Abstract: Sunflower seed peptides (SSPs) prepared from sunflower protein isolate by sequential two-step enzymatic hydrolysis with alkaline protease and acidic protease with and without ultrasonic assistance (used in the second stage) were assessed for their anti-nitrosation effects. Compared to the conventional hydrolysis method without ultrasonic assistance, the degree of hydrolysis and the yield of peptides resulting from ultrasonic treatment at 120 W power and 3:7 working time-to-intermission time ratio were increased by 17.3% and 16.2%, respectively. SSPs obtained by the ultrasonic-assisted method had more powerful inhibitory effect on nitrosation than those obtained by the conventional method, vitamin C and glutathione, and the maximum scavenging rate of sodium nitrite and blocking rate of nitrosamine synthesis were up to 84.5% and 92.4%, respectively.

Key words: sunflower seed peptides, nitrite sodium, nitrosamine, inhibitory effect