Structure, physicochemical properties, antioxidant, and hypoglycemic activities of water-soluble polysaccharides from millet bran.

This study aimed to investigate the composition, structure, in vitro antioxidant, and hypoglycemic activities of a novel water-soluble MBP-1, an extract from millet bran, isolated by DEAE-52 cellulose and purified by Sephadex G-100. The results showed that MBP-1 was mainly composed of xylose, mannose, galactose, rhamnose, and arabinose with a molar ratio of 0.72:0.59:76.26:1.04:0.83 and a molecular weight of 6.6×10 4  Da, and its purity was 98%, and the yield was 3.76%. MBP-1 has an irregular granular structure by atomic force microscopy and scanning electron microscopy, and the anomeric carbon in MBP-1 molecule has α-configuration and β-configuration by NMR and FTIR. The in vitro scavenging abilities of MBP-1 for·OH, DPPH, O2· - , and ABTS + were 73.5%, 80%, 69.8%, and 75.2%, respectively, and the chelating activity for Fe 2+ was 50%, and the inhibition rates of α-glucosidase and α-amylase were 78.5% and 74.6%, respectively, which indicated that MBP-1 possessed strong antioxidant and hypoglycemic activities. The results indicated that MBP-1 have certain application prospects in food-related fields.