Antioxidant and chelating activities from Lion fish (Pterois volitans L.) muscle protein hydrolysates produced by in vitro digestion using pepsin and pancreatin.

Abstract

The aim of the present research was to determine the antioxidant, and Cu²⁺ and Fe²⁺ chelating activities, amino acid content and estimated molecular weight of proteins and peptides from lion fish muscle-derived hydrolysates obtained by enzymatic hydrolysis with pepsin and pancreatin. The fillets were freeze-dried and hydrolysis was performed, taking aliquots at different times. The degree of hydrolysis, antioxidant activity against ABTS⁺ and DPPH, Cu²⁺ and Fe²⁺ chelating activity, as well as molecular weight estimated by SDS-PAGE and amino acid content by HPLC was determined. The highest degree of hydrolysis (DH) was at 180 min (37.75%). SDS-PAGE showed proteins with an estimated molecular weight of 45,259 and 42,487 Da, which could be associated with myofibrillar proteins. The progressive degradation of proteins by enzymes was also observed, detecting polypeptides with a EMW of 5,988 and 4,954 Da in the most representative hydrolysates. The H40 hydrolysate exhibited the highest ABTS and DPPH radical depuration activity, with values of 107.31 mM/mg protein and 54.27%, respectively. The iron and copper chelating activity was related to DH, since the highest values of iron and copper chelating activity were obtained in hydrolysates H120 and H140, with 90.83% chelation of Cu²⁺ and 56.33% chelation of Fe²⁺, respectively with no significant differences compared to subsequent times. In addition, the antioxidant and chelating activities were possibly related to Trp, Cys, Lys, Pro and Arg content. Lion fish muscle hydrolysates could be a potential source of functional ingredients due to their in vitro antioxidant and chelating activity.