Abstract:To optimize the preparation conditions of Tibetan sheep bone peptide and evaluate its antioxidant and hypolipidemic activities in vitro,peptides were prepared from Tibetan sheep bone. The degree of hydrolysis of the enzymolysis solution was used as the evaluation index. Suitable proteases were screened,and singlefactor tests were used to determine the optimal pH,temperature,substrate concentration,enzyme amount,and enzymolysis time for the selected proteases. The optimal enzymolysis conditions were further refined using a response surface test. In vitro antioxidant activity of the peptides was assessed by using the DPPH free radical scavenging rate and the ABTS+ free radical scavenging rate,while the inhibition rate on pancreatic lipase served as an indicator of hypolipidemic ability in vitro. The results indicated that the most suitable enzyme for hydrolyzing Tibetan sheep bone peptides was alkaline protease. The optimal enzymolysis conditions were as follows：pH of 3,temperature of 45 ℃,substrate concentration of 10%,enzyme amount of 8%,and enzymolysis time of 6 h. Under these conditions,the degree of hydrolysis reached 35.13%. The scavenging rates of Tibetan sheep bone peptides for DPPH and ABTS+ free radicals were 69.97% and 81.25%,respectively,with IC50 values of （3.78±0.12） mg/mL and （2.72±0.06） mg/mL,respectively. The inhibitory rate of bone peptides on pancreatic lipase was 43.59%,with an IC50 value of （14.48±0.51） mg/mL. This study successfully determined the optimal enzymolysis conditions for Tibetan sheep bone peptides,and preliminary results indicated that these peptides exhibited significant antioxidant and hypolipidemic activities in vitro.