Performance evaluation of a chimney solar dryer for Habanero pepper (Capsicum chinense Jacq)

Abstract

Habanero pepper (Capsicum chinense Jacq) is cultivated predominantly in the Volta, Central and Ashanti regions of Ghana and commonly utilised in most local dishes. Majority of consumers prefer the dried form of the pepper. However, farmers are usually confronted with the challenge of obtaining low-cost, locally fabricated dryers that can efficiently dry agricultural produce while mitigating quality and safety concerns. In this study, a model of the newly designed chimney solar dryer by the Horticulture Innovation laboratory of the University of California, Davis, in the United States of America, for crop drying in developing countries was constructed and its performance evaluated in comparison to open sun drying. Habanero pepper was used as a test crop. Subsequently, microbial analysis was carried out on the dried products. The mean chimney dryer temperature (46.4°C) was found to be higher than the ambient temperature (36.2°C). The relative humidity in the chimney solar dryer and the ambient ranged from 25% to 68% and 26% to 83%, respectively. During the period of the drying experiment, mean maximum solar insolation of 823.18 W/m2 was recorded at 11.30 am while a mean minimum solar insolation of 107.84 W/m2 was recorded at 4.30 pm. The solar-dried and sun-dried pepper recorded total drying time of 35 h and 55 h respectively. The mean performance coefficient of the chimney solar dryer was determined to be 1.21 which gives an indication of a high dryer performance. The mean yeasts and moulds counts of the solar-dried and sun-dried pepper were 4.30 x 104 cfu/g and 2.52 x 105 cfu/g, respectively. Also, the Staphylococcus aureus and Escherichia coli counts were <10 cfu/g for samples in both drying media. In conclusion, the chimney solar dryer was found to have performed better than open sun drying with shorter drying time and better quality of the dried product