Optimization of enzyme assisted extraction of polysaccharides from pomegranate peel by response surface methodology and their anti-oxidant potential

Objective： To optimize the enzymatic extraction conditions of polysaccharides from pomegranate peel using response surface methodology（RSM）, and invest the anti-oxidant activity of pomegranate peel polysaccharide in vitro for seeking novel biological components used as pharmaceutical products and functional foods.Methods： Effects of enzymolysis time, ratio of water to raw material, and the dosage of cellulase on the extraction yield of pomegranate peel polysaccharide were fully examined by Box-Behnken design of RSM. DPPH radical scavenging activity, hydroxyl radicals scavenging activity, superoxide anion radical scavenging activity, and reducing power assay were measured by microplate reader.Results： The optimal extraction conditions were as follows： enzymolysis temperature 55 °C, pH 5.0,enzymolysis time 88 min, ratio of water to raw material 22：1 mL/g, and dosage of cellulose 0.93%. Under the optimal extraction conditions, the yield of pomegranate peel polysaccharide was（22.31 ± 0.07）%,which was well matched with the predicted value 22.35% of the Box-Behnken design model. Also,pomegranate peel polysaccharide demonstrated appreciable anti-oxidant potential on DPPH（1,1-diphenyl-2-picrylhydrazyl） radical scavenging, hydroxyl radical scavenging, superoxide anion radical scavenging and reducing power in vitro.Conclusions： An optimized enzymolysis assisted method was proposed for the extraction of pomegranate peel polysaccharide, which can be used as a good anti-oxidant.