is suited to pan

bread character but not to crusty breads. In crusty breads, some extension of

freshness, i.e., retention of crust crispness, can be achieved by allowing

some moisture to escape from the product to the surrounding atmosphere so

that there is always a moisture gradient throughout the product. The negative


side to this approach is that the crumb moisture content falls rapidly to a

level that is organoleptically unacceptable. A perforated film is most com-

monly used to slow down moisture loss from crusty products while trying to

retain crust crispness (see Fig. 11.1).

The permeability of the wrapper may be deliberately increased to main-

tain the eating quality of the product. For example, semi-permeable wrappers

may be used to prevent pastry products from reaching equilibrium with their

fillings thereby maintaining pastry crispness. The link between the type of

packaging and the quality of stored foods is discussed in some detail by

Stollman et al. (1996).

The volume of air enclosed in the pack has a significant role to play as

the amount of moisture that can evaporate depends on the mass of moisture

that can be held by the air in the pack. Fluctuating temperatures, e.g., in

transport or storage, can create significant problems as the mass of water

that the air is capable of holding varies with temperatures. Wrapped products

moving from high to low temperatures are at risk from condensation with

subsequent quality losses and increased risks of microbial growth.

References


Effects. Wiley-Blackwell, Oxford, UK.

Stollman, U., Johansson, F., Leufven, A., 1996. Packaging and food quality. In: Man, C.M.D.,

Jones, A.A. (Eds.), Shelf Life Evaluation of Foods. Blackie Academic & Professional,

London, UK, pp. 40�51.

FIGURE 11.1 Perforated film with crusty bread product.








11.8 WHAT IS MEANT BY THE TERM ‘MODIFIEDATMOSPHERE PACKAGING’ AND HOW CAN WE USE THISAPPROACH IN THE PRODUCTION OF BAKED PRODUCTS?

Modified atmosphere packaging is the term used to describe the way the

atmosphere surrounding a product in its packaging material is changed from

air to some other combination of gases to extend its mould-free shelf-life

(MFSL). It is also known as ‘gas flushing’. The gases employed are usually

carbon dioxide or nitrogen, commonly as a mixture of the two.

This form of preservation is suitable for many types of baked product,

and whilst it has cost implications, it does not affect product flavour, aroma

or appearance, and it may not need to be declared as an ingredient on the

product label. Carbon dioxide has an inhibitory effect on the growth of aero-

bic microorganisms such as moulds. The greater the concentration of CO2,

the greater is the preservation effect (Cauvain, 2015). In some cases, it can

give up to 400% additional shelf-life days. It is often used for higher value

products. It is known that some moulds are more affected than others, e.g.,

those present on shorter shelf-life products such as breads are less sensitive

than those present on cakes with a lower ERH. Fig. 11.2 shows the typical

increases in MFSL for different bakery products at different concentrations

of CO2. As the packaging atmosphere is gaseous, it has the advantage of pro-

tecting all surfaces of the product.

The inert gas nitrogen can also be used as the flushing gas though it does

not exhibit any anti-mould activity. It is the fact that the nitrogen replaces

the oxygen and causes the atmosphere surrounding the product to become

anaerobic that inhibits mould growth. In this case, the percentage of nitrogen

in the headspace must be at least 99% by volume and great care must be

taken with the seals and wrapping material to ensure that no oxygen (as air)

can enter the pack. Nitrogen is more commonly used along with CO2 to pre-

vent the package collapsing as CO2 is absorbed into the product.

0

100

200

300

400

500

0 20 40 60 80 100Average CO2 concentration (% by

volume)

Incr

ease

in m

ould

-fr

ee s

helf-

life

%

Madiera cake

Crumpets, fruitpies

Rye bread, breadrolls

FIGURE 11.2 Increase in mould-free shelf-life of various bakery products packaged in differ-

ent concentrations of CO2.


Whether using carbon dioxide or nitrogen care must be taken over the

integrity of the seals of the packaging and the permeability of the packaging

material which is often laminated. If longer increases in shelf-life are

required, then a gas impermeable material should be used.

Reference


AG, Switzerland.




11.9 WE HAVE HEARD PEOPLE REFERRING TO SYNERGY INTHE USE OF INGREDIENTS IN BAKING PROCESSES, WHAT ISTHIS PROCESS AND CAN YOU IDENTIFY ANY EXAMPLES?

Synergy can be said to have occurred when the combined effect of a com-

posite addition of two or more ingredients is greater than the sum of the indi-

vidual contributions. In simple terms, it is like saying that if each of two

ingredients contribute two units of effect then the end benefit of adding them

in combination is greater than four, in other words it is a case of

2 1 2 5 5. In many cases when you encounter the term being used in bak-

ing parlance, it is being used to describe ‘additive’ effects when 21 25 4.

The term is most commonly used in connection with the mixture of com-

ponents that characterise bread improvers and dough conditioners and most

usually linked with dough or bread quality improvements in terms of loaf

volume and crumb softness.

A well-documented instance of synergy is that related to the addition of

ascorbic acid and potassium bromate in the manufacture of bread. The past

use of potassium bromate and ascorbic acid in the Chorleywood bread pro-

cess (Cauvain and Young, 2006) was an example of synergy in that the com-

bined action was not from an interaction between the two oxidants but from

individual reactions with different thiol groups of the flour proteins that were

unique to each of the two oxidants. It is also known that the application of

partial vacuum during mixing with the Chorleywood bread process had a

direct impact on the synergy and different mixers can also influence the

degree of synergy by changing the availability of oxygen.

Another example of synergy is the increased effectiveness of antimicrobial

ingredients when the pH of a bakery product is lowered. In this case, the

microorganisms are confronted with so-called ‘hurdle’ effects. The opportu-

nities for using pH to control microbial growth on bakery products are rela-

tively limited because most baked products have pHs in the range 5.0�7.5,

and in this range, most microorganisms will remain active. However, the com-

bination of preservative and pH can be very effective. For example, Cauvain

and Young (2008) cite data showing that in cake (92% ERH) treated with the

addition 1000-ppm sorbic acid, lowering the pH from 7.0 to 5.0 increased the

MFSL of the product from around 5 to 21 days. The addition of the sorbic

acid alone had only increased the shelf-life by 1 day (i.e., 4 to 5 days).

References


Cambridge, UK.








11.10 WHAT ARE POLYOLS AND HOW ARE THEY USEDIN BAKING?

Polyols, or polyhdric alcohols to use the full descriptor, is a term used to

cover a wide range of sugar alcohols, that is ingredients derived from the

reduction of sugars (both mono and polysaccharides). They have some com-

mon attributes including that they have fewer calories per gram than sugar

and are not associated with tooth decay. Because of these two properties,

polyols are often seen to be alternatives to sugars, especially in cakes and

biscuits, especially in the context of calorie reduced products. This some-

times leads to the claim that polyols can be used as fat-replacers, but in prac-

tice, they supply none of the functionality of fat in baked products.

