title: High-resolution NMR and diffusion-ordered spectroscopy of port wine.
abstract: The use of high-resolution NMR and high-resolution diffusion-ordered spectroscopy (DOSY) for the characterization of selected Port wine samples of different ages with the aim of identifying changes in composition is described. Conventional 1D and 2D NMR methods enabled the identification of about 35 compounds, including minor components such as some medium-chain alcohols, amino acids, and organic acids. High-resolution (HR) DOSY extended sample characterization, increasing the number of compounds identified and NMR assignments made, by providing information on the relative molecular sizes of the metabolites present. Port wines of different ages were found to differ mainly in their content of (a) organic acids and some amino acids, (b) an unidentified possible disaccharide, and (c) large aromatic species. The relative amount of these last high Mw aromatics is seen to decrease significantly in the oldest wine, as expected from the known formation and precipitation of anthocyanin-based polymers during red wine aging.
authors.affiliation: Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro, Portugal.
authors.forename: Mathias
authors.initials: M
authors.lastname: Nilsson
authors.forename: Iola F
authors.initials: IF
authors.lastname: Duarte
authors.forename: Cláudia
authors.initials: C
authors.lastname: Almeida
authors.forename: Ivonne
authors.initials: I
authors.lastname: Delgadillo
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Goodfellow
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gil
authors.forename: Gareth A
authors.initials: GA
authors.lastname: Morris
mesh_terms: D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009812:Odorants / Q000032:analysis; D013057:Spectrum Analysis / Q000379:methods*; D013997:Time Factors; D014920:Wine / Q000032:analysis*