ENZYME-CATALYZED EXTRACTION AND ANTIOXIDANT ACTIVITY OF POLYSACCHARIDES FROM PHELLINUS IGNIARIUS

A new process for the enzyme-catalyzed extraction of polysaccharides from Phellinus igniarius was developed Parameters included the pH value, temperature, enzyme dosage and extraction time. The effects of these parameters on extraction yields of P. igniarius polysaccharides (PIPs) were investigated and the optimal process was further determined by using response surface methodology (RSM). Assays to determine the total reducing power, ABTSfree-radical scavenging activity and DPPH radical scavenging activity were then used to determine the antioxidant activity of the extracted PIPs. The results showed that the optimal conditions for enzyme-catalyzed extraction included a pH value of 5.79, a reaction time of 1.5 h, an extraction temperature of 55.02 degrees C and enzyme dosage of 3.04%. Compared with conventional hot-water extraction, the extraction yield of PIPs was increased by 49.5%. In addition, the antioxidant activity of the PIPs was stronger than that of other fungus polysaccharides from Agrocybe aegirit, Hericium erinaceus, Flammulina velutiper and Lentinus edodes. When the PIP concentration was 4 g/L, total reducing power was 0.643 +/- 0.012, ABTS free-radical scavenging activity was 95.40 +/- 0.16% and DPPH radical scavenging activity was 69.08 +/- 3.03%. Thus, the development of an enzyme-catalyzed method for extracting PIPs from P igniarius was found to be feasible and to show high extraction efficacy, and the PIPs displayed good antioxidant activity.