Among their other properties polyols have a cooling effect on the tongue

and do not readily take part in Maillard browning reactions. A particularly

important property of some of the polyols is that their addition will lower the

water activity of a product with the benefits of increasing the MFSL of pro-

ducts. For example, sorbitol solids are twice as effective as sucrose (weight

for weight) at lowering product water activity and so may be used in cake

formulations to increase ambient shelf-life.

Polyols affect the glass transition temperature of baked products and so

may be used in product formulations for frozen products to minimise product

changes as the result of from storage or to encourage changes in product eat-

ing character, see Fig. 11.3 (Cauvain, 1998). Polyols have a significant

impact on starch gelatinisation characteristics so that when used in cake

making they will affect product shape.

One of the negative features of polyols and their use is that high levels

can contribute a laxative effect in the human body. For this reason, their

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 20 40 60 80 100Frozen storage time (days)

Cak

e cr

umb

cohe

sive

ness

SucroseLactitolSorbitol

FIGURE 11.3 Effect polyols and freezing on cake crumbliness.


levels of daily consumption may be subject to mandatory and voluntary

restrictions, especially in products aimed at children or the elderly. You

should check the position for your own part of the world before undertaking

any product development as this may limit the practical levels of addition

that you might make. Remember that if you use more than one polyol, it is

the total of their addition which must be used in making any estimates as to

likely daily consumption.

Examples of polyols include:

� Sorbitol, 2.6 calories/g, approximately 50�70% sweetness of sucrose,

used in cakes to lower water activity (see above), available as an

aqueous-based liquid.

� Xylitol, 2.4 calories/g, 100% sweetness of sucrose, used in special dietary

foods.

� Maltitol, 2.1 calories/g, approximately 75% sweetness of sucrose, used in

cakes and chocolate.

� Isomalt, 2.0 calories/g, approximately 45�65% sweetness of sucrose,

used in wafers.

� Lactitol, 2.0 calories/g, approximately 30�40% sweetness of sucrose,

used in cakes, cookies and chocolate.

� Mannitol, 1.6 calories/g, approximately 50�70% sweetness of sucrose,

used in chocolate flavoured coatings.

� Erythritol, 0.2 calories/g, approximately 60�80% sweetness of sucrose,

used in low calorie foods.

� Hydrogenated starch hydrolysates, 3.0 calories/g, approximately 25�50%

sweetness of sucrose, used in low calories foods.

� Fructo-oligosaccharide, derived from sugar beet, 2.0 calories/g, approxi-

mately 30% sweetness of sucrose, used in cakes, cookies, crackers and

biscuits.

� Tagatose, derived from lactose, 1.5 calories/g, approximately 92% sweet-

ness of sucrose, used in frostings and fillings.

� Trehalose, occurs in nature (e.g., honey), commercially derived from

corn starch, 4 calories/g, approximately 50% sweetness of sucrose, used

in frosting and fillings, claimed to have cryoprotectant effect on protein

structures and cell structures which may be dehydrated or frozen. The lat-

ter claim is commonly linked with freezing bakers’ yeast.

Reference

Cauvain, S.P., 1998. Improving the control of staling in frozen bakery products. Trends Food

Sci. Technol. 9, 56�61.

Further readingNelson, A.L., 2000. Sweetners: Alternative. Eagan Press, St. Paul, MN.






11.11 WHAT IS ACRYLAMIDE? WHERE DOES IT COME FROMAND HOW DO WE LIMIT IT?

Acrylamide is a neuoptoxin suspected to be a carcinogen in animals and

humans. It is formed as a result of side reactions that take place in starchy/

high carbohydrate foods alongside the Maillard reaction and in the presence of

asparagines, a reducing sugar (such as glucose) and heat (baking, frying or

toasting). Asparagine is a natural occurring amino acid present in some

protein-rich raw materials of plant origin which includes grains and flours.

The levels of acrylamide which form in baked products are very low and only

occur at temperatures above 120�C. This means than any acrylamide which is

present is most commonly associated with the crust of baked products.

It can be limited by controlling the formation of the precursors to acryl-

amide (mainly asparagines) by altering the mechanisms by which it is

formed; e.g., by reducing the temperatures and time in baking or reducing or

replacing some of the acrylamide-promoting ingredients, such as the reduc-

ing sugars, in the formulation. It is claimed that when using some types of

processing, such as prolonged fermentation, acrylamide formation can be

minimised. Introducing steam in the final part of baking has been shown to

reduce the formation of acrylamide (www.heatox.org). It has also been

shown to be limited by the addition of ingredients such as free glycine

(another naturally occurring amino acid), but it should be noted that adding

high quantities of glycine to bread dough may lead to reduced yeast activity.

Some ingredient manufacturers have developed enzyme preparations

based on aspariginase from Aspergillus niger or Aspergillus oryzae or bacte-

ria as part of an acrylaimde reduction strategy (de Boer et al., 2005). These

enzymes convert asparagines into another naturally occurring amino acid

called aspartate or aspartic acid. This means that the asparagine is no longer

available for taking part in the acrylamide-forming reaction, and it is claimed

that such enzymes do not affect the nutritional properties, browning or taste

aspects of products.

In the EU, the Confederation of the Food and Drink Industries (CIAA)

has released a series of ‘Toolbox’ guides advising manufacturers on how

they can reduce acrylamide in the manufacture of foods (http://www.food-

drinkeurope.eu/publications/category/toolkits/).

Reference

de Boer, L., Meermans, C.E.M., Meima, R.B., 2005. Reduction of acrylamide formation in bak-

ery products by application of Aspergillius niger asparaginase. In: Cauvain, S.P., Salmon,

S.E., Young, L.S. (Eds.), Using Cereal Science and Technology for the Benefit of

Consumers. Woodhead Publishing Ltd, Cambridge, UK.


http://www.heatox.org

http://www.fooddrinkeurope.eu/publications/category/toolkits/

http://www.fooddrinkeurope.eu/publications/category/toolkits/





11.12 WHAT IS OSMOTIC PRESSURE AND WHAT IS ITSRELEVANCE TO BAKING?

Osmotic pressure refers to the concentration of soluble particles in two solu-

tions which are separated by a permeable membrane; this is a membrane

which can allow the free intermingling of the two solutions. This intermin-

gling will occur if the concentration of soluble particles on one side of the

membrane is different to that on the other side. The natural movement is for

the particles in the concentrated solution to move through the membrane to

the diluter solution. Eventually, the concentrations of the two solutions will

become equal, and at that moment, the osmotic pressure will become zero.

Thus osmotic pressure can only exist when the concentration of particles in

the two solutions are unequal.

