Optimal process of extraction and antioxidant activity of polysaccharide fromUmbilicaria esculenta (Miyoshi) Minks in Yellow Mountain

The optimal process of extraction with combined-enzyme method and antioxidant activity of polysaccharide fromUmbilicaria esculentain Yellow Mountain were investigated in this paper.Firstly,the best ratio of cellulase,pectinase and papain was determined by single factor and L9(33)orthogonal experiments,the optimum amount is adding 240 Ucellulase,720Upectinase and 2 400 Upapain per 0.2g polysaccharide sample.Then,the extraction time,extraction temperature,pH value,and material-water ratio of the optimal extraction of polysaccharide were considered by single factor and L9(34)orthogonal experiments,the best extraction temperature was 60°C,extraction time was 1h,pH value was 6,and material-solvent ratio was 1∶40(W/V).The yield of polysaccharides reached to 12.52%after optimal process.Besides,the alcohol precipitation time,alcohol precipitation temperature,and ethanol concentration ratio of the optimal alcohol precipitation of polysaccharide were considered by single factor and L9(33)orthogonal experiments and the results showed that the optimal alcohol precipitation temperature was 5°C,alcohol precipitation time was 5h,and ethanol concentration ratio was 80%(V/V).The polysaccharide yield proportion was 10.52%.Finally,the in-vitro antioxidant experimental results indicated that the crude polysaccharide had good antioxidant activities,and the scavenging activities of ABTS free radical,DPPH free radical and OH free radical approached82.95%,74.58%and 70.87%,respectively.