Author(s)

Janet Too^1*, John Wanyoko², Thomas Kinyanjui¹, Kelvin Moseti², Francis Wachira³

¹Department of Chemistry, Egerton University, Njoro, Kenya.
²Kenya Agricultural and Livestock Research Organization, Tea Research Institute, Kericho, Kenya.
³Association for Strengthening Agricultural Research in East and Central Africa, Entebbe, Uganda.

A study was carried out to quantitatively estimate the L-theanine content in 19 teas commercially available in the Kenyan market by High Performance Liquid Chromatography (HPLC). The test tea samples analyzed were green (n = 4), black (n = 8) and flavored (n = 7) teas from different origins viz., Kenya (n = 4), Uganda (n = 2), Tanzania (n = 5), Rwanda (n = 4), Cameroon (n = 1) and Sri-Lanka (n = 2) commercially available in the Kenyan market. The estimated Limit of Detection (LOD) of the current method was 0.01% L-theanine. The L-theanine content ranged from below the detection limit (<0.01% L-theanine) to 1.60% L-theanine on a dry weight (d.w) basis. Statistically significant differences (p < 0.05) were observed in the L-theanine contents of black, green and flavoured teas. Rwandan green tea contained the highest L-theanine content with 1.60% d.w. whereas six of the seven flavoured teas had very low theanine levels (<0.01%) that could not be quantified by the current method.

Food Analysis, Food Composition, HPLC, L-Theanine, Non-Protein Amino Acids, Tea

Too, J. , Wanyoko, J. , Kinyanjui, T. , Moseti, K. and Wachira, F. (2016) Quantitative Estimation of γ-Glutamylethylamide in Commercially Available Made Teas [Camellia sinensis (L.) O. Kuntze, Theaceae] in Kenya. American Journal of Plant Sciences, 7, 55-62. doi: 10.4236/ajps.2016.71006.