Osmotic pressure is particularly relevant to yeast fermentation. The con-

tents of the yeast cell are contained within a double cell wall; this is the

equivalent of the membrane described above. There are many soluble materi-

als dissolved within the water inside the yeast cell and thus when cells are

placed in contact with other solutions which have a different concentration

to that within the cell an osmotic pressure gradient will be set up. This gradi-

ent will affect the movement of materials through the yeast cell wall mem-

branes in either direction and in doing so can affect both the integrity of the

cells and their efficacy. The principle is illustrated in Fig. 11.4.

The most practical implications of osmotic pressure in baking are related

to the impact of salts and sugars on fermentation. The most commonly

observed effects are the ‘liquification’ of yeast if it comes into direct contact

with undissolved salts and sugars. Because of their affinity for water, salts and

sugars will draw the water from within the cells (i.e., there is a high osmotic

pressure) and a pool of liquid forms. The practical consequences of such an

interaction is that the integrity and vitality of the yeast cells are disrupted with

subsequent negative effects in breadmaking. Even the concentration of salts

and sugars in the water of the dough formulation can have a negative effect

on fermentation but because of the dilution the effect is not as dramatic.

Water Water

Yeast cell membrane

FIGURE 11.4 Principle of osmotic pressure across the yeast cell membrane. Black dots repre-

sent soluble particles in water. Left, equal concentrations � No osmotic pressures; middle and

right, unequal concentrations with direction of water flow across the membrane as indicated.


11.13 WHAT IS RESISTANT STARCH?

Starch is a carbohydrate which consists of long chains of glucose molecules

linked together. Although many starches are readily broken down into glu-

cose molecules by enzymic action in the human digestive system, some types

of starch are more resistant to digestion in the large intestine than others and

are considered in medical terms to act like dietary fibre and so are known by

the generic descriptor ‘resistant starch’.

The term actually covers four types of resistant starch:

� RS1 � Considered to be physically inaccessible as part of intact or partly

milled grains.

� RS2 � Resistant starch granules in their ‘natural’ form as might be found

in potato, green bananas, some legumes and high amylose starches.

� RS3 � Retrograded starches from typical sources such as cooked and

cooled potato, bread crusts and some flaked products.

� RS4 � Includes a wide range of modified starches.

As noted above, some resistant starches occur naturally (RS1 and RS2),

whereas others are formed during normal food processing (RS3) or by delib-

erate modification of the properties of a basic starch (RS4). More than one

form of resistant starch can exists in the bakery product. Bread is the most

common bakery product to contain resistant starch.

Resistant starches may be considered, in dietary terms, to be the equiva-

lent of soluble fibre and as such to make a positive contribution to well-

being as that of dietary fibre. Although the physiological effects of resistant

starch may be similar to that of dietary fibre, resistant starches do not neces-

sarily analyse as dietary fibre so care must be taken if they are to be used as

part of any health-related claims for a food in which they are used.

A technological benefit of using resistant starches is that many of them

are able to hold greater quantities of water in their structure than un-modified

starches.


11.14 WHAT ARE THE ORIGINS OF THE COTTAGE LOAF?

Bread is made and baked in a variety of shapes and sizes, one of these being

the ‘cottage’ loaf. Its origins are not known for certain. There would not

seem to be any particular reason why a loaf should be made from two

moulded dough pieces and then assembled one on top of the other before

baking. Loaves made in this fashion have been known for hundreds of years.

In ancient times a loaf called a Nastus, was made in this form and

Nicostratus an ancient poet, wrote of it as follows:

Such was the size, O Master, of the Nastus,

A large white loaf. It was so deep; its top

Rose like a tower quite above its basket;

Its smell when that the top was lifted up,

Rose up, a fragrance not unmixed with honey.

Although there would not seem to be any misunderstanding nowadays as

to what is meant by a cottage loaf, there seems little available information as

to how it has obtained and retained its name. It is possible that many years

ago, when baking was largely done at home, and where accommodation was

limited and family sizes larger than today, the housewife had to invent some

means of getting sufficient bread baked to satisfy the demands of the family.

By placing one ‘cake’ of bread on top of another, keeping the top smaller

than the bottom so that it would not topple over in the oven or come into

contact with the walls of the oven the housewife created a single loaf com-

posed of two ‘cakes’ of bread. The two ‘cakes’ were held together by a deep

indentation (perhaps by the baker’s elbow) made vertically downwards from

the upper into the lower portion.

This of course is supposition, but in all probability, it was lack of space

in the oven that first made the cottager experiment with one loaf on top of

another and so evolved what easily might be called the ‘cottager’s’ loaf,

which has now become a cottage loaf. A variation of the loaf is one called a

‘cottage brick’ where two brick-shaped dough pieces were baked on top of

the other.

The cutting or ‘notching’ of the product is as much about controlling loaf

shape as it is about providing a distinctive appearance (see Fig. 11.5).

Both versions of the cottage loaf are notoriously difficult to make. Each

part, head and base, is processed separately and then combined before final

proof is reached. It is also important to get the balance of weights right

between the head and base and that care is taken that the two surfaces which

are to be joined are flat with the pressure of joining the pieces applied right

through the base; often punching the end of a thin pastry roller though the

two pieces will make an effective join. In the prover and the early stages of

baking, the pressure build-up in the base dough can cause the whole loaf to

topple over if the balance of weights is not judged correctly (Fig. 11.6).


Further reading

David, E., 1977. English Bread and Yeast Cookery. Allen Lane, London, UK, pp. 203�204.

FIGURE 11.5 Cottage loaf cutting.

FIGURE 11.6 Incorrect dough piece weights in the manufacture of a cottage loaf.




Index

Note: Page numbers followed by “f ” and “t” refer to figures and tables, respectively.

