Study on the Extraction and Antioxidant Activity of Polysaccharides from Gelidium amansii

Polysaccharides(GAP) was extracted from Gelidium amansii by water-extraction and ethanol precipitation method.The effects of extraction temperature,time,the ratio of raw material to water and extraction times on the yield of GAP were investigated by single factor and orthogonal experiments.The results showed that the optimum extraction conditions were as following: the ratio of raw material to water is 1g∶30mL,extraction temperature 75℃,extraction time 2h,and frequency of extraction 3 times.The scavenging capacity of GAP to hydroxyl free radical and superoxide anion free radical were studied,and the results indicated that GAP had good antioxidant activity and its scavenging capacity to ·OH was much higher than that of O2-·.