8
Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872 Digital Re-print - September | October 2012 Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug www.gfmt.co.uk

Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Embed Size (px)

DESCRIPTION

Wheat quality can be defined in terms of inherent quality attributes those under genetic control and seasonal quality attributes. One of the parameters of wheat quality is insect-damage.

Citation preview

Page 1: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872

Digital Re-print - September | October 2012

Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

www.gfmt.co.uk

Page 2: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Wheat quality can be defined in terms of inherent quality attributes those under genetic

control and seasonal quality attributes (Table 1, 2). One of the parameters of wheat quality is insect-damage.

It is widely accepted that insect-damaged wheat contains a bug salivary proteinase, which causes rapid relaxation of dough and, consequently, results in the production of loaves with poor volume and texture (Cressey, 1987, Every et al., 1996). Damage to wheat and its baking quality, due to pre-harvest insect attack, has been reported across the world including Germany, Spain, Hungary, Italy, Turkey, Iran, Iraq, and New Zealand amongst others.

Damage to the wheat crop in Syria, where nearly the whole harvest in a relatively small area was affected, caused a loss of 24 million Francs in 1924. The affected area doubled in 1925 and was six-fold in 1926, but damage decreased in 1927 and 1928, although the insect damage covered a larger area. Part of Ukraine also suffered severe damage in 1901 and 1909. In Turkey, insect damage to wheat, first time, was reported in 1932 and 1937. The damage caused by bugs to the New Zealand crop is usually low, but its incidence varies from year to year. There have been five major outbreaks of bug damage in New Zealand, since the problem was first reported in 1936. The problem regained importance after the 1980s in Afghanistan, Iran, Iraq, Syria, Russia, Bulgaria, and Romania as well as in Turkey (Lorenz. and Meredith, 1988). In recent years, it has reappeared in Black Sea region.

The insects which cause the damage have been identified a Eurygaster integriceps and Aelia rostrata in Europe and in the Near East.

In New Zealand, Nysius huttoni is thought to be the cause of the problem (Lorenz and Meredith, 1988).

This article reviews the economical importance and varietal susceptibility of insect damage, methods for the prediction of damage, effects on baking quality, suni bug management and improvement of bread quality.

Economical importanceThe economical importance of the cereal

bug E. integriceps on the wheat plant con-centrates on two main points of negative effects. First of all, the bite of only one mature insect, which survives under the winter conditions, is more than enough to kill the plant body. Yield losses attributable to direct feeding typically range between 50 and 90 percent.

Secondly, five nymph generations feeding on the ear of the plant have completed their larva era, but are still not mature insects or the young bugs increase the rate and number of bitten kernels, which in turn result in a sharp decline in the quality of bread.

If immature grain is attacked in the field by insects, there is damage to the mature grain. The dough made from this grain is very weak, owing to the action of a protease presumably injected by the insect. Because of the severe results on dough formation and baking quality, bug-damaged grain is severely downgraded, generally warranting only feed grade prices (Wrigley and Batey, 2003; Trissi, 2006).

The damage caused by the cereal bug shows important differences which are influ-enced by a number of criteria such as cli-mate and weather conditions, availability of water, characteristics of the wheat type, and

time of ripening of wheat, or a combination of these factors.

According to Paulian and Popov (1980) some 10-15 million hectares (25-37 million acres) of cereal cultivation are at risk, and in certain years chemical treatments may be applied to seven million hectares (about 17 million acres) in an attempt to limit the dam-age, especially if the crop is wheat.

A report prepared and published in 1993 by FAO/ICARDA authorities, states that about 1.3 million acres field is inflicted by E. integriceps, and a part of 582.000 acres are

Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

This article was derived from the presentation made in 4th International Mühlenchemie Symposium, September 8-9, 2011.

by Prof. Dr. M. Hikmet Boyacioglu, Group R&D Director-Cereal Foods Institute Director, Doruk Group Holding, Turkey

Table 2: Seasonal Quality Attributes

Soundness and maturity,

Plumpness and hence actual milling yield,

Actual protein content,

Weather damage,

Content of broken, shriveled, dry green, or frosted grains,

Contamination of foreign seeds,

Presence of unmillable material, e.g. chaff, white heads,

Presence of moldy, insect damaged, or infested grain,

Moisture content.

Table 1: Inherent Quality Attributes

Protein type and quality (extensibility, stability to mixing),

Potential to produce grain with protein content in a given range (either high or low),

Grain hardness,

Potential to produce grain having a high milling yield (high milling release),

Resistance to weather damage-dormancy.

Grain&feed millinG technoloGy22 | September - october 2012

FEATURE

Page 3: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Wheat quality can be defined in terms of inherent quality attributes those under genetic

control and seasonal quality attributes (Table 1, 2). One of the parameters of wheat quality is insect-damage.

