Regional origin assignment of red wines from Valencia (Spain) by 2H NMR and 13C IRMS stable isotope analysis of fermentative ethanol

The use of the stable hydrogen and carbon isotope ratios of fermentative ethanol as suitable environmental fingerprints for the regional origin identification of red wines from Valencia (Spain) has been explored. Monovarietal Vitis vinifera L. cvs. Bobal, Tempranillo, and Monastrell wines have been investigated by H-2 NMR and C-13 IRMS for the natural ranges of site-specific H-2/H-1 ratios and global delta(13)C values of ethanol over three vintage years. Statistically significant interregional and interannual H-2 and C-13 abundance differences have been noticed, which are interpreted in terms of environmental and ecophysiological factors of isotope content variation. Multivariate discriminant analysis is shown to provide a convenient means for integration of the classifying information, high discriminating abilities being demonstrated for the H-2 and C-13 fingerprints of ethanol. Reasonable differentiation results are achieved at a microregional scale in terms of geographic provenance and even grapevine genotypic features.