| Hypertension is a major risk factor for cardiovascular diseases such as heart failure, stroke, coronary heart disease, and myocardial infarction. One approach in the treatment of hypertension decreases the production of angiotensin II (a potent vasoconstrictor) through inhibition of angiotensin-converting enzyme (ACE), using soybean and casein peptides. Because soybean and casein are not able to exhibit their bioactive effects in the form of parent proteins, they were hydrolyzed using pepsin and pancreatin to mimic the digestion process in the gastrointestinal tract, and the hydrolysates were separated into fractions. The ACE-inhibitory activities of the fractions were determined using an in vitro method and the IC 50 (peptide concentration that reduced ACE activity by 50%) was calculated. The ACE-inhibitory activities of all fractions were dose dependent and at low concentrations were non-competitive. The radical scavenging activities of the peptide fractions were evaluated. Fluorescence spectroscopy showed that soy protein and casein peptides can induce structural changes in ACE. This study shows that soy protein and casein derived peptides have ACE-inhibitory activity. |
