Abstract:Tartary buckwheat flour was used as raw materials to extract tartary buckwheat protein.The proteins were hydrolyzed by alkaline protease，pepsin and trypsin，and the antioxidant activities of different enzymatic products were compared by DPPH assay，so as to screen the optimal enzyme for preparing antioxidant peptides from tartary buckwheat protein by hydrolysis.The hydrolysis conditions were optimized by single factor test and response surface method.Results showed that the antioxidant activities of different enzymatic products was：pepsin＞trypsin＞alkaline protease，and the DPPH free radical scavenging rate of pepsin enzymatic products was 68.47%.The optimum hydrolysis conditions of pepsin were：time 2.5 h，temperature 38℃，and pH 2.0.Under these conditions，the degree of hydrolysis reached 32.68%.Ultrafiltration was used to separate and purify tartary buckwheat protein hydrolysates.Results indicated that the hydrolysates with molecular weight＜3 kDa had significant antioxidant activity.On this basis，three elution peaks were further isolated by gel filtration chromatography，and the peak components with the smallest molecular weight showed the strongest antioxidant activity.