In this study, a novel polysaccharide FVP2a was extracted and purified from F. velutipes. Ac-FVP2a was prepared by chemical acetylation. The preparation process of Ac-FVP2a was optimized using the response surface method based on three experimental factors including reaction time, reaction temperature, and the ratio of FVP2a to acetic anhydride. The physicochemical characteristics and antioxidant activities of Ac-FVP2a in vitro were investigated. The results showed that the optimal preparation process of Ac-FVP2a was a reaction time of 2.5 h, reaction temperature of 45℃ and ratio of FVP2a to acetic anhydride of 1:37 (g/mL), respectively. The monosaccharides of Ac-FVP2a with an average molecular weight of 1.97 × 10 5 Da were galactose, glucose, rhamnose, xylose, and arabinose and the molar ratio were 1.65:1:0.13:0.26:1.12. FT-IR suggested that Ac-FVP2a was prepared successfully. Ac-FVP2a had stronger antioxidant activities with better thermal stability than FVP2a. Ac-FVP2a might have the potential to become a novel antioxidant in the food industry.

In this study, polysaccharides from Flammulina velutipes Scraps (FVSP) were extracted. The preparation conditions of the Phosphorylated derivative of FVSP (Ph-FVSP) were optimized based on single experiments and response surface analysis. Characterization and antioxidant properties of FVSP and Ph-FVSP were investigated. The optimum phosphorylation modification process of FVSP obtained was as follows: The mass ratio of STPP/STMP was 1:2, the reaction temperature was 70℃, the reaction time was 5.4 h and the pH was 9.2. Infrared spectroscopy suggested that the phosphorylation of FVSP was successful. Compared with FVSP, Ph-FVSP was more capable of scavenging hydroxyl radicals and superoxide anions. Our results revealed that Ph-FVSP had potential as a novel food additive and antioxidant in the food industry.