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Titre du document / Document title

Kinetics and equilibria of tea infusion. IX: The rates and temperature coefficients of caffeine extraction from green Chun Mee and black Assam Bukial teas

Auteur(s) / Author(s)

SPIRO M. ; JAGANYI D. ; BROOM M. C. ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

Imperial coll. sci. technology medicine, dep. chemistry, London SW7 2AY, ROYAUME-UNI

Résumé / Abstract

The rates of infusion of caffeine from green Chun Mee tea and from black orthodox Assam Bukial tea, using leaf of size 1.70-2.00 mm, were measured over a range of temperatures. The activation energies were found to be 62 and 40 kJ mol-1, respectively. The diffusion coefficients of caffeine within the tea leaves, calculated from the first-order rate constants at 80oC, were respectively 96 and 132 times smaller than the diffusion coefficient of caffeine in water at 80oC. These results show that diffusion of caffeine through the leaf is a greatly hindered process

Revue / Journal Title

Food chemistry    ISSN  0308-8146   CODEN FOCHDJ 

Source / Source

1992, vol. 45, no5, pp. 333-335 (7 ref.)

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Kidlington, ROYAUME-UNI  (1976) (Revue)

Mots-clés anglais / English Keywords

Tea

;

Infusion

;

Extraction

;

Kinetics

;

Caffeine

;

Mots-clés français / French Keywords

Thé

;

Infusion

;

Extraction

;

Cinétique

;

Caféine

;

Mots-clés espagnols / Spanish Keywords

;

Infusión

;

Extracción

;

Cinética

;

Localisation / Location

INIST-CNRS, Cote INIST : 17810, 35400003068229.0050

Nº notice refdoc (ud4) : 5574362



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