Application of Molecular spectroscopy and chemometrics for authentication and quality control of tea (Camellia sinensis L.): a review

Tea, derived from Camellia sinensis L., is considered as the most popular beverages in the world. The quality of teas may vary depending on harvesting location and geographical origins, thus the traceability of teas according to their origins is very essential to assure tea's quality. Due to economic reasons, high quality tea products may be added with foreign materials or adulterated with low quality ones, as a consequence, some analytical methods have been proposed and developed to quality control of tea. During the recent years, the application of molecular spectroscopic techniques (UV-Vis, Fluorescence, Near Infrared, Mid Infrared, Raman) in combination with multivariate data analysis has emerged as rapid and reliable analytical tool in the quality control of food, including food authentication. The objective of this review is to update the application of molecular spectroscopy (UV-Vis, fluorescence, infrared and Raman) for the quality control and authentication of tea products either geographical origins issue or detection of potential adulterants. The variables obtained during molecular spectral measurement involve hundreds or thousands of data, which make data analysis rather complex. Fortunately, the specific chemometrics tools can solve the problems arising from big data coming from analyte signals, spectral interferences and overlapping peaks. This review paper provides an overview of the recently developed approaches and latest research carried out in molecular spectroscopic techniques in combination with chemometrics for the quality control and for authentication of teas.