Polar lipid of donkey milk fat: Phospholipid, ceramide and cholesterol composition

Donkey milk, except for fat content, has a composition very similar to that of human milk, thus it is considered a potential alternative for cow milk intolerant infants. There have been various studies on the health-promoting effects of phospholipids, whereas cholesterol, which is always associated to cardiovascular diseases in adults, is essential for the correct development of brain and endocrinous system in infants. In our research a characterization of the minor lipid compounds of donkey milk was carried out, on samples collected from a pool of 11 breeds, plus samples coming only from Martina Franca and Romagnolo breeds, as well. Among the phospholipids (PL), phosphatidylethanolamine, followed by phosphatidylcholine and sphingomyelin, was the most concentrated one, independently of the breed and the season. In addition significant amounts of lactosylceramide and glucosylceramide were identified, by LC/MS/MS, for the first time in donkey milk. The fatty acid composition of PL fraction did not contain 4-10 carbon atom fatty acids, but showed higher values of long-chain saturated fatty acids and linoleic acid, with respect to the neutral lipid fraction. The values of cholesterol were highly correlated to those of total phospholipid content, in accordance with their common location on the milk fat globule membrane.