IDENTIFICATION OF THE LESS COMMON ISOLOGOUS SHORT-CHAIN TRIACYLGLYCEROLS IN THE MOST VOLATILE 2.5-PERCENT MOLECULAR DISTILLATE OF BUTTER OIL

The isologous short-chain triacylglycerols of the most volatile 2.5% distillate of butter oil were resolved by reversed-phase high-performance liquid chromatography (HPLC) with mass spectrometry. The molecular species were identified by means of the [MH](+) and the [MH-RCOOH](+) ions in positive chemical ionization mode. A set of empirically determined incremental elution factors was found that could be used to calculate the accurate elution order of natural butterfat triacylglycerols when analyzed by reversed-phase HPLC. The triacylglycerols were also resolved by temperature-programmed gas-liquid chromatography on capillary columns coated with polar liquid phases. The high polarity of the columns provided separation of triacylglycerols on the basis of the degree of unsaturation, as well as on the nature of the shortest acyl chain, with the isologous species having the shortest chainlength eluting last. Both saturated and unsaturated triacylglycerols containing normal and branched-chain odd-carbon fatty acids in combination with short-chain acids were identified, and over 150 molecular species were quantitated.