It is widely accepted that insect-damaged wheat contains a bug salivary proteinase, which causes rapid relaxation of dough and, consequently, results in the production of loaves with poor volume and texture (Cressey, 1987, Every et al., 1996). Damage to wheat and its baking quality, due to pre-harvest insect attack, has been reported across the world including Germany, Spain, Hungary, Italy, Turkey, Iran, Iraq, and New Zealand amongst others.

Damage to the wheat crop in Syria, where nearly the whole harvest in a relatively small area was affected, caused a loss of 24 million Francs in 1924. The affected area doubled in 1925 and was six-fold in 1926, but damage decreased in 1927 and 1928, although the insect damage covered a larger area. Part of Ukraine also suffered severe damage in 1901 and 1909. In Turkey, insect damage to wheat, first time, was reported in 1932 and 1937. The damage caused by bugs to the New Zealand crop is usually low, but its incidence varies from year to year. There have been five major outbreaks of bug damage in New Zealand, since the problem was first reported in 1936. The problem regained importance after the 1980s in Afghanistan, Iran, Iraq, Syria, Russia, Bulgaria, and Romania as well as in Turkey (Lorenz. and Meredith, 1988). In recent years, it has reappeared in Black Sea region.

The insects which cause the damage have been identified a Eurygaster integriceps and Aelia rostrata in Europe and in the Near East.

In New Zealand, Nysius huttoni is thought to be the cause of the problem (Lorenz and Meredith, 1988).

This article reviews the economical importance and varietal susceptibility of insect damage, methods for the prediction of damage, effects on baking quality, suni bug management and improvement of bread quality.

Economical importanceThe economical importance of the cereal

bug E. integriceps on the wheat plant con-centrates on two main points of negative effects. First of all, the bite of only one mature insect, which survives under the winter conditions, is more than enough to kill the plant body. Yield losses attributable to direct feeding typically range between 50 and 90 percent.

Secondly, five nymph generations feeding on the ear of the plant have completed their larva era, but are still not mature insects or the young bugs increase the rate and number of bitten kernels, which in turn result in a sharp decline in the quality of bread.

If immature grain is attacked in the field by insects, there is damage to the mature grain. The dough made from this grain is very weak, owing to the action of a protease presumably injected by the insect. Because of the severe results on dough formation and baking quality, bug-damaged grain is severely downgraded, generally warranting only feed grade prices (Wrigley and Batey, 2003; Trissi, 2006).

The damage caused by the cereal bug shows important differences which are influ-enced by a number of criteria such as cli-mate and weather conditions, availability of water, characteristics of the wheat type, and

time of ripening of wheat, or a combination of these factors.

According to Paulian and Popov (1980) some 10-15 million hectares (25-37 million acres) of cereal cultivation are at risk, and in certain years chemical treatments may be applied to seven million hectares (about 17 million acres) in an attempt to limit the dam-age, especially if the crop is wheat.

A report prepared and published in 1993 by FAO/ICARDA authorities, states that about 1.3 million acres field is inflicted by E. integriceps, and a part of 582.000 acres are

Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

This article was derived from the presentation made in 4th International Mühlenchemie Symposium, September 8-9, 2011.

by Prof. Dr. M. Hikmet Boyacioglu, Group R&D Director-Cereal Foods Institute Director, Doruk Group Holding, Turkey

Table 2: Seasonal Quality Attributes

Soundness and maturity,

Plumpness and hence actual milling yield,

Actual protein content,

Weather damage,

Content of broken, shriveled, dry green, or frosted grains,

Contamination of foreign seeds,

Presence of unmillable material, e.g. chaff, white heads,

Presence of moldy, insect damaged, or infested grain,

Moisture content.

Table 1: Inherent Quality Attributes

Protein type and quality (extensibility, stability to mixing),

Potential to produce grain with protein content in a given range (either high or low),

Grain hardness,

Potential to produce grain having a high milling yield (high milling release),

Resistance to weather damage-dormancy.

Grain&feed millinG technoloGy22 | September - october 2012

FEATURE

thus treated with pesticides. The calculated cost for the treatment of one acre with pesticides is about US$10, making a total of US$5,870,000.

In a report prepared by specialists about the cereal bug problem in Turkey, it was stated that should no plant protection meas-urement and precautions be taken against the insect during plague years, the damage could reach a ratio of 90 percent to as much as 100 percent. Moreover, if sufficient pre-cautions are taken against the plague, savings with an amount of US$40,000,000 could be achieved (Kınacı, 1994).

Varietal susceptibility Many researchers have noted that the

genetic quality of the insect-damaged vari-ety influences the degree of quality dete-rioration (Cressey et al, 1987). Paulian and Popov (1980) reported that hard wheats are attacked more severely by the insect E. integriceps than soft wheats.

