Structural Characterization, Rheology, Texture, and Potential Hypoglycemic Effect of Polysaccharides from Brasenia schreberi.

Brasenia schreberi (BS) is a perennial aquatic plant of the water lily family, of which the recognition as a functional food is on the rise. Polysaccharides from BS have been found to possess antihyperglycemic and antihyperlipidemic activities. This study aimed to partially clarify the structural and evaluate the hypoglycemic potentials of Brasenia schreberi polysaccharide (BSP). In this study, BSP was isolated from the mucilage covering the surface of Brasenia schreberi (BS). SEM and AFM results verified that BSP molecules were tightly connected and formed a ring-shaped network structure. Further structural analysis showed that BSP was an acidic heteropolysaccharide with a molecular weight of 2.47 × 10(4) Da. It had 1,2,3-linked α-D-Galp, 1,2-linked α-D-Manp, and 1,4-linked β-GlcA residues as the main chain, with 1,3-linked α-Galp, 1,3-linked α-Fucp, 1,3-linked α-Xylp, T-Araf, and T-Rhap as side chains. The rheological results indicated that the BSP solution was a pseudoplastic fluid and exhibited shear-thinning properties. Moreover, the gel strength and texture properties of BSP tended to be higher as the BSP and Ca(2+) concentration increased. More importantly, BSP exhibited good inhibitory activity against α-amylase and α-glucosidase, indicating that it may be a good candidate for a hypoglycemic functional food.