Physicochemical properties and regulatory effects on db/db diabetic mice of β-glucans extracted from oat, wheat and barley

Abstract

Physicochemical properties of different β-glucan purified from oat, barley and wheat, were investigated by measuring the composition, molecular weight, intrinsic viscosity ([η]), and rheological properties. The main objective was to investigate the relationship between effects of regulation of cholesterol metabolism and antioxidant property on db/db diabetic mice of β-glucans and their molecular weights and viscosities. Metformin was used as the positive control. The levels of blood glucose, serum lipid, liver lipid, superoxide dismutase (SOD) and malondialdehyde (MDA) in liver were determined. Results showed that average values of molecular weight (MW) of β-glucan from oat, wheat and barley were 172 kDa, 635 kDa and 743 kDa; the viscosities of β-glucans were positively correlated with their corresponded molecular weights, and wheat and barley β-glucan showed significant shear thinning ability compared to oat β-glucan; Barley β-glucans had higher G′ compared to wheat and oat, and the latter had higher G″. Blood glucose differences were not significant due to high variability, however serum TC, TG, liver TC, TG and LDL-C were lower in β-glucan fed groups compared to control. Moreover, the HDL-C was higher in β-glucan fed groups compared to control group. The addition of β-glucan fed to the db/db diabetic mice significantly (P < 0.05) increased their liver SOD activities and reduced their MDA levels (P > 0.05). A correlation between the measured biological parameters and the molecular weight or viscosity of β-glucan was observed. Lack of β-glucanase degeneration was the main cause of the low MW β-glucan and its diminished physiological effect.