Abstract:To obtain the optimal protease for tuna blood peptides and to optimize the enzymatic preparation process，five proteases were used to hydrolyze tuna blood，and the optimal protease was selected based on the degree of hydrolysis. The optimal enzymatic hydrolysis conditions were determined via single-factor experiments combined with response surface methodology，and the effect of the process on the amino acid content of tuna blood was analyzed. The tuna blood contained （74.03±0.99） g/100 g protein，（0.73±0.03） g/100 g fat，and（9.03±0.04） g/100 g ash. Flavor protease was selected as the most suitable enzyme. The optimal enzymatic hydrolysis process was 230 minutes at 65 ℃ and pH of 8.8，under which the degree of hydrolysis reached 21.32%，closely matching the predicted value. Furthermore，the content of essential amino acids in the tuna blood peptides were abundant and generally consistent with the essential amino acid pattern standards recommended by FAO/WHO.