EFFECTS OF COOKING ON THE FATTY-ACIDS OF 3 FRESH-WATER FISH SPECIES

The effects of cooking on the fatty acid concentrations and the stability of long chain n-3 fatty acids in fish flesh were studied. The cooking methods used were boiling, baking in the normal and microwave oven and frying with sunflower and rapeseed oils. Three freshwater fish species (rainbow trout, vendace and pike) with different sizes and lipid contents were studied. The concentrations of long chain n-3 fatty acids in fish flesh increased in most cases due to the cooking process. This was mostly caused by the loss of moisture. However, in baked and microwave-cooked vendace their concentrations increased about 70% even when calculated on a dry weight basis. Frying oils were efficiently absorbed into lean vendace and pike, and to some extent into medium fatty rainbow trout. The absorption of n-6 fatty acids from cooking oils may interfere with the biological effects of n-3 fatty acids.