Characterization of flavan-3-ols in seeds of grape pomace by CE, HPLC-DAD-MSn and LC-ESI-FTICR-MS

AbstractThe aim of this study was to evaluate the profile of galloylated and non-galloylated flavan-3-ols and the presence of enantiomers of catechin and epicatechin in seeds of pomace from the vinification of different grape varieties with a view to their exploitation as a source of natural antioxidants. Chiral capillary electrophoretic analysis showed that the fermentation process of winemaking did not give rise to (−)-catechin and (+)-epicatechin enantiomers. Only (+)-catechin and (−)-epicatechin were detected. High-performance liquid chromatography coupled with a diode array detector and an ion trap mass spectrometer (HPLC/DAD-MSn) showed the presence of several galloylated and non-galloylated flavan-3-ol compounds and the presence of condensed products of catechin with acetaldehyde. Fourier-transform ion cyclotron resonance mass spectrometry (LC-ESI-FTICR-MS) enabled the assignment of elemental compositions to 251 different flavan-3-ol compounds in Cabernet Sauvignon variety, including isomers of 28 different molecular classes. The data obtained may support the exploitation of grape seeds as a source of natural antioxidants