Improvement of the Bitterness and Astringency of Green Tea by Sub-Critical Water Extraction

Green tea is known for its high content of functional catechins and is commonly consumed for its health-promoting effects. However, green tea catechins are highly bitter and astringent, and thus the development of products that can be consumed regularly is necessary for their efficient, routine intake. The aim of this study was to use sub-critical water extraction (SWE) to produce a green tea extract both less bitter and less astringent than typical green tea. Results from chemical evaluation using a taste sensor analyzer indicated that SWE reduced bitterness, astringency and unpleasant taste while it retained the original fragrance in the green tea extract. Furthermore, the SWE-produced extract had higher amounts of arginine and water-soluble pectin, which are thought to mask the bitterness and astringency of green tea.

[1]  S. Adachi,et al.  Properties of Rice Straw Extract after Subcritical Water Treatment , 2012, Bioscience, biotechnology, and biochemistry.

[2]  Masashi Omori,et al.  Evaluation of the Taste of Tea with Different Degrees of Fermentation Using a Taste Sensing System , 2011 .

[3]  M. Narukawa,et al.  Taste characterisation of green tea catechins , 2010 .

[4]  H. Ikezaki,et al.  Beta-cyclodextrin/surface plasmon resonance detection system for sensing bitter-astringent taste intensity of green tea catechins. , 2010, Journal of agricultural and food chemistry.

[5]  A. Morita,et al.  Sub-Critical Water Extraction of Residual Green Tea to Produce a Roasted Green Tea-Like Extract , 2010, Bioscience, biotechnology, and biochemistry.

[6]  Takanobu Takihara,et al.  HPLC behavior of tea catechins on cyclodextrin-bonded silica column , 2009 .

[7]  S. Adachi,et al.  Production of Emulsifying and Antioxidative Substances from Defatted Rice Bran by Two-step Subcritical Water Treatment , 2009 .

[8]  S. Adachi,et al.  Extraction of defatted rice bran by subcritical water treatment , 2008 .

[9]  Shin'ichi Suzuki,et al.  Subcritical Water Extraction of Barley to Produce a Functional Drink , 2008, Bioscience, biotechnology, and biochemistry.

[10]  Takanobu Takihara,et al.  Effect of Cyclodextrins on the Thermal Epimerization of Tea Catechins , 2008 .

[11]  Shunsuke Suzuki,et al.  Antioxidant compounds from Eucalyptus grandis biomass by subcritical liquid water extraction , 2008, Journal of Wood Science.

[12]  S. Adachi,et al.  Production of functional substances from black rice bran by its treatment in subcritical water , 2007 .

[13]  S. Adachi,et al.  Properties of extracts from defatted rice bran by its subcritical water treatment. , 2007, Journal of agricultural and food chemistry.

[14]  P. Roach,et al.  A green tea extract lowers plasma cholesterol by inhibiting cholesterol synthesis and upregulating the LDL receptor in the cholesterol-fed rabbit. , 2007, Atherosclerosis.

[15]  P. Pristovsek,et al.  Green tea catechins inhibit bacterial DNA gyrase by interaction with its ATP binding site. , 2007, Journal of medicinal chemistry.

[16]  B. Mackey,et al.  Structure-activity relationships of tea compounds against human cancer cells. , 2007, Journal of agricultural and food chemistry.

[17]  Nobuyuki Hayashi,et al.  Techniques for Universal Evaluation of Astringency of Green Tea Infusion by the Use of a Taste Sensor System , 2006, Bioscience, biotechnology, and biochemistry.

[18]  E. Ibáñez,et al.  Sub- and supercritical fluid extraction of functional ingredients from different natural sources: Plants, food-by-products, algae and microalgae: A review , 2006 .

[19]  H. Nagai,et al.  Changes in O-methylated Catechin and Chemical Component Contents of 'Benifuuki' Green Tea (Camellia sinensis L.) Beverage under Various Extraction Conditions , 2005 .

[20]  Ryuichi Matsuno,et al.  Degradation kinetics of monosaccharides in subcritical water , 2005 .

[21]  N. Hayashi,et al.  Reduction of Catechin Astringency by the Complexation of Gallate-Type Catechins with Pectin , 2005, Bioscience, biotechnology, and biochemistry.

[22]  Takahiro Uchida,et al.  The combination effect of L-arginine and NaCl on bitterness suppression of amino acid solutions. , 2004, Chemical & pharmaceutical bulletin.

[23]  T. Fujimori,et al.  Evaluation of Japanese Green Tea Extract Using GC/O with Original Aroma Simultaneously Input to the Sniffing Port Method (OASIS) , 2003 .

[24]  Yu Huang,et al.  Degradation of green tea catechins in tea drinks. , 2001, Journal of agricultural and food chemistry.

[25]  T. Yokozawa,et al.  Antioxidative activity of green tea treated with radical initiator 2, 2'-azobis(2-amidinopropane) dihydrochloride. , 2000, Journal of agricultural and food chemistry.

[26]  T. Goto,et al.  Efficiency of the extraction of catechins from green tea , 1999 .

[27]  M. Ono,et al.  Reduction of persimmon astringency by complex formation between pectin and tannins , 1997 .

[28]  Yuko Yoshida,et al.  Simultaneous analysis of individual catechins and caffeine in green tea , 1996 .

[29]  S. Miura,et al.  The inhibitory effects of tea polyphenols (flavan-3-ol derivatives) on Cu2+ mediated oxidative modification of low density lipoprotein. , 1994, Biological & pharmaceutical bulletin.

[30]  K. Hara,et al.  Studies on Preservation of Constituents in Canned Drinks. Part II. Effects of pH and Temperature on Reaction Kinetics of Catechins in Green Tea Infusion. , 1993 .

[31]  K. Ina,et al.  Comparison of Caffeine and Catechin Components in Infusion of Various Tea (Green, Oolong and Black Tea) and Tea Drinks , 1987 .

[32]  H. Kato,et al.  Interaction between Polyphenols of Tea and Amino Acids during Heating , 1984 .

[33]  M. Nakagawa,et al.  Changes in Contents of Some Ingredients During Heating of Green Tea , 1981 .

[34]  M. Nakagawa,et al.  Relation between Infusing Condition of Green Tea and Soluble Component , 1972 .

[35]  筬島 豊,et al.  Colorimetric estimation of pectin , 1965 .

[36]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.