Changes in Tea Shoots and Made Tea Due to or During Withering: A Review

Quality of made tea depends not only on chemical composition of green tea shoots, but much on physical and biochemical changes that take place in the shoots during processing. Changes taking place in each of the four stages of black tea manufacture, namely, withering, distortion (rolling or CTC), polyphenol oxidation (fermentation) and drying, warrant attention, especially for control of the manufacturing process at different stages to achieve desired quality in made tea. As withering is the first and preparatory stage of black tea manufacture, it may affect the changes that take place in the subsequent stages and determine largely the quality of final product, i.e., made tea. Literature on changes of tea shoots occurring due to or during withering and effects of these changes on made tea has been reviewed in this paper.