Effects of frying and warmholding on fatty acids and cholesterol of sole (Solea solea), codfish (Gadus morrhua) and hake (Merluccius merluccius)

Fatty acids and cholesterol contents of various fish dishes made from sole (Solea solea), hake (Merluccius merluccius) and codfish (Gadus morrhua) were analysed to determine the effect of deep-fat frying and ‘warmholding’ (internal temperature 65 °C, 3 h). The results showed an increase in the ratio cis-polyunsaturated/saturated fatty acids (PUFAs/SFAs) due to the absorption of the oil used in the culinary process. Furthermore, an increase in the ratio ω-6/ω-3 PUFAs was observed, giving rise to a negative effect on the benefits related to the intake of eicosapentaenoic and docosahexaenoic acids. Cooking did not impart a significant variation in the cholesterol supply. Warmholding showed some differences in the content of fatty acids as compared to immediately cooked fish. The ratio ω-6/ω-3 PUFAs slightly increased with warmholding for codfish and sole, and decreased for hake. Cholesterol content was slightly affected by warmholding.