Also, in New Zealand, the semi-hard wheat cultivar Karamu has shown more effects and the soft, white wheat cultivar Arawa has fewer effects of bug damage than other cultivars (Every et al, 1996). In a study to investigate the susceptibility of various New Zealand wheat cultivars and breed-ing lines to attack by N. huttoni, Every et al (1996) stated that the hard wheat cultivar Domino was clearly the least susceptible

and the soft type breeding line WW378 was clearly the most susceptible to Nysius infestation.

A similar study performed in Turkey by Kınacı (1994) has proven that the cereal bug E. integriceps prefers to attack white, soft and/or semi-hard wheats and it is astonish-ing that the first priority of the insect is to select those high quality kernels. The same study showed that E. integriceps rarely attacks hard wheats. The latest genotypes of wheat which the bug preferred to attack were hard red wheats. Also it was observed that the density of the cereal bug among wheat hav-ing thick, hard and tightly adhered seed coats

is much less (Kınacı, 1994).

Effects on baking qualityIn 1931, wheat producing a ‘slimy gluten’

was reported by Berliner. This wheat was completely unsuitable for processing into bread because doughs formed from the flour quickly relaxed, becoming very sticky and difficult to mould.

Loaves of bread baked from these doughs typically had low volume, coarse texture, and knobbly tops. Gluten was washed out of the flour with difficulty, and instead of having the normal elastic properties; it was ‘slimy’ or ‘rotten’ (Lorenz and Meredith, 1988).

Grain&feed millinG technoloGy September - october 2012 | 23

FEATURE

Page 4: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Dough made from flour stinkbug-damaged wheat has lost much of its elasticity and is sticky or slimy.

A review of several overseas studies (Nuorteva and Veijola, 1954) indicates that in general a level of two to five percent affected grain is necessary before baking quality is degraded.

Meredith (1970) claimed that three to four bug-damaged grains per thousand could seriously affect baking quality.

Effects of attack by suni bug were studied on the size of Russian grains and percent of damaged grain was found to be higher in smaller fractions; the proportion of fully destroyed grains and the degree of damage on the whole sample set both increased in smaller fractions (Yakovenko, 1985).

The influence of wheat infestation by suni bug on bread making properties of Bulgarian wheat was investigated and results showed that suni bug infestation had a marked impact on bread making properties, with even one percent infestation affecting bread quality (Vasileva et al., 1998).

Methods for the prediction of damagePhysical Tests - Currently, the most widely used method to determine insect damage in wheat is the visual method. Wheat bug damage to wheat kernels can be examined visually since they are recognised as pale, slightly elevated patches, often with one or more black dots considered to be the marks of bug stylet punctures. No such damage can be found in uninfested samples.

Chemical and Biochemical Tests - The prediction of the extent of insect-damage to wheats prior to milling has gained impor-tance as the enzyme secreted by cereal bugs results in the production of runny and sticky dough and, subsequently, a low quality of bread.

Most of the test methods determine the quality of gluten and dough, since the enzyme influences the gluten structure.

To determine the bug damage in wheats, Greenway et al (1965) developed a method which is based on wheat sedimentation test. The method has been found to be effective and sensitive when two hydration times, such as five and 180 minutes, were used.

Atlı et al (1988) modified this method by applying a two-hour hydration period after the addition of bromphenol solution (Table 3, 4).

In New Zealand, Cressey and McStay (1987) proposed an autolytic assay method that is based on the decrease in SDS-sedimentation volume of bug-damaged flours by incubating in distilled water for 30 minutes at 37oC. It has been suggested that the method is specific for bug damage and is free of interference from other grain defects such as heat damage, field sprouting and laboratory germination.

However, this method needs considera-

Although puncture marks on wheat sug-gested attack by sap-sucking insects, the ability of affected wheat to ruin sound grain indicated that slimy gluten was caused by an enzyme. Two insects of the genera Eurygaster and Aelia were considered to be responsible for producing wheat with dam-aged gluten (Kretovich, 1944; Lorenz and Meredith, 1988).

Brooke (1936) states that as little as one or two percent of stinkbug-damaged kernels may injure the baking quality of wheat, depending on the severity of the damage in the damaged kernels. Much larger quantities of damaged kernels are often found in wheat from fields where the infestation was heavy.

Initially it was not known whether slimy gluten was produced by a new kind of wheat or by normal wheat that had been damaged in some way. Whatever the cause of the problem, it was clearly of considerable concern to European millers.

According to later investigations, wheat that produced slimy gluten had a proportion of grains with small dark puncture marks surrounded by a patch of lighter colour. Wheat without puncture marks gave ‘sound’ gluten even if the grain was selected from a batch produced ‘slimy’ gluten. However only relatively low levels (approximately 3%) of puncture-marked wheat were needed to ruin the remaining sound grain (Lorenz and Meredith, 1988).

