title: Ethylidene-bridged Flavan-3-ols in red wine and correlation with wine age.
abstract: Condensed tannins are responsible for astringency and bitterness and participate in the color stability of red wines. During wine making and aging, they undergo chemical changes including, for example, acetaldehyde-induced polymerization. Following this study, the ethylidene-bridged flavan-3-ols were monitored in different vintage wines made from grapes collected in the same vineyard in three wineries in Bordeaux, Pauillac, and Saint Julien. Flavan-3-ol ethylidene bridges were quantified by wine 2,2'-ethylidenediphloroglucinol (EDP) phloroglucinolysis. This method was based upon the analysis of EDP, a product formed after acid-catalyzed cleavage of wine flavan-3-ols in the presence of excess phloroglucinol. The flavan-3-ol ethylidene bridges were then compared to flavan-3-ol contents (phloroglucinolysis), phenolic contents, and color measurements. Low amounts of flavan-3-ol ethylidene bridges (0.8-2.5 mg L(-1)) were quantified in wines. Flavan-3-ol ethylidene bridges represent less than 4% of flavan-3-ol bonds, but the proportion of these linkages relative to native interflavan bonds increased with wine age. This proportion correlated with pigmented polymers.
authors.affiliation: Faculté d'Oenologie de Bordeaux, Université Victor Segalen Bordeaux 2, UMR 1219 INRA ISVV, 351 Cours de la Libération, 33405 Talence Cedex, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Drinkine
authors.forename: Paulo
authors.initials: P
authors.lastname: Lopes
authors.forename: James A
authors.initials: JA
authors.lastname: Kennedy
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Teissedre
authors.forename: Cedric
authors.initials: C
authors.lastname: Saucier
mesh_terms: D003116:Color; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry*; D010636:Phenols / Q000032:analysis; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000737:chemistry; D013997:Time Factors; D014920:Wine / Q000032:analysis*
chemical_list: C520047:2,2'-ethylidenediphloroglucinol; D005419:Flavonoids; D010636:Phenols; C404987:flavan-3-ol; D010696:Phloroglucinol