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Oxford Cambridge Philadelphia New Delhi

Number 248

Cereal grains for the food and beverage industriesElke K Arendt and Emanuele Zannini

www.woodheadpublishingonline.com

Woodhead Publishing, 1518 Walnut Street, Suite 1100, Philadelphia, PA 19102-3406, USA Woodhead Publishing India Private Limited, G-2, Vardaan House, 7/28 Ansari Road, Daryaganj, New Delhi – 110002, India

www.woodheadpublishingindia.com

First published 2013, Woodhead Publishing Limited

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British Library Cataloguing in Publication Data

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ISBN 978-0-85709-413-1 (print)

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Author contact details ix

Woodhead Publishing Series in Food Science, Technology and Nutrition xi

Foreword xxiii

Preface xxv

1 Wheat and other Triticum grains 1

1.1 Introduction 1

1.2 Structure of wheat grain 5

1.3 Wheat carbohydrate composition and properties 9

1.4 Wheat protein composition and properties 15

1.5 Other constituents of wheat 20

1.6 Flour milling 23

1.7 Bakery products based on wheat 32

1.8 Durum wheat products 42

1.9 Products based on other types of wheat 47

1.10 Beverages based on wheat 50

1.11 Conclusions 56

1.12 Future trends 56

1.13 References 57

2 Maize 67

2.1 Introduction 67

2.2 Maize carbohydrate composition and properties 77

2.3 Other constituents of the maize kernel 81

2.4 Maize processing 87

2.5 Applications of maize in foods 91

2.6 Applications of maize in beverages 101

2.7 Conclusions 103

2.8 Future trends 103

2.9 References 104

3 Rice 114

3.1 Introduction 114

3.2 Rice carbohydrate composition and properties 122

3.3 Other constituents of the rice kernel 125

3.4 Rice processing 132

3.5 Food and beverage applications of rice 137

3.6 Conclusions 145

3.7 Future trends 145

3.8 References 146

4 Barley 155

4.1 Introduction 155

4.2 Barley carbohydrate composition and properties 165

4.3 Other constituents of the barley kernel 170

4.4 Barley milling 174

4.5 Applications of barley in foods 177

4.6 Applications of barley in beverages 184

4.7 Conclusions 190

4.8 Future trends 190

4.9 References 191

5 Triticale 201

5.1 Introduction 201

5.2 Chemical composition of the triticale kernel 205

5.3 Triticale milling and applications in foods and beverages 210

5.4 Conclusions 215

5.5 Future trends 215

5.6 References 216

6 Rye 220

6.1 Introduction 220

6.2 Chemical composition of the rye kernel 229

6.3 Rye milling and applications in foods and beverages 234

6.4 Conclusions 237

6.5 Future trends 238

6.6 References 238

7 Oats 243

7.1 Introduction 243

7.2 Oat carbohydrate composition and properties 253

7.3 Other constituents of the oat kernel 259

7.4 Oat milling 266

7.5 Food and beverage applications of oats 269

7.6 Conclusions 273

7.7 Future trends 273

7.8 References 274

8 Sorghum 283

8.1 Introduction 283

8.2 Chemical constituents of the sorghum kernel 292

8.3 Sorghum milling 299

8.4 Applications in foods and beverages 299

8.5 Conclusions 304

8.6 Future trends 305

8.7 References 305

9 Millet 312

9.1 Introduction 312

9.2 Proso millet carbohydrate composition and properties 318

9.3 Proso millet protein composition and properties 322

9.4 Other constituents of proso millet 329

9.5 Processing of proso millet 335

9.6 Food and beverage applications of proso millet 339

9.7 Future trends 342

9.8 References 343

10 Teff 351

10.1 Introduction 351

10.2 Chemical composition of the teff kernel 356

10.3 Teff milling and applications in foods and beverages 361

10.4 Conclusions 365

10.5 Future trends 365

10.6 References 365

11 Buckwheat 369

11.1 Introduction 369

11.2 Buckwheat carbohydrate composition and properties 373

11.3 Buckwheat protein composition and properties 379

11.4 Other constituents of buckwheat 386

11.5 Food and beverage applications of buckwheat 392

11.6 Conclusions 400

11.7 Future trends 401

11.8 References 401

12 Quinoa 409

12.1 Introduction 409

12.2 Chemical composition of quinoa seed 417

12.3 Quinoa milling and applications in foods and beverages 425

12.4 Conclusions 432

12.5 Future trends 432

12.6 References 433

13 Amaranth 439

13.1 Introduction 439

13.2 Amaranth carbohydrate composition and properties 444

13.3 Other constituents of amaranth 450

13.4 Amaranth processing and applications in foods and beverages 460

13.5 Conclusions 466

13.6 Future trends 466

13.7 References 466

Index 475

Professor Elke Arendt and Dr Emanuele ZanniniSchool of Food and Nutritional Sciences

