Q-NMR measurements: quantitative analysis of wine composition applied to Bordeaux red wines authenticity control

Abstract

Traceability of wine is today a consumer demand and a scientific challenge. The methods of analysis must be able to control three fundamental parameters: the geographical origin, the grape varieties, and the vintage. With these focus, the CIVB supports the creation of a VRAI platform (Wine-Research-Authenticity-Identity) within the ISVV (Institute of Vine and Wine Sciences). This platform aims to develop analytical tools to guarantee the origin of a wine. Quantitative Nuclear Magnetic Resonance (qNMR) may be a great tool to help authenticate wines. The acquisition of a large number of wine parameters requires a small volume (a few hundred microliters) and the analysis is performed in a few minutes. This innovative analytical technique can therefore be useful to characterize wines quality and authenticity particularly in the context of priceless wine. 

A NMR-based metabolomics method was developed to semiautomatically quantify many wine components [1]. An original approach based on similarity score (s-score) was developed for wine comparison. Using this approach, a comparative evaluation of the results obtained for three sets of authentic high-valued wines and suspect wines was studied with two methodologies: (i) usual wine analysis, based on the use of multiple techniques, which is the traditional way of analysis for wine authentication and (ii) q-NMR profiling [2]. In order to consider a global aging uncertainty, samples from the same batch from old vintages were analyzed to estimate aging impact on wine composition. Results showed that q-NMR can detect cases of fraud by comparison with the original wine provided by the estate, according to conclusions of official methods. 

More, a database of commercial French wines was built with q-NMR data to examine the specific Bordeaux red wines fingerprinting. Several statistical analyses were performed to classify wines according to their geographical origin, vintage. Results revealed a singular imprint of Bordeaux wines in comparison with other French wines, with classification rates ranging from 71 % to 100 %. These analysies highlighted several specific metabolites of Bordeaux red wines and showed the influence of terroir in the discrimination. Also, Bordeaux subdivisions were investigated, and effects of wines evolution during bottle aging and vintage were pointed out. These studies provide a global and practical description of the potential of q-NMR for wine authentication. 

[1] Gougeon, L., Da Costa, G., Le Mao, I., Ma, W., Teissedre, P. L., Guyon, F., & Richard, T. (2018). Wine Analysis and Authenticity Using 1H-NMR Metabolomics Data: Application to Chinese Wines. Food Analytical Methods, 11(12), 3425-3434. 
[2] Gougeon, L., Da Costa, G., Richard, T., & Guyon, F. (2019). Wine Authenticity by Quantitative 1H NMR Versus Multitechnique Analysis: a Case Study. Food Analytical Methods, doi: 10.1007/s12161-12018-01425-z.