Abstract:

Objective: To optimize the preparation technology of angiotensin I-converting enzyme (ACE) inhibitory peptide from casein by the proteases produced by Lactobacillus helveticus using response surface methodology. Methods: Through singlefactor test, the effects of five enzymatic hydrolysis conditions including substrate concentration, hydrolysis temperature, pH, enzyme to substrate ([E]/[S]) ratio, pretreatment temperature of substrate and hydrolysis time on the total peptide content in the hydrolysate and the ACE inhibitory activity were investigated, and three key factors, including hydrolysis temperature, pH and [E]/[S], were optimized by response surface methodology. Results: The optimum pretreatment temperature of substrate, hydrolysis temperature, pH, [E]/[S] ratio, substrate concentration and hydrolysis time were 90℃, 8.94, 0.92% (W/W), 6% (W/W) and 8 h, respectively. Under these conditions, the ACE inhibitory activity was 92.67%.

Key words: ACE inhibitory peptide, casein hydrolysate, response surface methodology