Phospholipids in milk and dairy products

A rapid HPLC method has been developed for the analysis of the phospholipids in milk and dairy products. A concentrate of the phospholipids was obtained by chromatography on a cartridge of silica gel. The relative proportions of the different phospholipids were then determined by HPLC, and by means of the addition of an internal standard, dipalmitoyl phosphatidyldimethylethanolamine, the absolute amounts present were also measured. After the reproducibility of the method was demonstrated with fresh whole milk, it was applied to skimmed milk, buttermilk and various products of ultra-high temperature processing. Small differences only were seen in the relative compositions of phospholipids in different milk products, but the absolute amounts varied appreciably. In some samples, it was tentatively concluded that the phospholipids had undergone extensive autoxidation.