Distribution of the major fatty acids of human milk between<i>sn</i>‐2 and<i>sn</i>‐1,3 positions of triacylglycerols

Abstract

Abstract Human milk triacylgycerols (TAG) were analyzed by tandem mass spectrometry. The SIMPLEX method and a simple linear model were used to interpret the distribution of fatty acids between the sn ‐2 and sn ‐1,3 positions in 24 major molecular weight groups of TAG. The number of regio‐isomeric pairs of TAG varied between 3 and 18 in each of these groups. Hexadecanoic (16∶0), tetradecanoic (14∶0) and dodecanoic acids (12∶0) typically occupied the sn ‐2 position in TAG containing less than 54 acyl carbons, whereas long‐chain C18 and C20 acids were predominantly located at the primary positions. The positions of the three fatty acids within a TAG molecule were shown to depend on the fatty acid combination. The maximum of 12∶0 in the sn ‐2 position appeared at acyl carbon number (ACN) 48, the maxima of 14∶0 were at ACN 44 and ACN 50, and for 16∶0 at ACN 46 and 52.