The structure-activity mechanism of the changes in the physicochemical properties of Flammulina velutipes polysaccharides during ultrasonic extraction.

BACKGROUND The high yield of ultrasonic extraction was widely studied. However, the effects of ultrasound on the properties of products were generally ignored. In this study, the structural characteristics, rheological properties, and thermal stability of Flammulina velutipes polysaccharides (FVPs) under different ultrasonic power (200, 600, 1000 W) and time (10, 20, 30 min) were investigated to explore the effects of ultrasonic extraction on FVPs and the structure-physicochemical properties relationship. The ultrasonic intensity at the corresponding rated power was also measured. RESULTS The results showed that the molecular weight, particle size, and zeta potential of FVPs decreased as the ultrasonic intensity or time increased. The contents of galactose, mannose, and fucose were increased but the content of glucose was decreased by ultrasonic extraction. Viscosity and weak gel strength were positively correlated with molecular weight. Thermal degradation enthalpy was positively correlated with contents of galactose and fucose. CONCLUSIONS The ultrasound reduced the viscosity and gel strength of FVPs by breaking the polysaccharide chain and improving contents of galactose and fucose, which improved the thermal stability of FVPs. This work provides a theoretical basis for the development of FVPs foods with a clear structure-function relationship, which makes it possible to directionally produce FVPs by adjusting ultrasonic parameters during extraction. This article is protected by copyright. All rights reserved.