Figure 1. Farinogram, based on Brabender Farinograph Standard Procedure, shows 2.6% insect damage on wheat

Courtesy of DORMAR Flour Mills, Turkey.

Figure 2. Extensigram, based on Brabender Extensigraph Standard Procedure, shows 2.6% insect damage on wheat

Courtesy of DORMAR Flour Mills, Turkey.

Figure 3. Alveogram, based on Alveo-AH Standard Procedure shows insect damage on wheat

Courtesy of POLEN Gıda, Turkey.

Grain&feed millinG technoloGy24 | September - october 2012

FEATURE

Page 5: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Dough made from flour stinkbug-damaged wheat has lost much of its elasticity and is sticky or slimy.

A review of several overseas studies (Nuorteva and Veijola, 1954) indicates that in general a level of two to five percent affected grain is necessary before baking quality is degraded.

Meredith (1970) claimed that three to four bug-damaged grains per thousand could seriously affect baking quality.

Effects of attack by suni bug were studied on the size of Russian grains and percent of damaged grain was found to be higher in smaller fractions; the proportion of fully destroyed grains and the degree of damage on the whole sample set both increased in smaller fractions (Yakovenko, 1985).

The influence of wheat infestation by suni bug on bread making properties of Bulgarian wheat was investigated and results showed that suni bug infestation had a marked impact on bread making properties, with even one percent infestation affecting bread quality (Vasileva et al., 1998).

Methods for the prediction of damagePhysical Tests - Currently, the most widely used method to determine insect damage in wheat is the visual method. Wheat bug damage to wheat kernels can be examined visually since they are recognised as pale, slightly elevated patches, often with one or more black dots considered to be the marks of bug stylet punctures. No such damage can be found in uninfested samples.

Chemical and Biochemical Tests - The prediction of the extent of insect-damage to wheats prior to milling has gained impor-tance as the enzyme secreted by cereal bugs results in the production of runny and sticky dough and, subsequently, a low quality of bread.

Most of the test methods determine the quality of gluten and dough, since the enzyme influences the gluten structure.

To determine the bug damage in wheats, Greenway et al (1965) developed a method which is based on wheat sedimentation test. The method has been found to be effective and sensitive when two hydration times, such as five and 180 minutes, were used.

Atlı et al (1988) modified this method by applying a two-hour hydration period after the addition of bromphenol solution (Table 3, 4).

In New Zealand, Cressey and McStay (1987) proposed an autolytic assay method that is based on the decrease in SDS-sedimentation volume of bug-damaged flours by incubating in distilled water for 30 minutes at 37oC. It has been suggested that the method is specific for bug damage and is free of interference from other grain defects such as heat damage, field sprouting and laboratory germination.

However, this method needs considera-

Although puncture marks on wheat sug-gested attack by sap-sucking insects, the ability of affected wheat to ruin sound grain indicated that slimy gluten was caused by an enzyme. Two insects of the genera Eurygaster and Aelia were considered to be responsible for producing wheat with dam-aged gluten (Kretovich, 1944; Lorenz and Meredith, 1988).

Brooke (1936) states that as little as one or two percent of stinkbug-damaged kernels may injure the baking quality of wheat, depending on the severity of the damage in the damaged kernels. Much larger quantities of damaged kernels are often found in wheat from fields where the infestation was heavy.

Initially it was not known whether slimy gluten was produced by a new kind of wheat or by normal wheat that had been damaged in some way. Whatever the cause of the problem, it was clearly of considerable concern to European millers.

According to later investigations, wheat that produced slimy gluten had a proportion of grains with small dark puncture marks surrounded by a patch of lighter colour. Wheat without puncture marks gave ‘sound’ gluten even if the grain was selected from a batch produced ‘slimy’ gluten. However only relatively low levels (approximately 3%) of puncture-marked wheat were needed to ruin the remaining sound grain (Lorenz and Meredith, 1988).

Figure 1. Farinogram, based on Brabender Farinograph Standard Procedure, shows 2.6% insect damage on wheat

Courtesy of DORMAR Flour Mills, Turkey.

Figure 2. Extensigram, based on Brabender Extensigraph Standard Procedure, shows 2.6% insect damage on wheat

Courtesy of DORMAR Flour Mills, Turkey.

Figure 3. Alveogram, based on Alveo-AH Standard Procedure shows insect damage on wheat

Courtesy of POLEN Gıda, Turkey.

Grain&feed millinG technoloGy24 | September - october 2012

FEATURE

instru-ments.

