Titre du document / Document title

Catechins depletion patterns in relation to theaflavin and thearubigins formation

Auteur(s) / Author(s)

NGURE Francis Muigai ⁽¹⁾ ; WANYOKO John K. ⁽²⁾ ; MAHUNGU Symon M. ⁽¹⁾ ; SHITANDI Anakalo A. ⁽¹⁾ ;

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

⁽¹⁾ Department of food science, Egerton University, Njoro, P.O. Box 536, Egerton, KENYA
⁽²⁾ Tea Research Foundation of Kenya, P.O. Box 820, Kericho, KENYA

Résumé / Abstract

The determination of the depletion pattern of catechins in black tea processing is important in achieving optimum tea quality. This study investigated catechins (unoxidised di- and trihydroxylated) depletion patterns in relation to theaflavin and thearubigin formation. It was during the process of green leaf fermentation at selected temperature and time combinations. The tea leaves were obtained from three clones (6/8, 303/577 and 311/287) within the Tea Research Foundation of Kenya. The results were showed that unequal depletion rates of di- and trihydroxylated catechins led to a decline in total theaflavin and an increase in thearubigins levels. An equitable decline in both groups of catechins corresponded to a subsequent rise in theaflavins content. The decline in the catechins levels was much faster at higher temperatures resulting in a shorter fermentation time to achieve a peak of the theaflavins content. Clone 311/287 had the highest mean theaflavins content (26.99 μmol/g) and the least mean percent thearubigins (15.02%) level. Theaflavins content correlated positively with liquor brightness determined by a spectrophotometer and tea tasters (r = 0.7221, p <.0001). The thearubigins content was however found to relate negatively with liquor brightness. It was concluded that the experimental conditions tested form a good basis for clonal specific processing conditions that can be utilised in manufacturing quality black tea.

Revue / Journal Title

Food chemistry    ISSN  0308-8146   CODEN FOCHDJ 

Source / Source

2009, vol. 115, n^o1, pp. 8-14 [7 page(s) (article)] (1/4 p.)

Langue / Language

Anglais

Editeur / Publisher

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

Mots-clés anglais / English Keywords

Polyphenol

;

Pigments

;

Flavonoid

;

Tea

;

Theaflavin

;

Catechin

;

Flavanol

;

Mots-clés français / French Keywords

Polyphénol

;

Pigment

;

Flavonoïde

;

Thé

;

Théaflavine

;

Catéchine

;

Flavanol

;

Mots-clés espagnols / Spanish Keywords

Polifenol

;

Pigmento

;

Flavonoide

;

Té

;

Teaflavina

;

Catequina

;

Flavanol

;

Mots-clés d'auteur / Author Keywords

Clonal tea

;

Di- and trihydroxylated catechins

;

Theaflavins

;

Thearubigins

;

Localisation / Location

INIST-CNRS, Cote INIST : 17810, 35400018705807.0020