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The polysaccharide was about4%contained from jujube. In this experiment, two kinds of methods were used to extract polysaccharide from jujube. In the ultrasonic extraction process of jujube polysaccharide, the ultrasonic time was the main factor which affects the yield of jujube polysaccharide.The optimum extraction conditions were:the ratio of material to liquid1:10, ultrasonic time25min, ultrasonic temperature40℃and the yield of polysaccharide was3.68%. The assisted-enzyme extraction process of jujube polysaccharide, pectinase was choosed to use. The analysis of orthogonal test results was that the influence of pH on the yield of polysaccharides was significant.The optimal conditions was:pH4.5, temperature40℃, time3h, enzyme dosage0.2%and the yield of polysaccharide was3.84%.From the process can abtain the rough jujube polysaccharide.The best decolorization of rough jujube polysaccharide was macroporous resin AB-8, the decolorization rate was61.43%and the rate of polysaccharide preservation was75.14%. In the experiment of removing protein in the rough jujube polysaccharide, the optimum process conditions were obtained from orthogonal test:the amount of enzyme0.2%, enzymolysis temperature40℃, hydrolysis time1.5h, the rate of removal protein and the rate of polysaccharide preservation was70.58%and79.51%respectively.The semi-product of jujube polysaccharide were eluted with DE-52. Only with distilled water,0.3mol/LNaCl,0.5mol/L NaCl could elute elution peaks, JPl, JP2, JP3, for a single elution peak. Among them, JP3was the highest content of the semi-products, JP2was the least content. JP1by SephadexG-100column eluted was a single good symmetrical elution peak. It could seem to be a single component. Then use SephadexG-100gel to purify JP3, separated by a small peak and a main peak, named JP3a and JP3b separately. JP3b has the higher sugar content.After separation and purification, five groups of jujube polysaccharide were obtained to analyse the antioxidant activity:rough jujube polysaccharide (JP) and purified jujube polysaccharide polysaccharides groups (JP1, JP3, JP3a, JP3b) can effectively remove DPPH, OH, O2-, H2O2, and the reducing capacity, the lipid peroxidation inhibition.The total antioxidant capacity and concentration of jujube polysaccharide showed a positive relationship, which increasing concentration reduced antioxidant ability strengthens gradually.
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