SELECTION OF FOODSTUFFS

SELECTION OF SELECTION OF FOODSTUFFSFOODSTUFFS

Ingrid SteinerVienna University of Technology

Institute of Chemical Engineering

I. Steiner, FOODMIGROSURE - Baveno 27.9.06

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SELECTION OF FOODSTUFFS -Fundamentals

To classify foodstuffs/food groups with respect to those physico-chemical properties which can be expected to influence the behaviour of food as a sorption matrix for the uptake of migrants. To select a list of approximately 15 to 20 (max. 25) foodstuffs which can be considered to berepresentative based on the following criteria:

with respect to the spectrum of migration relevant physico-chemical parametersaccording to up-to-date and available food consumptionstatistics and market share. This should at least includethe foodstuffs most frequently consumed and deservetherefore consideration at higher priority.


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Consumption of foodstuffs in Europe

Graph by C. Simoneau et al., EC JRC, IHCP


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Establishing the final list of foodstuffs

From the aspects considered before the two representative and established lists of foodstuffs may vary to a small or even large extent. Some harmonisation was necessary to end up with one representative list which fulfilled the best the purpose of this project idea which is to model migration into foodstuffs for exposure estimates as broad and general as possible.


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Categories of food

Aqueous and acidic foodsFatty foodsDry foods


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Aqueous and acidic foodstuffs

Orange juice, unsweetened, fresh with pulpApple sauceTomato ketchupCarbonated beverage (cola drink)BeerWineMilk, consumer milk, min. 3,5% fat


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Fatty foodstuffs (I)

Margarine (80% fat content)Mayonnaise (80% fat content)Cheese Philadelphia(~70 % fat in dry matter)Cheese Gouda, 45 % fat content (in dry matter)Cheese sauce (18,5% fat)Cottage cheese (fresh cheese, ~10 % fat content in dry substance)


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Fatty foodstuffs (II)

Whipping cream, UHT (~30% fat)Condensed milk (10% fat)Yoghurt drink, (0,9 % fat)Chocolate, dark, milk free, min. 40 % cocoa content (30% fat)Chocolate spread (25% fat)Meat, lean pork meat (minced, fat content ≤ 5%),mixed with lard to get fat contents up to 50%Salmon


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Dry foodstuffs

Milk powderButter toast (4% fat)Wheat flourRiceHoney


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Physico-chemical specifications of selected foodstuffs

establish the representative physico-chemical parameters for the foodstuffsfinally selected before

The measurements were done in the majority of cases according to standard or state-of-the-art methods or were adopted from the labelling of the foodstuff.

⇒ basis for a representative and general applicability of the model


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Physico-chemical parameters in detail

DensityMass-to-volume ratio(“Schüttgewicht”)StructureParticle size

Median particlediameterMean specific surfacearea

Water contentSolids (dietary fibre)CarbohydratesProteinsFatAlcoholAsh (minerals)pH


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Data of aqueous and acidic foodstuffs

Food Water(%)

Fat(%)

Solids(%)

CH(%)

Protein(%)

0,15 ---

0

1

---

---

3,3

Applesauce

79 0 --- 21 3,60 1,10

0,20

---

---

---

3,5

pH Density

Orange juice

87,1 12,9 12 3,95 1,05

Tomatoketchup

64,5 35,5 29 3,20 1,17

Cola drink 89 11 10,6 3,10 1,05

Beer (EtOH 5%)

91,3 3,7 --- 3,90 1,01

Wine(EtOH 11,5%)

86,7 1,8 --- 3,25 1,00

Milk 88,5 11,5 4,7 5,35 1,03


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Data of fatty foodstuffs (I)Food Water

(%)Fat(%)

Protein(%)

CH(%)

pH Density

Margarine 19,3 80 0,2

0,9

Gouda 48,0 2950 FDM

21 2 5,70 1,11

6,5

12,7

9,5

0,3 4,20 0,88

Mayonnaise 16,8 82 0,3 3,60 0,86

CheesePhiladelphia

61,8 2868 FDM

3,1 5,00 1,02

Cottage cheese

82,0 2,210 FDM

3,1 4,30 1,06

Cheese sauce 62,4 19 7,9 5,00 1,14


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Data of fatty foodstuffs (II)

Food Water(%)

