Antioxidant activity of polysaccharide extracted from Pleurotus eryngii using response surface methodology.

Ultrasonic technology was applied for polysaccharide extraction from the fruiting bodies of P. Eryngii, and response surface methodology (RSM) was used to optimize the effects of processing parameters on polysaccharide extraction yield. Three independent variables were extraction time (A), ultrasonic power (B) and the ratio of solvent to sample (C), respectively. Results showed that the maximum yield of P. eryngii polysaccharide (PEPS) was obtained at an optimum condition: extraction time 39 min, ultrasonic power 517 W, the ratio of water to material 19 mL/g, and the PEPS extracting yield reached 34.3% under the conditions. PEPS were precipitated into three crude polysaccharides, PEPS30, PEPS60 and PEPS80, by different concentrations of ethanol respectively. The antioxidant activities of these three polysaccharides were evaluated. The results showed that PEPS80 had the best reducing power, DPPH radical scavenging ability and oxygen radical scavenging ability followed by PEPS60 and PEPS30.