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% d istillate of butter oil were resolved by reversed-phase high-performan ce 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 determ ined incremental elution factors was found that could be used to calcu late the accurate elution order of natural butterfat triacylglycerols when analyzed by reversed-phase HPLC. The triacylglycerols were also r esolved by temperature-programmed gas-liquid chromatography on capilla ry columns coated with polar liquid phases. The high polarity of the c olumns provided separation of triacylglycerols on the basis of the deg ree of unsaturation, as well as on the nature of the shortest acyl cha in, with the isologous species having the shortest chainlength eluting last. Both saturated and unsaturated triacylglycerols containing norm al and branched-chain odd-carbon fatty acids in combination with short -chain acids were identified, and over 150 molecular species were quan titated.