Abstract
Theanine is a specific amino acid in tea, which has positive effects on health. Theanine contents of different grade Turkish teas, variations in the theanine content during tea processing, and the effects of different rolling processes on theanine content were determined. Theanine content of Turkish tea varying between 0.32 and 0.43 % has been reported for the first time by this study. Theanine content decreased in all processing steps from 10.0–3.42 to 7.73–3.97 mg g−1 dw in Orthodox and Cay-Kur methods, respectively. In both methods, the highest theanine loss (almost 50 %) was observed in the withering step, which was followed by drying step. Caffeine content of Turkish tea was determined varying between 1.8 and 2.2 %. While the caffeine content increased in the withering step, it decreased in other steps. The correlation between theanine and caffeine contents was evaluated. A high correlation (R 2 = 0.87) between the caffeine and theanine contents was found in teas classified by Cay-Kur method, and caffeine/theanine ratio was found to be around 5.3 in general.
Similar content being viewed by others
References
Khokhar S, Magnusdottir SGM (2002) Total phenol, catechin, and caffeine contents of teas commonly consumed in the United Kingdom. J Agric Food Chem 50:565–570
Thippeswamy R, Mallikarjun G, Rao DH, Martin A, Gowda LR (2006) Determination of theanine in commercial tea by liquid chromatography with fluorescence and diode array ultraviolet detection. J Agric Food Chem 54:7014–7019
Juneja LR, Chu D, Okubo T, Nagato Y, Yokogoshi H (1999) L-theanine-a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Tech 10:199–204
Ekborg-Ott KH, Taylor A, Armstrong DW (1997) Varietal differences in the total and enantiomeric composition of theanine in tea. J Agric Food Chem 45:353–363
Kvasnička F, Krátká J (2006) Isotachophoretic determination of theanine. Cent Eur J Chem 4:216–222
Mejia EG, Ramirez-Mares MV, Puangpraphant S (2009) Bioactive components of tea: cancer, inflammation and behavior. Brain Behav Immun 23:721–731
Balentine DA, Wiseman S, Bouwen LCM (1997) The chemistry of tea flavonoids. Crit Rev Food Sci Nutr 38:693–704
Zhao W, Yang RJ, Wang M, Lu RR (2009) Effects of pulsed electric fields on bioactive components, colour and flavour of green tea infusions. Int J Food Sci Tech 44:312–321
Vuong QV, Bowyer MC, Roach PD (2011) l-Theanine: properties, synthesis and isolation from tea. J Sci Food Agric 91:1931–1939
Li GL, Kang JJ, Yao XY, Xin YQ, Wang Q, Ye Y, Luo L, Yin ZM (2011) The component of green tea, l- theanine protects human hepatic L02 cells from hydrogen peroxide-induced apoptosis. Eur Food Res Technol 233:427–435
Fernández PL, López A, Pablos F, González AG, Martín MJ (2003) The use of catechins and purine alkaloids as descriptors for the differentiation of tea beverages. Microchim Acta 142:79–84
Tomlins KI, Mashingaidze A (1997) Influence of withering, including leaf handling, on the manufacturing and quality of black teas-a review. Food Chem 60:573–580
Özdemir F, Gökalp HY, Nas S (1992) Effects of rolling method on physical characteristics of rolled tea leaves. Sri Lanka J Tea Sci 61:51–58
Turkmen N, Velioglu YS (2007) Determination of alkaloids and phenolic compounds in black tea processed by two different methods in different plucking seasons. J Sci Food Agric 87:1408–1416
Sari F, Velioglu YS (2011) Effects of particle size, extraction time and temperature, and derivatization time on determination of theanine in tea. J Food Comput Anal 24:1130–1135
Roberts GR, Sanderson GW (1966) Changes undergo by free amino-acids during the manufacture of black tea. J Sci Food Agric 17:182–188
Caffin N, D’Arcy B, Yao L, Rintoul G (2004) Developing an index of quality for Australian tea. Australian Gov. RIRDC Publ. Nr. 04/033, Australia
