Oxidation process affecting fatty acids and cholesterol in fried and roasted salmon

Salmon was processed by three different culinary techniques: pan-frying wit h olive oil, pan-frying with soya oil, and roasting. Roasting did not modif y the fat content from that of raw samples. Frying increased the fat conten t 2-fold, with no difference between samples fried with different oils. Tot al cholesterol oxidized products (COPs) were 0.74, 2.98, 3.35, and 7.38 mug /g fat in raw, fried with olive oil, fried with soya oil, and roasted salmo n, respectively, which represent 0.01, 0.08, 0.09, and 0.15% of cholesterol . A significant correlation (r = 0.902, less than or equal to 0.01) was fou nd between acidity index and total COPs. The most abundant COPs were 7-keto cholesterol, which appeared in all the samples, and cholestanetriol (one of the most citotoxic COP), which appeared only in cooked samples (1.05-1.33 mug/g fat). All cooked samples supplied more omega -6 polyunsaturated fatty acids (PUFAs) than raw samples and showed higher omega -6/omega -3 ratios. Roasted salmon showed the lowest omega -3 content and the highest PUFAs/(S FAs)-C18:0 and MUFAs+PUFAs/(SFAs-C18:0) ratios.