Enhanced in Vitro Antioxidant Activity of Polysaccharides From Enteromorpha Prolifera by Enzymatic Degradation

In order to improve the antioxidant activity of polysaccharide derived from Enteromorpha prolifera (PEP), PEP was hydrolyzed to relatively low molecular weight polysaccharides in the presence of either pectinase or gluco-amylase. Response surface methodology was employed to optimize the hydrolysis conditions based on the polysaccharide degradation rate. Optimum hydrolysis for pectinase was found to be: enzyme concentration 9.36 U/mL, reaction temperature 56C and pH 4.45; for gluco-amylase, the optimum conditions were: enzyme concentration 14.20 U/mL, reaction temperature 49C and pH 4.48. The enzymatic hydrolysates of polysaccharide obtained under optimal conditions were evaluated for their antioxidant activities by determining their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl, hydroxyl and superoxide anion radicals. The results indicate that the enzymatic hydrolysates of polysaccharide exhibited stronger free radical scavenging ability than nondegraded polysaccharide, while pectinase hydrolyzed polysaccharide was found to possess superior radical scavenging ability to that of gluco-amylase hydrolyzed polysaccharide. Practical Applications In order to fully utilize polysaccharide resources, an effective method to improve the antioxidant activity of Enteromorpha prolifera was established by enzymatic degradation. The hydrolysates obtained by this method may be used as ingredients of functional foods due to their antioxidant activity.