Evaluation of fatty acid‐related nutritional quality indices in processed and raw (Lethrinus lentjan) fish fillets

The Lethrinus lentjan fish is economically and nutritionally important in Iran. Therefore, knowledge of their chemical composition can help in the development of functional foods. In the present study, proximate and fatty acid compositions were determined in fresh and marinated Lethrinus lentjan fish. Fatty acids were identified by gas chromatography. The 24 pieces of fresh L. lentjan fish with an average weight of 470 ± 125 g were prepared. After removing wastes, the fish fillet was placed in a dish containing acetic acid, salt, garlic, and red pepper. The marinade product contained n‐6PUFA (7.94%) and n‐3PUFA (3.46%). The results showed that moisture content in the marinade sample decreased, while fat, protein, and ash contents increased and carbohydrate content was also decreased compared to the raw sample. The marinating process increased PUFA percentage (19.32%) and ratio of PUFA and SFA (0.61). The fresh and processed samples showed superior nutritional quality and the lowest h/H ratio, but AI and TI ratios were relatively favorable (p < .05). The thrombogenicity index (TI) (0.46) and atherogenicity index (AI) (3.56) were more than the recommended in terms of risk of coronary heart disease. It can be concluded that fresh and processed fish samples represent an excellent source of high‐quality fat, demonstrating that this fish species’ freshwater can be considered optimal for human consumption.