Effect of oxidation of frying oil on the sensory value of fried fish fillet

Fresh sunflower seed oil and used oil were compared as media for deep fat frying of cod fillet. The oxidized oil had more rancid, varnish like and intensive fried flavours. Hydroperoxides present in used frying oil were decomposed into benzidine-active compounds. The sample fried in used oil had lower overall sensory quality, especially poorer flavour and odour. The flavour profile of the fried product was modified by oxidation products in used oil as well. The latter profile consisted of significantly more intensive rancid and stale flavours and significantly stronger old meat flavour. In contrast to this, the product fried in fresh oil had slightly stronger meat flavour. There was no difference in the intensity of fish flavour.