University College Cork

Western Road

Ireland

E-mail: e.arendt@ucc.ie; e.zannini@ucc.ie

Science, Technology and Nutrition

1 Chilled foods: a comprehensive guide Edited by C Dennis and

M Stringer

2 Yoghurt: science and technology A 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 fi bre: chemical and biological aspects Edited by

D A T Southgate, K W Waldron, I T Johnson and G R Fenwick

11 Vitamins and minerals in health and nutrition M Tolonen

12 Technology of biscuits, crackers and cookies Second edition

D 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 fragrances Edited 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 edition N L Kent and A D Evers

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

31 Biscuit, cookie and cracker manufacturing manuals Volume 2: biscuit

doughs D Manley

32 Biscuit, cookie and cracker manufacturing manuals Volume 3: biscuit

dough piece forming D Manley

33 Biscuit, cookie and cracker manufacturing manuals Volume 4:

baking and cooling of biscuits D Manley

34 Biscuit, cookie and cracker manufacturing manuals Volume 5:

secondary processing in biscuit manufacturing D Manley

35 Biscuit, cookie and cracker manufacturing manuals Volume 6: 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 edition A Y Tamime and

R K Robinson

39 New ingredients in food processing: biochemistry and agriculture

G Linden and D Lorient

40 Benders’ dictionary of nutrition and food technology Seventh edition 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 edition

P 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 labelling Edited by J R Blanchfi eld

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 edition Edited 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

53 Cereals processing technology Edited by G Owens

54 Baking problems solved S 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 modelling Edited by L M M Tijskens,

M L A T M Hertog and B M Nicolạ

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 to

environmental and other audits Edited by M Dillon and C Griffi th

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

67 Fruit and vegetable biotechnology Edited by V Valpuesta

68 Foodborne pathogens: hazards, risk analysis and control Edited 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 fi sh 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 quality Edited 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-fl avours in foods Edited by B Baigrie

81 Yeasts in food Edited by T Boekhout and V Robert

82 Phytochemical functional foods Edited by I T Johnson and

G Williamson

83 Novel food packaging techniques Edited 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 processing Edited 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

96 Handbook of herbs and spices Volume 2 Edited by K V Peter

97 Texture in food Volume 2: solid foods Edited by D Kilcast

98 Proteins in food processing Edited 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 Edited by P Richardson

105 Pesticide, veterinary and other residues in food Edited by D Watson

106 Starch in food: structure, functions and applications Edited by

109 Using cereal science and technology for the benefi t of consumers:

S P Cauvain, L S Young and S Salmon

110 Improving the safety of fresh meat Edited by J Sofos

111 Understanding pathogen behaviour: virulence, stress response and resistance Edited by M Griffi ths

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 food Edited by S Koppelman and S Hefl e

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

125 Optimising sweet taste in foods Edited by W J Spillane

126 Brewing: new technologies Edited by C Bamforth

127 Handbook of herbs and spices Volume 3 Edited by K V Peter

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 interactions

Edited 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

142 Improving the fl avour of cheese Edited 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 fl avour 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 fi elds: from research to

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

152 Technology of functional cereal products Edited by B R Hamaker

153 Case studies in food product development Edited 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 fl avour: recent advances and future prospects

Edited by B Brückner and S G Wyllie

156 Food fortifi cation 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 Tomás-Barberán and M I Gil

158 Improving seafood products for the consumer Edited by T Børresen

159 In-pack processed foods: improving quality Edited by P Richardson

160 Handbook of water and energy management in food processing

Edited by J Klemeš, R Smith and J.-K Kim

161 Environmentally compatible food packaging Edited by E Chiellini

162 Improving farmed fi sh 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

166 Improving the sensory and nutritional quality of fresh meat

Edited by J P Kerry and D A Ledward

167 Shellfi sh safety and quality Edited 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 future

prospects Edited by M Wilson

173 Handbook of hydrocolloids Second edition Edited by G O Phillips

and P A Williams

174 Food processing technology: principles and practice Third edition

P J Fellows

175 Science and technology of enrobed and fi lled 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 effi ciency, quality and environmental management Edited by G Burnell and

G Allan

179 More baking problems solved S P Cauvain and L S Young

180 Soft drink and fruit juice problems solved P Ashurst and R Hargitt

181 Biofi lms 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

185 Delivering performance in food supply chains Edited 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 Edited by M Griffi ths

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

quality in milk products Edited by M Griffi ths

190 Cereal grains: assessing and managing quality Edited by C Wrigley

193 Winemaking problems solved Edited 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 modelling Edited by

C J Doona, K Kustin and F E Feeherry

198 Freeze-drying of pharmaceutical and food products T.-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 applications

