Simultaneous Quantification of Mixed-Acid Triacylglycerol Positional Isomers and Enantiomers in Palm Oil and Lard by Chiral High-Performance Liquid Chromatography Coupled with Mass Spectrometry

Abstract

Palm oil and lard are edible fats which are rich in palmitic (P) and oleic acids (O). In this study, triacylglycerol (TAG) positional isomers (symmetric and asymmetric isomers) and enantiomers (asymmetric isomers) in palm oil and lard were quantified simultaneously by using liquid chromatography/mass spectrometry. The CHIRALPAK IF-3 column used in our previous study recognized the difference of TAG isomers consisting of P and O in palm oil and lard, separated sn-OPP/sn-PPO/sn-POP and sn-OPO/sn-OOP/sn-POO into each isomer peak, and enabled the quantification of these TAG isomers with good recovery (95–120%). Although sn-POP and sn-OPO were the major TAGs in palm oil and lard, a comparison of the abundance ratios of TAG enantiomers such as sn-PPO/sn-OPP and sn-OOP/sn-POO revealed that there were slightly more TAG enantiomers with O at the sn-1 position and P at the sn-3 position in palm oil and P at the sn-1 position and O at the sn-3 position in lard. These results were consistent with previous reports for the positional distribution of fatty acids of palm oil and lard. This is the first study that has enabled all TAG isomers consisting of P and O in natural oils and fats to be individually quantified by mass spectrometry.

Keywords

• triacylglycerol
• isomer
• palm oil
• lard
• chiral HPLC