RAPID-DETERMINATION OF PALMITIC ACID AND OCTADECENOIC ACIDS IN MILK-FAT USING TRIGLYCERIDE ANALYSIS BASED UPON SUITED FAT EXTRACTION METHODS

Palmitic acid (C16) or the sum of all octadecenoic acids (C18:1) as we ll as, in particular, the ratio C16/C18:1 are sensitive parameters for classifying butterfat hardness and the spreadability of butter which is to be expected. Selective feeding measures of the cows for improvin g the spreadability of butter or, in particular, a classification of r aw milk according to ''butterfat hardness'' with a view to quality pay ment presuppose, on the one hand, suited rapid extraction methods of f at from milk and, on the other hand, analytical methods which are appl icable in a few minutes. Since gas chromatographic fatty acid analysis is time-consuming triglyceride formulae have been developed which ena ble the fully automated exact-determination of C16, C18:1 or the direc t determination of C16/C18:1 within 5-10 min. Between these classifica tion parameters of milk fat and iodine number correlation coefficients of 0.97, 0.98 and 0.96 have been established. in addition, extraction methods, e.g., according to the BDI method (use of detergents) or usi ng a rapid method based on extrelut columns allowing the gentle isolat ion of milk fat from butter have been compared. Here, it could be demo nstrated that, according to the BDI method, the fat composition does n ot correspond any more to the initial composition in the milk fat glob ules which is the result of disintegrated triglycerides in milk.