Flavanol composition and caffeine content of green leaf as quality potential indicators of Kenyan black teas

Journal of the Science of Food and Agriculture

Volumn 74, Issue 2, 1997, Pages 209-215

  Obanda, Martin ^a   Owuor, P Okinda ^a   Taylor, Sarah J ^b  

^a Tea Research Foundation Kenya   (Kenya)

^b UNIVERSITY OF GREENWICH   (United Kingdom)

Author keywords

( )Epicatechin; ( )Epicatechin gallate; ( )Epigallocatechin gallate; Astringency; Brightness; Caffeine; Flavanols; Theaflavin; Thearubigin

Indexed keywords

EID: 0030847192     PISSN: 00225142     EISSN: None     Source Type: Journal    
DOI: 10.1002/(SICI)1097-0010(199706)74:2<209::AID-JSFA789>3.0.CO;2-4     Document Type: Article

References (30)

1. Berkowitz J E, Coggon P, Sanderson G W 1971 Formation of epitheaflavin and its transformation to thearubigins during fermentation. Phytochemistry 10 2271-2278.
2. Bhatia I S 1961 Composition of leaf in relation to liquor characters of made tea. Two and a Bud 8 (3) 11-14.
3. Bhatia I S 1963 Chemical aspects of green leaf processing. Two and a Bud 10 (2) 28-33.
4. Brown A G, Falsaw C P, Haslam E, Holmes A, Ollis W D 1966 The constitution of theaflavins. Tetrahedron Lett 11 1193-1204.
5. Brown A G, Eyton W B, Holmes A, Ollis W D 1969 The identification of thearubigins as polymeric proanthocyanidins. Phytochemistry 8 2333-2340.
6. Collier P D, Mallows R, Thomas P E 1972 Interactions between theaflavins and caffeine. Proc Phytochem Soc II 867.
7. Deb S B, Ullah M R 1968 The role of theaflavins (TF) and thearubigins (TR) in the evaluation of black tea. Two and a Bud 15 101-102.
8. Dev Choudhury M N, Goswami M R 1983 A rapid method for determination of total polyphenolic matters in tea (Camellia sinensis L). Two and a Bud 30 59-61.
9. Ding Z, Kuhr S, Engelhardt U H 1992 Influence of catechins and theaflavins on the astringent taste of black tea brew. Z Lebensm Unters Forsch 195 108-111.
10. Ellis R T, Cloughley J B 1981 The importance of theaflavin (TF) in tea liquors. Int Tea J 2 7-8.
11. Hilton P J 1973 Tea. In: Encyclopedia of Industrial Chemical Analysis (Vol 18), ed Snell F D & Ettre L S. John Wiley, New York, USA, pp 455-516.
12. Hilton P J, Palmer-Jones R 1973 Relationship between flavanols composition of fresh tea shoots and the theaflavins content of manufactured tea. J Sci Food Agric 24 813-818.
13. Kuhr S, Engelhardt U H 1991 Determination of flavanols, theogallin, gallic acid and caffeine in tea using HPLC. Z Lebensm Unters Forsch 192 526-529.
14. McDowell I, Bailey R G, Howard G 1990 Flavonol glycosides in black tea. J Sci Food Agric 53 411-414.
15. Millin D J, Crispin D J, Swaine D 1969 Non-volatile components of black tea and their contribution to the character of the beverage. J Agric Food Chem 17 171-122.
16. Obanda M, Owuor P O, Njugnua C K 1992 The impact of clonal variation of total polyphenols content and polyphenol oxidase activity of fresh tea shoots on plain black tea quality parameters. Tea 13 (2) 129-133.
17. Owuor P O 1992 Changes in the quality parameters of commercial black seedling tea due to the time of the year in the Eastern highlands of Kenya. Food Chem 45 119-124.
18. Owuor P O 1994 Clonal variations in the response of black tea quality parameters to time of the year in Western Kenya highlands. Trop Sci 34 225-230.
19. Owuor P O, Chavanji A M 1986 Caffeine contents of clonal tea; Seasonal variations and effects of plucking standards under Kenyan conditions. Food Chem 20 225-233.
20. Owuor P O, Obanda M 1995 Clonal variation in the individual theaflavin levels and their impact on astringency and sensory evaluations. Food Chem 54 273-277.
21. Owuor P O, Reeves S G, Wanyoko J K 1986a Correlation of theaflavins content and valuations of Kenyan black teas. J Sci Food Agric 37 507-513.
22. Owuor P O, Tsushida T, Horita H, Murai T 1986b Comparison of chemical composition of black teas from main tea producing parts of the world. Tea 7 71-78.
23. Roberts E A H 1962 Economic importance of flavonoid substances in tea fermentation. In: The Chemistry of Flavonoid Compounds, ed Geissman T A. Pergamon Press, London, UK, pp 468-500.
24. Roberts E A H, Smith R F 1963 Phenolic substances of manufactured tea. II. Spectrophotometric evaluation of tea liquors. J Sci Food Agric 14 689-700.
25. Robertson A 1983 Effects of physical and chemical conditions on the in vitro oxidation of tea catechins. Phytochemistry 22 889-896.
26. Sanderson G W, Berkowitz J E, Co H, Graham H N 1972 Biochemistry of tea fermentation: Products of the oxidation of tea flavanols in model tea fermentation system. J Food Sci 37 399-404.
27. Sanderson G W, Ranadive A S, Eisenberg L S, Farell F J, Simons R, Manley C H, Coggon P 1976 Contribution of phenolic compounds to the taste of tea. 'Phenolic sulphur and nitrogen in foods and flavours symposium'. Am Chem Soc Symp Ser 26 14-46.
28. Smith R F 1968 Studies on the fermentation and composition of 'cream' in tea infusions. J Sci Food Agric 19 530-534.
29. Takino Y, Imagawa H, Harikawa H, Tanaka A 1964 Studies on the mechanism of the oxidation of tea catechins. Part III. Formation of a reddish orange pigment and its spectral relationship to some benzotropolone derivatives. Agric Biol Chem 28 (1) 64-71.
30. Taylor S, Baker D, Owuor P O, Orchard J E, Othieno C O, Gay C 1992 A model for predicting black tea quality from carotenoid and chlorophylls composition of fresh green tea leaf. J Sci Food Agric 58 185-191.