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Bovine milk contains 3–5% of fat, of which the dominant portion (about 98%) is in the form of triacylglycerols, whereas polar lipids such as glycerophospholipids and sphingolipids are minor components (0.5–1%) of milk fat. Milk fat is thought to contain several thousand lipid species, making it the most complex material in nature in terms of lipid composition. Significant progress has been made in the past two decades in the identification and quantification of lipid species of milk thanks to the advance in analytical tools especially high-resolution mass spectrometers (MS). Currently, milk lipids are characterized mainly in two ways, i.e. global fatty acid composition profiling by gas chromatography and lipid molecular species identification and quantification by liquid chromatography tandem MS; the former provides information related to the physicochemical properties and nutritive quality of milk fat, whereas the latter provides the detailed chemical structure of lipid species. Until now, only about 400 lipid species have been described in bovine milk, with many low-abundance species remaining to be discovered. The merits and limitations of various separation techniques and different MS methodologies applied to lipid structural elucidation and quantification are critically reviewed and the challenging problems to be solved in milk lipidomic analysis highlighted. [ABSTRACT FROM AUTHOR]

Using LC-LTQ-Orbitrap MS we were able to identify 10 major phosphatidylinositol (PI) species present in 32 infant formulas (IF) collected from Australia, Europe and the USA. Based on the species fingerprint, the 32 formulas can be classified into several distinct groups by PCA analysis; this grouping pattern reflects origin and the label information of the formulas. The total content of all PI species was determined by LC-Triple Quadrupole MS in negative MRM mode using external standard calibration. The content of PI showed large variation between formulas and was very high in certain cases, which is believed to be related to the use of soybean lecithin in these products. Our study indicates that the content and speciation of PIs have significant contribution to the total amount of inositol in all 32 products surveyed; this contribution may be important for the fine nutritional profile and biological functions of IF products. [ABSTRACT FROM AUTHOR]

Considered as dietary fibres with properties of prebiotics, fructo-oligosaccharides have great potential to be used as food additives to promote human health. Accurate quantification of such compounds in food crops is thus an important step in evaluating and developing designer food products. Here we describe the development and validation of a liquid chromatography–mass spectrometry (LC–MS) based method for accurate quantification of three major tri-saccharides (1-kestose, 6G-kestose and raffinose) in wheat flour. The tri-saccharides were extracted from flour using hot water, separated with a Prevail Carbohydrate ES column and quantified by a Q-TOF mass spectrometer. The validated method was applied to a large number of random flour samples, allowing us to define the natural variation of each tri-saccharide and to reveal a clear correlation ( R 2 = 0.69, P < 0.001) between 6G-kestose and total fructan content in wheat flour. [ABSTRACT FROM AUTHOR]