Abstract: Lipids are extremely complex and diverse biomolecules, and at least more than 400 types of milk fat triacylglycerol （TAG） have been reported. The content of nearly 60 reported types of TAG exceed 1% in milk fat. At present, liquid chromatography-mass spectrometry （LC-MS） is the commonly used method to separate and identify TAG molecules, including reversed-phase high-performance liquid chromatography （RP-HPLC）, silver ion high-performance liquid chromatography （Ag⁺-HPLC）, two-dimensional high-performance liquid chromatography （2D-HPLC）, and supercritical fluid chromatography （SFC）. Moreover, the mainly used molecular ionization methods are electrospray ionization （ESI） and atmospheric pressure chemical ionization （APCI）. Mass spectrometry can determine molecular weight and fatty acid positions, but molecular isomer identification remains a challenge. Systematic researches on TAG for cattle, goats, horses, camels, yaks and buffalos are limited in China. The establishment of the TAG profile can not only evaluate the nutritional characteristics of milk fat and guide the scientific improvement of breeding methods, but also help to establish an identification model of species, breeding methods, origin and processing methods of milk. This article reviews the research progress on determination and analysis methods of milk fat triacylglycerol, in hoping to provide a theoretical basis for dairy product quality control as well as food integrity and authenticity identification.

Key words: triacylglycerol, fatty acids, milk fat, liquid chromatography, mass spectrometry