抄録
The chemical properties of frying oil were compared using two types of pan with and without a coating of titanium dioxide (powder impact plating titanium). The average temperatures of the frying oil in the stainless steelpans (A) were approximately 1°C higher than those in the aluminum-pans (B). The oil absorption rate (7.6-7.9%), dehydration rate (37.5-39.0%) and moisture contents (53.6-54.4%) of the fried potato were not different between the same type of frying pan with or without the coating, although the weight decrease of the fried potato was significantly higher with the coating than without. The carbonyl value (COV), p-anisidin value (ANV), acid value (AV), peroxide value (POV) and polar compounds (PC) increased with the number of uses of the frying oil. ANV of the coated B pan was lower than that without the coating up to 12 times of frying. These results suggest that the aluminum-pan coated with titanium dioxide might have contributed to the inhibitory effect on oxidation of the frying oil. The number of uses negatively correlated with the dehydration rate, whereas the oil absorption rate positively correlated with the dehydration rate, suggesting that the rate of exchange from water to oil inside the fried potato decreased with the number of uses which caused the oily taste of the fried materials.
