The Physical Properties of Milk Fats of Different Chemical Compositions

Abstract

A series of milk fats of different fatty acid composition has been obtained by supplementing the diet of the dairy cow with tallow, a mixture of palm oil/palmitic acid or soya oil. The melting behaviour of the milk fats has been studied using the differential scanning calorimeter. Dietary soya oil yielded a butterfat which was fairly soft (50 per cent of the crystalline material melting at 8oC), whilst palm oil/palmitic acid gave a relatively hard butterfat (50 per cent of the crystalline material melting at 18‐3oC), with the product derived from feeding tallow intermediate between these extremes, but closer in its behaviour to the butterfat obtained by feeding palm oil/palmitic acid. In order to eliminate the effect on the melting behaviour of milk fat triglycerides having non‐random structures, thermograms were also obtained for samples of the experimental butterfats after they had been inter‐esterified. The results suggest that, for the milk fats having the compositions used in this work, melting behaviour is dominated by the proportion of palmitic acid present.

Effect of oil-enriched diets on the milk yield and composition, and on the composition and physical properties of the milk fat, of dairy cows receiving a basal ration of grass silage

“…there are 2 melting regions in all samples, designated L (the fraction melting below the melting gap) and H (the fraction melting above the melting gap). This melting gap has been observed in milk fats resulting from a diet based on hay and containing large amounts of fat (Banks et al 19766), but not, as in this case, in those derived from low-fat, control diets.…”

Effect of feeding protected lipid to dairy cows in early lactation on the composition of blood lipoproteins and secretion of fatty acids in milk

“…The marked changes in gross fatty acid composition of milk fat which resulted from feeding the protected tallow would have influenced considerably the physical properties of milk fat (Dunkley et al 1977) but a full assessment of this aspect requires additional information on changes in the proportions of different isomers, particularly those of oleic acid (Banks, Clapperton & Ferrie, 19766).…”

Dietary manipulation of the content and fatty acid composition of milk fat

“…Free Amount of fat given Cg/l milk produced) Changes in fatty acid composition are accompanied by altered melting spectra of the milk fats (Banks et al 1976a, 1 9 8 0~) .…”

“…It is characterized by a fairly distinctive fatty acid composition, the dominant features of which are an enhanced content of C,, polyunsaturated and monounsaturated acids, with decreases in the 16:o and, more markedly, in the 18:o fatty acids (Clapperton et al 1980). In milk fats derived from normal diets, a linear relation exists between the proportions of 18:o and 18: I fatty acids (Banks et al 1974). In the case of the low-fat-milk syndrome, this relation is not found (Banks et ul.…”