Abstract:Jujube polysaccharide （JP） was prepared by water extraction and alcohol precipitation method. The products of JP including JP-30,JP-60 and JP-90 were prepared by the H2O2-VC method. The structural characterization and antioxidant activities of the native polysaccharide and its degraded products were comparatively investigated. According to the result,the yield of JP was （6.57±0.33）%. The carbohydrate and uronic acid content of the JP and its degradation products were 54.58%-60.69% and 60.95%-66.74%,mainly composed of rhamnose,arabinose,xylose,glucose and galactose with different molar ratios. The molecular weights of JP,JP-30,JP-60,and JP-90 were 81.46,13.50,12.65,11.92 kDa,respectively. The results of infrared spectroscopy,circular dichroism,and scanning electron microscopy showed that degradation could significantly affect the senior structure of the polysaccharide. Meanwhile,the degradation could significantly improve the antioxidant activity of the polysaccharide,and JP-90 had the strongest scavenging ability against ABTS+and DPPH free radicals with half-inhibitory concentrations of 0.060 0 and 0.004 4 mg/mL,respectively.