AAcetic acid, 107�108, 158

Acids

added to puff pastry, 338

correct proportions in baking powders, 130

dark spots from undissolved, 306

fast and slow acting, 290

white cake batters, 277

Acrylamide, 496

Activated Dough Development (ADD), 142

Additives, 133. See also Improvers

Aeration of whipped cream, 406

Air classification, 67

Alcohol

addition in cakes, 284

Aleurone layer, 56

Alkalis, 130

All-butter shortbread, 305

Almond

macaroons, 404

paste, 392, 394

‘Alpha gel’ GMS, 105�106

Alpha-amylase

activity, 58�60, 114, 140f, 155

forms, 139�140

sources, 139

Alveograph, 53

Amino compounds, 179

Ammonium bicarbonate, 308, 318

Ammonium carbonate (vol), 301, 303, 380

Amylograph Units, 64

Amylopectin, 114, 116, 139, 223

Amylose, 69, 114, 116, 139, 223

Analysis, 9�11

Anthocyanin, 260

Antistaling agents, 116, 209

Antistaling enzymes, 114, 116

Apple pie filling, 412

Arabinogalactans, 486

Arabinoxylans, 56

Arbinose, 114�115

Ascorbic acid (AA), 136�137

Ash, 43�46, 61, 231, 357, 473

Asparagine, 496

Aspariginase, 496

Aspartate, 496

Aspartic acid, 496

Autolysis, 125

BBacillus subtilis, 158

Bacterial alpha-amylase, 139�140

Baguette, 156�157, 161

Baked custards, 364

Baked products

acrylamide, 496

Chinese steamed bread and CBP, 232�233

cinnamon twist bread, 234

colour measurement, 8�9, 35

doughnut, 217, 226, 426�428

extended mould-free shelf-life, 95, 102,

107�108, 412, 431, 491

farls, 422

flour Tortilla, 431

fragility of defrosted finger rolls, 231

GI categories, 484

glass transition temperature, 116, 461, 488,

494

glycaemic index and load

comparison of some typical bakery

foods, 485

hamburger buns, 118, 143, 219�220, 224

hydration and hydrolysis, 487

ingredients synergy in baking processes,

493

lack of gloss of fondant, 399

Milton Keynes Process, 465�466

modified atmosphere packaging, 491�492

mould-free shelf-life with different

concentrations of CO2, 491, 491f

perforated film with crusty bread, 490f

polyols, 431, 494�495

pro and pre-biotics, 486

retarding rolls, 230

scones, 383, 385�391

Staffordshire oatcakes, 421

stains around fruit pieces, 229

vacuum cooling principles, 467

501

Bakers’ chocolate, 418�419

Bakers’ yeast

fermentation, 34, 97, 224

lag phase, 127

precautions in handling, 123�124

types, 128�129

Bakery fats, 79�80

Baking

changes in bread dough during, 185�186

changes in cake during, 274�275

conditions, 155, 179, 190, 244, 246,

278�280, 288, 292, 317, 364�365,

370, 373, 384, 473

Baking powder

correct proportions of acid and alkali, 130

insufficient in sponge cake, 288

level and sponge cake, 286�287, 287f

Balady bread, 435

Banbury biscuits, 328

Barley, 40, 63, 112, 438

Batter

changes in properties with time, 291

conversion to cake in the oven, 274

curdled, 238

discolouration from fruit, 260

freezing cake batters, 246

gluten formation in wafer batters, 327

pikelet, 416

slab cake

batter temperature and quality of cake,

239

specific gravity and relative density, 472

viscosity, 266

Baumkuchen, 297�298

Benzoates, 111

Beta-amylase, 114, 139, 487

Bifidobacteria, 486

Billets, 360

Biscuits and cookies

coated biscuits, 312, 326

dark brown spots, 285

fat level reduction, 91�92

impact of fat solids on cookie weight, 317f

impacts of sugar crystal size, 319�320

role of dough and batter temperatures,

299�302

rotary moulded, 76, 300, 314

savoury puff, 323

semi-sweet, 119, 299, 315�318

short dough, 76, 300, 319

soft-eating, 310�311

sucrose alternatives, 320�321

sugar level reduction, 320

surface cracking, 316f

wafer sheet breaking, 325

Blackcurrants, 260

Blackgram, 432�433

Bleaching, 138

Bleeding, 259

Blind crumpets, 415

Blisters, 81�82

Blocking out, 369

Bloomer, 168, 180, 191�193, 191f

Blueberries, 260

Boards, cake, 250

Bohn’s spot test, 480

Boil-out, 373

Bottom crust detached, cake, 289�290

Brabenders Amylographs, 64

Brabenders Extensographs, 76

Bramley apples, 414

Bran, 341

Bread improvers, 133�134

Bread rolls. See Rolls: bread

Bread V Squeeze rig, 476

Bread/breadmaking, 153

ascorbic acid, 172, 195

balady bread, 435

bloomer, 180, 193

CBP, 170

cottage loaf, 499�500

crusty bread, 187�188, 199

dough. See Dough

effects of changing proof time, 178

final moulder, 161�162, 450

flying top, 201

Grant loaf, 440

heat balance calculation, 173f

ice crystals in bread pack, 461f

ingredient and processing factors affecting

quality, 12

kebab bread, 434

keyholing, 3, 5f

low volume, 4

optimum dough temperature, 172

pan bread, 153�154, 161�167, 193, 198

part-baked breads, 465

production of carbon dioxide by yeast, 122,

127

syneresis, 409, 481�482

texture measurement, 475�476

trencher bread, 438�439

volume, 3�4, 13, 39, 56, 103, 115, 126,

139, 141, 176�178, 189, 195, 209

502 Index

Buffering agents, 224

Bulk fermentation, 53, 58�60, 120, 127, 178,

194�195, 201, 443, 450�451, 455�456

Buns, 93�94, 100, 204, 229, 377

Butter, 86�87

Buttercream, 401

fishy taint, 408

walnuts and discolouration, 104

Buttermilk, 422

Butyric acid, 89

CCake decorations, 393

Cakes/cakemaking, 235�236

batter deposit weights and different pan

sizes, 279�280

Baumkuchen, 297�298

browning in fruit cakes, 261, 277

butter in, 86�87

cake batter temperatures

calculation, 240�241

effect on cake quality and volume, 239

cake flour characteristics, 71

cake muffins, 276, 294�296, 294f

cream cakes, 410f

delayed-soda method, 285

factors affecting water migration

cream filling formulation, 253

packaging, 253

potential routes of moisture migration,

253

factors controlling shape and appearance

heat transfer rate during baking, 279

mechanical and chemical aeration

balance, 283

sucrose solution concentration, 282


flour particle size, 67, 426

key characteristics of low- and high-ratio

recipes, 150

key ingredient and process factors, 12

relationship between cake type and level of

baking powder, 278f

role of fat, 85

rules of recipe balance, 147

shape

effect of baking powder level, 282f

effect of increasing sugar level, 282f

effect of rate of baking powder reaction,

281f

sponge cakes, 87, 105, 235, 287

variable results with natural colours, 262

Calcium carbonate, 43, 109, 224

Calcium lactate, 414

Calcium propionate, 107t, 129, 158, 204, 431

Candida, 129

Caramelisation, 179, 261, 483

Carbon dioxide. See Gas bubbles; Gas

production; Gas retention

Cardboard, 382

Caved-in loaf sides, 155

CBP. See Chorleywood Bread Process (CBP)

