摘要 : Molecular structure and solution properties of three branched polysaccharides: amylopectin, glycogen and dextran have been described and compared. Their applications in food industries have also been described. Amylopectin, glycog... 展开 Molecular structure and solution properties of three branched polysaccharides: amylopectin, glycogen and dextran have been described and compared. Their applications in food industries have also been described. Amylopectin, glycogen and dextran are generally products of plant, animal and microbial polysaccharides, respectively. The three polysaccharides are homoglucans with α-type glycosidic bonds in main or branched chains and a monomer unit of glucose. The polymers may contain numerous branched points. Both amylopectin and glycogen have the same α-D- (1-4) -glucopyranosyl back bone residues. Amylopectin consists of 95-96% α-D- (1-4)- glucose units and 4-5% of α-D- (1-6)- glucose units in branched points, whereas glycogen has 7-10% of branched points. Laminated, tree-like, and grape-like structures have been proposed for amylopectin and glycogen. Dextran consists of α-D- (1-6)-glucose units in backbone and α-D- (1-3)-, α-D-(1-4)- or α-D- (1-2)- glucose units in branched points. The α-D- (1-6)- linkage is more flexible than α-D- (1-4)- linkage. The effective chain length, the effective volume, and the viscosity of a branched polysaccharide solution are smaller than their corresponding values for its linear counterpart with equal molecular weight. Amylopectin can be used to increase the expansion and crispness of snack foods. Glycogen occurs in foods in minor amounts. Consumption of glycogen as a food ingredient is due to its immune-modulating activity. Dextran is used in food industries as a thickener, an emulsifier and a stabilizer. The principal potential uses of dextran in foods appear to be related to its capacity to prevent crystallization and retain moisture. 收起