AJPS  Vol.5 No.4 , February 2014
Selected Inorganic Nutrients in Black Tea from Three Tea Growing Agro-Ecological Areas in Kenya
Abstract: The tea plant absorbs dissolved nutrients from soils for its normal growth and development, though to different extents. Nutrients play vital roles in various metabolic processes, their deficiency or excess being deleterious to living organisms. A study was carried out to quantitatively assess the inorganic nutrient content (K, P, Ca, Mn, Fe, Zn and Cu) of twelve black tea samples sourced from Murang’a, Meru and Kisii tea growing agro-ecological areas in Kenya. K and P were quantified using a flame photometer and a UV-Vis spectrophotometer respectively whereas Ca, Mn, Fe, Zn and Cu were quantified using an Atomic Absorption Spectrophotometer (AAS). The general accumulation pattern of the inorganic nutrients in the tea samples was established to be; K (1.6% ± 0.05%-2.1% ± 0.01%) > P (0.30% ± 0.01%-0.37% ± 0.04%) > Ca (0.16% ± 0.01%-0.62% ± 0.03%) > Mn (0.07% ± 0.009%-0.13% ± 0.004%) > Fe (136 ± 8-320 ± 5 μg/g) > Zn (27 ± 1-39 ± 7 μg/g) > Cu (10 ± 3-16 ± 1 μg/g). Statistically significant differences (p < 0.05) were observed in the inorganic nutrient contents of the black tea from the different tea factories as well as agro-ecological areas. These data demonstrate the tea plant’s ability to accumulate the studied nutrients, further underlining tea consumption as a potential dietary source of the nutritionally essential inorganic nutrients.
Cite this paper: M. Mose, K. Moseti, J. Wanyoko, J. Kinyua, D. Kariuki, E. Magiri and M. Obanda, "Selected Inorganic Nutrients in Black Tea from Three Tea Growing Agro-Ecological Areas in Kenya," American Journal of Plant Sciences, Vol. 5 No. 4, 2014, pp. 473-479. doi: 10.4236/ajps.2014.54061.

[1]   J. Ruan and M. H. Wong, “Accumulation of Fluoride and Aluminium Related to Different Varieties of Tea Plant,” Environmental Geochemistry and Health, Vol. 23, No. 1, 2001, pp. 53-63.

[2]   T. K. Mondal, A. Bhattacharya, M. Laxmikumaran and P. S. Ahuja, “Recent Advances of Tea (Camellia sinensis) Biotechnology—Review of Plant Biotechnology and Applied Genetics,” Journal of Plant Cell, Tissue and Organ Culture, Vol. 76, No. 3, 2004, pp. 195-254.

[3]   S. Seenivasan, N. Manikandan, N. M. Muraleedharan and R. Selvasundaram, “Heavy Metal Content of Black Teas From South India,” Food Control, Vol. 19, No. 8, 2008, pp. 746-749.

[4]   N. S. Mokgalaka, R. I. McCrindle and B. M. Botha, “Multielement Analysis of Tea Leaves by Inductively Coupled Plasma Optical Emission Spectrometry Using Slurry Nebulization,” Journal of Analytical Atomic Spectrometry, Vol. 19, No. 10, 2004, pp. 1375-1378.

[5]   S. G. Reeves, P. O. Owuor and C. O. Othieno, “Biochemistry of Black Tea Manufacture,” Tropical Science, Vol. 27, 1987, pp. 121-133.

[6]   K. C. Wilson and M. N. Clifford, “Tea: Cultivation to Consumption,” Chapman and Hall, London, 1992, p. 792.

[7]   R. M. Gesimba, M. C. Langat, G. Liu and J. N. Wolukau, “The Tea Industry in Kenya; the Challenges and Positive Developments,” Journal of Applied Sciences, Vol. 5, No. 2, 2005, pp. 334-336.

[8]   A. Anandacoomaraswamy, W. A. J. M. De Costa, H. W. Shyamalie and G. S. Campbell, “Factors Controlling Transpiration of Mature Field-Grown Tea and Its Relationship with Yield,” Agricultural and Forestry Meteorology, Vol. 103, No. 4, 2000, pp. 375-386.

[9]   Kenya Tea Development Agency, “From Bush to Cup (Tea Life Cycle),” 2011.

[10]   Tea Board of Kenya, “Surviving the Economic Meltdown,” 2012.

[11]   F. L. Chung, J. Schwartz, C. R. Herzog and Y. M. Yang, “Tea and Cancer Prevention: Studies in Animals and Humans,” The Journal of Nutrition, Vol. 133, No. 10, 2003, pp. 3268-3274.

[12]   P. Katharine, “Yet More Roles for Tea in Disease Prevention,” Trends Pharmacology Science, Vol. 22, No. 10, 2001, p. 501.

[13]   R. Richard, “Green Tea Extract May Have Neuro-Protective Effects in Parkinson’s Disease,” Lancet, Vol. 358, No. 9279, 2001, p. 391.

[14]   T. O. Cheng, “Why Did Green Tea Not Protect against Coronary Artery Disease but Protect Against Myocardial Infarction,” The American Journal of Cardiology, Vol. 91, No. 10, 2003, pp. 1290-1291.

[15]   R. Hirano, et al., “Comparison of Green Tea Intake in Japanese Patients with and without Angiographic Coronary Artery Disease,” The American Journal of Cardiology, Vol. 36, 2003, pp. 64-70.

