Profiling of triacylglycerol composition in arachidonic acid single cell oil from Mortierella alpina by using ultra-performance liquid chromatography-electrospray ionization-quadrupole-time-of-flight mass spectrometry

Despite the increasing interest in arachidonic acid single-cell oil (ARA-SCO), the information about its triacylglycerol (TAG) composition still limited, keeping in mind that the profiling of TAG composition considered a challenging task due to the complexity of its structure. For tackling such a task, a comprehensive characterization of TAG molecular species in two different samples of ARA-SCO from Mortierella alpina was performed by using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). In the first sample, a total of 77 different TAGs were identified, while 73 TAGs were identified in the other sample. The most abundant TAG species in the first sample were (20:4-20:4-20:4), (20:3-20:4-16:0), (20:4-16:0-20:4), (18:1-16:0-20:3) and (24:0-20:3-18:1) with a relative content of 13.36, 8.43, 6.63, 4.52 and 4.27%, respectively. While (20:4-20:4-20:4), (20:4-24:0-20:4), (20:3-20:4-16:0), (20:4-16:0-20:4) and (18:1-16:0-20:3) were the major species in the second sample with a relative content of 11.47, 8.65, 7.84, 6.34 and 4.31%, respectively. Moreover, arachidonic acid, lignoceric acid, and palmitic acid were the predominant fatty acids in both ARA-SCO samples. This is the first work that reported an extensive characterization of TAG fractions of ARA-SCO, which might represent the key point for further studies and applications in the field of structured lipids and lipidomics.