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 quantification
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.