Umudike Journal of Engineering and Technology

Huge losses of vegetables due to inadequate processing systems are obvious among farmers in South-Eastern Nigeria. In order to abate this problem a medium scale direct mode passive solar dryer of capacity 50 kg of sliced okra was developed and evaluated at Michael Okpara University of Agriculture, Umudike between July and October 2014. A cabinet solar dryer housed with plastic corrugated transparent material was constructed for this study. Fresh okra sliced to a thickness of 15 mm was spread in single layer to dry in a solar dryer and in open sun as a control. Results obtained showed that the solar dryer raised the drying air temperature 31.82 ^oC to 45.54^oC, which was 30.11 percent above the average ambient air temperature during the drying period. The ambient relative humidity was reduced from 73 % to 23.5 % in the solar dryer drying chamber where the sliced product was loaded. The moisture content of sliced okra reduced from 88% wet basis to 5% wet basis at 28 hours solar dryer effective drying time. The dryer achieved 40.1%  drying efficiency based on the effective drying time. Sliced okra samples dried in the solar dryer were of high qualities when compared with the sample dried in open sun.