Geographical Origin Traceability of Tea (Camellia sinensis): A Comprehensive Review of Analytical Techniques, Chemometric Approaches, and Future Perspectives

The geographical origin fraud of tea is a serious challenge faced by the global tea market. This review systematically sorts out the full chain technical system from analysis and detection to data analysis in the field of tea origin traceability, reviews the traceability mechanism and application boundaries of four core technologies including stable isotopes, mineral element fingerprints, spectroscopy and mass spectrometry metabolomics, and emerging sensors, reveals the differential masking effect of the processing techniques of the six major tea types on chemical fingerprints, and systematically analyzes the methodological evolution of chemometrics and machine learning in origin discrimination. This article provides a systematic reference for understanding the overall pattern of the tea origin traceability technology system and the selection of differentiated traceability strategies for different tea types.