Clonal plain black tea quality parameters responses of hard physical withered leaf to rehydration and fermentation durations

Abstract

Hard physical withers in tea processing result in reduced plain black tea quality parameters, but improve
flavoury black tea quality. Chemical withers with minimal moisture loss improve plain black tea quality parameters.
But chemical withered leaf is normally bulky and not flaccid thus reducing maceration rates. Hard physical withers
reduce polyphenol oxidase activity, thereby impairing ability of the leaf to produce high amounts of plain black tea
quality parameters, especially theaflavins and thearubigins. This study examined if rehydrating hard physical withered
leaf could improve its fermentability and influence fermentation duration, and if such changes are cultivar dependent.
Rehydrating hard physical withered leaf increased (p≤0.05) total theaflavins, thearubigins, brightness, total colour and
sensory evaluation of resultant black teas. The patterns of the responses did not vary with cultivars or fermentation
duration. The theaflavins and brightness declined (p≤0.05) while thearubigins and total colour increased (p≤0.05) with
long fermentation durations irrespective of withering regime. Results demonstrate that problems of plain black tea quality
reduction due to hard physical withers can be partially reversed by rehydration to chemical wither standard, but the
withering regime does not influence when maximum plain black tea quality parameters are produced.