Effect of fish diet and cooking mode on the composition and microstructure of ready-to-eat fish fillets of gilthead sea bream (Sparus aurata) juveniles.

The effect of fish diet and cooking modality was described for Gilthead sea bream juveniles (Sparus aurata). Three feeds were tested: a control diet containing fish meal (FM>26%) and fish oil (FO>6%) and two diets where FM and FO were replaced with more sustainable alternatives (FM<14%; FO<5%). Fillets were analyzed raw and after cooking at increasing intensities: sous-vide , boiling, roasting and microwave oven baking. The overall quality of fish fillets was assessed by measuring their appearance by Image Analysis, by characterizing their proximate composition, fatty acid profiles, quality indices, and their microstructural features by Magnetic Resonance Imaging and relaxometry. The analysis of experimental data suggested that fish diet specifically characterized the nutritional quality of cooked fillets by affecting their fatty acid profiles, irrespective of the cooking process. Appearance (color, image texture) and muscle microstructure were only influenced by the intensity of cooking, regardless of diet. As cooking intensity increased, water and oil distribution in myofibrils was progressively reorganized and muscle fibers shrunk, causing relevant microstructural changes, especially in roasted and microwave oven baked fillets. The paper provides a useful guide for the production of ready-to-eat meals derived from sustainable aquaculture processes and characterized by high sensory and nutritional quality. [Display omitted] • Magnetic Resonance relaxometry and Image Analysis can guide fish fillet processing. • Fatty acids, color and muscle microstructure of fillets were differentially affected. • Diet affected nutritional quality while cooking mostly color and microstructure. • Combined effect of fish diet and processing on quality is studied for the first time. [ABSTRACT FROM AUTHOR]