ACE inhibitory and antioxidative activities of Goby (Zosterissessor ophiocephalus) fish protein hydrolysates: Effect on meat lipid oxidation

The incorporation of protein hydrolysates is of increasing commercial interest. The present study investigated the angiotensin-I converting enzyme (ACE) inhibitory activities and antioxidant properties of goby protein hydrolysates (GPHs) obtained by treatment with various gastrointestinal fish proteases. All hydrolysates displayed ACE-inhibitory activity. The hydrolysate generated by the grey triggerfish proteases (GPH-TF) displayed the highest ACE-inhibitory activity (99 +/- 1.4%, at 1.5 mg/ml) followed by that obtained by smooth hound proteases (GPH-SH) (87.5 +/- 0.7%). Additionally, results indicated that GPHs showed varying degrees of antioxidant activities, evaluated by using various antioxidant assays. Hydrolysate obtained by treatment with crude protease from golden mullet (GPH-GM) showed the most pronounced DPPH-radical scavenging effect, followed by bovine trypsin hydrolysate (GPH-T), while that obtained by triggerfish proteases (GPH-TF) displayed the highest beta-carotene bleaching inhibitory effects. Moreover, all hydrolysates, except GPH-SH, showed high chelating effect and lipid peroxidation inhibition, even at low concentrations. Further, addition of GPH-TF in turkey meat sausage resulted in products with improved antioxidant activity. The results suggested that GPHs are good source of natural ACE-inhibitory and antioxidant peptides. (C) 2013 Elsevier Ltd. All rights reserved.