Abstract: Using Pleurotus ostreatus fungus bran as raw material, the conditions for extracting polysaccharides were optimized through single-factor test analysis. The optimal extraction conditions were temperature 100 ℃, soaking time 0.5 h, extraction time 1.5 h, and the ratio of material to liquid was 1∶15, under which the extraction rate of polysaccharides from fungus bran was the highest; and the polysaccharide content in the P. ostreatus bran was 5.48%. The hydroxyl radical scavenging method was used to compare the antioxidant activity of the fungus bran polysaccharides. The results showed that when the polysaccharide concentration was 0.1 g/L, the effect of scavenging hydroxyl radicals was 17.77%, not much different from the antioxidant properties of vitamin C at the same concentration. The method of thermal denaturation and acetone precipitation was used to study the extraction and determination of SOD in P. ostreatus fungus bran, then the pyrogenic auto-oxidation method was used to determine the activity of SOD. It was found that the content of SOD in P. ostreatus fungus bran was 25.119 μg, and the enzyme activity was 22.28 U/mL.

Key words: Pleurotus ostreatus fungus bran, polysaccharide, SOD