Abstract (EN):
Monomer and polymer flavan-3-ols and anthocyanins are the two major groups of phenolic compounds in red wine and one of the most important reactions during red wine ageing is the condensation reaction, either direct or indirect, between these two classes of compounds. In this work, the reaction of (+)-catechin, (-)-epicatechin and dimer procyanidin B(2) with malvidin 3-glucoside, in the presence of acetaldehyde, was carried out in wine model solutions at pH 1.7 and 3.2. Identification of the reaction products was carried out by high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and MS(n) analysis. Various reaction products were detected. The structures of three condensation products - malvidin-3-glucoside-ethyl-(epi)catechin-1 ''-hydroxyethyl, malvidin-3-glucoside-ethyl-dimer-vinyl and malvidin3-glucoside-ethyl-dimer-1 ''-hydroxyethyl - were identified in a model solution for the first time. Moreover, in the reaction solution containing dimer B(2) at pH 3.2, monomer epicatechin, trimer and tetramer procyanidins were also detected indicating that, under these conditions, dimer procyanidins can either be hydrolyzed to monomers or polymerized to higher oligomer or polymers. Copyright (C) 2007 John Wiley & Sons, Ltd.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
10