Compositions of fatty acids and structural identification in human breast milk

Lipidomic analyses of transient breast milk are far more limited than those of other dairy products. As a preliminary analysis of breast milk lipidomes, analytical methods for polar and nonpolar lipids from transient breast milk were developed, and detailed fatty acid profiles were determined in this study. The newly developed methods include solvent fractionation of phospholipids and acyl glycerol, one-pot derivatization to FAMEs and pyridylcarbinol esters, and instrumental analysis, including GC-FID and GC-MS. The results indicate that breast milk contains 16 major common fatty acids with 8-22 carbons. Additionally, 29 minor fatty acids were identified, including odd-numbered fatty acids and branched analogues with 11-23 carbons. Their detailed concentrations in different fractions were measured using the internal standard method. In addition to ordinary fatty acids, breast milk contains several branched fatty acids, including iso/anteiso acids with 15-18 carbons. Structural studies have been performed on selected minor fatty acids via chemical synthesis.