Physicochemical Properties of β-Glucan from Acid Hydrolyzed Barley

This study was performed to investigate changes in the content and purity, as well as physical characteristics of β-glucan extracted from acid hydrolyzed whole grain barleys. Waxy and non-waxy barleys (Hordeum vulgare) were hydrolyzed with different concentrations of HCl (0.1~0.5 N) for 1 h. As the HCl concentration increased, the contents of total and soluble β-glucan from acid hydrolyzed barley decreased. However the ratio of soluble/total β-glucan content and purities of β-glucan significantly increased. The ratio of β-(1→4)/β-(1→3) linkages, molecular weight, and viscosity of soluble β-glucan of raw barleys were 2.28~2.52, 6.0~7.0×10(5) g/mol, and 12.8~32.8 centipoise (cP). Those of isolated soluble β-glucan were significantly decreased to 2.05~2.15, 6.6~7.8×10(3) g/mol, and 3.6~4.2 cP, respectively, with increasing acid concentration. The re-solubility of raw barley β-glucan was about 50%, but increased to 97% with increasing acid concentration. Acid hydrolysis was shown to be an effective method to produce β-glucan with high ratio of soluble β-glucan content, purity, water solubility, and low viscosity.