Cooking-freezing-reheating (CFR) of sardine (Sardina pilchardus) fillets. Effect of different cooking and reheating procedures on the proximate and fatty acid compositions

The sequential cooking-freezing-reheating (CFR) method was studied. Sardine (Sardina pilchardus Walb) fillets were cooked by frying, oven-baking or grilling, frozen, and then reheated using conventional or microwave ovens in order to study changes occurring in the proximate and fatty acid compositions. Both cooking and freezing-reheating affected (P < 0.001) the proximate composition. Frying produced the highest water loss and fat gain, followed by grilling, and then by oven-baking. Microwave oven-reheating (MR) induced higher dehydration than conventional oven-reheating (OR), with grilled-frozen-MR samples also loosing fat and ash. Frying significantly (P<0.001) affects the fatty acid composition of sardine, increasing oleic and linoleic acids and decreasing eicosapentaenoic and docosahexaenoic acids. Oven-baking and grilling minimally affected the fatty acid content. Freezing-reheating significantly affected (P < 0.001) the fatty acid composition with the content of oleic acid increasing and those of the ω-3 fatty acids, decreasing more in MR than in OR. Thus, according to the positive effect attributed to ω-3 fatty acids, cooked samples with no further treatment would be preferred to their respective CFR counterparts. However. OR should be used instead of MR when the CFR system is performed.