L-theanine—a unique amino acid of green tea and its relaxation effect in humans

Juneja, Lekh Raj; Chu, Djong-Chi; Ōkubo, Tsutomu; Nagato, Yukiko; Yokogoshi, Hidehiko

doi:10.1016/s0924-2244(99)00044-8

Cited by 300 publications

(240 citation statements)

References 16 publications

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“…It is considered the main component responsible for the taste of green tea, which in Japanese is called umami. It has been shown that theanine not only gives flavor and taste to green tea but also produces a noticeable relaxation effect in human beings [6].…”

Section: Introductionmentioning

confidence: 99%

Isotachophoretic determination of theanine

Kvasnička

Krátká

2006

Open Chemistry

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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.

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Section: Introductionmentioning

confidence: 99%

Isotachophoretic determination of theanine

Kvasnička

Krátká

2006

Open Chemistry

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“…2) Theanine elicits umami (flavor potential) and a sweet taste of green tea. 3) Besides the graceful taste, theanine has been a focus of attention due to its many favorable physiological functions in several animals [4][5][6][7][8] including human beings, 9) which suggests increasing demand for theanine not only as a taste-enhancing additive but also as a supplement to improve and/or maintain human health.…”

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confidence: 99%

Cloning and Expression ofMethylovorus maysNo. 9 Gene Encoding γ-Glutamylmethylamide Synthetase: An Enzyme Usable in Theanine Formation by Coupling with the Alcoholic Fermentation System of Baker’s Yeast

Yamamoto

Wakayama

Tachiki

2008

Bioscience, Biotechnology, and Biochemistry

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“…Theanine (-glutamylethylamide) is an unique amino acid that renders the gracefully sweet taste of Japanese tea, 1) and the quality of tealeaves is influenced by its contents. Recently, the demand for theanine has become great not only as a food-additive to enhance flavor, but also as a supplement to improve and/or maintain human health because of its favorable physiological functions toward several animals, including human beings.…”

mentioning

confidence: 99%