Effects of herbal yogurt with fish collagen on bioactive peptides with angiotensin-I converting enzyme inhibitory activity

Abstract Illicium verum (IV; dried fruit), Psidium guajava (PG; dried leaves), and Curcuma longa (CL; dried rhizome) water extract and/or fish collagen were added into yogurt to determine their effects on acidification and the proteolysis of milk up to 21 days of storage at 4°C. The angiotensin-I converting enzyme (ACE) test was conducted to analyze the inhibitory activity of bioactive peptides produced during proteolytic activity on the ACE enzyme. The addition of fish collagen in PG- yogurt significantly decreased pH compared to control on day 7 of storage. The presence of IV, PG, and CL enhanced (p<0.05) OPA peptide amount during 7 & 14 days of storage. The highest ACE inhibitory activity was shown on day 7 for all herbal yogurt. Herbal yogurt either in the presence or absence of fish collagen may improve the manufacture and formulation of yogurt with anti-ACE activity.