Barley for Food and Health: Science, Technology, and Products

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YEAST BREADS MADE WITH BARLEY FLOUR 153 A research group in India (Gujral et al. 2003) incorporated roller-milled barley flour into bread dough at 10 and 20%, together with wet gluten and ascorbic acid at two levels, in an attempt to overcome the gluten-diluting effect of barley on volume. At the 20% barley flour level, with 15% wet gluten and 20 ppm ascorbic acid, bread texture and volume were near those of control wheat bread. In addition, the additives gluten and ascorbic acid had an antistaling effect. The three ingredients in combination had a synergistic effect on bread quality factors. Dhingra and Jood (2004) roller-milled Dolma hulless barley, then blended this flour 50 : 50 with full-fat and defatted soy flour. Those 50 : 50 supplemented blends were incorporated into wheat flour at 5, 10, 15, and 20% levels for production of breads. These researchers evaluated the breads for physicochemical characteristics, nutritional composition, and organoleptic factors. The gluten content and sedimentation value of flour blends decreased and water absorption capacity increased with increases in the level of supplementary flour. All of the breads supplemented at the 20% level were nutritionally superior to control wheat bread in protein, dietary fiber, and lysine, but did not score as well by taste panels. The authors concluded that inclusion of 15% barley flour or either of the barley–soy blends produced acceptable breads with significant nutritional enhancement. Czubaszek et al. (2005) compared breads made from three spring and three winter barley cultivars grown in Poland over two years’ harvests. The environment influenced protein content, dough properties, and bread quality. Pastes of winter cultivars were of higher viscosity than those of spring cultivars, and cultivar differences were measured in dough development time and speed of softening. Bread quality improved when wheat gluten, dry skim milk, and margarine were added to bread formulas. In Australia, a new hulless barley cultivar with high-amylose starch, Himalaya 292 (later renamed BarleyMax), and two other barley cultivars were milled into flour and evaluated for breadmaking quality (Mann et al. 2005). Himalaya 292 is unique for its high levels of β-glucan (9.7%), protein (16.4%), and amylose (81.6%). The other two cultivars in this study were consistent with standard barley starch composition, about 25% amylose. Admixtures of wheat flour and barley flour were prepared in wheat–barley ratios of 80 : 20, 60 : 40, 50 : 50, 40 : 60, and 20 : 80. Himalaya 292 was used in the admixtures as whole-meal flour rather than as a roller-milled flour, due to insufficient flour yield from the material available. The effects of barley addition on the rheological properties of the doughs varied among cultivars. Himalaya 292 dough had increased strength but reduced extensibility, whereas doughs of the other two barleys had both reduced strength and extensibility. Optimum water absorption values determined by the Micro Z-arm micromixer also varied between doughs, with Himalaya 292 having a significantly higher value than those of the other barleys. Because of its unusual starch character, together with high fiber and protein contents, this barley has unique functional characteristics. Consequently, these researchers compared three different wheat flours for suitability for a wheat–barley blend to produce good-quality bread. A statistical method that uses combinations of a set of variables to derive new variables, called principal components, was utilized to define parameters
154 BARLEY FOOD PRODUCT RESEARCH AND DEVELOPMENT that were the best predictors of the baking quality of wheat–barley admixtures. Two parameters that showed promise were the content of high-molecular-weight glutenin subunits of the base wheat and the extensibility of the dough measured by a texture analyzer. This study demonstrated the dynamics of wheat flour and barley flour composition and interaction in breadmaking. The effects of substitution of cooked barley flours for part of the wheat flour in yeast bread were reported by Gill et al. (2002) in Canada. These cereal scientists used two hulless barleys, CDC Candle (waxy starch and high β-glucan) and Phoenix (normal starch and β-glucan). These were first pearled and then pin-milled into flour. The flours were stirred in water to form a slurry before cooking in a steam-jacketed kettle at 100 ◦ C for 25 minutes. The cooked and gelatinized slurry was then oven dried, reground, and sieved. Dextrose equivalents of flours were determined, to measure the reducing capacity, which influences the browning of bread crust. Cooked barley flours had higher dextrose equivalents than any of the native (raw) barley flours. Mono-, di-, and oligosaccharide composition of flours and content of these sugars was highest in cooked Candle, possibly due to breakdown of its β-glucan and starch. The cooked barley flours and their original native barley flours were made into breads, replacing wheat flour at the 5, 10, and 15% levels. All breads made with barley predictably had lower loaf