Oil Losses during the Deep Fat Frying

Abstract

The object of this study was the quantitative determination of oil losses during the deep fat frying of soybean curd, “Tofu”.The possibilities for the loss of oil during the deep fat frying result from the formation of volatile products of fat degradation and absorption of oil in fried foods. The chief factors governing the amount of oil lost during the deep fat frying were the time of cooking, the temperature of oil used, and the composition of the food.15 cakes of Tofu were fried in 1kg of oil. They were fried for a minute one after another; one side for 30 seconds, the other for 30 seconds. Then the oil losses and the weight of fried Tofu were measured, and from these data, vapourized water was calculated. The fried Tofus were wiped with dried filter paper and the amount of oil attached to the food surface was measured.The results were as follows : Our frying tests did not reveal any significant differences in oil absorptions among the soybean oil, cottonseed oil and rapeseed oil used.Being cooked for 1 miunte at 240, 220, and 200°C, significant differences were seen in oil temperature. The longer they were fried, the more the oil was lost. When deteriorated oil or foaming oil were used, oil decreased significantly. It was mostly caused by their sticking to the surface of food being fried, whereas the amount of oil absorbed in the food was rather small.