Volume 5, Issue 2, June 2020, Page: 13-19
Effects of Different Fertilizer Rates on Total Polyphenols and Catechins of Selected Clones of Green Tea (Camellia sinensis L. [O] Kuntze)
Evans Kenanda Okemwa, Department of Research and Extension, Kisii University, Kisii, Kenya
Koskei Kipkoech Silvanuss, Department of Chemistry, School of Pure and Applied Sciences, Kisii University, Kisii, Kenya
Received: Jun. 4, 2020;       Accepted: Jun. 18, 2020;       Published: Jun. 28, 2020
DOI: 10.11648/j.wjac.20200502.11      View  309      Downloads  127
Application of inorganic NPK (nitrogen: phosphorus: potassium) fertilizers on tea (Camellia sinensis) has been common among small-scale tea farmers to increase production. However, the cost of fertilizers has been increasing and reducing their net returns. Fertilizers applications also affect the quality of the crop which is mainly dictated by the total polyphenols and catechins; these metabolites are responsible for its anti-oxidant activity, taste and aroma. The focus of this work was on the effect of varying NPK fertilizer application rate on the levels of total polyphenols and catechins of green tea made from three tea cultivars and development of an optimum NPK fertilizer application rate. Samples of three varieties, AHP S15/10, TRFK 6/8 (Tea Research Foundation of Kenya), and BBK 35, were collected from Mettarora, Arroket and Monire tea estates within Sotik highlands. Randomized complete block design sampling was used and sampling was done 6-8 weeks after application of the treatment. The fertilizer used was inorganic plain NPK fertilizer and NPK fertilizer supplemented with Molybdenum. The experimental treatments consisted of six treatments made up NPK 25:5:5; at 0, 75, 150, 225, 300, and 375 kg N/ha/year. The collected samples were processed as non-aerated green CTC (Cut, Tear and Curl) teas at the miniature processing factory unit at Kenya Agricultural and Livestock Research Organisation - Tea Research Institute (KALRO-TRI) at Kericho County. Processed tea samples were milled and chemical analysis done to quantify the levels of biochemicals in the samples. Data obtained were subjected to Analysis of Variance (ANOVA) and mean separation was done using the least significant difference test at p ≤0.05. TRFK 6/8 was found to have the highest mean percentage total polyphenols of 25.90 followed by BBK 35 with a mean percentage total polyphenols of 25.75. AHP S15/10 recorded the least mean percentage total polyphenols of 23.70. A similar trend was observed in the mean percentages of catechins with TRFK 6/8, BBK 35 and AHP S 15/10 recording 20.7%, 18.87% 18.46% respectively. Hence, use of optimum NPK fertilizer application rate specific to each clone supplemented with Molybdenum boosts the levels of polyphenols and catechins in green tea.
Cultivars, Polyphenols, Catechins, Fertilizers, Anti-oxidant Activity
To cite this article
Evans Kenanda Okemwa, Koskei Kipkoech Silvanuss, Effects of Different Fertilizer Rates on Total Polyphenols and Catechins of Selected Clones of Green Tea (Camellia sinensis L. [O] Kuntze), World Journal of Applied Chemistry. Vol. 5, No. 2, 2020, pp. 13-19. doi: 10.11648/j.wjac.20200502.11
Copyright © 2020 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
J. Kitzes, M. Wackernagel, J. Loh, A. Peller, S. Goldfinger, D. Cheng, K. Tea. “Shrink and share: humanity's present and future Ecological Footprint”. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 2008, 363 (1491), 467-475.
D. Bonheure, K. C. Willson. (1992). “Mineral nutrition and fertilizers in Tea. Springer, Dordrecht, 1992.
ISO 14502-1-2005 “Reference, method for determination of polyphenolic compounds in green and black tea”.
M. Fazel, M. A. Sahari and M. Barzegar. Determination of Main Tea Seed Oil Antioxidants and Their Effects on Common Kilka Oil. International Food Research Journal, (2008) 15, 209-217
K. O. George, T. Kinyanjui, J. Wanyoko, O. K. Moseti, and F. Wachira. Extraction and Analysis of Tea (Camellia sinensis) Seed Oil from Different Clones in Kenya. African Journal of Biotechnology, (2013) 12, 841-846. [7]
Yahaya, L. E., Wang, Y., Sun, D., Chen, H., Qian, L. and Xu, P. (2011) Fatty Acid Composition and Antioxidant Activity of Tea (Camellia sinensis L.) Seed Oil Extracted by Optimized Supercritical Carbon Dioxide. International Journal of Molecular Science, 12, 7708-7719.
C. P. Lee and G. C. Yen. Antioxidant Activity and Bioactive Compounds of Tea Seed (Camellia oleifera Abel.) Oil. Journal of Agricultural and Food Chemistry, 2006, 54, 779-784.
P. O. Owuor. “High rates of nitrogen on tea. Effects of Fertilizers on Tea Yields and Quality”. 2001, Preventive medicine, 21 (3), 334-350.
M. Obanda, P. O. Owuor, S. J. Taylor. “Flavanol composition and caffeine content of green leaf as quality potential indicators of Kenyan black teas”. Journal of the Science of Food and Agriculture, 1997, 74 (2), 209-215.
A. Gulati. “Tea Manufacture”. Science of Tea Technology, 2013, 401.
L. Bravo. “Polyphenols: chemistry, dietary sources, metabolism, and nutritional significance”. Nutrition reviews, 1998, 56 (11), 317-333.
D. G. Nagle, D. Ferreira, Y. D. Zhou. “Epigallocatechin-3-gallate (EGCG): chemical and biomedical perspectives”. Phytochemistry, 20065, 67 (17), 1849-1855.
S. Ramkumara, P. S. kumarb, J. Gandhi, A. S. Geethac, P. Mohankumard, V. K. Gopalakrishnan. Biochemical and molecular analysis of Camellia sinensis (L.) O. Kuntze tea from the selected P/11/15 clone. Journal of Genetic Engineering and Biotechnology. (2016) 14, 69-75
X. Ruan,. Wu, Härdter. “Effects of potassium and magnesium nutrition on the quality components of different types of tea”. Journal of the Science of Food and Agriculture, 1999, 79 (1), 47-52.
H. N. Graham. Green tea composition, consumption, and polyphenol chemistry. Preventive medicine, 1992, 21 (3), 334-350.
Y. Hara. Green tea: health benefits and applications. CRC press 2001.
B. N. Kaiser, K. L. Gridley, B. J. Ngaire, T. Phillips, S. D. Tyerman. “The Role of Molybdenum in Agricultural Plant Production”. Annals of Botany, 2005, 96 (5), 745–754.
K. O. George, T. Kinyanjui, J. Wanyoko, O. K. Moseti, and F. Wachira. Quantitation of the Total Catechin Content in Oils Extracted from Seeds of Selected Tea (Camellia sinensis (L) O. Kuntze, Theaceae) Clones by RP-HPLC. American Journal of Plant Sciences, 2015, 6, 1080-1089
F. M. Ngure, J. K. Wanyoko, S. M. Mahungu, and A. A. Shitandi. Catechins Depletion Patterns in Relation to Theaflavin and Thearubigins Formation. Food Chemistry, 115, 2009, 8-14.
Browse journals by subject