Volume 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

206 Postharvest biology and technology of tropical and subtropical fruits

Volume 1: fundamental issues Edited by E M Yahia

207 Postharvest biology and technology of tropical and subtropical fruits

Volume 2: açai to citrus Edited by E M Yahia

208 Postharvest biology and technology of tropical and subtropical fruits Volume 3: cocona to mango Edited by E M Yahia

209 Postharvest biology and technology of tropical and subtropical

fruits Volume 4: mangosteen to white sapote Edited by

E M Yahia

210 Food and beverage stability and shelf life Edited 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

221 Reducing saturated fats in foods Edited by G Talbot

222 Handbook of food proteins Edited by G O Phillips and

P A Williams

223 Lifetime nutritional infl uences on cognition, behaviour and

psychiatric illness Edited by D Benton

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

228 Handbook of herbs and spices Second edition Volume 2 Edited by

K V Peter

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

231 Infectious disease in aquaculture: prevention and control Edited by

B Austin

232 Diet, immunity and infl ammation Edited by P C Calder and

P Yaqoob

233 Natural food additives, ingredients and fl avourings 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 nutraceuticals Edited 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

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

consumer goods (FMCG) Edited by Neil Farmer

245 New analytical approaches for verifying the origin of food Edited by

P Brereton

246 Microbial production of food ingredients, enzymes and

nutraceuticals 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

251 Metabolomics in food and nutrition Edited by B Weimer and

C Slupsky

252 Food enrichment with omega-3 fatty acids Edited by C Jacobsen,

N Skall Nielsen, A Frisenfeldt Horn and A.-D Moltke Sørensen

253 Instrumental assessment of food sensory quality: a practical guide

Edited by D Kilcast

254 Food microstructures: microscopy, measurement and modelling

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 nutraceuticals

Edited by H Domínguez

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

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

Jeffrey Hoorfar

I set my mind to wondering about how my life would be without cereals or pseudo-cereals And I concluded that it would be pretty nigh impossible, either from a practical survival, functional or life-worth-living perspective The day was approaching its conclusion and I was mellowing in my corner whilst sipping a Scotch It had been a long one (day that is, not the whisky), starting with a breakfast of porridge oats and a slice of wheat toast

In the brewery, my assistant was experimenting with a beer recipe for folks with coeliac disease, the principle grist components being buckwheat We had tasted some others, especially the most common ones founded on sorghum and millet, but we thought we could do better

All this cogitation certainly sparked an appetite, sated by a soup and sandwich lunch with a visitor Neat restaurant, very bohemian but charming and the Creamy Cannellini Bean and Amaranth Soup with half Reuben was delicious As was the beer!

Somehow, though, at the working day’s end I had worked up suffi cient appetite to look forward to a hearty supper My good lady has me on a health kick – making for my projection outside to cook some corn on the grill while she cobbled together something vegetarian including quinoa and some fl atbread that I hadn’t seen before ‘Made with teff fl our – it’s Ethiopian,’ I was told For pudding there was some portion-controlled rice pudding, but strictly no jam I confess that, being a carnivore, I missed

my meat

It was a pleasant evening, so off for a stroll – and I admit to smuggling one of those nutritious health-food bars with me Packed with goodness – and laden with who-knows-what fabulous fi bre from cereals inclusive of triticale

A little artistic license here? Of course there is But I think the point is made, that cereals and pseudo-cereals are at the heart of pretty much any lifestyle Civilization as we know it commenced in the Fertile Crescent 8000 years ago (or longer) when a nomadic lifestyle was exchanged for a static existence involving the cultivation and processing of grain into breads and beers It would be somewhat impossible to conceive of a world in which cereals and their derived products were not at the heart, either as source

of food, directly for the human or for the animals that we farm, or for other purposes, notably the furnishing of fi bre and fuel In this book, my friend Elke Arendt and her colleague Emanuele Zannini have delivered a tim ely and compelling summary of the major cereals and pseudo-cereals, a volume that will prove invaluable to scientists and technologists and users of this diverse array of agricultural staples

Charles W Bamforth, PhD, D.Sc

Professor Department of Food Science and Technology

University of California, Davis

This book represents a comprehensive collection of material relating to cereal grains, ranging from the economic impact of the grains to their food and beverage products, whilst also providing an in-depth investigation of grain morphology, grain constituents and food processing.

