Optimization of Microwave-assisted Extraction Process of Polysaccharide from Passiflora edulis Sims Peel and Evaluation of Antioxidant Activity in vitro

Response surface methodology was applied to optimize the microwave-assisted extraction process of polysaccharide from Passiflora edulis Sims peel and its antioxidant activities in vitro were evaluated. On the basis of single factor test,the ratio of raw material weight to water volume,the extraction time,the microwave power were analyzed and optimized by the Box-Behnken design. The optimized parameters of the microwave-assisted extraction technology were obtained as follows:the ratio of raw material weight to water volume was 1∶27;the extraction time was 3.4 min;the microwave power was 420 W and the extraction rate of polysaccharide was 14.12%±0.41%,which was 1.5 times of that of traditional water bath extraction. Antioxidant activities in vitro of polysaccharide indicated that the DPPH· and ·OH scavenging rates of polysaccharide were 74.02% and 14.41% respectively when the concentration was at 1.0 mg/mL,and the IC₅₀values of 0.374 and 61.06 mg/mL,respectively.