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 80^oC, were respectively 96 and 132 times smaller than the diffusion coefficient of caffeine in water at 80^oC. 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, n^o5, 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

Té

;

Infusión

;

Extracción

;

Cinética

;

Localisation / Location

INIST-CNRS, Cote INIST : 17810, 35400003068229.0050