Authenticating teas using multielement signatures, strontium isotope ratios, and volatile compound profiling

Marine Reyrolle (1, 2) , Gilles Bareille (1) , Ekaterina Epova , Julien Barre , Sylvain Bérail , Thierry Pigot (1) , Valérie Desauziers (1, 2) , Lydia Gautier , Mickael Le Béchec (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
2 RIME - Equipe RIME - Recherche sur les Interactions des Matériaux avec leur Environnement

High value food products are subject to adulterations and frauds. This study aimed to combine, in our knowledge for the first time, inorganic chemical tracers (multi-elements and Sr isotopy) with volatile organic compound (VOCs) to discriminate the geographic origin, the varieties and transformation processes to authenticate 26 tea samples. By measuring Sr isotope ratio using the multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), 6 out of 11 regions were successfully discriminated. The combination with the ICP-MS inorganic pattern allowed to discriminate 4 more regions with a significance level of 0.05. VOCs fingerprints, obtained with selected ion flow tube mass spectrometer (SIFT-MS), were not correlated with origin but with the cultivar and transformation processes. Green, oolong, and dark teas were clearly differentiated, with hexanal and hexanol contributing to the discrimination of oxidation levels. With this multi-instrumental approach, it is possible to certify the geographical origin and the tea conformity.

Mots clés: Authenticity of food products; Inorganic pattern; Sr isotope ratio; Tea; Traceability; Volatile organic compounds profiling

Domaines: Chimie; Chimie analytique

Marine Reyrolle, Gilles Bareille, Ekaterina Epova, Julien Barre, Sylvain Bérail, et al.. Authenticating teas using multielement signatures, strontium isotope ratios, and volatile compound profiling. Food Chemistry, 2023, 423, pp.136271. ⟨10.1016/j.foodchem.2023.136271⟩. ⟨hal-04102107⟩