C-Cell bread slice imaging system, 477

Cell structure

bread, 3�4

lack of bubble stability, 159�160

vacuum pump problems with CBP,

170�171

cakes and sponges

coarse in sponges, 286�287

frozen unbaked pizza bases, 425

Cellulose, 34�35

Cellulose-based film, 382

Cellulose-gum, 244

Cereal alpha-amylase, 139

Chalk, 45

Chamfering of sponge cake base,

289

Chapattis, 436

Checking in biscuits, 307

Cheesecake toppings, 429�430

Cherry cake, 471

Chinese steamed bread, 232�233

Chlorinated flour, 69�70

Chlorination, 63, 67�71, 426

Chocolate

cracking in coatings, 326, 417

flaking, 419

fondant, 99

white bloom, 305, 418

Chopin Alveograph, 76

Chorleywood Bread Process (CBP), 81, 142

partial vacuum and cell structure, 170�171

role of energy, 448�449

Choux pastry, 375�376

eclairs, 99, 375, 377, 381

Christmas cakes, 251

Christmas puddings, 249

Ciabatta, 450�451

Cinnamon twist bread, 234

Cis fats, 80

Coated biscuits

bowed shape, 312

sources of moisture in packed, 312�313

Index 503

Cocoa powder, 293

Codex Alimentarius Commission of the Food

and Agricultural Organisation of the

United Nations, 65

Co-extruded polypropylene film, 489

Coffee meringues, 403

Collapse

bread doughs, 81�82

cakes, 67

choux buns, 36

doughnuts, 210�211

fruited buns, 217

sponge sandwiches, 286�287

sultana cake, 264

whipped cream, 406�407

Colour. See also Discolouration

crumb, 259

crust, 179

retention by fresh fruits, 260

Colour Grade Figure, 45�46

Colour Grader, 45

Colour solid, 474, 474f

Commission Internationale de l’Eclairage, 473

Composite bakery shortenings, 81�82

Computer-based systems, 26�27

Concentrates, 133. See also Improvers

Conduction, 269

Confectioners’ biscuits, 328

Consistograph, 53

Convection, 269

Cookies, 94, 299, 483

Cooling, 272

Copper, 408

Cores

in cake sheets, 256

sponge sandwiches, 286�287

Cottage loaf, 499�500

Couverture, 418, 420

Crackers, 307

role of dough and batter temperature,

299�302

role of fermentation time in manufacture, 324

Cracking in

almond macaroons, 404

biscuits, 326

chocolate coatings, 326, 417

fondant coatings, 396

frozen unbaked pastry, 362

ginger nuts, 309

meringue shells, 402

sheeting of short pastry, 361

Swiss rolls, 292

Cream, 306, 410�411

Cream buns, 376�377, 380

Cream cakes, 410�411

seepage of jam after freezing,

409

Cream eclairs. See Eclairs

Cream of tartar, 130

Cream powder, 130

Crispness

pork pie pastry, 367�368

sweet pastry, 371�372

Croissants, 353�354

different forms, 350�352

frozen fully-proved, 355

key recipe and process features, 350�351

Cross-panning, 453�454

Crumb cell structure, 159�160, 189, 384,

425, 448, 457�458

Crumb colour

bread, 45

cakes and sponges

discolouration, 259

Crumb softness

bread, 133, 189, 451

cakes and sponges, 475

Crumbling, prevention, 359

Crumpets, blind, 415

Crust colour

bread, 3


Crusty bread

shelling, 221�222, 463

softening when wrapped, 187�188

structure, 199

Cryo-protection, 389

Crystal formations, 429

Cup cakes, 254

Curdled batters, 238

Custard, baked, 364�365

Custard tarts, 364�365, 364f

Cutting

cottage loaf, 500f

direction and croissant shape, 353�354

surface of bread doughs, 180�181

Cysteine, 142

DDamaged starch, 59�60

Danish pastry, 344

DATA esters, 141, 214, 322

Datem, 141, 322

504 Index

De-aeration, 291

Deep-freezing, 463�464. See also Freezing/

frozen products

Deformation testing, 54

Dehydro-ascorbic acid (DHA), 120, 195

Delayed-soda method, 285

Dextrin, 58�60, 114, 139, 487

Dextrose, 95, 97, 129, 364, 414

Dextrose equivalent, 95

Dextrose monohydrate, 95

Diacetylated tartaric acid esters (DATA

esters), 141

Diastatic malt powders, 112

Dietary fibre, 35, 65, 486, 498

Diglyceride, 115, 141, 322

Dipix Technologies Inc, 8

Di-saccharides, 95, 97

Disaccharides, 95, 97, 204

Discolouration

all-butter shortbread, 305

in apple pie filling, 413

cake crumb

due to low temperature baking,

275

fruit cakes, 259

choux buns, 379

meringues, 400

royal icing, 394

scones, 383, 386

unbaked puff pastry, 341

Disulphide bonds, 448�449

Double-acting baking powder, 73

Dough

changes during baking, 185�186

collapse, 81�82

control of temperature, 178

freezing and storing unproved, 184

fundamental rheology measurements, 54

lack of oven spring, 4, 81

softening in, 40, 58�60, 443

Dough conditioners, 133. See also Improvers

Dough stickiness, 48�49, 103, 114�115, 172

Doughnuts, 210�211

cake, 210

crystalline growth on cake doughnuts

during storage, 427�428

types, 426, 426f

Dried fruit, 216, 259. See also Fruit breads;

