Identification and quantification of phospholipids in strawberry seeds and pulp (Fragaria × ananassa cv San Andreas) by liquid chromatography with electrospray ionization and tandem mass spectrometry.

Abstract

An extensive characterization and quantification of intact phospholipids (PLs) in strawberry (Fragaria × ananassa cv San Andreas) seed and pulp was carried out by hydrophilic interaction liquid chromatography (HILIC) and electrospray ionization (ESI) coupled to either Fourier-transform (FT) orbital-trap or linear ion-trap tandem mass spectrometry (LIT-MS/MS). More than 150 intact polar lipids including phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), phosphatidylglycerols (PGs), phosphatidic acids (PAs), phosphatidylinositols (PIs), lysophosphatidylcholines (LPCs), and lysophosphatidylethanolamines (LPEs) were identified in negative ESI mode. PC 18:2/18:2 and 18:2/18:3 were found to be the major components of strawberry lipid extracts at concentrations of 230 ± 36 and 189 ± 32 μg/g, respectively, in seeds and at concentrations of 330 ± 50 and 140 ± 22 μg/g, respectively, in pulp. The lipidic extracts of both strawberry seeds and pulp exhibited the dominance of LPC 16:0/0:0 at a content of 132 ± 19 and 114 ± 16 μg/g, respectively, and LPC 0:0/18:2 at 236 ± 20 and 150 ± 20 μg/g, respectively. The other most abundant species of strawberry seeds and pulp were PE 18:2/18:2, 40 ± 9 and 190 ± 40 μg/g, followed by PI 16:0/18:2, 51 ± 15 and 24 ± 8 μg/g, respectively, while PG, PA, and LPE show comparable abundance below 10 μg/g. The most recurrent fatty acyl substituents of PLs were C18:3 (α-linolenic acid), C18:2 (linoleic acid), C18:1 (oleic acid), C18:0 (stearic acid), C16:0 (palmitic acid), and relatively high contents of a shorter chain such as C14:0 (myristic acid).