Production and identification of antioxidant and angiotensin-converting enzyme inhibition and dipeptidyl peptidase IV inhibitory peptides from bighead carp (Hypophthalmichthys nobilis) muscle hydrolysate

We investigated bioactive peptides obtained from muscle protein hydrolysate of bighead carp by evaluating in vitro dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibitory capacities and antioxidant activity. Peptide sequences were identified from pepsin hydrolysates. Met-Lys-Ala-Val-Cys-Phe-Ser-Leu was one of the most effective sequences with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (EC50 = 4.58 ± 0.15 μM) and relatively high ACE inhibitory capacity (IC50 = 3.68 ± 0.13 μM). Tyr-Asn-Leu-Lys-Glu-Arg-Tyr-Ala-Ala-Trp (IC50 = 1.35 ± 0.23 μM) and Tyr-Asn-Arg-Leu-Pro-Glu-Leu (IC50 = 3.42 ± 0.39 μM) exhibited the most potent ACE inhibitory activity. Ile-Ala-Asp-His-Phe-Leu showed the highest DPP-IV inhibitory activity with an IC50 value of 610.1 ± 82.6 μM. All selected peptides were non-toxic, and most were non-allergenic according to in silico predictions. These results indicate the promising potential of bighead carp muscle hydrolysates as functional additives in foods and pharmaceuticals.