UHPLC-QTOF-HRMS metabolomics insight on the origin and processing authentication of thyme by comprehensive fingerprinting and chemometrics

The metabolic composition of thyme, one of the most used aromatic herbs, is influenced by environmental and post-harvest processing factors, presenting the possibility of exploiting thyme fingerprint to assess its authen-ticity. In this study, a comprehensive UHPLC-QTOF-HRMS fingerprinting approach was applied with a dual objective: (1) tracing thyme from three regions of production (Spain, Morocco, and Poland) and (2) evaluating the metabolic differences in response to processing, considering sterilized thyme samples. Multivariate statistics reveal 37 and 33 key origin and processing differentiation compounds, respectively. The findings highlighted the remarkable terroir influence on thyme fingerprint, noticing flavonoids, amino acids, and peptides among the most discriminant chemical classes. Thyme sterilization led to an overall metabolite enrichment, most likely due to the facilitated compound accessibility as a result of processing. The findings provide a comprehensive metabolomics insight into the origin and processing effect on thyme composition for product traceability and quality assessment.

Automated summary

A comprehensive UHPLC-QTOF-HRMS fingerprinting approach was used to trace thyme from three different production regions and evaluate the metabolic differences in response to processing. 37 key compounds related to origin and 33 key compounds related to processing differentiation were identified. The study highlights the terroir influence on thyme composition, with flavonoids, amino acids, and peptides being the most discriminant chemical classes. Thyme sterilization was found to enrich the overall metabolite content, potentially due to increased compound accessibility.