Effects of ultrasonic degradation on physicochemical and antioxidant properties of Gleditsia sinensis seed polysaccharides.

In this study, two degraded polysaccharides from Gleditsia sinensis seed were obtained under ultrasonic power treatments of 300 and 450 W. The physicochemical properties, structural characteristics, and antioxidant activities of the degraded and undegraded polysaccharides were studied and compared. Ion exchange chromatography and methylation analysis showed that the polysaccharides had similar basic structural features and were composed of the same monosaccharide units before and after degradation, but the ultrasonic treatment increased the total monosaccharide content and changed the Mannose/Galactose value. Furthermore, with the increase in the ultrasonic power, the molecular weight and intrinsic viscosity of polysaccharides decreased, and the micromorphology became looser. The scavenging capacities for 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radicals and the reducing ability were significantly increased by the ultrasonic treatment. In conclusion, ultrasonic treatment may be an effective way to improve the antioxidant activities of polysaccharides from G. sinensis seed, and further studies on its antioxidant mechanism are still needed.