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.