Effect of the season on the production and chemical properties of fish protein hydrolysates and high-quality oils obtained from gurnard (Trigla spp.) by-products

Currently valorization of fish discards by-products is becoming fundamental for the sustainable management fisheries and seafood transforming industries. Thus, we have studied changes in production chemical properties protein hydrolysates (FPH) oils from (heads (He) skins + bones (SB)) gurnard (Trigla spp.) captured at different seasons. Hydrolyses were performed by Alcalase (2.5 mL/kg by-product) pH 8.60, 60.6 °C, 200 rpm, 3 h. Seasonality effect was not significant majority FPH properties, obtaining high digestion yields excellent amino acid contents (more than 43% essential acids per total He). However, maximum degree hydrolysis He higher (24–26.5%) observed SB (19–23.6%). In case oil, concomitantly recovered to hydrolysates, yield recovery largest landing on autumn (89 SB) winter (67 SB), best content ω-3 fatty also found (257 g/kg oil). general, oil residues productive, compositional nutritional terms, indicating their valuable interest as potential food nutraceutical ingredient.