It has been sug-gested that it is necessary to record the farino-grams and alveograms immedi-ately after the dough is made

and again after it has stood in a warm place for 60 to 90 minutes, as the disintegration of the dough takes place only after it has rested. Farinograph curves of flour show the effects of bug damage particularly at higher temperatures (45oC). The curve of a sound flour is wider and the decrease in consistency with mix-ing occurs less rapidly. The increasing soften-ing of the dough also shows as an irregular band towards the end of the curve (Lorenz and Meredith, 1988).

According to Brabender Procedure; do the normal Farinogram for 10 minutes, stop the mixer (via soft-ware) (value here is for example 480 BU), leave the dough in the mixer, and restart via software after 20 minutes pause. If the values of the second mixing continue on the level from the first mixing (around 480 BU in this example), there is no bug damage. If the values are lower (for example total 50 BU), there is strong bug damage. From the second mixing, the bug damage in the sample could be estimated (Figure 1).

The Brabender Extensigraph is another instrument used to determine

ble amount of sample and enzyme (Swallow and Every, 1991). In addition, there is no available information that this method can be also used to detect the damage of Eurygaster and Aelia, since it has been developed for different type of bug-damage.

Every (1991) developed an economical and sensitive SDS-protein gel method, based on the determination of enzyme activity, to test the activities of different protease types. This method measures the reduction in the gel-formation capacity of glutenin proteins by the enzyme. However, it is not known yet if this method can be used for the damage caused by Eurygaster and Aelia.

The methods based on the washing of gluten after a resting period of 30 minutes at 25oC of the dough gives a better under-standing of changes in the quantity and qual-ity of gluten (Atlı et al., 1988).

Gluten index method also has been found to be useful in determining the pres-ence of slimy gluten, due to the attack of wheat kernels by wheat bugs (Perten, 1989).

A method for rapid indication of infec-tion was proposed involving incubation of wheat in water at 30oC, to activate the insect proteinases, followed by PAGE to determine gluten profile and thus, the amount of deg-radation that has occurred (Corbellini et al., 2001).

Rheological TestsInsect bug damage could be reliably

predicted by using Brabender Farinograph, Brabender Extensigraph, and Chopin Alveograph and Chopin Mixolab instruments.

For the estimation of the bug-damage, another method which has been developed in France uses Chopin extensimeter and has been made official by special regulation (Kretovich, 1944).

Kretovich (1944) indicated that bug dam-age could be reliably predicted by using Brabender farinograph and Chopin alveograph

Table 3:

Wheat Type‘Suni Bug

Damage’, %Sed., cc Del. Sed., cc

Bezostia 0.7 48 65

Mix 1.1 35 41

White-Red 2.3 22 9

White-Red 2.4 38 10

White 2.5 20 10

Courtesy of DORMAR Flour Mills, Turkey

Table 4:

Sedimentation Value, cc Gluten Quality

<25 Weak

25 – 30 Medium

>30 Good

Grain&feed millinG technoloGy September - october 2012 | 25

Westeel: International 2012 Grain & Feed Milling Techniques: 90 mm x 270 mm" CMYK, Jan-Feb/2012

Publication

Our grain storage systems come with six continents of experience.Westeel offers a full line of professionally engineered grain storage products and systems for international sale – all backed by Westeel’s superior service and product support.

Commercial Grain Storage Bins (up to 674,000 �bushels/18,343 tonnes)On-Farm Grain Storage Bins (starting from �2,390 bushels/65 tonnes)Aeration Systems �Bin Unload and Grain Handling Systems �Systems Engineering and Design �

westeel.com

P.O. Box 792, 450 Desautels Street Winnipeg, Manitoba, Canada R3C 2N5 Tel: (204) 233-7133 Fax: (204) 235-0796 [email protected]

Management Systems Registered to ISO 9001:2008. MF21589-0112

EuropeAsia

North America

21589 Westeel International 2012 G&FMT.indd 1 1/11/12 5:03:02 PM

FEATURE

Page 6: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Cleaning-tempering Dıraman et al (2001) studied the

effect of steam tempering on some pro-tein fractions and farinogram values of commercial wheat having sunn pest dam-age at several levels. The evaluation of farinogram data combined with positive changes in protein fractions show that 70oC temperature applied during steam tempering did not cause any negative changes in rheological properties of sunn pest damaged samples.

Köksel et al (2002) investigated mitigation of the detrimental effects of suni bug dam-age to wheat by cleaning and washing prior to milling and by elimination of mill streams of lower quality. They concluded that ˃50 percent of insect-damaged kernels can be removed by dry and wet cleaning prior to milling and that flour streams with minimal insect damage can be selected.

MillingBogdan (1969) reported that bread of

good quality can be produced from flour of bug-damaged cereals when flour from dam-aged grains is blended with good quality flour, ascorbic acid and yeast are added in adequate amounts, or intensive kneading is applied.

