Evaluation and demonstration of direct solar potato dryer
Livestock Research for Rural Development
Bahir Dar Agricultural Mechanization and Food Science Research Centre, P.O. Box 133, Bahir Dar, Ethiopia; Food, Medicine and Health Care Administration and Control Authority of Ethiopia, P.O. Box 5681, Addis Ababa, Ethiopia
This study was conducted to evaluate the performance of two models of direct solar potato dryers and to demonstrate to farmers around potato producing areas, in Amhara Regional State. Wooden box dryer and Pyramid shape dryer models were evaluated. Dryers were compared with open sun drying methods. Temperature, relative humidity as well as the rate of moisture removal as expressed by loss-in-weight were recorded and analyzed. Results showed that on the average there was a 10-20 °C temperature difference between ambient condition and the drying chambers. Besides, the weight of sliced potato which was initially 0.90 kg was reduced to about 0.19 kg within two days. This showed an overall reduction in drying time by 2-3 hours compared to open sun drying. This result, however, was not perceived to be large enough under existing testing condition. But considering other benefits of the driers like protecting the drying material against contaminants, dust, and insects resulting in better quality product, this result is acceptable. On the other hand, comparing the performances of the two driers, Pyramid dryer was found better in creating more conducive drying environment with optimal temperature and lower relative humidity. Moreover, considering manufacturing costs, simplicity in design to manufacture in rural area from almost any kind of available building materials by locally available workmen, Pyramid dryer is better than Box dryer. Demonstration and practical training on the use of solar dryers and methods of food preparation out of the dried potato slices was provided for a group of farmers. Participant farmers actively participated in the potato menu preparation and informal sensory evaluation. They have showed high interest in diversified potato utilization as it enhances their feeding habits. This dryer was found suitable for drying small quantities (10-15 kg) of agricultural products which suits best for household level. Therefore, Pyramid (pyramid shape) dryer models should be recommended for further promotion.