Fat(%)

Protein(%)

CH(%)

pH Density

Whippingcream

60,0 32,0

9,0

0,9

31,3

30,0

8,0 --- 5,50 1,00

Condensedmilk

28,6 8,2 54,2 5,55 1,29

Yoghurt drink

83,6 2,7 12,8 3,70 1,06

Chocolatedark

1,8 2,7 53,1 --- 1,34

Chocolatespread

2,0 7,0 59,0 6,20 1,32


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Data of fatty foodstuffs (III)

Food Water(%)

Fat(%)

Protein(%)

pH

Pork meat 65 - 72 1,4 - 5 17,5 – 21,6 5,80

Chicken meat(breast)

70 - 74 ~ 6 ~ 22 6,30

Salmon 59 - 66 ~ 14 ~ 20 6,60


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Pork meat: Correlation between fatcontent and density

Correlation fat/density for pork meat

0,5

1

1,5

0 20 40 60 80 100 120

Fat content (%)

Den

sity


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Data of dry foodstuffsFood Water

(%)Fat(%)

Protein(%)

CH(%)

Density„Schüttgewicht“

Med. particlediameter(µm)

Mean spec. surfacearea (cm2/g)

Milk powder

3,0 26,0 26,0 39,0 0,48

0,60

0,23

0,84

1,44

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Wheatflour

14,0 1,0 10,6 74,0

125

75

---

5,1-5,7 mm(76 %)

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Butter toast

44,0 4,0 4,0 47,0 ---

Rice 12,0 1,4 6,8 79,8 11

Honey 17,0 --- 3,0(incl. ash etc.)

80,0 --- ---


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Milk powder – particle size


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Special structures and matrices of somefoodstuffs

Orange juiceMilkCheeseOther milk productsPowders


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Orange juice and other foodstuffscontaining fibres

Adsorption effects of pectin and otherunsoluble substances

⇒ Higher migration values also of lipophilic substances than expected


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Milk

Electron micrograph of homogenized milkfat globulesFrom: http://distans.livstek.lth.se:2080/microscopy/foodmicr.htm

http://distans.livstek.lth.se:2080/microscopy/foodmicr.htm


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Heated milk

Casein micelle in heated milk Casein micelles forming a chain

Pictures from: http://distans.livstek.lth.se:2080/microscopy/foodmicr.htm



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Milk powder

Dents in the large particle have been caused by small hard dry particles

A small particle (surrounded by a 'crater' rim) has been captured by a large particle.




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Difference of milk powders depending on drying process

Instantization results in agglomeration of powder particles

Roller-dried milk particles are produced as fragments of a dried milk sheet.




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Influence of cheese production on structure of milk particles

Junctions in stirred curd cheeses (e.g. Gouda)Pictures from: http://www.foodsci.uoguelph.ca

http://www.foodsci.uoguelph.ca/dairyedu/whcream.html


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Cream (soft) cheese

Microstructure of Cream cheese made from high-fat cream and acid-coagulated hot milk Fat globules (brown), curd (which shows the core-and-shell ultrastructure of casein particles - dark blue), aqueous phase (yellow).

Microstructure of traditional Cream cheese Fat globule clusters (dark yellow) are covered with protein (dark blue) in the aqueous medium (light yellow)




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„Cottage“ cheese

Distinct casein micell clusters; green: bacteria

Picture from: http://distans.livstek.lth.se:2080/microscopy/foodmicr.htm



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Casein micelle chains in yoghurt and micelle aggregates in cheese

Yoghurt

Cheese




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Structure of yoghurt depending on content of milk solids

20%Milk solids content 10% 15%




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Matrix of yoghurts produced in a different way

Yoghurt made from unfortified milk Yoghurt made from milk fortified with whey proteins




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Questions

Is there a correlation between themigrational key parameters diffusioncoefficients and partition coefficients of theselected model migrants and foodcategories specified by physico-chemicalproperties?Have food categories and theircorresponding model migrants to berevised caused by measured migrationalvalues?


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Thanks for excellent cooperation to

Peter VolanskyHerbert Hafner

Catherine Simoneau (WP 2 and 7)All project partnersCoordinator Roland Franz and his team


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Thank you for your attention!

Is it safe?

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SELECTION OF FOODSTUFFS