Concentrations and solubility of selected trace metals in leaf and bagged black teas commercialized in Poland

Abstract

The objective of this study was to determine the concentrations of heavy metals in bagged and leaf black teas of the same brand and evaluate the percentage transfer of metals to tea infusion to assess the consumer exposure. Ten leaf black teas and 10 bagged black teas of the same brand available in Poland were analyzed for Zn, Mn, Cd, Pb, Ni, Co, Cr, Al, and Fe concentrations both in dry material and their infusion. The bagged teas contained higher amounts of Pb, Mn, Fe, Ni, Al, and Cr compared with leaf teas of the same brand, whereas the infusions of bagged tea contained higher levels of Mn, Ni, Al, and Cr compared with leaf tea infusions. Generally, the most abundant trace metals in both types of tea were Al and Mn. There was a wide variation in percentage transfer of elements from the dry tea materials to the infusions. The solubility of Ni and Mn was the highest, whereas Fe was insoluble and only a small portion of this metal content may leach into infusion. With respect to the acceptable daily intake of metals, the infusions of both bagged and leaf teas analyzed were found to be safe for human consumption.

Comparison of Infusions from Black and Green Teas (Camellia sinensis L. Kuntze) and Erva-mate (Ilex paraguariensis A. St.-Hil.) Based on the Content of Essential Elements, Secondary Metabolites, and Antioxidant Activity

“…They followed the order Mn > Zn > Fe > Cu. The quantities of metallic elements assayed in the study are in agreement with the values found in other research on tea, erva-mate, or medicinal herb infusions (Pozebon et al 2015;Polechonska et al 2015;Salahinejad and Aflaki 2010;Konieczynski et al 2015Konieczynski et al , 2016. However, the level of Zn and Cu is higher in all erva-mate samples than that determined in black and green teas, as confirmed by post hoc Tukey's test.…”

Analysis of Tea for Metals by Flame and Graphite Furnace Atomic Absorption Spectrometry with Multivariate Analysis

“…Herbal beverages (teas and herbal teas) are used worldwide due to their nutritional values and for health benefits, since they usually are not biologically aggressive (Pytlakowska et al 2012). It is known that billions of cups are consumed worldwide (Polechońska et al 2015).…”

Investigation of Some Metals in Leaves and Leaf Extracts of Lippia javanica: Its Daily Intake

“…The observation that Mn and Cu appeared to be released more into the infusion than brew extracts was explained for Camellia sinensis in terms of their potential for chelation with tannins and tannic acid which exudes on boiling (brew) such that when chelates precipitate, element content decreases [35]. In separate studies, little or no Pb was detected in leaves, made tea, and infusions from Camellia sinensis , common tea [32, 35, 36]. Camellia sinensis has been shown to release high concentrations of Mn in made tea and its infusions [28, 30, 36].…”