Extraction and radicals scavenging activity of polysaccharides with microwave extraction from mung bean hulls

Abstract

Extraction variables of microwave extraction mung polysaccharides (MEMPs) from mung bean hulls were optimized by Box-Behnken design. The optimal extraction parameter of MEMP was 700 W, 70 s and 17 mL/g, and highest recovery was 60.03±2.56 mg GE/g DW, which was agreed closely with predicted values. Two purified polysaccharide fractions (MEMP-1 and MEMP-2) were successfully isolated through DEAE cellulose-52 chromatography and Sephadex G-100 size-exclusion chromatography in steps. MEMP-1 was mainly composed of mannose and galactose while that of MEMP-2 was rhamnose and galactose. MEMP and purified fractions both had great radicals scavenging activities of hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and MEMP-2 possessed highest antioxidant activity. The results suggested that MEMP-2 could be the suitable natural antioxidants and may be the functional foods for humans.