Fruit cakes; Fruited buns

Dry gluten, 55

Dry heat-treated flour, 68

Dryness in fruited cakes, 267

EEating qualities, 93, 151, 272, 300, 410, 426

Eclairs, 99, 377

storage of cases, 381

Egg proteins (albumen), 105, 364, 371, 375

Egg washing, 387

Electronic nose, 9

Emulsifiers

bread, 82, 141, 189

sponge cakes, 87�88, 105�106

Enchilada, 437

Energy, 448�449

Enzyme activity, 125, 215

bread, 122

lipase, 304


Enzymes, 63, 90

Equilibrium relative humidity (ERH), 247

Erythritol, 495

Ethanol, 50, 123

Ethyl alcohol, 110

Excessive gas retention, 5

Extensograph, 53, 76

Extraction rate, 44, 436

FFalling Number, 58

Farinograph, 53

Farls, 422

Fast-acting acid, 285

Fat, 77�92, 214

bloom, 305, 418

critical properties, 77�78

migration, 367, 410�411

replacers, 91�92, 494

Fatty acids, 77, 79, 374

Fermentation, 121�122

Fermented products, 210�234

Ferrous sulphide, 379

Fillings

apple pie, 412

avoiding ‘boil-out’, 373

Final proof, 81, 199, 201, 450, 499

Finger rolls

fragility of defrosted, 231

Firmness

bread, 34, 116, 189�190, 209, 223

crumb, 223

fat, 77�78

Fishy taint, 408

Flaking of chocolate coatings, 419

Index 505

Flash heat, 269�270

Flour, 43�76

alpha-amylase, 58

ash content, 43�44

functions of different components, 33�35

new harvest effect, 39

rationale in mixing different wheats, 36

relationship between flour ash and grade

colour figure, 44f

resistant starch, 65�66

self-raising, 71, 73�74

water absorption capacity, 47�49, 76

wholemeal bread flour

characteristics and specifications, 56

Flour Colour Grade, 45

Flour confectionery products, freezing, 272

Flour Tortilla, 431

Flour-batter method, 235�236

Flying ferments, 194

Flying top, 201, 201f

Foams, 85

transition to sponge, 210, 274

Foils, pastries in, 369�370

Fondant

crack in fondant coating, 396

crystalline formations, 429�430

excessive moisture in chocolate fondant, 99

Four-piecing, 453�454

Fractionation, 80

Fragility, 231

Freezer burn, 219�220, 463

Freezing/frozen products

cake batters, 246

cracking in meat pie lids, 362

flour confectionery products, 273

off-odours in cakes, 252

problems with bread products, 463�464

seepage of jam in fresh cream cakes, 409

unbaked pizza bases, 425

unproved bread dough, 184

French sticks, 156�157

Fresh fruits, 260

apple pie filling, 412

Frozen bread products

snow or ice in bags, 219

Frozen eggs, 376

Fructooligosaccharide, 486

Fructose, 306

Fruit breads, 216

Fruit cakes

discoloration of crumb, 259

dryness, 267�268

hardening of marzipan in wedding cakes,

398

large holes in slab cake, 263

mould inhibition in heavily fruited cakes,

249

settling of fruit to bottom, 244�245

Fruited buns, 217�218

Fudge icing, 395

Functional ingredients. See Improvers

Fundamental dough rheology

measurements, 54

Fungal alpha-amylase, 139�140

GGanache, 420

Gas bubbles

expansion, 52, 82, 199

stability/stabilisation in

bread, 81�82

bread rolls, 213

sponge cakes, 88, 105�106

Gas flushing, 491

Gas production

excessive in retarding, 227�228

slow proving, 216

from yeast, 122, 182

Gas retention

keyholing and excessive, 4�6

lack of, 81, 213

Gelatinisation, 34, 223, 294

Germ, 33�35

German-type rye breads, 64

Ginger, 132

Ginger nuts, 309

Glass transition temperature, 116, 461, 488,

494

Glucono-delta-lactone (GLD), 130

Glucose, 95, 398�399, 484

Glucose syrup, 95, 99, 261, 308, 311, 364,

373, 396, 429

Glutathione, 119�120, 124�125

Gluten, 50, 384

dry, 55

formation in short pastry, 361

formation in wafer batter, 327

quality, 52

Gluten-free breads, 138

Glycaemic index, 484�485

Glycaemic load, 484�485

Glycerine, 236, 247, 385, 389, 392, 395

Glycerol, 79, 99, 261, 371, 389, 411, 431

506 Index

Glycerol monostearate (GMS), 86, 105, 141,

189, 385, 410

Golden syrup, 261

Grade colour figure, 35, 43, 44f, 45�46, 231,

357

Grant wholemeal loaf, 440�441

Greasiness, in doughnuts, 212

Ground almonds, 245

HHagberg Falling Number, 57�58, 61, 63, 114

Hamburger buns, pH and TTA of brew, 224

Hand squeeze test, 475�476

Hearth-style breads, 156�157

Heat balance, 173�174, 173f

Heat of hydration, 68, 241

Heat transfer rate, 210, 279, 289

Heat-treated flour, 68

Heat-treated milk, 101

Heavily fruited cakes, 249

Hemicellulases, 114�115

Hemicellulose, 114�115

High fructose corn syrup, 95, 97, 311

High-ratio cakes, 71

batter viscosity, 266

cherry cake, 471

Holes

bread rolls, 213

in crumb of pan breads, 161�162

in fruited slab cake, 263

under top crust of retarded products, 225

Honey, 261, 297, 495

Hot cross buns, 100

Hot water method, 358

Humidity, 182

Hurdle effects, 493

Hydration, 68

Hydrogen ion concentration, 469�471

Hydrogen peroxide, 115, 387

Hydrogenated fats, 366

Hydrogenated starch hydrolysates, 495

Hydrogenation, 79�80

Hydrolysis, 89, 179, 413, 487

IIce slush, 173, 446

Iced Christmas cakes, 251

Icing

fudge, 395

odours in from cake decorations, 393

royal, 392, 394

Improvers, 133�134, 214�215

Information sources, 16�27

Ingredients

balancing of ratios, 265

factors affecting product quality, 145

Insects, detection of, 479

Interesterification, 80

Inulin, 486

Invert syrup, 261

Iodine value, 77

Iron, 104, 226

Isomalt, 495

Italian meringue, 401

JJam

seepage in fresh cream cakes, 409

watery, 95

KKebab bread, 434

Keyholing, 3, 5f

Kjeldahl method, 50�51

Knocking-back the dough, 120, 455�456

Knowledge-based systems, 26�27

LLactic acid, 486

Lactitol, 495

Lactobacilli, 224

Lactose, 96, 257

Lactulose, 486

Laminated products, 331�356

effect of rework, 11f

key ingredient and process factors,

145�146

lift

causes, 331�332, 337, 348�349

failure, 333

fat and, 346�347

variations with Scotch method, 334

optimum levels of lamination, 344

processing pattern on pastes, 349f

purposes of resting periods, 335�336


299�300

L-cysteine, 118

L-cysteine hydrochloride, 142

Lecithin, 117

Leucoanthocyanins, 413

Index 507

Lignin, 65

Lipase, 304

Lipids, 35, 114�115

Lipoxygenase, 138

Loaf shape, 234, 278, 499

Loaf style cakes, 151

Loaves

breaking on one side of the pan, 198

external appearance, 196f

internal appearance, 197f

stains around fruit pieces, 229

touching loaf, 205�206, 205f

MMacaroons, 404

Maillard-type reactions, 179

Malt flour, 40, 112

Malted grains, 40

Malting process, 40, 112

Maltitol, 495

Maltogenic amylases, 139, 190

Maltose, 96, 114, 116, 139, 179, 185, 229

Manchet bread, 438

Mannitol, 495

Man-t’ou, 232

Marshmallow, 401

Marshmallow teacakes, 417

Marzipan, 394

hardening on wedding cakes, 398

Meat pies, 362

Mechanical shock, 211, 217

Melted butter, 87

Meringues, 400�403

Micro-encapsulated baking acid, 391

Micronized wheat, 42

Microwave, 90

Milk, 101

Milk ganache, 420

