DETERMINATION OF TRACE ELEMENTS IN SOME BRANDS OF GREEN TEA USING WET DIGESTION, INFUSION AND DRY ASHING METHODS
Abstract
The concentrations of trace elements (Cu, Zn, Fe, Mn and Ni) in some commercially available brands of green tea sold within Katsina metropolis coded (SGT, HGT, LGT, AGT and GGT) were determined using wet acid digestion, water infusion, and Dry Ashing methods by Atomic Absorption Spectroscopy (AAS). Among the trace elements analyzed Nickel and Manganese recorded the highest value ranged 1.0 – 3.5 mg kg-1 and1.0 – 5.5 mg kg-1 in dry ashing and wet digestion respectively. Fortunately, almost all the elements analyzed were within the standard permissible limit of WHO. The content of trace elements was found highest in the Dry Ashing method and lowest values recorded in tea infusion. The contributory factors responsible for the differences found in tea samples could be from a varying concentration of metals in the soil, conditions of cultivation and preparations, and these vary between both countries of origin and for the type of tea. Further work is recommended on these brands to study other important parameters
References
Adriano, D. C. (1986). Trace elements in the terrestrial environment (pp. 105-123). New York: Springer Verlag.
Brun, L. A., Maillet, J., Hinsinger, P., & Pépin, M. (2001).Evaluation of copper availability to plants in copper-contaminated vineyard soils. Environmental Pollution, 111, 293-302.
Fiedman, M., (2007). Overview of antibacterial, antitoxin, antiviral and antifungal activities of tea flavonoids and (tea .Mol).Nutr.Food Res. 51,116-134.
Fung, K. F., and M. H. Wong, (2002).Effects of Soil pH on the Uptake of Al, Fe and other elements by tea plants.J. Sci. Food Agri., 82(1), 146-152.
Khokhar, S.; Magnusdottir, S.G. (2002).Total phenol, catechin, and caffeine contents of teas commonly consumed in the United Kingdom.
Kumar, A., Nair, A. G. C., Reddy, A. V. R., & Garg, A. N. (2005). Availability of essential elements in Indian and US tea brands. Food Chemistry, 89, 441-448.
Karak, T; Bhagat, R.M.(2010). Trace elements in tea leaves, made tea and tea infusion: A review.
Kawada, T., Lee, Y., Suzuki, S., & Rivai, I. F. (2002). Copper in carrots by soil type and area in Japan: A baseline study.Journal of Trace Element and Medical Biology, 16, 179 -182.
McLaughlin, D. (2002). Soil investigation and human health risk assessment for the Rodney Street Community, Port Colborne. Ontario Ministry of the Environment, Toronto: Queen's Printer for Ontario.
Narin, I., Colak, H., Turkoglu, O., Soylak, M., & Dogan, M. (2004). Heavy metals in black tea samples produced in Turkey. Bulletin of Environmental Contamination andToxicology, 72, 844-849.
Powell, J.J., Burden, T.J. and Thompson, R.P.H. (1998). In vitro mineral availability from digested tea: A rich dietary source of manganese. Analyst, 123:17211724. pp. 259-263, ISSN 0889-1575
Robert B., and Gustav K., (2014).“Chemical Heritage Foundationâ€.Retrieved 2014-07-29.
Ramakrishna, R. S., Palmakumbura, S., & Chatt, A. (1986). Varietal variation and correlation of trace metal levels with catechins and caffeine in Sri Lanka tea. Journal of Food Science and Agriculture, 38(4), 331-339.
Salahinejad, M., & Aflaki, F. (2010). Toxic and essential mineral elements content of black tea leaves and their tea infusions consumed in Iran. Biological Trace Element Research, 134, 109-117.
Sabhapondit, S.; Karak, T.; Bhuyan, L.P.; Goswami, B.C.; Hazarika, M. (2012).Diversity of catechin in northeast Indian tea cultivars.
Tanaka,T.; Kouno, I.(2003). Oxidation of Tea Catechins: Chemical Structures and Reaction Mechanism.Food Science and Technology Research.
USEPA (1992). Guidelines for Exposure Assessment, EPA/600/Z-92/001. Risk Assessment Forum, Washington, DC.
WHO/EU (1993) Drinking water standards comparative. www.lenntech.com/who-eu-water-stndards.htm
Zerabruk, S., Chandravanshi, B. S., and Zewge, F., (2010). Fluoride in black and green tea (Camellia sinensis) liquors in Ethiopia: Measurement and safety evaluation. B. Chem. Soc. Ethiopia, 24(3), 327 - 338.
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