Non-galloylated and galloylated proanthocyanidin oligomers in grape seeds from Vitus vinifera L. cv. Graciano, Tempranillo and Cabernet Sauvignon

Abstract

Non-galloylated and galloylated flavan-3-ol composition in seeds from Vitis vinifera L. var. Graciano, Tempranillo and Cabernet Sauvignon grapes harvested in 2000, 2001 and 2002 at the same geographical area were determined using normal-phase HPLC coupled with electrospray ionization mass spectrometry (LC/ESI-MS) detection. Non-galloylated and monogalloylated flavan-3-ols up to octamers, and di-, and trigalloylated flavan-3-ols up to heptamers were identified in all grape seeds. Comparisons of the flavan-3-ol composition in three grape varieties harvested in three different years indicate that levels of non-galloylated flavan-3-ols decrease as the degree of polymerization increased, whereas the monogalloylated dimers were present in the highest levels in all varieties and vintages. The levels of other monogalloylated flavan-3-ols varied in different vintages. Tempranillo contained the lowest levels of non-galloylated and monogalloylated flavan-3-ols, whereas Graciano contained the highest levels, with the exception of non-galloylated flavan-3-ols in vintage 2001, and non-galloylated monomers in vintages 2000 and 2002. Grape seeds from vintage 2000 contained the highest levels of both non-galloylated and galloylated structures. Statistical analyses indicate that the distribution of the flavan-3-ols is primarily determined by genetic factors and is also strongly influenced by climate conditions.