Abstract: Purification, recovery, and antioxidant activity were investigated in crude polysaccharide fractions RPCL1, RPCL2, RPCL3 and RPCL4 by fractional precipitation with 20%, 40%, 60% and 80% of ethanol, respectively, from cooking liquid of Manila clamRuditapesphilippinarum, by Congo red test, infrared spectroscopy, differential calorimetric scanning and monosaccharide composition analysis in order to extract the polysaccharide components from the clam. The results showed that there were purity of up to 73.46% and recovery rate of up to 48.31% in RPCL3 crude polysaccharide precipitated by 60% ethanol， significantly higher than other components. Only RPCL1 had a triple helix structure, without much difference in the infrared spectra of the four polysaccharides. The differential calorimetry scan indicated that there were great differences in sugar chain spatial structure of each component polysaccharide. Fucose (Fuc) and glucose (Glc) were detected in all polysaccharides, and glucuronic acid (GlcUA) component was detected in RPCL2 and RPCL3 polysaccharide fractions. In RPCL2, RPCL3,and RPCL4 polysaccharide groups, the galacturonic acid (GalUA) was detected in the fractions,without aminogalactose hydrochloride (GalN) and glucosamine (GlcN). The antioxidant property test revealed that the scavenging abilities of the four polysaccharides to DPPH· and hydroxyl radicals were gradually elevated with the increase in sugar concentration, with dose-dependent. The findings indicated that there were great differences in purity, monosaccharide composition and spatial structure of sugar chain in the components of the four polysaccharides with antioxidant activity.
2018, Vol. 33 
