Comparison of Distribution and Physicochemical Properties of Β-Glucan Extracted from Different Fractions of Highland Barley Grains.

Highland barley grains were roller-milled to produce five different fractions (B-1, B-2, B-3, B-4, and B-5). The distribution and physicochemical properties of beta-glucans from five roller-milled fractions were investigated. The B-4 fraction contained the highest concentration of beta-glucan (4.40%), and the outermost bran (B-1) had the lowest beta-glucan content (1.01%). Besides, beta-glucans from inner core B-5 (BG-5) had higher M-w (6.482 x 10(5) g/mol), whereas beta-glucans from outer bran B-1 (BG-1) showed lower M-w (5.859 x 10(4) g/mol) than those from other fractions. Accordingly, the viscosity of BG-5 was highest (0.038-0.365 Pa.s), and the water solubility index of BG-1 was highest (50.43-90.71%). BG-5 showed stronger foam stability and emulsifying properties but weaker foaming capability, while BG-1 exhibited stronger foaming capability. The foaming capability and emulsifying properties of beta-glucan samples were better under the neutral condition (pH = 7). The foam capabilities of all beta-glucan samples displayed higher values at 65 degrees C, and emulsifying properties exhibited higher values at 45 degrees C. This study is expected to promote the application of highland barley beta-glucans in food industry.