Intramolecular Fatty Acid Distribution in the Milk Fat Triglycerides of Several Species

Abstract

The distribution of fatty acids in the triglycerides of some milk fats of nutritional importance was examined by pancreatic lipase hydrolysis. The milk fats studied were from the cow, Indian buffalo, goat, sheep and human. A substantially shortened hydrolysis period was used. Its use was validated by comparing the original triglyceride composition with the residual mono-glyceride composition of a randomly interesterified milk fat subjected to such hydrolysis. Certain fatty-acids had a similar distribution pattern in all of the milk fats examined, but there were some differences between the ruminant and human fats in the relative concentration of individual fatty-acids esterified at either the 2- or the 1-,3-positions of the triglycerides. The short-chain fatty-acids C4:0 and C6:0 were esterified predominantly, (though not exclusively,) at the 1-,3-positions in all species. The C14:0 and C15:0 acids were preferentially esterified at the 2-position, whereas C18:0 was concentrated at the 1-,3-positions in each fat. Human milk fat has a greater proportiong of C16:0 in the 2-position, and of C18:0 and C18:1 in the 1-,3-positions than the milk fats of ruminants.