title: Quantitative analysis of Bordeaux red wine precipitates by solid-state NMR: Role of tartrates and polyphenols.
abstract: Stability of wines is of great importance in oenology matters. Quantitative estimation of dark red precipitates formed in Merlot and Cabernet Sauvignon wine from Bordeaux region for vintages 2012 and 2013 was performed during the oak barrel ageing process. Precipitates were obtained by placing wine at -4°C or 4°C for 2-6 days and monitored by periodic sampling during a one-year period. Spectroscopic identification of the main families of components present in the precipitate powder was performed with (13)C solid-state CPMAS NMR and 1D and 2D solution NMR of partially water re-solubilized precipitates. The study revealed that the amount of precipitate obtained is dependent on vintage, temperature and grape variety. Major components identified include potassium bitartrate, polyphenols, polysaccharides, organic acids and free amino acids. No evidence was found for the presence of proteins. The influence of main compounds found in the precipitates is discussed in relation to wine stability.
authors.affiliation: Institute of Chemistry & Biology of Membranes & Nano-objects, CBMN UMR 5248, CNRS University of Bordeaux, Bordeaux National Institute of Technology, Allée Geoffroy St Hilaire, 33600 Pessac, France.
authors.forename: Shipra
authors.initials: S
authors.lastname: Prakash
authors.affiliation: BioLaffort, 126 Quai De La Souys, 33100 Bordeaux, France.
authors.forename: Nerea
authors.initials: N
authors.lastname: Iturmendi
authors.affiliation: Institute of Chemistry & Biology of Membranes & Nano-objects, CBMN UMR 5248, CNRS University of Bordeaux, Bordeaux National Institute of Technology, Allée Geoffroy St Hilaire, 33600 Pessac, France.
authors.forename: Axelle
authors.initials: A
authors.lastname: Grelard
authors.affiliation: BioLaffort, 126 Quai De La Souys, 33100 Bordeaux, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Moine
authors.affiliation: Institute of Chemistry & Biology of Membranes & Nano-objects, CBMN UMR 5248, CNRS University of Bordeaux, Bordeaux National Institute of Technology, Allée Geoffroy St Hilaire, 33600 Pessac, France. Electronic address: e.dufourc@cbmn.u-bordeaux.fr.
authors.forename: Erick
authors.initials: E
authors.lastname: Dufourc
mesh_terms: D011232:Chemical Precipitation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D059808:Polyphenols / Q000032:analysis*; D013634:Tannins / Q000737:chemistry; D013644:Tartrates / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry*; D014920:Wine / Q000032:analysis*
chemical_list: D059808:Polyphenols; D013634:Tannins; D013644:Tartrates
keywords: Glycerol; Polyphenols; Polysaccharides; Precipitate; Solid- and solution-state NMR; Wine ageing; Wine coloring matter