The component acids of phosphatides present in cow's milk fat

Abstract

ALTHOUGH until quite recently phosphatides were considered to play an important part in the production of the characteristic glycerides present in milk, or even to be the precursors ofthe latter, a quantitative statement ofthe composition of the mixed fatty acids in milk fat phosphatides was lacking until the fatty acids of phosphatides from butter milk. powder were examined by Kurtz et al. [1934]. Previously, however, Osborne & Wakeman [1915] had reported the presence of saturated acids of m.P. 62-65' and of liquid acids of iodine value 85-7 in phosphatides isolated from cow's milk, whilst Sasaki & Hiratzuka [1931], who had prepared parified phosphatides from dried milk, observed lauric, myristic 'and palmitic acids amongst the fatty acids present, but found no evidence of the presence of unsaturated acids. Kurtz et al. [1934] extracted the phospholipids from 300 lb. of buttermilkVowder with a mixture of 75 % ethyl alcohol and 25 % of light petroleum and separated the material precipitated from acetone into two fractions, (a) phosphatides soluble in ether at 00 and (b) substances insoluble in this medium which appeared to be of the nature of sphingomyelin and cerebrosides (vide infra, pp. 27, 29). The phosphatides of fraction (a) yielded on hydrolysis 62 % offatty acids, the component acids ofwhich were observed to be myristic 5-2, stearic 16-1,' arachidic 1F8, oleic 70-6 and dicos- tetraenoic 6*3 % (wt.). These authors were unable to detect any palmitic acid, but identified myristic, stearic and arachidic acids in the ester fractiohs which they obtained; of unsaturated acids, they established the presence of oleic acid in quantity, and also of a highly unsaturated -acid of higher molecular weight for which the analytical data indicated a formula C22H.O2, but found no evidence for di-or tri-enoic C18 acids. They also found that, in contrast to butter *fat, the phosphatides contained none of the lower saturated fatty acids.