The change ability of the teaflavans and tearubigines in the production of georgian black tea
Author(s): Revazi G. Melkadze
Abstract: The nature of transformation of teaflavans and tearubigins of Georgian black tea during fermentation was investigated. To evaluate the control of the fermentation process the methods of depth of oxidation of phenol compounds and the index of teaflavans / tearubigins are considered. It is shown that in the depth of oxidation of phenol substances the maxima of intensity of the color of infusion observed in the fermentation of semi-manufactured goods at fermentation of the leaf during 150-180 min - for the first fraction of the first twisting and 180-210 min - for the third fraction of the third twisting. With increasing duration of fermentation increases the content of teaflavans and tearubigins and reaches maximum over 3 hours. The ratio of absorbance of optical density E380 / E460 at a wave length of 380 nm for teaflavans and tearubigins are respectively 1.7-2.3 and for the first fraction - 1,9-5,5 - for the 1st fraction of the first twisting and 1.7-2.5 and 2,8-8,0 â€“ for the third fraction to the third twisting. The optimum duration of fermentation corresponding to the maximum percentages of teaflavans and tearubigins and minimum values of their relations, respectively, 1 :( 8,38-8,87) - for the first fraction and 1 :( 7,90-8,04) - for the third fraction . Both methods of control of the fermentation process of tea considered by us can be a supplement to the organoleptic methods of estimation of black tea.