关键词: 乌贼墨, 酶水解, 黑色素, 2,3,5-三羧酸吡咯（PTCA）, 抗氧化, sepia, enzymatic hydrolysis, melanin, Pyrrole-2,3,5-tricarboxylic acid (PTCA), antioxidation

Abstract: The present study discussed about the ultrasound-assisted protease hydrolysis from sepia. The enzymatic hydrolysis degree was investigated to screen the optimum protease, while enzymatic hydrolysis conditions were optimized by single factor test and L16 (45) orthogonal test. The experimental results showed that acid protease was the optimum protease, whose optimum hydrolysis condition was optimized as follows: temperature 50℃, reaction time 2 h, pepsin amount 3.0%, pH 3.5 and solid liquid ratio 1:15. Under the optimized conditions, the degree of hydrolysis of sepia was 11.45%. The content of oxidation product PTCA of hydrolyzed melanin was 17.621 μg/mg and the total antioxidant capacity of hydrolyzed melanin was 18.9 U/g, while the retention rate was 99%.