Evaluation of Different Sun Drying Methods in Chilli

Dorji Gyeltshen & Sonam Tashi


Chilli is one of the main cash crops for many farmers in Bhutan,including farmers of Kazhi geog under Wangduephodrang dzongkhag. It is either sold or bartered. However, during the peak chilli production season the price drastically drops forcing farmers to resort to drying. Dried chillies during lean season command a very high price. However, drying is challenging in absence of a more efficient and economic dryer. Further, open sun drying is a laborious job in addition to poor quality and contamination by dusts. Therefore, the main aim of the study was to improvise the present traditional method of open sun drying and compare the drying loss and economics of the existing method with other improvised drying methods. The study conducted in Bjaktey village under Kazhi geog, Wangduephodrang dzongkhag followed RCBD with four treatments and three replications each. The parameters measured were final weight, percent loss, cost benefit, drying duration, and water activity of different treatments. The results indicated that T4 (poly tunnel drier) performed better in six of the seven parameters measured, namely loss percent (least at 0.03%), water activity (least at 0.41), drying duration (11 days), temperature (highest at 41.59°C), relative humidity (lowest at 19.54%) and economics (highest net income at Nu. 728.9/m²). The seventh parameter, the final weight lost, in T4 (at 2.47 kg) was significantly different from the control (T1) (at 2.31 kg), but not from the other two treatments T2 (raised bamboo mat) and T3 (raised bamboo mat with plastic roofing). There was no significant difference between T1 and T2 in five of the seven parameters measured, namely loss percent, water activity, drying duration, temperature attained and relative humidity retained. The high temperature and low relative humidity difference facilitated the produce to dry quickly and lower water activity (aW) in T4. It may be concluded that poly tunnel on raised bamboo mat is comparatively convenient, efficient and economical for drying chillies compared to other methods.


Chilli, Economics,Loss percent,Open sun drying,Poly tunnel dryer.




Akarslan, F. (2012). Solar-Energy Drying Systems. In Modeling and Optimization of Renewable Energy Systems: InTech.

Amunugoda, P. N., Senanayake, N. S., Wijeratnam, R., & Kulatunga, K. (2013). Quality Enhancement of Dehydrated Products through the Modification of Solar Tunnel Dryer for Continuous Operation in Rural Communities. International Journal of Energy Engineering, 3(1), 7-14.

Basunia, M. A., Al-Handali, H. H., Al-Balushi, M. I., Rahman, M. S., & Mahgoub, O. (2011). Drying of Fish Sardines in Oman Using Solar Tunnel Dryers Journal of Agricultural Science and Technology, 1, 108-114.

Chavan, B. R., Yakupitiyage, A., & Kumar, S. (2011). Drying Performance, Quality Characteristics, and Financial Evaluation of Indian Mackerel Dried by a Solar Tunnel Dryer. Thammasat Institute Journal of Science and Technology, 16(2), 11-25.

Chavda, T. V., & Kumar, N. (2009). Solar Dryers for High Value Agro Products Paper presented at the International Solar Food Processing Conference 2009, Indore, India.