Deep-fat frying modifies high-fat fish lipid fraction

The lipid composition of three high-fat fishes (sardines, mackerel, and salmon) was analyzed to study the effect of deep-fat frying with sunflower ail and warmholding (65 degrees C, 3 h). Only sardines increased total fat content with cooking. Saturated fatty acids content decreased, especially in sardines and mackerel, mostly because of the palmitic acid reduction. Raw sardines and mackerel presented an important content of omega-3 polyunsaturated fatty acids (24.0 and 16.6 g/100 g of fat, respectively), but it decreased significantly during frying (6.6 and 5.4 g/100 g of fat, respectively). Salmon, despite having the lower amount of eicosapentaenoic acid and docosahexaenoic acid in raw samples, was the best source of these fatty acids after frying (1.7 g/100 g of food). The ratio of total omega-6 fatty acids to total omega-3 fatty acids increased with cooking from 0.12 to 1.07 in salmon, from 0.12 to 6.19 in mackerel, and from 0.07 to 5.98 in sardines. Cholesterol content was differently affected by frying: it increased in salmon and mackerel and decreased in sardine. Fatty acid and cholesterol were slightly affected by warmholding in all fishes.