Abstract
A fast and straightforward sample preparation procedure of the dialyzable fraction of infusions of teas prior to their analysis on Al, Ba, Ca, Cu, Fe, Mg, Mn, Ni, Sr, and Zn contents by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma optical emission spectrometry (ICP OES) was developed and validated. The proposed methodology was based on acidification with HNO3 only and demonstrated good analytical performance, i.e., precision (0.80–5.0%), accuracy (< 5%), recoveries of elements (97.4–105%), and their detection limits (0.075–1.1 μg L−1) along with linearity of calibration curves in the whole studied concentration ranges. Applicability of the evaluated procedure, being a useful alternative to time-consuming wet digestions, was tested by determining bioaccessibility of elements in 20 infusions of black (BT) and green (GT) teas as assessed with the aid of in vitro gastrointestinal digestion. Average contributions of bioaccessible fractions (%) of studied metals were as follows: 1.18 (Al)–40.7% (Ca) and 4.65% (Al)–46.3% (Ca) for BTs and GTs, respectively. Drinking daily four cups (1 L) of tea, recommended dietary intakes (RDIs) of Ca, Cu, Fe, Mg, and Zn were covered to a small degree (< 1.5%). Only bioaccessibility of Mn highly contributed to RDI for this metal. According to provisional tolerable weekly intakes (PTWIs) for toxic elements such as Al and Ni, consumption of both types of teas should not represent any health risk. Additionally, analysis of variance of results clearly indicated that BTs and GTs were mostly differentiated due to concentrations of the bioaccessible fraction of Al, Ba, Cu, and Ni.
Highlights
IntroductionElement analysis of tea infusions is overwhelmingly concerned on determination of total concentrations of various metals to assess quality and safety of this ubiquitous beverage or estimate recommended daily intakes (RDIs) for nutritionally relevant or toxic metals
Brewed teas are a valuable source of antioxidants as well as essential elements
Concentrations of metals in both separated soluble or dialyzable fractions are determined by spectrometric methods such as flame atomic absorption spectrometry (FAAS), inductively coupled plasma optical emission spectrometry (ICP OES), or inductively coupled plasma mass spectrometry (ICP-MS) [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]
Summary
Element analysis of tea infusions is overwhelmingly concerned on determination of total concentrations of various metals to assess quality and safety of this ubiquitous beverage or estimate recommended daily intakes (RDIs) for nutritionally relevant or toxic metals. In the latter can be added, enabling to assess the dialyzable fraction of metals (bioaccessibility). Samples of infusions were incubated with gastric juice and adjusted to pH 6.5 to simulate intestinal pH They simulated absorption of metals in the villi by ultrafiltration over membranes with 3, 10, and 30 kDa molecular weight cut-offs (MWCOs). After in vitro GID, samples were just centrifuged, filtered, and measured directly using ICP-MS
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
