Further experiences with the recommendations of the german society for the study of fats in the assessment of used frying and cooking fats
Von Zeddelmann, H.
Fette Seifen Anstrichmittel 88(4): 121-124
First a survey about the fatty raw material is given which is used in the Federal Republic of Germany for the production of frying and cooking fats. Because of their different composition they behave during heating under frying conditions very differently. Some fats undergo in a relatively short time such sensoric changes that they can no longer be used. Whereas the analytically obtained data are absolutely found within the allowed limits. Other fatty raw substances, however, behave absolutely contrary. Sensoric points (taste, odour, appearance) can absolutely be inconspicuous, when the analytical data already exclude any marketability. Of the common estimation criteria the smoke point is usuable only with some restraint for various reasons. First the obtained data vary strikingly just in the limit of acceptance between the individual laboratories in spite of improved investigation method. Beyond also the fresh initial fats show significant differences in their smoke points which is elucidated by different raffinates of palm oil and hardened ground nut oil. Therefore the recommendation must be critically reviewed that a fat is no longer marketable if the smoke point decrease compared with fresh fat is higher than 50.degree. The other limits as 0.7% petrolether unsoluble oxidated fatty acids as well as 27% by column chromatography determined polar amounts have proved, indeed. The determination of the polar amounts is preferred because of the simple operation method, the quicker performance and the lower error of the method. The "Fritest" as a quick test has become more popular in process control and preselection of suspicious fats, because the handling is very easy and results are available with sufficient reliability.