Abstract:

Objective: To optimize the preparation technology of ACE inhibitory peptide from WPC-80 whey protein concentrate hydrolyzed by the proteases produced by Lactobacillus helveticus using response surface methodology. Methods: Through single- factor test and response surface methodology, the effects of five enzymatic hydrolysis conditions including temperature, pH, enzyme to substrate ([E]/[S]) ratio, substrate concentration and time on the degree of hydrolysis (DH) of WPC-80 whey protein concentrate and the ACE inhibitory activity were investigated. Results: All of five factors affected the production of ACE inhibitory peptide, and among them temperature, pH and [E]/[S] ratio were the key factors. The optimum temperature, pH, [E]/[S] ratio, substrate concentration and time were 38.90 ℃, 9.18, 0.6%, 6% and 8.0 h, respectively. Under these conditions, the ACE inhibitory activity was 92.21%, its IC50 was 0.375mg/ml, and the DH was 18.76%. Conclusion: The response surface methodology is feasible to optimize the enzymatic hydrolysis conditions for ACE inhibitory peptide preparation.

Key words: ACE inhibitory peptide, whey protein hydrolysis, response surface methodology