Effect of different drying methods on antioxidant activities of polysaccharides extracted from Flammulina velutipes

Flammulina velutipes was used as raw materials. Polysaccharides from Flammulina velutipes ( FVP) were extracted using conventional water extraction.FVP-H, FVP-V and FVP-F were obtained with hot-air drying, vacuum drying and freeze drying, respectively.Component and antioxidant activities of FVP-H, FVP-V and FVP-F were investigated.The results showed that FVP were acidic polysaccharides.Different drying methods had no effect on the monosaccharide species. However, it could change the monosaccharide composition and uronic acid content.The relative molecular weight of FVP-H, FVP-V and FVP-F were not obvious, which were 2342309, 2375843 and 2358437 Da, respectively. FVP-H, FVP-V and FVP-F had a stronger scavenging ability of DPPH radical, hydroxyl radical, superoxide anion free radical and reducing power. In a certain concentration range, FVP were positively correlated with the antioxidant activity and reducing capacity.Different drying methods had different effects on the antioxidant activity of FVP. FVP-F had highest antioxidant activities, followed by FVP-V and FVP-H. Freeze-drying was the best drying method for preparation of FVP.