ANGIOTENSIN-I CONVERTING ENZYME (ACE) INHIBITIORY ACTIVITY OF ACE INHIBITORY BIOACTIVE PEPTIDES PRODUCED DURING FERMENTATION OF PIGEON PEA (Cajanus cajan) TEMPE

Fermentation products are source of angiotensin-I converting enzyme (ACE) inhibitory peptides used for hypertension treatment. This research investigated the effect of fermentation time on the ACE inhibitory activity produced during fermentation of pigeon pea tempe to determine the optimal fermentation time to obtain pigeon pea tempe with highest ACE inhibitory activity. Pigeon pea were inoculated with Raprima® (0.02% w/w) containing Rhizopus oligosporus then fermented for 0-96 h. Protein pattern, degree of hydrolysis, soluble protein content and ACE inhibitory activity were observed during fermentation. The results of protein pattern showed that protein hydrolysis starterd at 12 h of fermentation. Protein hydrolysis is also indicated by an increase in  degree of hydrolysis (23.99%) and soluble protein content (3.15 mg mL -1 )which reached maximum at 96 h of fermentation. Fermentation increased the ACE inhibitory activity of pigeon pea tempe compared to unfermented pigeon pea. The highest ACE inhibitory activity were obtained from pigeon pea fermented for 48 h (76.14%) with IC 50 values of0.65 mg/mL then decreased until the end of fermentation. It can be concluded that the optimal fermentation time to obtained pigeon pea tempe which has the highest ACE inhibitory activity is for 48 h of fermentation.