Abstract
The objectives of the present study were to test the new analytical method, which has been developed by Urakami et al., for evaluation of oils used for frying various food items, simulating conditions actually encountered in family cooking and to compare the results obtained with those of model systems reported previously.
Food items used were parsley, fritters of carrot and burdock, sweet potato, cuttlefish, and shrimp. They were fried continuously for 35min. per batch at 160180°C and frying was repeated 11 times, allowing the used oils to stand at room temperature for varying lengths of time. P/AP (the absorbance ratio of a polar one fraction at 233nm to apolar), AV, IV, and viscosity were determined at intervals.
Despite some fluctuation of the last 3 values, particularly after standing 4 months, P/AP valnes showed a steady increase. This results give the good reliability for the new method in evaluation of an extent of deterioration. Large amounts of water depleted from food items and their large surface areas promoted deterioration of oils in such a manner as to give similar P/AP value in half of the period required for previous model system.
