Acetylation modification and antioxidant activity of polysaccharides from Agrocybe cylindracea

In this paper, polysaccharides from Agrocybe cylindracea (ACPs) were chemically acetylated. Effects of reaction time, reaction temperature and acetylated reagent amounts (acetic anhydride) on the degree of substitution (DS) of acetylated groups were investigated based on single factor experiments. Response surface analysis method was used to optimize acetylation process of ACPs. The maximum DS of 0.475 +/- 0.011 was obtained at optimal acetylation process as follows: reaction time was 3.3 h, reaction temperature was 53 celcius and acetylated reagent amounts was 3 mL. Characteristic bands in FT-IR spectra indicated that the structural modification of acetylated ACPs (Ac-ACPs) was successful. The antioxidant activities of Ac-ACPs and ACPs in vitro were determined. Ac-ACPs exhibited stronger DPPH radical and superoxide anion scavenging capacity than ACPs. The results indicated that Ac-ACPs could be potentially used in food and pharmaceutical industries as a new food additive and antioxidant supplement.