Study on the Extraction,Sulfation Modification and Antioxidant Activity of Yam Polysaccharides

In order to improve the application value of polysaccharides from Chinese yam,the polysaccharides were extracted and isolated from the Chinese yam.Gas chromatography/mass spectrometry (GC/MS),fourier transform infrared spectroscopy,multi-angle laser light scattering (MALLS) and nuclear magnetic resonance (NMR) were used to characterize the structure of yam polysaccharides.Then,yam polysaccharides were sulfated by chlorosulfonic acid-pyridine method,and identified by FT-IR.Finally,the antioxidant activities of the polysaccharides and its derivatives were determined.The results showed that,the main monosaccharides in yam polysaccharides were 84.5% glucose,11.4% xylose,2.3% galactose and 1.4% arabinose.And the main structures were β-1,3-glucan and β-1,4-glucan.The content of α-glucan was low.The molecular weight of the yam polysaccharide was 6.6×10⁴ Da.However,the molecular weight of sulfated yam polysaccharide was lower than 1.0×10⁴.At the same mass concentrations,the antioxidant activities of sulfated yam polysaccharides were higher than that of yam polysaccharides.