Antioxidant, chelating, and angiotensin-converting enzyme inhibitory activities of peptide fractions from red lionfish (Pterois volitans L.) muscle protein hydrolysates.

Peptide fractions from marine animal hydrolysates can have biological activity. Red lionfish (Pterois volitans L.) is an invasive fish species in the tropical Atlantic, and harvest is a proposed control mechanism. With the aim of identifying possible bioactivity in peptides from red lionfish, an evaluation was done for the antioxidant, Cu2+ and Fe2+chelating, and angiotensin- converting enzyme inhibitory (ACE-I) activities of ultra-filtered peptide fractions derived from lionfish muscle enzymatically hydrolysed with the commercial enzyme Alcalase®. Hydrolysates were generated at 0, 30, 60, and 90 min, and the degree of hydrolysis (DH) were determined. The 30-min hydrolysate yielded the highest DH (30.78 ± 1.57%). This hydrolysate was ultra-filtered using four cut-offs (10, 5, 3, and 1 kDa), and the resulting polypeptides were analysed to generate their amino acids profile and estimated molecular weight (EMW). The F 5-3, F 3-1, and F < 1 kDa peptide fractions yielded the highest copper-chelating activity with values of approximately 88%. Fractions F > 10 and F 10-5 kDa yielded the highest iron-chelating activity with values of approximately 18.8%. The β-carotene bleaching test showed that the F 10-5, F 5-3, F 3-1, and F < 1 kDa fractions to have high antioxidant capacity, inhibiting more than 80% of β-carotene discoloration versus the control. The F 5-3 kDa fraction exhibited the highest ACE inhibition (34.57%), possibly due to the presence of amino acids such as Gly, Leu, Phe, Tyr, and Pro. Polypeptides with an EMW of 6.51 to 3.49 kDa were identified in F > 10, and 2.17 kDa in F 5-3. Peptide fractions from hydrolysed red lionfish muscle exhibit in vitro activities, and could serve as potential source of functional ingredients. [ABSTRACT FROM AUTHOR]