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

In this study, a novel polysaccharide FVP2a wasextracted and purified from F. velutipes. Ac-FVP2a was prepared bychemical acetylation. The preparation process of Ac-FVP2a was optimized usingthe response surface method based on three experimental factors includingreaction time, reaction temperature, and the ratio of FVP2a to aceticanhydride. The physicochemical characteristics andantioxidant activities of Ac-FVP2a in vitro were investigated. The results showed that the optimalpreparation process of Ac-FVP2a was a reaction time of 2.5 h, reactiontemperature of 45℃ and ratio of FVP2ato acetic anhydride of 1:37 (g/mL), respectively. The monosaccharides of Ac-FVP2awith an average molecular weight of 1.97 × 10⁵ Da were galactose,glucose, rhamnose, xylose, and arabinose and the molar ratio were1.65:1:0.13:0.26:1.12. FT-IR suggested that Ac-FVP2a was prepared successfully.Ac-FVP2a had stronger antioxidant activities with better thermal stability thanFVP2a. Ac-FVP2a might have the potential to become a novel antioxidant in thefood industry.