Purification and Estructure Elucidation of Crown procyanidins

Entity: Universitat Rovira i Virgili (URV)

Confidenciality: No

Education area(s): Begudes Fermentades

Title in different languages: Purification and Estructure Elucidation of Crown procyanidins

Abstract: Purification and Structure Elucidation of crown procyanidins ABSTRACT The wine phenolic composition will depend on the original grape phenolic profile but also on the extraction and winemaking techniques used. Recently three surprisingly polar tannins oligomers (one tetramer and two pentamers) were detected by Zeng (2015). These oligomers turned out to belong to a new sub class of condensed tannin oligomers, which were never been reported before in wine as well in plant kingdom and was named crown procyanidin. As this kind of compounds has never been identified and detected in grape berries, an extraction method has been developed using acetone/water (70/30, v/v) acidified with 5 g/L of tartaric acid follow by methanol/water (40/60, v/v) with 5 g/L of tartaric acid. Using this extraction method, the crown procyanidin appeared to be tissue specific since they were detected only in the grape skin of Merlot and Cabernet Sauvignon. Moreover, the comparison between the two grape varieties revealed that crown procyanidin tetramer concentration was higher in Cabernet Sauvignon than in Merlot. Besides, the extraction rate of the crown procyanidins during the fermentation process has been estimated. The observed trend revealed that the crown procyanidins are extracted very quickly at the beginning of the vinification which is an opposite trend compare to regular B- type condensed tannins which need ethanol to be extracted. So, the fact that these tannins are very polar, highly soluble in water and exclusively located in skin might be the reason of this specific and unexpected behaviour. KEYWORDS Grape, wine, Cabernet-Suavignon, Merlot, Bordeaux

Subject: Vinicultura

Academic year: 2015-2016

Language: Anglès

Work's public defense date: 2016-06-22

Subject areas: Enology

Student: Riveiro Canosa, Marina

Department: Bioquímica i Biotecnologia

Creation date in repository: 2016-09-07

TFM credits: 15

Keywords: Bordeaux, Cabernet-Sauvignon, Merlot

Title in original language: Purification and Estructure Elucidation of Crown procyanidins

Access Rights: info:eu-repo/semantics/openAccess

Project director: Jourdes, Michael