According to Valtadoros (1979), by using air classification, flour from bug-damaged wheat may be separated into fractions suit-able for bread making and those suitable for biscuit manufacture.

Bread making The effect of insect damage on bread

making quality of wheat depends on degree of damage or ratio of infested kernel and quality of infested wheat.

In case of less than average five per-cent damage and good protein quality and quantity, effect of insect damage in wheat flour could be lessen by using, improvers, additives such as ascorbic acid (Bogdan, 1969), vital wheat gluten, transglutaminase (Köksel et al., 2001), DATEM, etc. and modified methods such as short fermenta-tion (Swallow and Cresley, 1987), use of sour dough procedure, etc (Dizlek and Gül, 2007).

ConclusionThe suni bug is one of the most serious

pests of wheat in Europe (except north-ernmost areas), North Africa and Asia. Yield loss from its damage is commonly estimated at 50-90 percent in wheat and heavy attack causes wheat stems to break before harvest.

Even if two to three percent of the grain is damaged, entire lots may be unsuitable for bread making. Therefore, there is a need for simple and fast routine tests, which can be used by the millers during the purchase of wheat, since the baking experiment is relatively time-consuming.

ReferencesAvailable on request

Bread making TestIn spite of the availability of

many methods developed for the prediction of Eurygaster and Aelia damage to wheat quality, the most reliable and sensi-tive method is a bread making experiment.

However, there is still need for simple and fast routine tests, which can be used by the millers during the purchase of wheat, since the baking experiment is

relatively time-consuming.

Suni bug managementThe current strategies for suni bug

management rely mainly on chemical and cultural controls; in most cases, chemical control is the primary means of manage-ment. This is a costly and unsuitable means of pest management and has resulted in resistance of suni bug to various types of insecticides.

The current novel management studies involve the use of resistant wheat varieties, insect pathogens, predators, parasites, and parasitoids. Among the most promising of these natural controls are the egg parasitoids (Trissi, 2006).

Cereal growing, especially wheat, in mar-ginal lands; overgrazing of rangeland which results in the destruction of natural vegeta-tion and hence habitat of sunn pest preda-tors; reduction in the area of fallow land by the continuous growing of cereals instead of increasing food or forage legumes within a rotation; the use of broad spectrum insecti-cides, especially by aerial spraying, might also have increased the difficulties of controlling the sunn pest problem in Turkey (Kınacı et al.,1998).

Improvement of bread qualityThere are various studies on to improve the

quality of insect damaged wheats and their flours.

Wheat treatmentsIn the USSR, high-frequency heating was

used for treatment of wheat infested with the shield bug and recommended as a meas-ure for restitution of the baking performance of deteriorated grain (Pruidze et al, 1984).

Dıraman (2010) investigated the effects of microwave treatment on technological and rheological properties of flours produced from sound wheat and wheat damaged by sunn pests (Eurygaster spp.). The results for Zeleny sedimentation, Gluten Index and alveogram values suggest that certain micro-wave treatment times (120-180 seconds) caused positive effects on thermal inactivation of insect enzyme damage of wheat.

Blending Wrigley and Batey (2003) stated that

because of the involvement of enzymatic action, the effects of mixing bug-damaged grain with sound grain are disproportionate to the proportions of samples mixed.

insect damage in wheat due to two or three resting periods (45, 90 and 135 minutes) between dough resistance and extensibility measurements (Figure 2).

Currently, the Chopin Alveograph is also used for the measurement of insect-damage to wheat. The method involves testing of three dough pieces out of five after resting 20 minutes and after three hours for the remaining dough pieces. It has been claimed that this method could detect about 0.9% insect damage by measuring the reduction in P, L, and W values (Anonymous).

Since the enzyme delivered by insect needs time and temperature to show its effect, standard alveograph method, which uses 20 minutes resting time, does not show the presence of insect-damage. However, modified Alveograph method shows the effect of insect damage since it uses extend-ed time of three hours - degradation test.

The degradation test protocol involves: - a first series of alveograph tests after 20 minutes of rest (ISO 5530/4, ICC121, AACC54-30 approved method) - a second series of balls of dough is tested after three hours rest. If the wheat contains bugs, a drop in baking strength (W) is observed due to protein hydrolysis caused by the insect’s proteolytic enzymes (Figure 3).

It has been claimed that this method could detect about 0.9% insect damage by measur-ing the reduction in P, L, and W values.

Atlı et al (1988) suggested a modification of this method by using a two-hours resting period for the dough pieces.

Aspesteguia et al (2003) reported that kneading temperature did not influence glu-ten degradation; however, resting tempera-ture significantly influenced when assessing wheat damaged by wheat bugs.

