The Unsaturated Fatty Acids of Milk Fat I. Methyl Ester Fractionation and Isolation of Monoethenoid Constituents

Abstract

The concns. (wt. %) of the unsaturated fatty acids of a California milk fat, as calculated from methyl ester distillation data obtained by conventional methods, were as follows decenoic, 0.19; dodecenoic, 0.27; tetradecenoic, 1.52; hexadecenoic, 3.12; octadecenoic, 33.14; linoleic plus other unsaturated acids, 4.03. Subsequent lots of esters were prepared by methanolysis using milk reaction conditions and pentane as solvent. Low temp. crystallization from pentane was more convenient and efficient than extractive crystallization with urea for separation of saturated and unsaturated methyl esters. Methyl esters of the monoethenoid fatty acids from decenoic to octadecenoic were isolated by vacuum fractional distillation and partially purified by low temp. crystallization.