Milk Lipids | Fatty Acids

Milk fat contains more than 400 fatty acids, however, only 15 or 16 fatty acids are present at concentrations above 1%. These can be identified as saturated, monounsaturated, or polyunsaturated fatty acids depending on the number of double bonds. The fatty acids arise from two sources: from de novo synthesis in the mammary gland and from plasma lipids. The plasma lipids are derived mainly from the diet and hence the diet can have a large effect on the fatty acid composition of the milk. However, changes in the polyunsaturated fatty acids in the diet normally affect only the saturated and monounsaturated fatty acids in the milk fat because the polyunsaturated fatty acids are extensively hydrogenated by microorganisms in the rumen of the cow.