Abstract: An ultra-high pressure (UHP)-assisted alcalase hydrolysis process was established to prepare angiotensin converting enzyme (ACE) inhibitory peptides for corn gluten meal (CGM) in order to simultaneously increase the ACE inhibitory activity of CGM hydrolysate and the hydrolysis efficiency. A comparative analysis of the effect of UHP-assisted enzymatic hydrolysis, enzymatic hydrolysis after UHP pretreatment and enzymatic hydrolysis under atmospheric pressure was made on the inhibition rate of ACE. In the UHP-assisted enzymatic hydrolysis method, the operating parameters substrate concentration, time, pressure, pH and temperature were evaluated for their effects on the inhibition rate of ACE. These preparation conditions were optimized by response surface methodology (RSM). The ACE inhibition rate of the hydrolysate obtained by UHP-assisted hydrolysis (for 15 min) was increased by 55% compared with that obtained under atmospheric pressure, and 30% higher than that obtained with UHP pretreatment. pH was found to be the main factor affecting the ACE inhibition rate, followed by pressure, substrate concentration and time. The effect of temperature was not obvious. The results indicated that the ACE inhibition rate was up to 74.30% under the optimized conditions: substrate concentration 4.78%, high pressure holding time 14 min, pressure 372 MPa, and pH 8.4. UHP-assisted alcalase hydrolysis could not only increase the ACE inhibition rate but also shorten the hydrolysis time to within 15 min, which would provide a basis for the green and efficient preparation of corn protein-derived functional peptides.

Key words: ultra-high pressure, com gluten meal, alcalase, ACE inhibitory peptide, response surface methodology