Cereal Chem 67:327-333 | VIEW
Some Nutritional Properties of Starch and Dietary Fiber in Barley Genotypes Containing Different Levels of Amylose.
I. Bjork, A.-C. Eliasson, A. Drews, M. Gudmundsson, and R. Karlsson. Copyright 1990 by the American Association of Cereal Chemists, Inc.
The nutritional properties of starch and dietary fiber (DF) were studied in barley genotypes containing different amylose contents: Waxy Campana (approximately 8% amylose); Alva, Lina, and Glacier normal (normal varieties, 25-27% amylose); and Glacier high (approximately 35% amylose). On an equivalent starch basis, all barley varieties showed a somewhat higher availability to alpha-amylase than a wheat reference. Among the barley flours, starch in the waxy variety was most available to alpha-amylase when tested raw. With excess water (90% H2O), the gelatinization was completed at about 80 C, as measured with differential scanning calorimetry, irrespective of amylose content. At lower moisture (50% H2O), the temperature interval for gelatinization was considerably broadened. However, the differences in gelatinization behavior between the barley varieties were small. No differences in rate of starch hydrolysis were seen between boiled barley flours, in contrast, autoclaving produced a slower coars of amylolysis in glacier high, despite complete gelatinization. This material also contained a somewhat higher level of retrograded enzyme-resistant starch, 3% (starch basis). The content of soluble DF was lower in Alva and Lina (4.8%) compared with 6.5% in the other genotypes (dwb). the viscosity of suspensions of isolated DF (1.6%, w/v) correlated to the proportion of soluble DF and was in decreasing order: Waxy greater than Glacier high greater than Alva. When added to a starch suspension, isolated barley DF preparations were equally effective in reducing the rate of gastric emptying in rats.