Analysis of molecular species of glycolipids in fruit pastes of red bell pepper (Capsicum annuum L.) by high-performance liquid chromatography-mass spectrometry

Five major glycolipid classes (acylated steryl glucoside, steryl glucoside, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, and glucocerebroside) from fruit pastes of red bell pepper were separated by silica gel column chromatography. The molecular species of each glycolipid were separated and characterized by reversed-phase high-performance liquid chromatography coupled with on-line mass spectrometry using atmospheric pressure chemical ionization. The molecular species of steryl glucoside were beta-sitosteryl and campesteryl glucosides, and those of the acylated steryl glucoside were their fatty acid esters. The dilinolenoyl species was predominant in monogalactosyldiacylglycerol in addition to small amounts of another five molecular species, whereas digalactosyldiacylglycerol consisted of seven molecular species varying in their degree of unsaturation. The glucocerebroside class contained at least seven molecular species, which were characterized by proton nuclear magnetic resonance spectroscopy.