title: Role of vinylcatechin in the formation of pyranomalvidin-3-glucoside-+-catechin.
abstract: Reactions between malvidin-3-glucoside (mv3glc) and 8-vinylcatechin were carried out to synthesize pyranomv3glc-(+)-catechin pigment and to study the formation of intermediates. A rapid decrease of mv3glc content concomitant with the formation of more complex structures such as mv3glc-vinylcatechin [precursor of pyranomv3glc-(+)-catechin pigment] and mv3glc-divinylcatechin was observed. On the other hand, 8-vinylcatechin undergoes acid-catalyzed dimerization in model wine solution, giving rise to 8-vinylcatechin dimers. These compounds were also found in the reaction between mv3glc and (+)-catechin mediated by acetaldehyde, which provides evidence for the formation of 8-vinylcatechin and its involvement in the formation of pyranoanthocyanins in aged red wines.
authors.affiliation: Departamento de Quimica, Faculdade de Ciencias, Centro de Investigacao em Quimica, Universidade do Porto, Porto, Portugal.
authors.forename: Luis
authors.initials: L
authors.lastname: Cruz
authors.forename: Natércia
authors.initials: N
authors.lastname: Teixeira
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.forename: Jose
authors.initials: J
authors.lastname: Borges
authors.forename: Victor
authors.initials: V
authors.lastname: de Freitas
mesh_terms: D000079:Acetaldehyde / Q000737:chemistry; D000872:Anthocyanins / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D019281:Dimerization; D005960:Glucosides / Q000138:chemical synthesis*; D014753:Vinyl Compounds / Q000737:chemistry*; D014920:Wine / Q000032:analysis
chemical_list: C539562:8-vinylcatechin; D000872:Anthocyanins; D005960:Glucosides; D014753:Vinyl Compounds; C539563:pyranomalvidin-3-glucoside-catechin; C458419:malvidin-3-glucoside; D002392:Catechin; D000079:Acetaldehyde