Abstract:With the extraction rate as the objective and the enzymolysis temperature,enzymolysis time,and enzyme dosage as variables,the process of α-amylase-assisted extraction of Panax notoginseng polysaccharides（PNP） was optimized by single factor and orthogonal test.The physicochemical properties and monosaccharide composition of PNP were determined by the phenol-sulfuric acid method,m-hydroxybiphenyl method,Bio-Rad microprotein method,and 1-phenyl-3-methyl-5-pyrazolone pre-column derivatization high performance liquid chromatography（PMP-HPLC）method,respectively.The antioxidant activity of PNP was analyzed with DPPH·,ABTS+·,and hydroxyl radicals as indicators.The results showed that the optimum conditions were as follows：enzymolysis temperature of 60 ℃,enzymolysis time of 2 h,and enzyme dosage of 4%.The extraction rate was 6.45%.The total sugar content of PNP was 67.33%；the uronic acid content was 13.47%；the protein content was 12.00%,and the monosaccharide composition and mole percentage were glucose （79.06%）,galactose（8.23%）,galacturonic acid （6.33%）,arabinose （5.07%）,and rhamnose （1.31%）,respectively.For three kinds of free radicals,PNP had a lower scavenging ability than ascorbic acid,but all of them had different scavenging effects,and the scavenging rate was positively correlated with the concentration,so it had antioxidant activity.