Purification of Potent Angiotensin Converting Enzyme (Ace)-Inhibitory Peptides Derived from Red Tilapia (Oreochromis Sp.) by-Products [(Penulenan Peptida Perencat Enzim Penukaran Angiotensin (ACE) daripada Produk Sampingan Ikan Tilapia Merah (Oreochromis Sp.))]

Abstract

Diet and lifestyle changes are essential alternative treatments for hypertension. Consumers are increasingly more interested in health-promoting ingredients. The use of red tilapia (Oreochromis sp.) by-products (RTBP) has been established as a precursor for protein hydrolysate with angiotensin I-converting (ACE)-inhibitory activity. However, the complexity of the protein hydrolysate reduces its potency. Thus, this work aimed to purify and characterise the ACE-inhibitory hydrolysate derived from red tilapia (Oreochromis sp.). Thermoase PC10F (EC 3.4.24.27) was used in this study to hydrolyse red tilapia by-products (Oreochromis sp.). Meanwhile, ultrafiltration (UF), anion-exchange principle (AEX) and hydrophobic interaction chromatogram (HIC) were applied to purify the hydrolysate. Two molecular weight cut-offs (MWCO) were used for ultrafiltration: 3 kDa and 1 kDa. The 1 kDa hydrolysate showed the highest bioactivity of 85.42% (IC50=0.41 mg mL-). Subsequently, the 1 kDa RTBP hydrolysate was purified based on charge using AEX. Positively charged hydrolysate demonstrated significant bioactivity of 72.32%. In the final purification steps, the hydrophobic fractions showed the highest ACE-inhibitory activity obtained through the hydrophobic interaction chromatogram. The chromatogram yielded two fractions of peaks of high ACE-inhibitory activity on the hydrophobic fraction, which were 90.44% and 95.28%...see more.