Muthumani T, Senthil-Kumar RS (2007) Influence of fermentation time on the development of compounds responsible for quality in black tea. Food Chem 101:98–102
Astill C, Birch MR, Dacombe C, Humphrey PG, Martin PT (2001) Factors affecting the caffeine and polyphenol contents of black and green tea infusions. J Agric Food Chem 49:5340–5347
Bhattacharyya N, Seth S, Tudu B, Tamuly P, Jana A, Ghosh D, Bandyopadhyay R, Bhuyan M, Sabhapandit S (2007) Monitoring of black tea fermentation process using electronic nose. J Food Eng 80:1146–1156
Ying Y, Ho JW, Chen ZY, Wang J (2005) Analysis of theanine in tea leaves by HPLC with fluorescence detection. J Liq Chromatogr RT 28:727–737
Obanda M, Owuor PO, Mang’oka R (2001) Changes in the chemical and sensory quality parameters of black tea due to variations of fermentation time and temperature. Food Chem 75:395–404
Schulz H, Engelhardt UH, Wegent A, Drews HH, Lapczynski S (1999) Application of near-infrared reflectance spectroscopy to the simultaneous prediction of alkaloids and phenolic substances in green tea leaves. J Agric Food Chem 47:5064–5067
Wang H, You X, Chen Z (2002) In: Zhen Y (ed) Tea-Bioactivity and therapeutic potential, CRC Press, Boca Raton, FL
Özdemir F, Topuz A, Erbaş M (1999) Mineral contents of different classes of black tea produced by Orthodox and Caykur methods. Turk J Agric For 23:809–815
Yang XR, Ye CX, Xu JK, Jiang YM (2007) Simultaneous analysis of purine alkaloids and catechins in Camellia sinensis, Camellia ptilophylla and Camellia assamica var. Kucha by HPLC. Food Chem 100:1132–1136
Erol NT, Sari F, Velioglu YS (2009) Polyphenols, alkaloids and antioxidant activity of different grades Turkish black tea. Gida 35:161–168
Özdemir F, Gökalp HY, Nas S (1993) Effects of shooting period, times within shooting periods and processing systems on the extract, caffeine and crude fiber contents of black tea. Z Lebensm Unters For 197:358–362
Zuo Y, Chen H, Deng Y (2002) Simultaneous determination of catechins, caffeine and gallic acids in green, oolong, black and pu-erh teas using HPLC with a photodiode array detector. Talanta 57:307–316
Sharma V, Gulati A, Ravindranath SD, Kumar V (2005) A simple and convenient method for analysis of tea biochemicals by reverse phase HPLC. J Food Comput Anal 18:583–594
Khanchi AR, Mahani MK, Hajihosseini M, Maragheh MG, Chaloosi M, Bani F (2007) Simultaneous spectrophotometric determination of caffeine and theobromine in Iranian tea by artificial neural networks and its comparison with PLS. Food Chem 103:1062–1068
Suteerapataranon S, Butsoongnern J, Punturat P, Jorpalit W, Thanomsilp C (2009) Caffeine in Chiang Rai tea infusions: effects of tea variety, type, leaf form, and infusion conditions. Food Chem 114:1335–1338
Wang Y, Yang X, Li K, Li C, Li L, Li J, Huang H, He Y, Ye C, Song X (2010) Simultaneous determination of theanine, gallic acid, purine alkaloids, catechins, and theaflavins in black tea using HPLC. Int J Food Sci Tech 45:1263–1269
Acknowledgments
This work is a part of Ferda Sari’s Ph.D. thesis. The authors thank TÜBİTAK (The Scientific & Technological Research Council of Turkey) for financial support (Project No. 108 O 576), and Kubilay Türkyılmaz and Nesrin Tekiner (CAY-KUR, Turkish General Directorate of Tea Establishments) for their assistance on collecting samples from tea factories.
Conflict of interest
None.
Compliance with Ethics Requirements
This article does not contain any studies with human or animal subjects.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sari, F., Velioglu, Y.S. Changes in theanine and caffeine contents of black tea with different rolling methods and processing stages. Eur Food Res Technol 237, 229–236 (2013). https://doi.org/10.1007/s00217-013-1984-z
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00217-013-1984-z