Milton Keynes Process, 465�466

Minerals and vitamins, 35

Mixing time, 176�177

Mixograph times, 103

Modelling techniques, 12�14

Modified atmosphere packaging, 491�492

Moisture barriers, 371�372

Moisture content

fruit cakes, 267�268

small fermented products, 214�215

Moisture migration, 187, 250, 253, 284,

310�311, 382, 390, 395, 410�411,

417, 489

Moisture Vapour Transpiration Rate, 188,

396, 489

Moisture-impermeable film, 489�490

Mono calcium phosphate, 290

Mono-glyceride, 215

Mono-saccharides, 95, 204

Mould

in cakes, 247�248

between cakes and boards, 250

iced Christmas cakes, 251

slow growth in heavily fruited cakes,

249

choux buns, 382

prevention in apple pie filling, 412

Mould inhibitors, 249

Mould-free shelf-life, 431

Moulding dough, 193, 499

Munsell colour chip-based system, 474

MVTR. See Moisture Vapour Transpiration

Rate

NNachos, 437

Nastus, 499

Natural pigments, 413

Near infrared reflectance (NIR), 51

Neutralising value, 130�131, 281, 391

New harvest effect, 39

New product development, 27�31

concept, 28�29

launch, 30�31

on-going maintenance/handover, 31

pre-launch trials, 30

prototype trials on the plant, 30

scale-up to commercialisation assessment,

30

Nitrogen, 50�51, 137, 170, 451, 459,

491�492

Nitrogen tunnel, 425

Nondiastatic malt powders, 112

Non-starch polysaccharides, 65

Nonwheat fibres, 65�66

Nuclear magnetic resonance (NMR), 77

OOatmeal, 41, 304, 421

Oats, 41, 304

Off-odours

cakes store in deep freeze, 252

in icing from cake decoration, 393

rope (‘fruity’ odour), 158

508 Index

Oil, 79�80, 85, 88

Oil absorption, 212

Oligosaccharides, 486

Organic flours, 75

Osmophilic yeasts, 429�430

Osmotic pressure, 97, 204, 497

Osmotolerance, 204

Oven

conditions and peaking in sponge cakes, 288

variations in cake quality, 269�270

Oven break, 198

Oven lift, 204

Oven spring, 133�134

lack of, 81, 216

Oven-bottom breads, 156�157

Over-greased tins, 440

Oxidases, 115

Oxidative rancidity, 304

Oxidising agents, 133�134. See also Improvers

Oxygen, 121

PPalate cling, 84, 366

Palm oil, 79�80

Pan bread

air occlusion, 165f

holes, 161�167

indents in bases (pan-lock), 153�154

large holes in crumb, 161�162

open-top, 168�169

smooth sided hole, 164f

stranded holes, 163f

trapped air pockets, 163�164, 166f

Papads, 432

Paper cases, detaching, 254

Pappadams, 432�433

Par-baked products, 221, 223

Part bake products, 221�222, 463, 465

Partial defrosting, 221

Partial hydrogenation, 80

Partial vacuum, 170�171

Particle size, flour, 67

Paste

dark marks on base, 363f

discolouration, 363

ingredient and process factors affecting

quality, 12

laminated, 84, 118�119, 331�356

pale colour, 364�365

puff. See Puff pastry

shortcrust, 357�374

Pastry

butter, 356

croissant, 344

effect of processing temperatures using

butter, 89, 352, 356


key ingredient and process factors

influence of ingredient temperature, 342

influence of processing temperature, 342

product lift, 348�349

role of rest periods, 360

shape distortion, 348�349

trimmings

age and

condition, 339

level of addition, 339

temperature, 339

shell, 357

water temperature calculation method,

359

Patent flour, 46

Peaking in sponge

sandwiches, 288

Pentosans, 34, 48, 64

Perforated films, 187�188

Personal experience, 17

PH meter, 480

PH scale, 469�471

Phenol red, 480

Phosphatase test, 479

Phosphate aftertaste, 285

Pikelet batter, 416

Pinning process, 225

Pitta bread, 434

Pizza bases, 425

Polish, 194

Polyhydric alcohols, 494

Polymorphism, 80

Polyols

effect on cake crumbliness, 494f

negative features, 494�495

Polyphenols, 341, 357

Pork pie pastry, 367�368

Potassium bicarbonate, 74

Potassium bromate, 137

Potassium chloride, 102

Potassium sorbate, 107, 412, 431

Powdered fructose, 306

Prebiotic, 486

Preservative, 412

effect of sorbic acid on shelf-life of cakes,

107, 108f

Index 509

Pressure board setting, 161�162

Pressure-vacuum mixer, 136�137

Probiotic, 486

Problem solving, 1

analysis, 9�11

approach, 2�6

guide, 28

how to problem solve, 2�6

information sources, 16�27

constructing knowledge trees and

knowledge fragments, 23�26

knowledge (computer)-based systems,

26�27

personal, 17

the Web, 27

written, 17�23

matching patterns and visualising changes,

14�16

modelling techniques, 12�14

new product development, 27�31

record, 6�9

divider record sheet, 7f

product scoring sheet, 10f

Process factors affecting quality, 2

Processing aids, 133. See also Improvers

Product scoring sheet, 10f

Professional bodies, 17, 27

Propionic acid, 107t, 158

Proteases, 115

Protein

content

effects of variations in, 50�51

quality measurement, 53�54

Proteinases, 115

Proteolytic activity, 40, 324

Proteolytic enzymes, 76, 100, 112, 115, 125,

144, 299, 360, 425

Proving

best conditions, 182�183

slow, 216

under-proved doughs, 156

Puff biscuits, savoury, 323

Puff pastry

fat in, 83

lift, 83�84, 331�332

optimum lamination, 344

Puffing, 436

Punching the dough, 455

QQuiches, 370

RRadiation, 269

Radio-frequency heating, 90

Ragged break, 126, 157, 199, 201

Ragged crust break, 156�157

Record of production, 6�9

Reducing agent, 118�120, 143�144

Reducing sugars, 179

Refreezing, 219, 221, 427, 463�464

Regrinding, 67, 71

Relative density, batter, 105, 286, 291, 472

Resilience, 214, 475

Resistant oligosaccharides, 65

Resistant starch, 65�66, 484, 498

Resting periods, 335�336

Retarded products, 226

Retarder-prover, 230

Retarding, 227�230

Rheology measurements, fundamental, 54

Rice paper, 372

Ring, shiny, 266

Roberts/Dobraszczyk dough inflation, 54

Roller-milled wholemeal flour, 57

Rolls

bread, 219�220, 226

low volume and large holes,

213

staling too quickly, 214�215

fruited, 229

retarded, 227f

Root cause analysis, 11

Rope, 158, 470

Rotary moulded biscuit lines

thickness variation, 314

wedging, 314

Rounded corners, 289�290

Royal icing

inadequate hardening, 392

yellowing, 394

Rye, 40, 64

Rye, flours, 64, 438

SSaccromyces cerivisii, 123, 128�129, 202

Saccromyces rosei, 129

Saccromyces rouxii, 129

Salt. See Sodium chloride

Salt-replacers, 102

Sandwich bread

characteristics, 286�287

crumb characteristics, 286�287

510 Index

most common forms of assessment

crumb softness, 105

moisture content, 325, 463

shape, 288

Satiety, 485

Saturated fats, 77, 79�80

Saturated solutions, 483

Savoury pastry, 358, 367, 371

Scald, 202

Scientific and technical literature, 12, 17

Scones, 383�387

carbon dioxide evolution during refrigerated

storage, 391f

retarding unbaked scones, 391

sensory qualities improvement,

390

variations in using fresh fruits, 388�389

Scotch method, 334

Scottish Oatcake, 421

Seepage of jam, 409. See also Fat: migration;

