Trisaturated Glycerides of Milk Fat

Summary A number of samples of milk fat have been analyzed for trisaturated glyceride by the mercaptoacetic acid method. The amount of trisaturated glyceride varied from 21.5 to 32.0% by weight. The amount of trisaturated glyceride was found to agree well with the amount calculated by random distribution. The fatty acid composition of the trisaturated glyceride was determined by gas phase chromatography and compared with that of the whole fat. The results show that there is no preferential selection or exclusion of any of the major saturated fatty acids from the trisaturated glycerides. These and other recently determined structural features of milk fat can best be explained in terms of the limited random distribution theory of Vander Wal. It was also found that the relation among the melting point of a fat and the melting point and amount of trisaturated glyceride, which has been found to hold for many fats, does not hold for milk fat. It is shown that this means that the heat of fusion of the last glyceride in the fat to melt changes from sample to sample.