Abstract: The enzymatic preparation of angiotensin I-converting enzyme (ACE) inhibitory peptides from porcine hemoglobin using pepsin was optimized by response surface methodology. ACE inhibitory rate in vitro and degree of hydrolysis (DH) were investigated with respect to hydrolysis parameters including temperature, pH, substrate concentration, enzyme dosage and time. As a result, a quadratic polynomial model was developed. The optimum conditions for enzymatic preparation of ACE inhibitory peptides from porcine hemoglobin were found to be hydrolysis at pH 1.98 and 37.60 ℃ for 4 h with a substrate concentration of  4.98 g/100 mL and a enzyme dosage of 3.04%. Under these conditions, the prepared peptides showed an ACE inhibitory rate of 70.09%.

Key words: porcine hemoglobin, ACE inhibitory peptide, enzymatic hydrolysis, response surface methodology