Production of Angiotensin I-converting Enzyme Inhibitor Derived from Egg White Protein Hydrolysates Using a Membrane Reactor

摘要

Egg white proteins (EWP) were hydrolyzed with four proteolytic enzymes, including Thermolysin, Alcalase, Esperase and Chymotrysin, to produce hydrolysates with angiotensin I-converting enzyme (ACE) inhibitory activity. The result indicated that EWP hydrolyzed for 0.5-24 hr with Thermolysin produced the highest ACE inhibitory activity among the four enzymes. Therefore, EWP-Thermolysin hydrolysate was produced and further fractionated using several membranes with molecular weight cut-off (MWCO) of 10,000, 3,000 and 1,000 daltons, sequentially. The 1 kDa permeate obtained from the hydrolysate treatment using 1,000 daltons MWCO membrane could further reduce its IC_(50) value from 54.1 to 17.2 mug protein/mL. A lower IC_(50) value represented higher ACE inhibitory activity. The operation stability study showed that the membrane reactor system could maintain a steady production of EWP-Thermolysin hydrolysate over 8 hr. The gastrointestinal protease in vitro effect on the ACE inhibitory activity of 1 kDa permeate indicated that gastrointestinal proteases have no significant effect (p > 0.05) on the ACE inhibitory activity of 1 kDa permeate.