Determination of phospholipid molecular species in pork meat by high performance liquid chromatography–tandem mass spectrometry and evaporative light scattering detection

Abstract

Normal phase high performance liquid chromatography has been optimized for both evaporative light scattering detection and tandem mass spectrometry in order to characterize the natural phospholipids (PL) (classes and molecular species) of raw and cooked pork meat. The PL fraction included phosphatidylcholine (PC) (42.9% ± 4.5 for raw vs 42.6% ± 8.0 for cooked meat), plasmalogen–phosphatidylethanolamine (pPE) and phosphatidylethanolamine (PE) (26.7% ± 3.1 vs 28.5% ± 2.3), cardiolipin (CL) (8.3% ± 2.9 vs 6.3% ± 0.7), sphingomyelin (Sph) (7.5% ± 0.9 vs 8.3% ± 2.1), phosphatidylinositol (PI) (6.8% ± 0.7 vs 6.5% ± 2.1) phosphatidylserine (PS) (4.9% ± 0.5 vs 4.6% ± 1.4) and lysophosphatidylcholine (LPC) (2.9% ± 1.3 vs 3.3% ± 2.6). Arachidonic acid (absent in Sph) was mainly present in pPE and PI and formed molecular species with a saturated fatty acid, such as stearic (as in PI, PS, PE and PC) or palmitic acid (as in PE and PC), or the respective vinyl ethers in pPE (p18:0 and p16:0); however, in PC, arachidonic acid also formed combinations with oleic and linoleic acid. Palmitic acid formed the most abundant molecular species in PC, but not in CL, PE, PI and PS. Unexpectedly, the cooked pork meat showed an increased content of the molecular species of PI and LPC with more unsaturated fatty acids (18:0/20:4 and 18:2, respectively) with respect to raw meat.