What’s in a wine? – A spot check of the integrity of European wine sold in China based on anthocyanin composition, stable isotope and glycerol impurity analysis

ABSTRACT

The international wine market has been repeatedly hit by cases of fraud in recent decades. While several studies attested a special vulnerability of the fast growing wine business in China, reports on chemical analyses of commercial wine samples are rare. We examined 50 predominantly red wines with European labelling, which were purchased on the Chinese market, for fraud-relevant parameters. More than 20% of the tested samples revealed anomalies in relation to the stable isotope ratios of D/H, ¹⁸O/¹⁶O and ¹³C/¹²C, contents of technical glycerol by-products or anthocyanin composition. These results strongly suggested watering of the wines, chaptalisation, glycerol addition or the use of non-Vitis anthocyanin sources, respectively. Some of these samples also showed suspicious spelling errors or other irregularities in the labelling, but the majority appeared genuine to the eye. Hence, this spot check demonstrates the importance of chemical authenticity analysis of market samples in order to detect fraudulent products. Moreover, we used the same sample set for an evaluation of the Chinese standard method for carbon stable isotope determination of wine ethanol in comparison to the current OIV (International Organisation of Vine and Wine) standard method. The results of a Bland-Altman analysis indicated that the methods can be applied interchangeably. As the two methods differ in their workflow and in the requested equipment, this might eventually enable more laboratories to perform ¹³C/¹²C analysis of wine and spirits.

Graphical abstract

KEYWORDS:

• Wine authenticity
• EU-China
• standard method
• stable isotopes
• technical glycerol addition
• watering
• chaptalisation

Acknowledgments

The authors would like to thank Werner Blaas, Barbara Brakowiecka-Sassy and Stephanie Panitz (BfR) for their technical assistance and comments on the manuscript. We thank Hongbo Gao, Guanghao Wang (CNRIFFI) as well as Rui Feng and Ming Ma (Ningbo Quarantine & Inspection Science and Technology Academic, NQISTA) for participating in the lab twinning activities and measurements of the wine samples.

Supplementary material

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Additional information

Funding

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727864 and No. 2017YFE0110800 from the Chinese Ministry of Science and Technology (MOST).