Abstract
After frying, the oil was filtered through various kinds of filter (jute, cotton, cotton/viscose rayon, cuprammonium rayon and viscose rayon) andthe change of the properties of the filtered oil during storage was investigated.
The results obtained were summarized as follows :
1) The change of the oil color was measured with the transmittance colorimeter. As compared with fresh oil, the parameter L decreased and parameter b increased, and also parameter a changed from negative (green) to positive values (red). During the storage of this treated oil, L and a showed some recovery tendency and then L value increased and a decreased also gradually.
Contrary to these two parameters, b value increased further and the color of oil became yellowish.
2) By the filtration, a value became smaller than this non-filtered oil.
3) The filtered oil after frying showed the higher acid value and viscosity, and contrary to these the lower iodine value than these characteristics of the fresh oil, and during the storage, only iodine value showed the significant decreasing tendency.
4) By the frying, the total transmittance was decreased and the haze was increased. After the storage, the value for the total transmittance obtained with non-filtered oil was generally smaller than the value from filtered oil.
5) As to the smell and taste, judged by the sensory evaluation, the kinds of filter employed had no significant differences.
