Abstract: In order to evaluate the oxidative stability of olive, sunflower seed and rice bran oils, their acid, iodine and peroxide values were determined under different conditions such as air exposure, light exposure and deep-frying, and the effects of three natural antioxidants including ferulic acid, lycopene and β-carotene on rice bran oxidation were explored during deep-frying. Frying resulted in the largest increase in acid and peroxide values, followed by light exposure and air exposure. Sunflower seed oil had the largest amplitude changes in acid, iodine and peroxide values, followed by rice bran oil and olive oil. The antioxidant effectiveness of the three antioxidants investigated declined in the following sequence: ferulic acid > lycopene > β-carotene.

Key words: olive oil, sunflower seeds oil, rice bran oil, acid value, iodine value, peroxide value, antioxidant