The Chopin Mixolab system measures real-time dough behaviour with regard to the dual constraint of kneading and tem-perature.

It is claimed that system measures insect damage in 45 minutes including rest time.

Investigations were conducted on the development of a rapid method (using viscosity measurement with the Rapid Visco Analyzer) for testing wheat for proteolytic determination due to infestation with insects of the genera Aelia and Eurygaster.

Results showed that this method is rapid (results within 10 minutes) and gives 97.27% correct classification over a wide range of proteolytic degradation. Repeatability and reproducibility were good (Caballero-Barrigon and Perez-Calvo, 2008).

Grain&feed millinG technoloGy26 | September - october 2012

FEATURE

Page 7: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

Cleaning-tempering Dıraman et al (2001) studied the

effect of steam tempering on some pro-tein fractions and farinogram values of commercial wheat having sunn pest dam-age at several levels. The evaluation of farinogram data combined with positive changes in protein fractions show that 70oC temperature applied during steam tempering did not cause any negative changes in rheological properties of sunn pest damaged samples.

Köksel et al (2002) investigated mitigation of the detrimental effects of suni bug dam-age to wheat by cleaning and washing prior to milling and by elimination of mill streams of lower quality. They concluded that ˃50 percent of insect-damaged kernels can be removed by dry and wet cleaning prior to milling and that flour streams with minimal insect damage can be selected.

MillingBogdan (1969) reported that bread of

good quality can be produced from flour of bug-damaged cereals when flour from dam-aged grains is blended with good quality flour, ascorbic acid and yeast are added in adequate amounts, or intensive kneading is applied.

According to Valtadoros (1979), by using air classification, flour from bug-damaged wheat may be separated into fractions suit-able for bread making and those suitable for biscuit manufacture.

Bread making The effect of insect damage on bread

making quality of wheat depends on degree of damage or ratio of infested kernel and quality of infested wheat.

In case of less than average five per-cent damage and good protein quality and quantity, effect of insect damage in wheat flour could be lessen by using, improvers, additives such as ascorbic acid (Bogdan, 1969), vital wheat gluten, transglutaminase (Köksel et al., 2001), DATEM, etc. and modified methods such as short fermenta-tion (Swallow and Cresley, 1987), use of sour dough procedure, etc (Dizlek and Gül, 2007).

ConclusionThe suni bug is one of the most serious

pests of wheat in Europe (except north-ernmost areas), North Africa and Asia. Yield loss from its damage is commonly estimated at 50-90 percent in wheat and heavy attack causes wheat stems to break before harvest.

Even if two to three percent of the grain is damaged, entire lots may be unsuitable for bread making. Therefore, there is a need for simple and fast routine tests, which can be used by the millers during the purchase of wheat, since the baking experiment is relatively time-consuming.

ReferencesAvailable on request

Bread making TestIn spite of the availability of

many methods developed for the prediction of Eurygaster and Aelia damage to wheat quality, the most reliable and sensi-tive method is a bread making experiment.

However, there is still need for simple and fast routine tests, which can be used by the millers during the purchase of wheat, since the baking experiment is

relatively time-consuming.

Suni bug managementThe current strategies for suni bug

management rely mainly on chemical and cultural controls; in most cases, chemical control is the primary means of manage-ment. This is a costly and unsuitable means of pest management and has resulted in resistance of suni bug to various types of insecticides.

The current novel management studies involve the use of resistant wheat varieties, insect pathogens, predators, parasites, and parasitoids. Among the most promising of these natural controls are the egg parasitoids (Trissi, 2006).

Cereal growing, especially wheat, in mar-ginal lands; overgrazing of rangeland which results in the destruction of natural vegeta-tion and hence habitat of sunn pest preda-tors; reduction in the area of fallow land by the continuous growing of cereals instead of increasing food or forage legumes within a rotation; the use of broad spectrum insecti-cides, especially by aerial spraying, might also have increased the difficulties of controlling the sunn pest problem in Turkey (Kınacı et al.,1998).

Improvement of bread qualityThere are various studies on to improve the

quality of insect damaged wheats and their flours.

Wheat treatmentsIn the USSR, high-frequency heating was

used for treatment of wheat infested with the shield bug and recommended as a meas-ure for restitution of the baking performance of deteriorated grain (Pruidze et al, 1984).

Dıraman (2010) investigated the effects of microwave treatment on technological and rheological properties of flours produced from sound wheat and wheat damaged by sunn pests (Eurygaster spp.). The results for Zeleny sedimentation, Gluten Index and alveogram values suggest that certain micro-wave treatment times (120-180 seconds) caused positive effects on thermal inactivation of insect enzyme damage of wheat.