Through use of a comprehensive review process, every effort has been made by the authors to ensure that the Cereal grains for the Food and Beverages Industries book covers this wide array of topics and is accurate, readable, and best represents currently known data The work is also exten-sively cross-referenced and indexed to ensure that the reader is easily able

to locate information as needed

This book will be a useful resource for ingredient manufacturers, cereal scientists, food technologists, marketing personnel, nutritionists, food chem-ists, policy-makers and health care professionals, as well as those interested

in grain sciences and working in the food and beverage industries This book should also be relevant to Food Science departments in Research Institutes and teaching Universities to aid with academic training and scientifi c explo-ration of cereal science and technology

We would like to thank our research team at the School of Food and Nutritional Sciences, UCC, Cork for their support, in particular Dr Deborah

M Waters, for her encouragement and helpful suggestions throughout the preparation of the book and additionally for offering valuable criticism during the proofi ng process We wish to thank Dr Giulia Cinti who has sup-plied hand drawn images, and also the authors, editors and publishers who have allowed reproduction of some of the illustrations and tables included

in the book

Finally, we would also like to thank the editorial and production team at Woodhead Publishing for their time, effort, advice and expertise We hope that this book will be enjoyed, and that it will serve as a long-term source

of knowledge and enlightenment for the reader

Elke K Arendt Emanuele Zannini

Wheat and other Triticum grains

DOI: 10.1533/9780857098924.1

Abstract: Wheat is an annual grass belonging to the Poaceae (Gramineae) family,

and represents one of the world’s most important fi eld crops In contrast to the other cereal grains, wheat possess the unique gluten proteins capable of forming the fully visco-elastic dough required to produce pasta, noodles and leavened baked products, especially bread Additionally, wheat and wheat derivatives such

as wheat malt, fl our and starch are commonly used as adjuncts in the brewing industry Wheat also provides essential amino acids, vitamins, minerals, benefi cial phytochemicals and dietary fi bre components to the human diet, particularly when whole-grain products are consumed Despite their important role in the human diet, wheat-based foods present health problems for a minority of

people due in particular to wheat intolerance and allergy as coeliac disease and baker’s asthma, respectively To meet the predicted future demand for wheat, improvements in wheat productivity through an effi cient wheat breeding plan and crop management innovations are required.

Key words: wheat, chemical composition, wheat utilization in food and

to form a visco-elastic dough, which is required to bake leavened bread in particular These gluten proteins are necessary for the production of the great variety of foods associated with wheat around the world This unique property is the reason why in 2009 the total world harvest was about 680 million tonnes (metric tons, t) with cultivation extending to all continents except Antarctica and reaching about 217 million hectares (world harvest area expressed in hectare) (FAO/UN, 2012) During the last 40 years, wheat

productivity has risen steadily, moving from 1.49 tonnes/ha in 1970 to

3 tonnes/ha in 2010, through the availability of better varieties, agriculture practices and markets and management (Dixon, 2007)

The key characteristic which has given wheat an advantage over other temperate crops is the unique properties of wheat dough that allow it to be processed into a range of foodstuffs (Quail, 1996) These properties depend

on the structures and interactions of the grain storage proteins, which together form the ‘gluten’ protein fraction Items of confectionery and snack bars can contain a high proportion of wheat, although its presence may not be obvious to the consumer Whole-wheat is also an important ingredient in breakfast cereals in their many different forms (Fast and

Caldwell, 2000) Further forms of wheat-based foods are burghul (bulgur)

and couscous, for which complete milling of the grain is not required, as

pearled or kibbled wheat is used instead In the case of burghul, fragmented wheat is parboiled or steamed and is used in dishes likes tabbouleh, kofta and kibbeh (Bayram, 2000).

1.1.1 History, production, price, yield and area

The genus Triticum (wheat) originated in the area that stretches from Syria

to Kashmir, and southwards to Ethiopia In the very distant past, wheats gradually evolved in this region from wild plants Since the early 1900s, it has been known that the wheat species and indeed all members of the Triticeae tribe have a basic chromosome number of n = 7

T aestivum probably generated spontaneously somewhere in the Iranian

highlands or nearby areas Archaeological fi nds indicate that this took place some 6000 years BC (Belderok, 2000) The unique milling and baking prop-erties of common bread wheat are not found among the diploid and tetra-ploid wheats The desirable quality characteristics of bread wheats have been attributed preponderantly to the presence of the D genome compo-

nent (Belderok, 2000; Tonk et al., 2010) The fi rst evidence for wheat

utiliza-tion comes from the Ohalo II site on the shore of the Sea of Galilee, Israel,

where barley (Hordeum vulgare) and brittle, wild tetraploid wild emmer wheat (Triticum dicoccum), dated as 19 000 years old, were found, suggest- ing the initial steps towards settled and cereal agriculture (Kislev et al.,

1992) Wheat and barley were among the earliest domesticated crop plants, domestication taking place 10 000 years ago in the Pre-pottery Neolithic

Near East (Lev-Yadun et al., 2000) The accumulation of surplus food

sup-plies enabled large settlements to be established, resulting in the emergence

of Western civilization The earliest cultivated forms of wheat were tially landraces selected by farmers from wild populations because of their superior yield and other characteristics However, domestication was also associated with the selection of genetic traits that separated them from their wild relatives Two of the most important traits pursued during the domes-tication were loss of shattering of the spike at maturity, which results in seed

essen-loss at harvesting, and presence of kernels in the free-threshing (naked) form (Shewry, 2009) In 2010, the production of wheat approached that of rice (Table 1.1) with 653.7 × 106 t (FAO/UN, 2012) produced worldwide Depending on the climate, soil condition, variety, agricultural practices and other conditions, wheat yields can range from 2.7 to 3.0 tonnes/ha (FAO/

