Advances on Current Techniques and Methodologies in Milk Lipidomics

Milk is a complex biological fluid containing lipids,proteins,carbohydrates and minerals,which are essential for infant growth.While the lipid portion constitutes only 3%-5% of the total milk composition,it accounts for over 50% of the infant’s daily energy intake.The dominant portion （approximately 98%） is in the form of triacylglycerols and polar lipids,such as glycerophospholipids and sphingolipids,forming minor components.Recently,with the development of lipidomics,important progresses have been made in milk lipidomics,and the identification and quantification of several milk lipids at the group and molecular species level has become a reality,thereby providing useful information for the infant formula industry.In this review,an overview of the separation of the main components of milk lipids was presented,including glycerolipids,phospholipids and sphingolipids.The analytical methods and strategies for milk lipidomics,including gas chromatography-mass spectrometry （MS）,capillary electrophoresis MS,nuclear magnetic resonance,matrix-assisted laser desorption ionization-MS,electrospray ionization-MS,shotgun lipidomics and liquid chromatography-MS,were reviewed.Additionally,the bioinformatics of lipidomics for milk lipid determination,including lipid classification,lipid databases and lipid analysis software,were investigated.This review would aid future investigations of the nutrition of milk lipids and refined researches on formula milk powder.