volume than that of the all-wheat control. The native barley flours had decreased loaf volume with increasing barley substitution level, and at the 15% level, Candle had the lowest volume, probably due to its higher β-glucan level. The cooked flour breads at all levels of substitution had lower loaf volume than those made with native flour, except for Candle at the 15% level. The cooking of Candle flour appeared to improve its bread quality and suggests the potential of inclusion higher than the 15% level. In other evaluations of these breads, firmness increased with barley proportion increases, except for the 15% cooked Candle bread, which had firmness comparable to that of the control wheat bread. Cooked Candle flour produced dough with a soft consistency that increased at higher substitution levels. Waxy starches tend to swell and bind more water than regular starch; therefore, during baking, native Candle would probably gelatinize and bind excess water, suppressing steam generation. However, the starch in cooked Candle flour was already gelatinized, and the lack of amylose contributed to lower crumb strength, lower volume, and increased firmness. Scanning electron microscopy indicated that cooked Phoenix flour had more large starch particles than Candle. Because of Candle’s high amylopectin content, particle agglomeration was minimal. The smaller particles with increased surface area may have improved starch–protein interactions and contributed to loaf volume and texture. Gaosong and Vasanthan (2000) had previously reported that Candle β-glucan undergoes molecular fragmentation when subjected to heat and shear, which could reduce viscosity and water-holding capacity. In the present study, the authors also considered the effects of starch character on firmness progression over time during storage, which is a factor of staling. The resulting breads of this study were analyzed for total (TDF), insoluble (IDF), and soluble (SDF) dietary fiber. One slice of 15% substituted Candle bread (28 g) contained 2.2 g of TDF,
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BARLEY FOR FOOD AND HEALTH Science,
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On a Seed “This was the goal of t
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Cover design by Jean Rose Johnston.
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CONTENTS Preface xiii 1 Barley Hist
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CONTENTS ix Infrared Processing, 12
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CONTENTS xi Asia, 221 Barley Mixed-
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xiv PREFACE In the concluding two c
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2 RELATIONSHIP OF HUMANS AND BARLEY
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10 RELATIONSHIP OF HUMANS AND BARLE
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2 Barley: Taxonomy, Morphology, and
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20 BARLEY: TAXONOMY, MORPHOLOGY, AN
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3 Barley Biotechnology: Breeding an
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34 BARLEY BIOTECHNOLOGY: BREEDING A
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4 Barley: Genetics and Nutrient Com
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58 BARLEY: GENETICS AND NUTRIENT CO
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96 BARLEY PROCESSING: METHODS AND P
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98 BARLEY PROCESSING: METHODS AND P
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100 BARLEY PROCESSING: METHODS AND
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Page 151 and 152: 134 EVALUATION OF FOOD PRODUCT QUAL
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9 Current Status of Global Barley P
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206 CURRENT STATUS OF GLOBAL BARLEY
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208 CURRENT STATUS OF GLOBAL BARLEY
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10 Barley Foods: Selected Tradition
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212 BARLEY FOODS: SELECTED TRADITIO
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APPENDIX 1 Glossary: Botany and Pla
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APPENDIX 2 Glossary: Food and Nutri
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APPENDIX 3 Glossary: Barley Terms T
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APPENDIX 4 Equivalent Weights and M
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SOURCES OF BARLEY AND BARLEY PRODUC
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Rancho Cucamonga, CA 91730 Ph: 888-
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SOURCES OF BARLEY AND BARLEY PRODUC
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E-mail:Tony.Steeper@csiro.au Web: h
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BARLEY RESOURCE ORGANIZATIONS 241 P
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INDEX Air classification, 102, 122-
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INDEX 245 Meat and barley casserole
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