Comparative study of the molecular species of chloropropanediol diesters and triacylglycerols in milk fat.

In an effort to establish the origin of the fatty acid esters of 3-chloropropanediol, which recently have been isolated in small amounts from goat milk, we compared the molecular species composition of the chlorohydrin diesters and of goat milk triacylglycerols. The chloropropanediol diesters were found to be composed of molecular species containing C10-C18 fatty acids and corresponded closely in carbon number to those calculated for the long chain sn-1,2-diacylglycerol moieties of goat milk triacylglycerols. The molecular species of goat milk total triacylglycerols contained C4-C18 fatty acids. It is suggested that triacylglycerols and chloropropanediol diesters are derived from the same pool of long chain fatty acids. A molecular distillate of bovine milk fat did not contain chloropropanediol diesters, while the available samples of human milk fat were shown to contain alkyldiacylglycerols as the major components of a neutral lipid fraction corresponding in polarity to the chloropropanediol diesters.