Tocopherol contents of nine vegetable frying oils,and their changes under simulated deep-fat frying conditions

The tocopherol contents and active oxygen method values of nine vegetable oils were determined and compared before and after the oils were treated under simulated deep-fat frying conditions. The saturated oils, coconut and palm, had much higher initial active oxygen method values than the unsaturated oils, soybean, safflower, etc., but the treatments caused a much sharper decrease of the active oxygen method value in saturated oils than in unsaturated ones. The ratio of tocopherol loss after treatment is also much greater in the saturated oils than the unsaturated ones. A similar tendency was observed when the saturated oils enriched with commercial tocopherol mixture were treated under the same conditions.