Abstract:On the basis of single factor tests，the extraction conditions of polysaccharide from lotus leaves，including pH，temperature，liquid-to-solid ratio，addition amount of complex enzyme （cellulase∶papain mass ratio=1∶1），and time were optimized by the response surface methodology with the yield of polysaccharide as the response value.Furthermore，the scavenging activities of the extracted polysaccharide against DPPH·and hydroxyl free radicals were measured.The results showed that the optimum extraction process was extraction at pH 7.0，52 ℃，liquid-to-solid ratio of 39∶1（mL/g），and complex enzyme addition of 0.7% for 116 min，under which the yield of polysaccharide reached 3.26%，consistent with the expected value.In addition，the lotus leaf polysaccharide had good antioxidant activity，with the IC50 values of 2.355 mg/mL and 0.331 2 mg/mL for scavenging DPPH and hydroxyl free radicals，respectively.