Preparation, Characterization and Antioxidant Activity of a Novel Acetylated Polysaccharide from Flammulina Velutipes

: 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.