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

• Published in: Food chemistry Vol. 423; p. 136271
• Main Authors: Reyrolle, Marine, Bareille, Gilles, Epova, Ekaterina N., Barre, Julien, Bérail, Sylvain, Pigot, Thierry, Desauziers, Valerie, Gautier, Lydia, Le Bechec, Mickael
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15-10-2023; Elsevier
• Subjects: Analytical chemistry; Authenticity of food products; Chemical Sciences; Inorganic pattern; Isotopes - chemistry; Mass Spectrometry - methods; Spectrum Analysis; Sr isotope ratio; Strontium Isotopes - analysis; Tea; Tea - chemistry; Traceability; Volatile Organic Compounds - analysis; Volatile organic compounds profiling; VOCs; PLS-DA; DIMS; PTR-MS; Authenticity of food products; Traceability; Tea; Inorganic pattern; Sr isotope ratio; MC-ICP-MS; SIFT-MS; PDO; ICP-MS; Volatile organic compounds profiling
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2023.136271

•VOCs profiles, 87Sr/86Sr ratio and multielement analysis were applied on tea.•87Sr/86Sr ratio discriminated 6 of the 11 regions of the sample collection.•Inorganic pattern improved the discrimination of Sr isotope ratio up to 10.•Volatile fingerprints were mainly impacted by the type of Camelia cultivar.•Hexanal and hexanol were highlighted for the classification with oxidation rate.
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.