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2006 | 4 | 2 | 216-222
Tytuł artykułu

Isotachophoretic determination of theanine

Treść / Zawartość
Warianty tytułu
Języki publikacji
EN
Abstrakty
EN
Free amino acids, the key quality components of tea, are contained in higher amounts in higher grade teas. Among free amino acids in tea, the content of theanine, which is the amino acid of the highest amount, shows high correlation to the price of green tea. A capillary isotachophoresis (CITP) method was developed for the analysis of L-theanine in tea and food supplements. The optimized electrolyte system was following: 0.01 mol/l HCl + 0.02 mol/l TRIS + 0.05% HEC (leading electrolyte), 0.01 mol/L-valine + barium hydroxide to pH 10 (terminating electrolyte). Good separation of L-theanine from other components of sample was achieved within 20 min. Method characteristics, i.e., linearity (0–200 mg/l), accuracy (99 ± 2 %), intra-assay (1.5 %), quantification limit (2 mg/l), and detection limit (0.7 mg/l) were determined. Sufficient sensitivity, low labouriousness (extraction only) and low running cost are important attributes of this method. It was proved that the developed method is suitable for the routine analysis of L-theanine in green tea and food supplements containing green tea extract.
Wydawca

Czasopismo
Rocznik
Tom
4
Numer
2
Strony
216-222
Opis fizyczny
Daty
wydano
2006-06-01
online
2006-06-01
Twórcy
  • Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague Technická 1905/5, Prague 6, Czechoslovakia, kvasnicf@vscht.cz
  • Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague Technická 1905/5, Prague 6, Czechoslovakia
Bibliografia
  • [1] T. Mukai, H. Horie and T. Goto: “Differences in Free Amino Acids and Total Nitrogen Contents Among Various Prices of Green Tea”, Tea Res. J., Vol. 76, (1992), pp. 45–50.
  • [2] Research Group of Green Tea Brewing Brewing Condition of Tasty Cup of Green Tea: J. Tea Res., Vol. 28, (1973), pp. 58–66.
  • [3] Y. Sakato: “The Chemical Constituents of Tea. III. A New Amide Theanine”, J. Agri. Chem. Soc., Vol. 23, (1949), pp. 262–267.
  • [4] Y. Sadzuka, Y. Yamashita, T. Sugiyama and T. Sonobe: “Effect of dihydrokainate on the antitumor activity of doxorubicin”, Cancer Lett., Vol. 179, (2002), pp. 157–163. http://dx.doi.org/10.1016/S0304-3835(02)00012-5[Crossref]
  • [5] T. Kakuda, A. Nozawa and A. Sugimoto: “Inhibition by Theanine of Binding of [3H]AMPA, [3H]Kainate, and [3H]MDL 105,519 to Glutamate Receptors”, Biosci. Biotech. Biochem., Vol. 66, (2002), pp. 2683–2686. http://dx.doi.org/10.1271/bbb.66.2683[Crossref]
  • [6] L.R. Juneja, D.C. Chu, T. Tsutomu Okubo, Y. Nagato and H. Yokogoshi: “L-theanine - a unique amino acid of green tea and its relaxation effect in humans,” Trends Food Sci. Tech., Vol. 10, (1999), pp. 199–204.
  • [7] K.H. Ekborg-Ott, A. Taylor and D.W. Armostrong: “Varietal Differences in the Total and Enantiomeric Composition of Theanine in Tea”, J. Agric. Food Chem., Vol. 45, (1997), pp. 353–363. http://dx.doi.org/10.1021/jf960432m[Crossref]
  • [8] Y. Ding, H. Yu and S. Mou: “Direct determination of free amino acids and sugars in green tea by anion-exchange chromatography with integrated pulsed amperometric detection”, J. Chromatogr. A, Vol. 982, (2002), pp. 237–244. http://dx.doi.org/10.1016/S0021-9673(02)01650-3[Crossref]
  • [9] C.N. Chen, C.M. Liang, J.R. Lai, Y.J. Tsai, J.S. Tsay and J.K. Lin: “Capillary Electrophoretic Determination of Theanine, Caffeine, and Catechins in Fresh Tea Leaves and Oolong Tea and Their Effects on Rat Neurosphere Adhesion and Migration”, J. Agric. Food Chem., Vol. 51, (2003), pp. 7495–7503.
  • [10] P. Li, X.C. Wan, Z.Z. Zhang, J. Li and Z.J. Shen: “A novel assay method for theanine synthetase activity by capillary electrophoresis”, J. Chromatogr. B Vol. 819, (2005), pp. 81–84.
  • [11] M. Kato, Y. Gyoten, K. Sakai-Kato and T. Toyo’oka: “Rapid analysis of amino acids in Japanese green tea by microchip electrophoresis using plastic microchip and fluorescence detection”, J. Chromatogr. A, Vol. 1013, (2003), pp. 183–189. http://dx.doi.org/10.1016/S0021-9673(03)01037-9[Crossref]
Typ dokumentu
Bibliografia
Identyfikatory
Identyfikator YADDA
bwmeta1.element.-psjd-doi-10_2478_s11532-006-0014-4
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