[16]   F. Pourmorad, S. J. Husseinimehr and N. Shahabimajd, “Antioxidant, Phenol and Flavanoid Contents of Some Selected Iranian Medicinal Plants,” African Journal of Biotechnology, Vol. 5, No. 11, 2006, pp. 1142-1145.

[17]   S. M. Karori, R. M. Ngure, F. N. Wachira, J. K. Wanyoko and J. N. Mwangi, “Different Types of Tea Products Attenuate Inflammation Induced in Trypanosoma brucei Infected Mice,” Parasitology International, Vol. 57, No. 3, 2008, pp. 325-333.

[18]   M. C. Sabu, K. Smitha and R. Kuttan, “Anti-Diabetic Activity of Green Tea Polyphenols and Their Role in Reducing Oxidative Stress in Experimental Diabetes,” Journal of Ethnopharmacology, Vol. 83, No. 1-2, 2002, pp. 109-116.

[19]   S. Asfar, et al., “Effect of Green Tea in the Prevention of and Reversal of Fasting Induced Intestinal Mucosal Damage,” Nutrition, Vol. 19, No. 6, 2003, pp. 536-540.

[20]   C. D. Wu and G. X. Wei, “Tea as a Functional Food for Oral Health,” Nutrition, Vol. 18, No. 5, 2002, pp. 443-444.

[21]   A. M. Haque, M. Hashimoto, M. Katakura, Y. Tanabe, Y. Hara and O. Shido, “Long Term Administration of Green Tea Catechins Improves Spatial Cognition Learning Ability in Rats,” Journal of Nutrition, Vol. 136, No. 4, 2006, pp. 1043-1047.

[22]   S. Ahmad, et al., “Determination of Mineral and Toxic Heavy Elements in Different Brands of Black Tea of Pakistan,” African Journal of Pharmacy and Pharmacology, Vol. 6, No. 15, 2012, pp. 1194-1196.

[23]   M. T. Soomro, E. Zahir, S. Mohiuddin, A. N. Khan and I. I. Naqri, “Quantitative Assessment of Metals in Local Brands of Tea in Pakistan,” Pakistan Journal of Biological Sciences, Vol. 11, No. 2, 2008, pp. 285-289.

[24]   U. Divrikli, N. Horzum, M. Soylak, and L. Elci, “Trace Heavy Metal Contents of Some Spices and Herbal Plants from Western Anatolia, Turkey,” International Journal of Food Science and Technology, Vol. 41, No. 6, 2006, pp. 712-716.

[25]   A. Mehra and C. L. Baker, “Leaching and Bioavailability of Aluminium, Copper and Manganese from Tea (Camellia sinensis),” Food Chemistry, Vol. 100, No. 4, 2007, pp. 1456-1467.

[26]   Tea Board of Kenya, “Fact Sheet on Kenya Tea. Tea Board of Kenya Statistics,” 2007.

[27]   K. O. Moseti, et al., “Fe, Zn, Cu, Pb and Cd in Tea Grown and Marketed in Kenya; a Quantitative Assessment,” International Journal of Environmental Protection, Vol. 3, No. 6, 2013, pp. 24-30.

[28]   K. Sitienei, P. G. Home, D. M. Kamau and J. K. Wanyoko, “Nitrogen and Potassium Dynamics in Tea Cultivation as Influenced by Fertilizer Type and Application Rates,” American Journal of Plant Sciences, Vol. 4, No. 1, 2013, pp. 59-65.

[29]   R. Thomas, R. W. Sheard and L. P. Moyer, “Comparison of Conventional and Automated Procedures From Nitrogen, Phosphorous and Potassium Analysis of Plant Material Single Digest,” Agronomy Journal, Vol. 59, No. 3, 1967, pp. 240-243.

[30]   A. G. Spencer, “Flame Photometry,” Lancet, Vol. 256, No. 6639, 1950, pp. 623-627.

[31]   MSTAT C, “A Micro-Computer Program for the Design, Management and Analysis of Agronomic Research Experiments, MSTAT Distribution Package,” MSTAT Development Team, Michigan State University, USA, 1993.

[32]   D. A. Armbruster and T. Pry, “Limit of Blank, Limit of Detection and Limit of Quantification,” Clinical Biochemistry Reviews, Vol. 29, Suppl. 1, 2008, pp. 49-52.

[33]   B. O. Kwach, P. O. Owuor, D. M. Kamau and J. K Wanyoko, “Evaluation of Foliar Analysis as a Diagnostic Tool of Predicting Nutrient Deficiencies of Clonal Tea in Kenya,” Asian Journal of Biological and Life Sciences, Vol. 1, No. 1, 2012, pp. 8-18.

[34]   W. N. Omwoyo, et al., “Availability of Some Inorganic Micronutrients and Effects of Grading on Their Levels in East African Black Teas and Their Infusions,” Asian Journal of Biological and Life Sciences, Vol. 2, No. 1, 2013, pp. 42-49.

[35]   A. Kumar, A. G. C. Nair, A. V. R. Reddy and A. N. Garg, “Availability of Essential Elements in Indian and US Tea Brands,” Journal of Food Chemistry, Vol. 89, No. 3, 2008, pp. 441-448.

[36]   J. K. Wanyoko and C. K. Njuguna, “Variation of Foliar Nutrients of Some Kenyan Tea and Their Relationship with Yield,” Tea, Vol. 4, No. 1, 1983, pp. 37-43.