The body fats of the pig

Abstract

Investigation of the composition of a pig back fat after its catalytic hydrogenation to varying stages of saturation has led to the following conclusions: The increase in the fully-saturated glycerides in a series of animal fats (pig, ox, sheep depot fats and cow milk fats), in which the total content of saturated acids progressively increases, is very similar to that displayed by the artificially hydro-genated pig back fats. The values for the natural fats, when plotted graphically, suggest that fully-saturated components would be absent from a fat of this group which contained only 25-30% of saturated acids (i.e., palmitic but no stearic acid). Estimations by 2 methods showed that the fat contained 15% (mol.) of tri-C13-glyceridea (other than tristearin, which was absent). The precise nature of this group (triolein, oleolinoleins, stearo- dioleins, or oleodistearin) was not ascertainable, but it is probable that it consists mainly of stearodioleins with perhaps a small proportion of tri-unsaturated glycerides. The monopalmito-compounds present in the fat consist very largely, and quite probably solely, of [beta]-palmito-glycerides ([beta]-palmitodi- "olein" and [beta]-palmitostearo-"olein," with a small amount of [beta]-palmitodistearin). Palmitodi-unsaturated glycerides (chiefly palmitodiolein) are the chief components of the original fat investigated, of which they may form from 42 to 57%; palmitostearo-"oleins" (21-36%) and the tri-C18-unsaturated (or semi-unsaturated) glycerides (15%) are the next most abundant constituents. The perinephric fats of the pig, which are more saturated, probably contain somewhat less of the palmitodi- "oleins" and not very different amounts of palmitostearo- "oleins," compared with the back fat; but there is a corresponding increase in the palmitostearins present.