Studio mediante le tecniche SNIF-NMR e IRMS dei fattori meteorologici che influenzano l’abbondanza isotopica nel vino

In this paper we present a research that took part in the frame of cooperation between the Department of Chemistry of the University of Turin and the Agrometeo Sector of Regional Phytosanitary Service of Piedmont. The purpose of the study was to investigate isotopic parameters of deuterium and carbon of ethanol extracted from wine and correlate them to meteorological data of the field in which plants grew up. Nebbiolo and Barbera samples of different years and coming from different areas of Piedmont (Castiglione Falletto, CN e Cuccaro, AL) were analyzed by SNIF-NMR (Site-Specific Natural Isotopic Fractionaction – Nuclear Magnetic Resonance) and IRMS (Isotopic Ratio Mass Spectrometry). The best correlations were achieved by taking into account rainfall and mean temperature of regions. In particular, we found an inverse linear correlation close to unit between methylic site of ethanol and rainfall. Further high correlations were achieved between methylic site and δ13C with temperature, whereas in general, one find a much less accurate correlation with the isotopic content of the methylenic site. Morover, we managed to classify wines coming from different areas of Piedmont. In detail, samples from Cuccaro showed significantly higher isotopic contents compared to the regional medium values. This fact demonstrates the presence of a microclimatic area with higher thermal trend than the rest of the region.