| Abstract: | Investigation of Deep-Frying-Fats; Correlations Between the Content of Petroleum Ether-Insoluble Oxidised Fatty Acids and the Content of Polar Substances or the Content of Polymeric Triglycerides Respectively In 1973, the Deutsche Gesellschaft für Fettwissenschaft issued a recommendation of the assessment of used deep-frying fats in which special importance has been attached to the content of petroleum ether-insoluble oxidised fatty acids. However, the determination is time-consuming. Moreover, according to definition, only small amounts of the total oxidised fatty acids are determined. The results of other, less time-consuming methods of investigation which, in addition, may be carried out directly in the deep-frying fat without necessitating chemical attacks have been compared with those of the method ?petroleum ether-insoluble oxidised fatty acids”?. Samples of 4 types of fat which had been used for deep-frying in snack bars under different conditions were investigated by the following procedures: - 1 Determination of the petroleum ether-insoluble oxidised fatty acids (ox FA)
- 2 Column chromatographic determination (CC) of the polar components
- 3 Liquid chromatographic determination (LC) of the sum of those substances which are more polar than unchanged triglycerides
- 4 Gel permeation chromatographic determination (GPC) of the polymeric triglycerides.
It was found that there are statistical relations between 1. and 2. resp. 3. resp. 4. The mean value of the distributions are laying approximately on parabolas. Thus, it is possible to replace the limit values for the content of petroleum ether-insoluble oxidised fatty acids of 0.7 or 1.0% recommended by DGF by corresponding values of the other methods. |
