To improve the efficiency of polysaccharide extraction, vacuum technology was used to breakdown the cell wall to extract polysaccharides from Lentinus edodes stipe, and the optimal parameters were optimized by response surface methodology. Then the antioxidant activities in vitro of the polysaccharides were evaluated. Results showed that the optimal conditions for polysaccharide extraction were temperature of 62 °C, vacuum of 0.08 MPa, stirring speed of 1200 r/min, time of 25 min and material/liquid ratio of 1:26 (g/mL). Under these conditions, the yield of polysaccharide was 4.28%. The decolorization rate and deproteinization rate of polysaccharides treated by kaolin and hydrogen peroxide were higher than that of activated carbon. However, there was no significant influence on the polysaccharide retention rate, that was about 80%. Results also indicated that polysaccharide treated with activated carbon could obtain higher antioxidant activity.
Keywords: Antioxidant activity; Extraction; Lentinus edodes stipe; Polysaccharide; Vacuum.