Scientific and Technological Aspects of Tea Drying and Withering: A Review
Keywords:Tea, withering, trough, theaflavins, thearubigins, theanine
Withering is the preliminary stage of tea processing where tea leaves undergo physical and chemical transformation for the next phases. In tea processing, the moisture content in the tea leaves matters a great deal. Withering is a partial drying process for removing superficial and core moisture of tea leaves. Drying removes moisture by evaporation from the fermented leaf. The withering trough is an indispensable organ in tea withering and research has been done to enhance and modify the design of the trough. During withering various biochemical changes take place. Like drying, withering is also an energy intensive process. However, less concentration has been given to the energy aspect of withering. It is required to make readiness among tea producers about utilizing sustainable power source for better financial returns. This paper gives a wide survey on the different scientific and technological aspects of tea withering and drying.