The modification of mammalian membrane polyunsaturated fatty acid composition in relation to membrane fluidity and function

The lipid composition and biochemistry of freshwater fish.

The chemical constitution of natural fats.

Lipid metabolism in the rumen

The purpose of this communication is to give a brief summary of the composition of the natural fats which come within the scope of a discussion upon the subject of triglyceride fats in human nutrition. This will be done by considering, first, typical compositions of human and other ,mammalian fats (depot, liver and milk) and, subsequently, the compositions of the vegetable and marine animal fats which are most commonly utilized as sources of human dietary fat. To describe these fats in terms of their constituent mixed glycerides would be too complex and lengthy; fortunately this is unnecessary for the present purpose. All natural fats are complicated mixtures of mixed glycerides, but each individual mixed triglyceride is, in nearly all instances, elaborated according to the operation of a simple principle, often referred to as ‘even’ or ‘widest’ distribution of the fatty acid groups between the glycerol molecules. This prevailing type of glyceride structure may be briefly described (Hilditch, 1947, p. 16) by saying that as soon as a given fatty acid forms about 35% of the total fatty acids in a fat it will occur at least once in every triglyceride molecule of the fat, and that no simple triglycerides containing three groups of the same fatty acid will occur until such acid forms nearly two-thirds, or more than two-thirds, of the total fatty acids. Each fatty acid, moreover, acts independently of the rest in competing for union with glycerol according to this general plan. This general rule, most clearly recognizable in the comparatively few natural fats which contain only two or three major component acids, has been found, with very few exceptions, to hold throughout the vegetable and animal kingdoms. In two classes of animal fats only does it fail accurately to describe the general glyceride structure of natural fats : animal depot fats which are unusually rich in mixed glycerides containing stearic groups, and milk fats in which the lower saturated acids from butyric to lauric are markedly prominent. In these classes it has been suggested (Hilditch, 1947, pp. 302, 304) that the specific glyceride types present are the result of biochemical modification of an original preformed mixture of glycerides (chiefly palmito-oleins) assembled on the usual ‘evenly distributed’ basis.

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The body fats of the pig: Some aspects of the formation of animal depôt fats suggested by the composition of their glycerides and fatty acids.

The component acids and glycerides of a horse mesenteric fat.

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Thomas Percy Hilditch

Papers

The chemical constitution of natural fats.

The chemical constitution of natural fats.

The body fats of the pig: Some aspects of the formation of animal depôt fats suggested by the composition of their glycerides and fatty acids.

The component acids and glycerides of a horse mesenteric fat.

The component acids of an ox bone marrow fat.