Abstract: Response surface methodology was used to optimize the microwave-assisted extraction of polysaccharides from Flammulina velutipes residue. A regression model describing the yield of polysaccharides with respect to microwave time,microwave power and solid-to-liquid ratio was established.The optimal conditions were determined to be:microwave time of 115 s,microwave power of 640 W and solid-to-liquid ratio of 1:26 (g/mL).Under these conditions,the actual extraction yield of polysaccharide was 7.53%,which was close to the predicted value (7.65%).Antioxidant experiments of the polysaccharides in vitro including reducing power (IC₅₀ value of 8.40 mg/mL),ABTS radical scavenging activity (IC₅₀ value of 1.01 mg/mL),and ·OH radical scavenging activity (IC₅₀ value of 1.95 mg/mL) were evaluated.The results suggested that the polysaccharides from F.velutipes residue had good antioxidant activity.

Key words: Flammulina velutipes Residue, polysaccharides, response surface method, microwave-assisted, antioxidant activity