One-step characterization of triacylglycerols from animal fat by MALDI-TOF MS.

Comparative characterization of milk fat, lard, and beef tallow triacylglycerols (TAG) has been achieved by using matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS). The samples formed characteristic patterns, with major TAG signals differing in quantity and intensity according to the fat. In milk fat, the significant contribution of short-chain fatty acids (C4-C10) extends the TAG number to the C20-C60 range. In lard and beef tallow, C12-C18 fatty acids restrict the range to C48-C54, also typical of vegetable oils. Fats originating from ruminants contain odd TAG missing in lard. Signature TAG were identified for each animal fat. C20-C46 specifically fingerprint milk fat; 52:5, 54:5 and 54:6 TAG mark lard; and 55:0, 55:1, 55:2 and 54:0 TAG typify beef tallow. Fats were also analyzed after hydrogenation or bromination; hydrogenation helped to fingerprint the low-abundant long-chain TAG and to distinguish short-chain native TAG from collision-induced fragments; bromination allowed clear separation of saturated and unsaturated TAG. Differences in the fatty acid composition amongst homologous isobaric TAG of different structures were identifie