title: A comprehensive investigation of guaiacyl-pyranoanthocyanin synthesis by one-/two-dimensional NMR and UPLC-DAD-ESI-MS(n).
abstract: In red and rosé wines, the grape anthocyanins are progressively converted to more stable pigments, including phenylpyranoanthocyanins. One-/two-dimensional NMR and UPLC-DAD-ESI-MS(n) measurements were used to monitor the synthesis of guaiacylpyranomalvidin 3-O-glucoside from malvidin 3-O-glucoside and vinylguaiacol in model solutions and identify the products formed during the reaction. The highest conversion rates (30%, determined by (1)H qNMR) were obtained with a small excess of vinylguaiacol in methanol/water (70/30) at pH 3 and 35°C. Two reaction pathways competed with the formation of guaiacylpyranomalvidin 3-O-glucoside. The first one only concerns malvidin 3-O-glucoside and consists in C-ring cleavage with formation of malvone and smaller molecular weight breakdown products. This pathway is favored at higher pH and incubation temperature. At lower pH values or in the presence of large vinylguaiacol excess, faster consumption of malvidin 3-O-glucoside resulted from the formation of more complex pyranoanthocyanins substituted by vinylguaiacol oligomers.
authors.affiliation: INRA, UMR1083 Sciences pour l'œnologie, Plateforme Polyphénols, 2, place Viala, Montpellier Cedex 34060, France; Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid 28029, Spain. Electronic address: avallverdu@ub.edu.
authors.forename: Anna
authors.initials: A
authors.lastname: Vallverdú-Queralt
authors.affiliation: INRA, UMR1083 Sciences pour l'œnologie, Plateforme Polyphénols, 2, place Viala, Montpellier Cedex 34060, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Meudec
authors.affiliation: INRA, UMR1083 Sciences pour l'œnologie, Plateforme Polyphénols, 2, place Viala, Montpellier Cedex 34060, France.
authors.forename: Nayla
authors.initials: N
authors.lastname: Ferreira-Lima
authors.affiliation: INRA, UMR1083 Sciences pour l'œnologie, Plateforme Polyphénols, 2, place Viala, Montpellier Cedex 34060, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sommerer
authors.affiliation: Université d'Avignon, UMR408 Sécurité & Qualité des Produits d'Origine Végétale, 84000 Avignon, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Dangles
authors.affiliation: INRA, UMR1083 Sciences pour l'œnologie, Plateforme Polyphénols, 2, place Viala, Montpellier Cedex 34060, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Cheynier
authors.affiliation: INRA, UMR1083 Sciences pour l'œnologie, Plateforme Polyphénols, 2, place Viala, Montpellier Cedex 34060, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Le Guernevé
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D044945:Proanthocyanidins / Q000032:analysis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D044945:Proanthocyanidins
keywords: Guaiacylpyranomalvidin 3-O-glucoside; NMR; Optimization; Synthesis; UPLC–DAD–ESI–MS(n)