UN, 2012) Nowadays, wheat yields worldwide tend to be higher than 2.8 tonnes/ha on average (FAO/UN, 2012) (Table 1.1) Wheat is cultivated

in 123 countries and China is currently the world’s leading wheat producer Table 1.2 lists the top 10 wheat-producing countries, over the fi ve-year period 2006–2010

Among the top 10 wheat-producing countries, China contributed, during the period 2006–2010, 13.7 % of the world’s wheat production from 8.6 %

of the world’s wheat-growing area, while India contributed 9.8 % of the production from 10.7 % of the area China produces a larger amount of wheat than India (89.0 compared to 63.6 million tonnes per year, 2006–2010) but from 4 % less wheat cultivation area (18.9 compared to 23.5 million hectares per year, 2006–2010) This is mainly due to the high wheat yield registered in China (4.7 tonnes/ha), second only to Germany and France with 6.7 and 7.0 tonnes/ha, respectively (FAO/UN, 2012) (Table 1.2) Throughout the last 10 years, wheat production has gradu-ally increased by approximately 10 %, growing from 585.7 × 106 to 653.7 ×

106 tonnes, mainly due to an improved yield that has been increased by

Wheat

as %

of total grains

Area wheat harvested (Mha)

Wheat yield (t/ha)

Producer price (US

As reported in Table 1.1, the last 10 years have seen wheat producer prices increase by 36.5 %, moving from 179.7 US $/tonnes to 283.3

US $/tonnes in 2010 Among the top 10 producer countries, Turkey and Russian Federation showed the highest (328.4 US $/tonnes) and the lowest (134.4 US $/tonnes) producer price, respectively For the leading producing country China, the producer price for 2009 was equal to 270.9 US $/tonnes (FAO/UN, 2012)

Wheat is an annual grass belonging to the Poaceae (Gramineae) family, tribe Triticae (Zohary, 2000) The wheats currently cultivated are the diploid

T monococcum (Einkorn wheat; 2n = 14, genetically described as AA

plants), the tetraploids T dicoccum (emmer wheat) and T durum (pasta

wheat or hard wheat) (2n = 28, genetically described as AABB plants),

and the hexaploids T aestivum (soft wheat or bread wheat) and T spelta

(spelt) (2n = 42, genetically described as AABBDD plants) Currently, about 95 % of the wheat grown worldwide is bread wheat, with most of the remaining 5 % being pasta wheat The latter is more adapted to the dry Mediterranean climate than bread wheat Small amounts of other wheat species (einkorn, emmer, spelt) are still grown in some regions including Spain, Turkey, the Balkans and the Indian subcontinent In Italy, these hulled wheats are together called farro (Szabó and Hammer, 1995), while spelt continues to be grown in Europe, particularly in Alpine areas (Fossati and Ingold, 2001)

Table 1.2 Wheat production estimates in the 10 leading producing countries;

fi ve-year average 2006–2010

World production (%)

a Average of wheat yield among the 10 leading-producing countries.

Source: Data from FAO/UN (2012).

Wheat for the purpose of trading is classifi ed into distinct categories according to grain hardness (soft, medium-hard and hard) and colour (red, white and amber) It may be further subdivided into subclasses based on growing habit (spring or winter) Each wheat subclass may also be grouped into grades, which are generally used to adjust the basic price of a wheat stock by applying premiums or penalties Wheat grades are indicators of the purity of a wheat class or subclass, the effects of external factors on grain soundness (rain, heat, frost, insect and mould damage) and the cleanli-ness (dockage and foreign material) of the wheat lot Today, wheat is a major component of most diets of the world because of its high agronomic adaptability, nutritional quality, the fact that it can be stored effectively indefi nitely before consumption (provided the water content is below about

15 % dry weight and pests are controlled) and the ability of its fl our to produce a variety of satisfying, interesting and palatable foods

1.2 Structure of wheat grain

The description that follows is based on bread wheat (T aestivum) This

species shares many morphological and chemical characteristics with other wheat species that are used commercially This section, therefore, may be considered a useful guide but not an exhaustive description of species other

than T aestivum Figure 1.1 shows a caryopsis, or kernel, of wheat in both

longitudinal and cross-sections The wheat kernel averages ~2.5–3.0 mm in thickness (or height as it stands on its base), 3.0–3.5 mm in width and 6.0–7.0 mm in length Wheat kernels average ~30–40 mg in weight (Delcour and Hoseney, 2010) Wheat grains contains 2–3 % germ, 13–17 % bran and 80–85 % mealy endosperm (all constituents converted to a dry matter basis) (Anonymous, 2000)

