ABSTRACT
The present study was conducted to extract ACE-I inhibitory peptides from duck egg using proteases from different sources viz. plant (papain and ficin), animal (trypsin) bacterial (Alcalase). Initially, the whole duck egg liquid was defatted with multiple washing with ethanol. The partially denatured whole duck egg proteins were subjected to hydrolysis using preoptimized conditions (enzyme substrate ratio, pH, temperature, incubation time) w.r.t. each enzyme. Four treatments viz duck egg hydrolysed with alcalase (DEA), duck egg hydrolysed with ficin (DEF), duck egg hydrolysed with papain (DEP) and duck egg hydrolysed with trypsin (DET) were prepared. The collected respective hydrolysates were fractionated using ultrafiltration to obtain different fractions on the basis of molecular weight (kilo dalton) viz. whole: DEPH, >10 kDa: DEPH-1, 5-10 kDa: DEPH-2, 1-5 kDa: DEPH-3 and <1 kDa: DEPH-4. The whole hydrolysates and their fractions were evaluated for their ACE-I inhibitory activity under in-vitro condition. Amongst all the hydrolysates and their fractions, the ACE-I inhibitory activity of DEPH were significantly (p<0.05) higher than their respective fractions and DEPH of DEP exhibited the highest activity. However, all the fractions displayed varied (p<0.05) ACE-I inhibitory activity with each other. Results suggested that the duck egg protein hydrolysates and their fractions have strong antihypertensive activity which can be exploited to develop nutraceuticals or functional foods