Relationship between the nutritional value of fatty acid profile and the morphometric characteristics of milk fat globules in ewe's milk

Over the last few years the interest of scientists in the nutritional value of milk and dairy products has been increasing as a result of the role of specific components such as individual fatty acids (FAs) in health maintenance and chronic diseases. Milk fatty acid composition has been reported to change with the morphometric characteristics of milk fat globules. Although some studies have investigated the relationship between milk fatty acids and the morphometric characteristics of milk fat globules in cows, this relationship has not been sufficiently explored in ewe's milk. The aim of this study was to check how the nutritional value of fatty acid profile in ewe's milk is linked to changes in the morphometric characteristics of milk fat globules (MFGs). The study involved sampling and analyzing bulk milk from a dairy that collects and manufactures milk from six flocks of Massese ewes. All the ewes were reared in the same area of Tuscany (Italy) and were fed according to a grazing system. Milk samples were taken over a month. Results highlighted a negative correlation between the number of milk fat globules/mL and the average diameter of the MFGs. In addition, the number of MFGs was positively related with n-3 docosapentaenoic acid, long chain FAs. monounsaturated FAs, and the n-3/n-6 ratio. It was negatively related on the other hand, with polyunsaturated fatty acids (PUFAs), n-6 FAs, thrombogenic index and the linoleic/linolenic acid ratio. MFGs >5 mu m were positively related with lauric and vaccenic acids, with short chain FAs. PUFAs, n-6 FAs, and the linoleic/linolenic ratio; whereas MFGs <2 mu m were negatively related with PUFAs, n-6 and the linoleic/linolenic ratio. In conclusion, adjusting the average diameter of MFGs could modify the nutritional value of ewe's milk and dairy products, favoring better health effects. (C) 2011 Elsevier B.V. All rights reserved.