title: New phenolic compounds formed by evolution of (+)-catechin and glyoxylic acid in hydroalcoholic solution and their implication in color changes of grape-derived foods.
abstract: The reaction between (+)-catechin and glyoxylic acid in model solution system was investigated by LC/DAD and LC/ESI-MS analyses. The formation of phenolic compounds exhibiting absorption maxima near 300 nm and presenting a shoulder around 350 nm was observed. Their structures consisted of a (+)-catechin unit with one or two aldehyde groups linked at positions 6, 8 or 6 and 8 of the A ring. In addition, new yellow pigments exhibiting UV-visible spectra similar to those of xanthylium salts with absorption maxima at 450 and 280 nm were also detected. The major yellow compound was isolated and identified by ESI-MS and 1D and 2D NMR spectroscopy. The implication of these compounds in color change and browning observed during aging of grape-derived beverages is also discussed.
authors.affiliation: ISVV-INRA Institut des Produits de la Vigne, Unité de Recherche Biopolymères et Arômes, 2 place Viala, 34060 Montpellier, France.
authors.forename: N E
authors.initials: NE
authors.lastname: Es-Safi
authors.forename: C
authors.initials: C
authors.lastname: Le Guernevé
authors.forename: V
authors.initials: V
authors.lastname: Cheynier
authors.forename: M
authors.initials: M
authors.lastname: Moutounet
mesh_terms: D000438:Alcohols / Q000737:chemistry; D002392:Catechin / Q000737:chemistry*; D003116:Color; D006038:Glyoxylates / Q000737:chemistry*; D010636:Phenols / Q000138:chemical synthesis*; D019685:Rosales; D012996:Solutions; D014867:Water
chemical_list: D000438:Alcohols; D006038:Glyoxylates; D010636:Phenols; D012996:Solutions; D014867:Water; D002392:Catechin; C031150:glyoxylic acid