抄録
An apparatus which is reproducible on repeated run has been designed and constructed for the experiments of pan-frying. A stainless steel frying pan was placed on an aluminum plate, the temperature of which had been kept constant. And the pan was heated on the whole surface of the aluminum plate and maintained at a fixed temperature. A definite quantity of each sample oil was applied onto the heated pan and quickly spread over its whole surface. After a definite time of oil heating, the pan was cooled rapidly by placing it on wet cloth.
The deterioration of edible oils and fats was investigated with regard to the changes in acid, peroxide and total carbonyl values under the simulated pan-frying conditions, and following results were obtained.
1) When soybean oil was thermal-oxidized to the extent of total carbonyl value of 50 meq/kg at the specific surface area of 82.5 cm2/g, a heating temperature-heating time relationship was as follows: at 160°C for more than 10 min, at 180°C for 6 min, at 200°C for 2.7 min, at 220°C for 1.1 min, at 240°Cfor 0.5 min and at 260°C for 0.25 min.
2) The rate of oxidation in soybean oil varied in proportion to the specific surface area. The more the heating conditions were strict, the more the specific surface area affected the rate of oxidation.
3) Out of oils tested, rice and corn oils were comparatively thermostable, but fats like lard and tallow were very easy to deteriorate at elevated temperatures.
