title: Evaluation of Macro- and Microelement Levels in Black Tea in View of Its Geographical Origin.
abstract: The aim of this study was to evaluate the elemental composition of black tea samples and their infusions in view of their geographical origin. In total, 14 elements were analyzed, 13 (Ca, K, Mg, Na, Mn, Fe, Zn, Cu, Cr, Ni, Co, Cd, and Pb) by flame atomic absorption spectrometry, and P by UV-Vis spectrometry, after mineralization of samples. It was found that K was the most abundant macroelement in the analyzed samples, whereas among microelements, the highest concentration was found for Mn. Based on the obtained data, the percentage of elements leached into the infusions as well as the daily elemental intake from tea were calculated. The daily intake from tea was compared to the recommended daily allowances (RDAs), and the highest percentages of the RDAs were found for Mn (15 %) and Co (10 %). To study the relations between elemental composition and country of origin of samples, factor analysis and cluster analysis were applied. These multivariate techniques proved to be efficient tools able to differentiate samples according to their provenance as well as plantation within the common regions.
authors.affiliation: Department of Food Sciences, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416, Gdańsk, PL, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Brzezicha-Cirocka
authors.affiliation: Department of Food Sciences, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416, Gdańsk, PL, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Grembecka
authors.affiliation: Department of Biology, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Ciesielski
authors.affiliation: Department of Chemistry, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway.
authors.forename: Trond Peder
authors.initials: TP
authors.lastname: Flaten
authors.affiliation: Department of Food Sciences, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416, Gdańsk, PL, Poland. pszef@gumed.edu.pl.
authors.forename: Piotr
authors.initials: P
authors.lastname: Szefer
mesh_terms: D004784:Environmental Monitoring; D005843:Geography; D013054:Spectrophotometry, Atomic; D013056:Spectrophotometry, Ultraviolet; D013662:Tea / Q000737:chemistry*; D014131:Trace Elements / Q000032:analysis*
chemical_list: D013662:Tea; D014131:Trace Elements
keywords: Black tea; Cluster analysis; FAAS; Factor analysis; PTWI; RDA