Blending Wrigley and Batey (2003) stated that

because of the involvement of enzymatic action, the effects of mixing bug-damaged grain with sound grain are disproportionate to the proportions of samples mixed.

insect damage in wheat due to two or three resting periods (45, 90 and 135 minutes) between dough resistance and extensibility measurements (Figure 2).

Currently, the Chopin Alveograph is also used for the measurement of insect-damage to wheat. The method involves testing of three dough pieces out of five after resting 20 minutes and after three hours for the remaining dough pieces. It has been claimed that this method could detect about 0.9% insect damage by measuring the reduction in P, L, and W values (Anonymous).

Since the enzyme delivered by insect needs time and temperature to show its effect, standard alveograph method, which uses 20 minutes resting time, does not show the presence of insect-damage. However, modified Alveograph method shows the effect of insect damage since it uses extend-ed time of three hours - degradation test.

The degradation test protocol involves: - a first series of alveograph tests after 20 minutes of rest (ISO 5530/4, ICC121, AACC54-30 approved method) - a second series of balls of dough is tested after three hours rest. If the wheat contains bugs, a drop in baking strength (W) is observed due to protein hydrolysis caused by the insect’s proteolytic enzymes (Figure 3).

It has been claimed that this method could detect about 0.9% insect damage by measur-ing the reduction in P, L, and W values.

Atlı et al (1988) suggested a modification of this method by using a two-hours resting period for the dough pieces.

Aspesteguia et al (2003) reported that kneading temperature did not influence glu-ten degradation; however, resting tempera-ture significantly influenced when assessing wheat damaged by wheat bugs.

The Chopin Mixolab system measures real-time dough behaviour with regard to the dual constraint of kneading and tem-perature.

It is claimed that system measures insect damage in 45 minutes including rest time.

Investigations were conducted on the development of a rapid method (using viscosity measurement with the Rapid Visco Analyzer) for testing wheat for proteolytic determination due to infestation with insects of the genera Aelia and Eurygaster.

Results showed that this method is rapid (results within 10 minutes) and gives 97.27% correct classification over a wide range of proteolytic degradation. Repeatability and reproducibility were good (Caballero-Barrigon and Perez-Calvo, 2008).

Grain&feed millinG technoloGy26 | September - october 2012

FEATURE

Uncoated Fine Paper Corrugated Bags & CoatingsEurope & International

Reap the Benefi ts!Customised industrial bags for quick fi lling and reliable protection of your fi lling goods.

www.mondigroup.com

SOLUTIONS.FOR YOUR SUCCESS.

AutomotiveIndustry

ChemicalIndustry

Farming &Agriculture

Industry

Food IndustryBuilding &Construction

Industry

Industrial Paper & Packaging

Industry

Office &Printing Paper

Industry

Pet Food Industry

Photographic & Graphic Industry

Toiletries &HygieneIndustry

OthersCreative Industry

Medical &Pharmaceutical

Industry

HouseholdIndustry

Hygienic

closure techniques

Window for presenting

the fi lling good attractively

and simple dosage

Compact

dimensionsSuitable for

food contactCompostable

bags with

biodegradable fi lm

Reliable

protection through

sealable valves

1

3

2

54

6

IB_Muehle_Mischfutter_297x210_+3mm_E.indd 1 21.04.11 18:07

Page 8: Insect-damaged wheat: suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

www.gfmt.co.uk

LINKS• Seethefullissue• VisittheGFMTwebsite

• ContacttheGFMTTeam

• SubscribetoGFMT

A subscription magazine for the global flour & feed milling industries - first published in 1891

In this issue:

• Insect damaged wheat:

suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug

• Managing mill maintenance

• Global grain & feed markets

September - October 2012

• A packaging evolution

• Probiotics: modulators of gut bacteria

dialogue

• Pellet production to save energy, improve feed

efficiency and safety

We have interactive content in this edition that requires a smart phone app - get it here for free to unlock our digital content!

ThisdigitalRe-printispartoftheSeptember|October2012editionofGrain&FeedMillingTechnologymagazine.Contentfromthemagazineisavailabletoviewfree-of-charge,bothasafullonlinemagazineonourwebsite,andasanarchiveofindividualfeaturesonthedocstocwebsite.Pleaseclickheretoviewourotherpublicationsonwww.docstoc.com.

Topurchaseapapercopyofthemagazine,ortosubscribetothepaperedi-tionpleasecontactourCirculationandSubscriptionsManageronthelinkadove.

INFORMATIONFORADVERTISERS-CLICKHERE

Article reprintsAll Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these have been used as point of sale materials, promotional materials for shows and exhibitions etc).

If you are interested in getting this article re-printed please contact the GFMT team for more informa-tion on - Tel: +44 1242 267707 - Email: [email protected] or visit www.gfmt.co.uk/reprints