title: Comparative study of ¹³C composition in ethanol and bulk dry wine using isotope ratio monitoring by mass spectrometry and by nuclear magnetic resonance as an indicator of vine water status.
abstract: The potential of wine (13)C isotope composition (δ(13)C) is presented to assess vine water status during grape ripening. Measurements of δ(13)C have been performed on a set of 32 authentic wines and their ethanol recovered after distillation. The data, obtained by isotope ratio monitoring by mass spectrometry coupled to an elemental analyser (irm-EA/MS), show a high correlation between δ(13)C of the bulk wine and its ethanol, indicating that the distillation step is not necessary when the wine has not been submitted to any oenological treatment. Therefore, the ethanol/wine δ(13)C correlation can be used as an indicator of possible enrichment of the grape must or the wine with exogenous organic compounds. Wine ethanol δ(13)C is correlated to predawn leaf water potential (R(2) = 0.69), indicating that this parameter can be used as an indicator of vine water status. Position-specific (13)C analysis (PSIA) of ethanol extracted from wine, performed by isotope ratio monitoring by nuclear magnetic resonance (irm-(13)C NMR), confirmed the non-homogenous repartition of (13)C on ethanol skeleton. It is the δ(13)C of the methylene group of ethanol, compared to the methyl moiety, which is the most correlated to predawn leaf water potential, indicating that a phase of photorespiration of the vine during water stress period is most probably occurring due to stomata closure. However, position-specific (13)C analysis by irm-(13)C NMR does not offer a greater precision in the assessment of vine water status compared to direct measurement of δ(13)C on bulk wine by irm-EA/MS.
authors.affiliation: Service Commun des Laboratoires, 3 Avenue du Dr. Albert Schweitzer, 33608, Pessac cedex, France. labo33@scl.finances.gouv.fr.
authors.forename: Francois
authors.initials: F
authors.lastname: Guyon
authors.affiliation: Bordeaux Sciences Agro, University of Bordeaux, ISVV, Ecophysiology and Functional Genomics of Grapevines, UMR 1287, 33140, Villenave d'Ornon, France.
authors.forename: Cornelis
authors.initials: C
authors.lastname: van Leeuwen
authors.affiliation: Service Commun des Laboratoires, 3 Avenue du Dr. Albert Schweitzer, 33608, Pessac cedex, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Gaillard
authors.affiliation: EBSI Team, CEISAM, UMR CNR6230, 2 rue de la Houssinière, BP 92208, 44322, Nantes cedex 3, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Grand
authors.affiliation: EBSI Team, CEISAM, UMR CNR6230, 2 rue de la Houssinière, BP 92208, 44322, Nantes cedex 3, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Akoka
authors.affiliation: EBSI Team, CEISAM, UMR CNR6230, 2 rue de la Houssinière, BP 92208, 44322, Nantes cedex 3, France.
authors.forename: Gérald S
authors.initials: GS
authors.lastname: Remaud
authors.affiliation: Service Commun des Laboratoires, 3 Avenue du Dr. Albert Schweitzer, 33608, Pessac cedex, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sabathié
authors.affiliation: Service Commun des Laboratoires, 3 Avenue du Dr. Albert Schweitzer, 33608, Pessac cedex, France.
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Salagoïty
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis*; D000431:Ethanol / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D027843:Vitis / Q000737:chemistry*; D014867:Water / Q000032:analysis*; D014920:Wine / Q000032:analysis*
chemical_list: D002247:Carbon Isotopes; D014867:Water; D000431:Ethanol
keywords: Carbon 13 isotope ratio; Isotope ratio monitoring 13C nuclear magnetic resonance; Isotope ratio monitoring mass spectrometry; Vine water status; Wine ethanol