Objective: Astragalus polysaccharide is an important active ingredient with the immune regulation

anti-oxidation

anti-cancer

anti-atherosclerosis and so on.To remove the proteins from astragalus polysaccharide is a critical procedure

because the content of protein in astragalus polysaccharide was higher than 15%.In this work

the purity would be improved by removing the proteins from astragalus polysaccharide

which can be in favor of the study on pharmacological activity and mechanisms of this effective site. Method: Astragalus polysaccharide was prepared by the water-extraction and alcohol-precipitation method

and the proteins in astragalus polysaccharide were removed by enzymatic-Sevage process

then the technolology was optimized with orthogonal test and single factor tests

respectively.Optimum technology was selected based on the purity of astragalus polysaccharide and the content of proteins. Result: Optimum process of deproteinization was as follows:the enzyme-substrate ratio of 2.0%

pH of 5.0

hydrolysis for 24 h at 50℃;under these conditions

the removal rate of proteins and the content of astragalus polysaccharide were 87.80% and 83.47%

respectively. Conclusion: This optimal technology is stable and feasible

enzymatic-Sevage method can significantly improve the purity of astragalus polysaccharide.