Solar drying of herbal wealth in Eastern Himalaya: a review

Solar dryers have proven to be one of the best environmentally friendly approaches for drying purpose of medicinal plants and agricultural crops. Use of solar radiations in drying purpose of plant parts has proven economically as well as environmentally responsible and sensible application. Plants are the treasure of nature with hidden medicinal properties to treat diseases. Plant material should be processed properly for extraction of medicinal molecules in terms drying to decrease the manufacturing loss and to increase the standard of product. Cognizances of ethnobotanical knowledge on plant wealth are extremely beneficial in utilization and exploration of natural resources. Conventionally, low drying temperatures between 30-40°C, with economically beneficial techniques are required to protect sensitive active ingredients. Therefore, the objective of reviewing research in medicinal plant drying is to find out optimum drying temperature and best solar dryer for drying purposes of plant parts in terms of quality and drying costs. Rendering to human requisites, solar appliances for drying purposes will be used as the best alternative to standard sun-drying technique. This review focused on effective drying is demand of present scenario for the application of heat trapped from solar radiations for drying purpose in order to maintain the quality and active ingredients of plants. Conventionally, low drying temperatures between 30-40°C, with economically beneficial techniques are required to protect sensitive active ingredients. Indirect type of solar dryers can easily fulfill all the terms for dying plant products in terms of standard and yield.