4. Conclusions
In this study, chemical composition (moisture, ash, caffeine, fluoride, polyphenols, and 15 metals from both tea leaves and infusions) was used as input data for identification of the
differentiating characteristics of tea samples. Undoubtedly, the best classification results were obtained when the elemental profile in the tea infusions was used. Some approaches provided 100% of discrimination: (1) PLS-DA using ‘‘All parameters’’; (2) PLS-DA using ‘‘Elements in tea infusions’’; (3) SPA-LDA using ‘‘All parameters’’; (4) SPA-LDA using ‘‘Total content of elements’’; and (5) SPA-LDA using ‘‘Elements in tea infusions’’. Despite of that, SPA-LDA using ‘‘Elements in tea infusions’’ provided the most important result, selection of the three telling chemical parameters (namely potassium, aluminum, and magnesium), corroborating that the elemental fingerprint (chemical signature) can be used for simultaneous discrimination of both varieties and geographical origin of teas. The result is extremely positive from the view point of chemical analyses, because the quantifica- tion of only three major elements in simple tea infusions provides a simpler, faster and more affordable methodology for tea discrimination. However, to guarantee any generalization of the proposed methodology, a larger (more varied) testing of tea samples using more varieties and geographical origins must be implemented.