The main morphological characteristics of the wheat kernel are its oval shape, the embryo at one end and the tuft of hair constituting the brush at the other The wheat kernel has a longitudinal crease (an elongated re-entrant region parallel to its long axis) on its ventral side (opposite the embryo) and is rounded on the dorsal side (the same side as the embryo) (Fig 1.1) The two cheeks formed by the crease, not only form a hiding place for insects, microorganisms and dust but also make it diffi cult for the miller

to separate the bran from the endosperm with a good yield The colour of the kernel varies from light buff or yellow to red brown according to the presence or absence of red pigmentation in the seed coat Purple and even black seeds are known but are not common The type and presence of pig-ments are controlled by three separate genetic loci and thus can be manipu-

lated by the plant breeder (Freed et al., 1976)

The pericarp, which surrounds the whole seed, is composed of several layers (Delcour and Hoseney, 2010a), including the outer epidermis (cuti-cule), hypodermis, cross cells, tube cells, seed coat (testa) and nucellar tissue

(Delcour and Hoseney, 2010a; Khan and Shewry, 2009) (Fig 1.1) The outer pericarp is easily detached and, because of its pale membranous appear-ance, is known to millers as ‘beeswing’ Its removal also aids movements of water into the kernel The outer epidermis of the pericarp is 15–20 μm thick and is composed of long narrow cells (80–300 μm long and 25–48 μm wide with walls 3–9.5 μm thick) (Bradbury et al., 1956b) The mature hypodermis

lies below the epidermis and forms, together with the epidermis and nants of the thin-walled parenchyma, the outer pericarp The inner pericarp

rem-is constituted of intermediate cells, cross cells and tube cells Neither the intermediate nor the tube cells completely cover the kernel The cross cells measure 100–150 μm long by 15–20 μm wide and 10–15 μm thick and have their long axis perpendicular to the long axis of the kernel (Delcour and Hoseney, 2010a) The tube cells (elongated and knobby in outline, 120–130 μm length, 12–15 μm wide, 5–10 μm thick) (Bradbury et al., 1956b)

which form an incomplete layer represent the inner epidermis of the carp and are confi ned to a narrow band on the dorsal side, spreading to provide complete coverage over the embryo and brush ends The long axis

peri-of the tube cells runs parallel to the axis peri-of the kernel The tube cells are not packed tightly and thus have many intercellular spaces The total peri-carp has been reported to comprise about 5 % of the kernel and consists of approximately 6 % protein, 2.0 % ash, 20 % cellulose and 0.5 % fat, with the remainder being non-starch polysaccharides

The seed coat and the pigment strand are not the same tissue but, together, they provide a complete covering around the seed They control the water relations between the enclosed seeds and its surroundings at the maturity stage (Delcour and Hoseney, 2010a) The seed coat is composed

of cells which are 100–191 μm long, 9–20 μm wide and 5–8 μm thick

(Brad-bury et al., 1956b) The seed coat consists of three layers: a thick outer

cuticle, a layer that contains pigments and an inner thin cuticle The seed coat consists of two compressed cell layers of cellulose containing little or

no pigment The nucellar epidermis is about 7 μm thick and tightly bound

to both the seed coat and the aleurone layer

The endosperm consists of two tissues: the aleurone layer and the mass

of mealy or starchy endosperm within in The aleurone cells, which enclose the starchy endosperm and, in modifi ed form, the embryo, occur in one or more (according to species) continuous layers at maturity The aleurone cells are heavy-walled and essentially cube-shaped They can vary in thick-ness from 30 to 70 mm within a single kernel, have thick (6–8 mm), double-

layered cellulosic walls and are free of starch at maturity (Bradbury et al.,

1956a) (See Plate I in the colour section between pages 230 and 231) The aleurone layer, which is generally one cell thick in wheat, completely sur-rounds the kernel, covering both the starchy endosperm and the germ, except for that adjacent to the scutellum Although the aleurone layer is anatomically a part of the endosperm, the miller regards the aleurone as the innermost layer of the bran Aleurone cells contain a large nucleus and

a large number of aleurone granules They are relatively high in ash, protein, total phosphor, phytate phosphorus, fat and niacin In addition, concentra-tions of thiamine and ribofl avin are higher in the aleurone than in the other parts of the bran Furthermore, the aleurone layer is particularly rich in enzymes, which play a vital role in the germination process (Anonymous, 2000) Over the embryo, the aleurone cells are modifi ed, becoming thin-walled cells, and may not contain aleurone granules (Delcour and Hoseney, 2010a) The aleurone cells are also common as a storage reserve for lipid droplets Most of the aleurone layer is removed as part of the bran during roller milling (Dexter and Wood, 1996).

