Pakistan is producing about 6 million tonnes of fresh fruit annually. This commodity is highly perishable in nature as it has an inherent tendency to spoilage due to physiological reasons, disease and pest infestation. Due to non-availability of post-harvest preservation technologies, about 30% of this produce is wasted from orchard gate till it reaches the consumer. The financial implications of post-harvest losses in fruit by applying percentage losses on their market value were estimated to be about Rs 5.0 billion per annum. To extend the storage (shelf) life of perishable fruit, and to increase their commercial value, an innovative drying technology was needed by the farmers.
Technology Development, Development and Demonstration
To address this issue, Farm Machinery Institute, NARC, Islamabad has designed and developed a solar-cum-gas fired fruit dryer. This consists of eight flat-plate solar collectors, an axial flow fan, a drying chamber and a supplementary source of heating i.e. gas. Initially, the performance of this dryer was evaluated at Nalkot, Swat, where the persimmon were dried using this dryer. The solar dryer was capable to process about 1 to 1.5 tonnes of fresh persimmon in a month. Later, the gas firing system was added to increase the drying capacity of this dryer. A unit of solar-cum-gas fired dryer was installed and evaluated at Dhaki, D.I. Khan in August 2003. Experimental results indicate that the dryer is capable to dry about 544 kg of fresh dates within 5 days. The seasonal drying capacity of the dryer was predicted about 4 tonns. The economic analysis revealed that one may earn Rs 72,100/- per season by using the solar-cum-gas fired dates dryer. It is a small scale on-farm dates drying technology, and is well suited to produce quality dried fruit in order to present them into international market. PARC has signed an agreement with a local manufacturer to commercialize this technology at large scale.
Ahmad, M., and A. S. Khan. (1997). Design and construction of a solar grain and fruit drying system. Agricultural Mechanization in Asia, Africa, and Latin America Vol. 28(4): 62-66, Tokyo, Japan.
Ahmad, M. (2001). Performance of solar fruit drying system. Journal of Engineering and Applied Sciences. Vol. 20(2): 45-52.