Classification of the geographical origin of Pinot noir wines from southwestern Switzerland using isotopes, volatile organic compounds, and chemometrics

This study examined the potential of carbon and nitrogen isotopes of wine solid residues with semi-quantitative amounts of volatile organic compounds to characterize Pinot noir wines from different regions in southwestern Switzerland. Significant differences in the ¹³C/¹²C (-30.6 to -26.4 mUr), ¹⁵N/¹⁴N (0.6-6.7 mUr), C/N (25-102), and contents of 38 volatiles exist between the wines. Principal component analysis identified three distinct clusters of wine regions: Valais, southern Vaud-Geneva, and Three Lakes. These clusters corresponded to a gradient in altitude, precipitation, temperature, and air humidity. The wine samples were satisfactorily classified according to their geographical origin using linear discriminant analysis on isotopic and molar ratios (84.8 % accurate prediction), selected volatile compounds (90.9 % accurate prediction), and the combination of both (95.5 % accurate prediction). Soil factors and aging in oak barrels did not affect the ability to classify wines based on the isotopic ratios and semi-quantified volatile compounds.