The wheat embryo, also called germ by millers, makes up 2.5–3.5 % of the kernel and lies on the lower dorsal side of the caryopsis At grain maturity, it comprises an embryonic axis (shoot or epicotyls, mesocotyl and radical) and

a scutellum, which is considered to be homologous with a cotyledon (Khan and Shewry, 2009) The scutellum lies between the embryonic axis and endo-sperm, and its name derives from its shield-like shape The germ is relatively high in protein (25 %), sugar (18 %) mainly sucrose and raffi nose, and ash (5 %) It also has the highest concentration of lipids (16 %) and hence lipid-soluble vitamins E of all the components of the wheat kernel, with levels of

up to 500 ppm (Delcour and Hoseney, 2010a) It also has the highest moisture

content among constituents of the mature grain (Song et al., 1998), but not all

water-soluble vitamins are found in their highest concentrations here (Michael, 2009) Nevertheless, the use of wheat germ is still challenging because of its poor stability and the presence of anti-nutritional factors such as: (i) raffi nose which is not digested by pancreatic enzymes but metabolized

by gas-producing bacteria of the large intestine, thus causing disorders such

as fl atulence (Rizzello et al., 2010); (ii) phytic acid which markedly decreases the mineral bioavailability (Febles et al., 2002); and (iii) wheat germ aggluti-

nin (WGA) which is responsible for the hyperplastic and hypertrophic

growth of the small bowel and pancreas (Matucci et al., 2004).

The starchy endosperm occurs as a solid mass occupying the centre of the kernel and represents the largest morphological component in all cereals, and it is also the component with the greatest value (Evers and Millar, 2002) It is composed of three types of cells that vary in shape, size

and location in the kernel (Greer et al., 1951) Peripheral or subaleurone

cells are the fi rst row of cells inside the aleurone layer, which they resemble

in size (60 μm in diameter) Next are several rows of prismatic starchy endosperm cells (130–200 μm long, 40–60 μm wide) They extended inward

to about the centre of the cheeks Central cells (2.6 μm thick, 72–144 μm long, 70–120 μm wide) occur in the centre of the cheeks (Bradbury et al.,

1956b; Michael, 2009) and they are more irregular in shape and size than the other cells The endosperm cell walls comprise about 75 % polysaccha-ride, the latter comprising about 70 % arabinoxylans, 20 % (1–3)(1–4)β-d-glucans, 7 % β-glucomannan and 2 % cellulose (Bacic and Stone, 1980) Proteins are also presents at a level of about 15 % Starch and proteins, two

major storage reserves, make up the bulk of the endosperm In the starchy endosperm, starch granules are surrounded by the matrix protein (Plate I) The protein is mostly gluten, the storage protein of wheat The latter, in mature cells appears as a continuous matrix rather than specifi c individual bodies in which form it develops The concentration of starch and matrix proteins also varies according to cell position

The peripheral cells have the lowest starch content, while the protein percentage is highest in these cells The increasing starch content found towards the centre of the cheeks causes progressive dilution of other com-ponents as well as protein (Evers, 1970)

1.3 Wheat carbohydrate composition and properties

1.3.1 Wheat composition: an introduction

Wheat is one of the major grains in the diets of about a half of the world’s population and therefore has an important impact on their nutritional quality Like other typical cereal grains, the wheat kernel contains three main anatomical parts – the embryo, the endosperm and the pericarp, which covers the endosperm The outermost bran layers, representing the pericarp, are fi bre rich Starch and proteins are concentrated in the endosperm, while the germ is high in fat The bran and germ fractions are also high in vitamins and minerals The nutritional role of wheat constituents needs particularly

to be taken into account when designing a process to transform wheat into bakery products Table 1.3 indicates fairly typical chemical constituent dis-tributions in the wheat kernel It must be realized, however, that these values are indicative, and that the actual composition may vary above or below these fi gures depending on the genotype (variety) (Hinton, 1953;

MacMasters et al., 1971; Morrison, 1978; Belitz et al., 2009), and the milling

process used, an evolution of which is illustrated in Fig 1.4 with a further description in Section 1.6.1 (Historical background)

At maturity, the wheat kernel consists of 85 % (w/w) carbohydrates (of which about 80 % is starch) found only in the starchy endosperm Wheat also contains mono-, di- and oligosaccharides at a level of 7 %, mainly con-centrated in the aleurone layer Fructans are also presents in the starchy endosperm and embryonic axis, while 12 % of the wheat kernel consists of cell wall polysaccharides, which are found in all kernel tissues (Henry and Saini, 1989; Knudsen, 1997; Bruce and Matthew, 2009) Wheat carbohy-drates have been studied extensively over the years in terms of structure and functionality as related to particular end-products like bread and bread-type products

