title: Development of a fractionation method for the detection and identification of oak ellagitannins in red wines.
abstract: During maturation and ageing in oak barrels wines improve their organoleptic properties. Ellagitannins can be released from wood to the wine and be involved in oxidation reactions and seem to influence the astringency and colour properties of the wine. Nevertheless, the ellagitannins levels are lower than those of other wine constituents and, consequently, they are not easily detected. This study has developed a two-step fractionation method consisting of a solid phase extraction in C-18 Sep-Pak cartridges followed by size exclusion chromatography in hand-packed Sephadex LH-20 minicolumn for the detection of oak ellagitannins in different types of wines. An HPLC method has also been developed which allows the separation of compounds with the same m/z ratios, facilitating the ellagitannin identification by means of the mass spectrometric analyses. The main oak ellagitannins (grandinin, vescalagin, roburin E and castalagin) were isolated, detected separately and identified in a spiked wine and in three real ones, proving the usefulness of the fractionation method.
authors.affiliation: Grupo de Investigación en Polifenoles (GIP), Unidad de Nutrición y Bromatología, Facultad de Farmacia, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: García-Estévez
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Escribano-Bailón
authors.forename: Julián C
authors.initials: JC
authors.lastname: Rivas-Gonzalo
authors.forename: Cristina
authors.initials: C
authors.lastname: Alcalde-Eon
mesh_terms: D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006027:Glycosides / Q000032:analysis / Q000302:isolation & purification; D006576:Heterocyclic Compounds, 4 or More Rings / Q000032:analysis / Q000302:isolation & purification; D047348:Hydrolyzable Tannins / Q000032:analysis* / Q000302:isolation & purification; D013058:Mass Spectrometry / Q000379:methods*; D029963:Quercus / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D014920:Wine / Q000032:analysis*
chemical_list: D006027:Glycosides; D006576:Heterocyclic Compounds, 4 or More Rings; D047348:Hydrolyzable Tannins; C479598:grandinin; C084709:vescalagin