Optimization of enzymatic protein hydrolysis conditions to obtain maximum angiotensin-iconverting enzyme (ACE) inhibitory activity from Angel Wing Clam (Pholas orientalis) meat

Abstract

Citation: Amiza, M.A.*, Liyana, H.A. and Zaliha, H. Optimization of enzymatic protein hydrolysis conditions to obtain maximum angiotensin-I-converting enzyme (ACE) inhibitory activity from angel wing clam (Pholas orientalis) meat. Abstract Optimization of enzymatic protein hydrolysis conditions of angel wing clam (Pholas orientalis) meat to yield maximum angiotensin I-converting enzyme inhibitory (ACE inhibitory) activity was carried out using Response Surface Methodology (RSM). Protein content in angel wing clam meat was 9.04 ± 0.06%. To determine food grade enzyme and range of hydrolysis time to be used in optimization study, screening study was carried out. Four commercial food grade enzymes (Alcalase ® , Protamex™, Neutrase ® and papain) at 2 and 4 hours hydrolysis time were used to yield the highest ACE inhibitory activity. A further screening study were done on Alcalase ® and papain at 1 hour hydrolysis time. It was found that Alcalase ® (75.86% ± 2.64) and papain (77.13% ± 2.63) at 1 hour hydrolysis time exhibited the highest ACE inhibitory activity. However, Alcalase ® was chosen for the hydrolysis in the optimization study. Four protein hydrolysis parameters including temperature (50˚C-60˚C), pH (6.5-8.5), hydrolysis time (30 minutes -90 minutes) and enzyme to substrate (E/S) ratio (1.0% -2.0%) were employed at three level using a face-centered central composite design (CCD) by using RSM. The enzymatic hydrolysis of angel wing clam meat towards ACE inhibitory activity can be predicted by using quadratic model. The optimum hydrolysis conditions to yield maximum ACE inhibitory activity was at 54.8˚C, pH of 7.7, 33 minutes of hydrolysis time and E/S ratio of 1.0%. It was found that the predicted value of ACE inhibitory activity (85.21%) was close to the experimental value (85.64%). This study shows that RSM can be applied successfully to describe interrelationship between hydrolysis conditions and ACE inhibitory activity. On the other hand, the half maximal inhibitory concentration (IC 50) value for angel wing clam meat hydrolysate prepared under optimum condition was 3.63mg/ml±0.48.