抄録
The physical and chemical properties of frying oil from 72 households were studied to determine the life span of frying oil.
The average values of carbonyl value (COV), anicidine value (AnV) and acid value (AV) were 22.4±11.7meq/kg,46.4±31.4meq/kg,0.4±0.2, respectively. These values were higher than those of fresh oil, but were lower than the guideline values of oil in take-out dishes and lunches defined by the Ministry of Health and Welfare of Japan. AnV in more than 50% of the samples was below 150 meq/kg, the upper limit value for rancidity, which means that these oils were thrown away even though they could still be used. There were significant positive correlations between the ΔE value of color (ΔE)and AV (r=0.736), and between ΔE and COV (r=0.478). Frying materials did not differ much among the households and the color of waste oils was not significantly different. These findings suggest that the level of deterioration of frying oil can be evaluated by its color of a standard solution and that comparison with the color of a standard solution can be useful for determining the life span of frying oil in households.
