Research Progress in the Structure and Physiological Activity of Soluble (1→3)(1→4)-β-D-glucan from Cereal

Abstract:

Cereal β-glucans are a type of linear homopolysaccharides formed by the linkage of β-D- glucopyranosyl units via (1→4)-β-linkage and separated by single (1→3)-β-linkages. They are the main component of water-soluble dietary fibers from cereals and are mainly found in barley, oat, hull-less barley, wheat, and rye. The physiological activity of soluble β-glucan from cereal is closely related to its unique structure of (1→3)(1→4)-β-D-glucan. This paper focused on the relationship between the characteristics of the molecular structure of cereal β-glucans and their physiological activity in the gastrointestinal tract. The physiological activities of cereal soluble β-glucans in reducing cholesterol, postprandial glycemic index, and insulin levels are summarized and new mechanisms underlying the effect of β-glucans on the intestinal flora and immune function are discussed. Studies on several mechanisms underlying the physiological activities of β-glucan are described. The viscosity level in the small intestine was increased, delaying the gastric emptying, digestion, and absorption of molecules, including glucose, dietary cholesterol, and bile acids. β-glucans bound with bile acid in the intestine to decrease the bile acid reabsorption, thus promoting the synthesis of bile acids from cholesterol. β-glucans improved insulin sensitivity by reducing postprandial glycemic index and insulin level and underwent colonic fermentation to improve intestinal health.