Publication no. C-2000-0210-04R |  VIEW ARTICLE

Distribution of beta-Glucan in the Grain of Hull-less Barley.

G. H. Zheng (1,2), B. G. Rossnagel (3), R. T. Tyler (1), and R. S. Bhatty (3). (1) Department of Applied Microbiology and Food Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, Canada S7N 5A8. (2) Corresponding author. Phone: 937/237-2573. Fax: 937/237-2529. E-mail: <tedzheng@cargill.com> Current address: Cargill, Inc., 3201 Needmore Rd., Dayton, OH 45414. (3) Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, Canada S7N 5A8. Cereal Chem. 77(2):140-144. Accepted November 5, 1999. Copyright 2000 American Association of Cereal Chemists, Inc.

Nine hull-less barley (HB) containing waxy (0-7% amylose), normal (approximately 25% amylose), or high amylose (approximately 42% amylose) starch with normal or fractured granule make-up and 4-9% (1-3)(1-4)-beta-D-glucans (beta-glucan) were pearled to remove 70% of the original grain weight in 10% intervals. The pearled fractions were analyzed for beta-glucan distribution within HB grain. Protein content of the pearled fractions indicated that the three outermost fractions contained pericarp and testa, aleurone, and subaleurone tissues, respectively. For all HB, beta-glucan and acid-extract viscosity were very low in the outermost 20% of the kernel. For low beta-glucan HB, beta-glucan content was the greatest in the subaleurone region and declined slightly toward inner layers. For high beta-glucan HB, however, more than 80% of grain beta-glucan was distributed more evenly throughout the endosperm. Acid extract viscosity was significantly (P < 0.01) correlated with total (r = 0.75) and soluble (r = 0.87) beta-glucan content throughout the kernel of all HB. Growing conditions, location and year, had significant effects on the concentration of protein, starch and beta-glucan. However, protein, starch, and beta-glucan distribution patterns were not affected by growing conditions. The difference in beta-glucan distribution between low and high beta-glucan HB may explain the difference in milling performance of HB with low or high beta-glucan.