1.3.2 Starch

Starch is formed out of carbon dioxide and water by the process of synthesis and is deposited in plant cells as microscopic particles of varying

size and conformation In wheat and other higher plants, starch is formed

in amyloplasts, each of which contains one starch granule Wheat has two types and sizes of starch granules The large lenticular (lens-shaped) gran-ules are 25–40 μm in the long dimension; the small, spherical granules are 5–10 μm in diameter Figure 1.2 shows a confocal laser scanning electron micrograph (CLSM) of starchy endosperm in which it is possible to observe the two types of wheat starch granules Wheat starch granules comprise

25 % amylose (Zeng et al., 1997) and 75 % amylopectin In addition to

amylose and amylopectine, wheat starch granules usually contain small amounts of proteins and lipids Amylose is composed of a glucopyranose unit linked through α-d-(1→4) glycosidic linkages and shows many of the properties of a linear polymer It has historically been considered to be a

linear polymer (average chain length of 270 units) (Takeda et al., 1987) with

a degree of polymerization of approximately 3000 or less (Fig 1.3), however,

it is now known that amylose contains a limited amount of branching involving α-d-(l-→6)-glucosidic linkages at the branch points (0.2–0.8 % of linkages) The second component, amylopectin, is a branched polymer con-taining about 4–6 % of α-d-(1→6)-glucosidic linkages as the branch points The average chain length is 20–25 units with an average degree of poly-merization in the thousands, and molecular weight in the millions (Fig 1.4) Amylopectin molecules are radially orientated in the granules and are constructed of unit chains containing 18–25 (1→4)-linked α-d-glucopyranosyl

A-type granule starch

B-type granule starch

50.0 μm

Fig 1.2 Confocal laser scanning microscopy (CLSM) of wheat starch granules

unit per chain Hundred of these units are linked together by linkages to form amylopectin

α-(1→6)-On the basis of X-ray diffraction experiments, starch granules are said

to have a semi-crystalline character, which indicates a high degree of entation of the glucan molecules About 70 % of the mass of a starch granule

ori-is regarded as amorphous and ca 30 % as crystalline The amorphous regions

DP < 3000, CL 50–500 (a)

Fig 1.3 Schematic representation of the structural elements of amylase (a) and

chain length.

Saddlestone Slab mill

contain the main amounts of amylose, but also a considerable part of the amylopectin The crystalline regions consist primarily of amylopectin.Most of the functional attributes of starch can be related to the temperature-dependent interactions of starch with water in the processes known as gelatinization, pasting and gelation (retrogradation) (Stone and

Krasowski, 1981; Atwell et al., 1988) As starch is heated (53–65 ºC) in the

presence of water, the granules swell and imbibe water, and hydrogen bonds are disrupted with eventual irreversible loss of crystallite structure (gelati-nization) Pasting generally refers to changes in viscosity just before, during and after gelatinization Upon further heating (pasting or cooking), swelling continues and the amylose and portions of the amylopectin leach from the granule producing a viscous suspension As a starch–water system cools, starch polymer–water hydrogen bonds are replaced with polymer–polymer hydrogen bonds, and a gel network is formed At a molecular level, this

re-association process is more aptly termed retrogradation Zeng et al

(1997) showed how the variation in amylose can largely infl uence the tinization, pasting and gelation properties of wheat starch Retrogradation

gela-is most rapid with amylose and much slower and more incomplete with amylopectin due to the short chain length of its branches Nowadays, gela-tinization temperature, paste viscosity and swelling power of starch have proved to be useful diagnostics of starch properties, that can be used as predictors of end-use functionality in industrial and food applications

(Crosbie et al., 1992; Zeng et al., 1997; McCormick et al., 1995) The damage

caused to starch during milling is also another important contributor to the end-use functionality of wheat, with damaged granules absorbing more water, the damage allowing more rapid water movement into the granule remnants Gelatinization thus proceeds more rapidly With regard to this,

Dexter et al (1994) showed how fl ours containing damaged starch

per-formed less well in the remix-to-peak baking test (long bulk fermentation),

a standard test used for evaluating the baking performance of bread wheat Loaf volume and crumb structure of the bread were negatively affected

As defi ned by Gebruers et al (2008) and Prosky (2001) ‘dietary fi bre (DF)

is the edible parts of plants or analogous carbohydrates, that are resistant

to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine.’ Dietary fi bre can be divided into soluble dietary fi bre (SDF) and insoluble dietary fi bre (IDF) where the SDF forms a solution when mixed with water, whereas IDF does not form

solutions (Elleuch et al., 2011)

The most important wheat DF components are the non-starch charides arabinoxylan (AX), mixed-linkage β-glucan (further referred to as β-glucan) and cellulose, and the non-polysaccharide compound lignin, all

polysac-of which are cell wall components The HEALTHGRAIN study, fi nancially