Authentication of Wine by1H-NMR Spectroscopy: Opportunities and Challenges

Abstract

The verification of wine identity and authenticity is of urgent importance in the current context of a growing market globalization. As a result, wine authentication is an indispensable as well as essential aspect in today's consumer protection. Regarding its chemical analysis the matrix wine is challenging, whereas its valuable characteristics are based on different factors, such as different types of tastes, the geographical origin associated with the growing conditions, vintage and grape variety. Accordingly, the range of analytical methods to enable a comprehensive characterization of these products is highly diversified. In this context, 1H-NMR spectroscopy is currently employed to characterize wine in terms of targeted as well as nontargeted analysis in only a few minutes and therefore allows the simultaneous investigation of diverse parameters. As the targeted approach enables an identification and quantification of different key ingredients in wine, the nontargeted, also called fingerprinting analysis, with subsequent statistical data evaluation investigates the whole spectrum of the matrix. Therefore, the capability to detect known adulterants, but also the ability to detect further abnormalities, and the assessment of challenging authentication parameters (grape variety, origin, vintage) appoint this technique of utmost interest for quality control, research and control institutions. Particularly concerning the nontargeted approaches, current relevant scientific literature is typically based on feasibility, demonstration or research studies within one laboratory on one instrument exclusively, which restricts validation possibilities and degrees. Validation of the whole analytical procedure including statistical data evaluation and consistency of the measurement over time, instruments and laboratories is, however, essential for routine application and in official control. Therefore, the use of nontargeted fingerprinting approaches is due to actual missing validation strategies still restricted for official control purposes, thereby offering complex challenges for the scientific community.