ACE-inhibitory peptides production from defatted wheat germ protein by continuous coupling of enzymatic hydrolysis and membrane separation: Modeling and experimental studies

To increase the yield and activity of angiotensin converting enzyme (ACE) inhibitory peptides from defatted wheat germ protein (DWGP), an efficient method of continuous coupling of enzymatic hydrolysis and membrane separation (CEH-MS) and its kinetics were systematically studied. The results showed the steady state theory fitted the continuous CEH-MS kinetics study well and the kinetic model was successfully established with K-m of 8.163 g/L and V-max of 0.790 g/L min. Both the degree of hydrolysis and the conversion rate of protein were significantly affected by substrate concentration. By the kinetic model prediction, the optimum substrate concentration was 10.65 g/L. Considering the safe pressures of flushing and backflushing ultrafiltration, the maximum runtime of the continuous CEH-MS reactor was 300 min. Under the optimum conditions of substrate concentration of 10.65 g/L, Alcalase quantity of 0.51 g, temperature of 50 degrees C, pH of 9.0, permeation flux of 0.011 L/min, effective volume of 0.4 L and runtime of 300 min, the continuous CEH-MS method showed high conversion rate of protein (65.21%), yield of peptides (34.10 g/g), and IC50 of peptides (0.452 g/L). The conversion rate of protein and yield of peptides were significantly increased by 63.4% and 7.1 times, and the IC50 of peptides was significantly reduced by 13.6% compared with the traditional EH and offline MS one. Therefore, the continuous CEH-MS reactor is beneficial to the efficient production of ACE-inhibitory peptides from DWGP. (C) 2013 Elsevier B.V. All rights reserved.