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

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. Copyright © 2006 Society of Chemical Industry