Improvement of chicken plasma protein hydrolysate angiotensin I-converting enzyme inhibitory activity by optimizing plastein reaction.

Dandan Gao,Hao Cheng,Shien Chen,Zhongren Ma,Gongtao Ding,Lili Ge,Zilin Qiao,Yiqiang Ke,Jialin Bai,Penghui Guo,Ruofei Feng,Xin Cao,Nurul I Nordin,Hongxin Ma

doi:10.1002/fsn3.1572

Abstract

Chicken plasma protein hydrolysate (CPPH) was prepared by trypsin with angiotensin I‐converting enzyme (ACE) inhibitory activity of 53.5% ± 0.14% and the degree of hydrolysis (DH) of 16.22% ± 0.21% at 1 mg·ml−1; then, five proteases, including pepsin, trypsin, papain, alcalase, and neutrase, were employed to improve ACE inhibitory ability by catalyzing plastein reaction. The results indicated that trypsin‐catalyzed plastein reaction showed the highest ACE inhibitory activity. The exogenous amino acids of leucine, histidine, tyrosine, valine, and cysteine were selected to modify the CPPH. The leucine‐modified plastein reaction released the highest ACE inhibitory activity. The effects of four reaction parameters on plastein reaction were studied, and the optimal conditions with the purpose of obtaining the most powerful ACE inhibitory peptides from modified products were obtained by response surface methodology (RSM). The maximum ACE inhibition rate of the modified hydrolysate reached 82.07% ± 0.03% prepared at concentration of hydrolysates of 30%, reaction time of 4.9 hr, pH value of 8.0, temperature of 40°C, and E/S ratio of 5,681.62 U·g−1. The results indicated that trypsin‐catalyzed plastein reaction increased ACE inhibitory activity of chicken plasma protein hydrolysates by 28.57%.

Highlights

Hypertension is a common disease among humans and often leads to cardiovascular disease (Fahmi et al, 2004)
The chicken plasma protein hydrolysate prepared in the present study had a degree of hydrolysis (DH) of 16.22% ± 0.21% and angiotensin I-converting enzyme (ACE) inhibitory activity of 53.5% ± 0.14%
When the hydrolysate was treated by plastein reaction catalyzed with different proteases at recommended conditions by each operational instruction, substrate concentration 30%, the results (Figure 1) showed that the plastein reaction catalyzed with trypsin and papain could significantly increase ACE inhibitory activities and decrease amount of free amino groups of treated hydrolysates

Summary

| INTRODUCTION

Hypertension is a common disease among humans and often leads to cardiovascular disease (Fahmi et al, 2004). Food-derived ACE inhibitory peptides have lower activity and stability compared with synthetic ACE inhibitors. A previous study showed that sea cucumber hydrolysates modified by plastein reaction of the exogenous proline increased the ACE inhibitory activity of natural peptides (Li, Liu, et al, 2018). Gao and Zhao (2012) reported that alcalase-catalyzed plastein reaction could be applied as a potential approach to enhance the ACE inhibitory activity of soybean protein hydrolysates in vitro. Chicken blood is a by-product of slaughterhouses and contains several proteins It can be used in both feed and food industries owing to good nutritional value and excellent functional properties (Rawdkuen, Benjakul, Visessanguan, & Lanier, 2004). This study aims to enhance the ACE inhibitory activity of chicken plasma protein hydrolysate (CPPH) by plastein reaction. The ACE inhibitory activities of modified products were analyzed and compared with that of the original hydrolysate, revealing the impacts of plastein reaction on ACE inhibitory activity of the modified product of CPPH

| MATERIALS AND METHODS

| RESULTS AND DISCUSSION

CONFLICTS OF INTERESTS

| CONCLUSION