Quality enhancement of dehydrated products through the modification of solar tunnel dryer for continuous operation in rural communities

Solar dehydration of food crops is an important area for the economic development of rural communities in Sri Lanka. However, the economic gain is marginal because of inadequate product quality and quantities achievable with present drying methods. Present solar dryers need a few days of drying to reduce the moisture content of perishables to safe levels causing unfavorable product qualities. In this study a solar tunnel dryer was modified by the attachment of a supplementary biomass heating source for day and night operation to shorten the drying duration and to preserve the product quality. The dryer was tested in five different locations in Sri Lanka using local perishables and spices with the participation of local communities. The dryer was well received by the rural sector as an alternative to traditional sun drying. The dehydrated products produced were of acceptable quality in terms of sensory parameters and market acceptability.