Analytical Assessment of Bioelements in Various Types of Black Teas from Different Geographical Origins in View of Chemometric Approach

Abstract

A comprehensive approach to the mineral composition of black teas of different origins was studied using the Flame Atomic Absorption Spectrometry (FAAS) method, supported by chemometric tools including Principal Component Analysis PCA) and Classification and Regression Trees (CART). Significant differences between the teas from seven countries (Japan, Nepal, Kenya, Iran, Sri Lanka, India, and China) were shown. K was the main element determined in all teas, with an average concentration of 11,649 mg/kg, followed by Ca, Mg and Mn. In general, regarding all investigated black teas, the element content was ranked in the following order: K > Ca > Mg > Mn > Fe > Na > Zn > Cu. The applied chemometric methods allowed us to recognize black tea clusters based on their mineral composition and place of cultivation, and allowed us to find correlations between particular elements in black teas. The performed analyses revealed interesting correlations between the concentration of various elements in black teas: K was negatively correlated with Na, Fe, Mn and Cu; K was positively correlated with the content of Ca and Mg. Significant positive correlations between Mn and Fe and Mn and Zn in the studied black tea samples were also revealed. It was shown that mineral composition may be a significant factor regarding the origin of the black tea, not only considering the country, but also the region or province.

Dietary Intake of Toxic Heavy Metals with Major Groups of Food Products—Results of Analytical Determinations

“…Black tea is very popular in European countries, and it was previously described that infusions prepared from this plant are the most popular beverage in the world, including Poland, after water [25,26]. Since black tea infusions may be a rich source of some elements (e.g., Mn, Mg) [27][28][29], and especially blended products, which are often of low quality and contaminated with heavy metals, this group of food products should be considered a significant source of toxic heavy metals for a general occupationally non-exposed population [30,31]. Because the consumption of black tea infusions in the studied population was high, it was hypothesized that the contribution of the group "Water and beverages" to the overall intake of some toxic metals would also be high.…”

Comprehensive applications of metabolomics on tea science and technology: Opportunities, hurdles, and perspectives

“…These findings showed that higher accumulation of amino acids and aromatic substances occurred in tea leaves from high elevation. Notably, a number of studies have attempted to differentiate tea samples from various geographic origins by measuring levels of the minerals, rare earth elements, and organic elements (C, H, O, and N) using the flame atomic absorption spectrometry, ICP‐MS, and elemental analyzer‐isotope ratio mass spectrometry (EA‐IRMS), which might be powerful technologies for following tea origin traits in the future (Koch et al., 2021; Zhao & Yang, 2019; Zhou, Li et al., 2019).…”

Special Issue “Natural Plant Substances—Structural and Application Aspects: A Theme Issue in Honor of Professor Wieslaw Oleszek”

“…One article is completely different from the remaining, as it does not describe plant natural products. Koch et al determined levels of several macro- and microelements in samples of black teas from different countries and locations, and evaluated the possibility of application of chemometric methods to distinguish the origin of black teas on the basis of their mineral composition [ 16 ].…”