Moisture migration

Self-raising flour, 73

Semisweet biscuits

blistering on the surface, 317�318

cavities and hollow bottoms,

317�318


299�302

shrinkage, 315�316

Settling of fruit, 244�245

Shape, 8

croissant, 353�354

Sheeting, 361

Shelling, 463�464

Shift change effect, 10

Shiny ring, 266

Shortcrust pastry, 357�374

flour characteristics, 357

waxy eating character, 366

Shortbread, 305

Short-dough biscuits


319

Shrewsbury biscuits, 328

Shrinkage

apple pie filling, 414

cup cakes, 254

doughnuts, 210�211

puff pastry, 337

Silicone, 287

Sinking, in cakes, 265

Size variations, biscuit, 308

Skinning, 225

Slab cakes

advantages of filled oven, 276

batter temperature and quality, 239

Sliced bread, 159�160

Slow proving, 216

Soapy taste

biscuits containing oatmeal, 304

short pastry trimmings, 374

Soda crackers, 480

Soda farls, 423

Sodium acid pyrophosphate (SAPP), 73

Sodium aluminium phosphate (SALP), 73

Sodium bicarbonate, 130, 277

in ginger products, 132

pikelet batters, 416

specks, 386

Sodium chloride, 102

alternatives, 111

Sodium metabisulphite, 76, 100, 118�119,

299, 322, 337

Sodium steroyl 2-lactylate (SSL), 141

Soft-eating cookies, 310�311

Softening

biscuits, 329

coffee meringues, 403

dough, 40, 58�60, 232, 324, 443

pastry, 367�368, 371

sugar paste shapes, 397

Softness

crumb, 189�190


Solid fat index, 77, 78f, 239, 410

Sorbic acid, 107, 111, 493

Sorbitol, 261, 494�495

Sourdough, 194

Soya flour, 138

Specific gravity, batter, 472

Specific volume, 472

Spices, 100

Spiral mixers, 176�177

Sponge, dough

preparation and usage with CBP,

203

recipe and method, 203

Sponge cakes, 286�287, 289�290

ingredient and process factors affecting

quality, 12

fat in, 88

role of emulsifiers, 105�106

Sponge drops, 291

Sponges, transition from foam to, 210f

Index 511

Spotting

biscuits, 306

on fudge icing, 395

speckles of sodium bicarbonate,

387

sugar spots on cake crusts, 258


white spots on retarded products, 227�228

Spray-dried egg, 376

Spring flush problem, 407

SSL. See Sodium steroyl 2-lactylate (SSL)

Stabilisers, cream, 407�408

Stable Micro Systems, 475

Staffordshire oatcakes, 41, 421

Staling

bread, 189�190

reducing in scones, 385�386

too fast in small fermented products,

214�215

Starch

damaged, 59�60

syneresis in bread, 409

Steam (wet) heat-treated flour, 68

Steamed bread, 232�233

Stock syrup, 398�399

Stoneground wholemeal flour, 57

Storage

breakage of biscuits in, 307

fermented products, 215

frozen cake batters, 246

long-term and wholemeal flour, 72

yeast, 126

Stotty cakes (stotties), 405

Sucrose

alternatives, 320�321

Sucrose hydrate, 427, 429

Sugar, 210, 308

crystals, 94, 319�320, 429

key requirements, 93�94

biscuit and cookies, 94

bread, 93

fermented products, 93�94

fruited cakes, 94

other bakery products, 94

pastries, 94

sponges and cakes, 94

main features of alternative sugars, 95�96,

320

main groups, 95

reducing sugars, 179

relative sweetness, 95, 95t

types, 94, 97, 309

Sugar burn, 306

Sugar paste shapes, 397

Sugar spots, 258

Sugar-batter method, 237

curdled batters, 238

Sulphur dioxide, 100, 111, 216

Sultana cakes, 264

Super-saturated solutions, 483

Surface cuts, 180�181

Sweet pastry, 371�372

Swiss rolls, 292

Syneresis, 409

in bread, 481�482

Synergy, 493

TTA.XTPlus Texture Analyser, 475

Taco, 437

Tagatose, 495

Taguchi methods, 13�14

Taints, fishy, 408

Tartaric acid, 130, 285, 290, 471

Teacakes, 214�215, 225

Temperature

batter temperature and quality of slab cake,

239

of cakes at point of wrapping, 271�272

controlling temperature of bread doughs, 178

oven temperature

and baking cakes, 274�275

and cake quality, 269�270

proving bread dough, 182�183

storage of yeast, 126

and whipping cream, 406�407

Tempering

butter, 86

chocolate, 419

fat, 89�90

Texture Profile Analysis, 9, 475, 476f

Top patent flour, 46

Tortillas, 437

Torulaspora, 129

Torulaspora delbrueckii, 129

Total titratable acidity, 224

Trans fats, 79�80

Trehalose, 495

Trencher bread, 438�439

Triglyceride, 77, 79, 115

Trimmings

puff pastry, 339�340

short pastry, 374

512 Index

Tristimulus instruments, 8

Tunnel holes, 294, 294f

Twin-arm type mixer, 459�460

UUK-style bloomers, 48

Under-proved doughs, 156�157

Unsaturated fats, 77

VVacuum pump, 170�171

Vacuum-cooling principles, 467

Viennese fingers, 329

Vine fruits, 249. See also Fruit breads; Fruit

cakes; Fruited buns

Vinegar, 109. See also Acetic acid

Viscosity, batter, 266

Vol (ammonium carbonate), 308, 380

Volume

bread, 3�4


choux pastry products, 375�376

loss of and heat-treated milk, 101

scones, 383


specific volume, 472

WWafer


299�302

sheets, 325

Walnuts, 104

Water absorption capacity

flours, 47�49

Water activity, 247

Water migration, 253, 382, 390, 411

Water vapour transpiration rate, 489

Wedding cake, 398

Wheat

berry, 56

flour, 33, 35, 41, 55, 97, 139, 436, 487

gluten, 50, 55�57

micronized, 42

starch, 64, 67, 71, 95, 131, 209�210, 245,

283, 487

Wheaten farl, 422

Wheatmeal, 422

Whipped cream, 406�407

White bloom, 418

White bread

characteristics, 61�62

flour treatments and additives, 61�62

Hagberg Falling Number, 61

level of bran particles, 61

protein content, 61

protein quality, 61

White cakes, 277

White farl, 422

Wholemeal bread flour

characteristics and specifications, 57

World Wide Web, 27

Wrapping

and softening of crusty breads, 187�188

temperature of cakes at point of, 271�272

XXylanases, 114�115

Xylitol, 495

Xylose, 114�115

YYeast

causes of dark brown patches, 125

impact of spices, 100

laminated products, 344

production carbon dioxide, 122, 182

Index 513

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