The inquiry about the utilization of edible oil and the limitation of its use was directed by the questionnaire method. Also the properties of deteriorated oil considered to be unusable and oil in use were determined.
The questionnaire was recovered from 299 homes in Kansai district, 248 homes in Kanto district and 175 mass feeding facilities. As for used out oils, 74 samples from homes and 116 samples from mass feeding facilities were collected. In regard to oils in use, the number of samples collected from home was 74 and from mass feeding facility was 116.
The criteria for changing the oil to new one at mass feeding facilities were in the order of color, number of times used, forming property, condition of fried foods and viscosity. Two or three of these factors mentioned above were taken into account. The home also used the same criteria and one or two of them were taken into account.
The properties of oils in use and also t hose out of use were measured with a few variables.
Over 90% of used ois were found to be their peroxide values below 10, either those collected from mass feeding facilities or those from homes, nevertheless these were in use or out of use.
Within oils of the same peroxide value, the color varied greatly. Even when the color was dark, its peroxide value was found to be not always high.
There were not many samples which showed high acid value or viscosity.
It should be concluded, from these results, that there is no significant corelationship between acid value and color, or viscosity and color.
