Drying characteristics of coconut in solar tunnel dryer.

摘要

Coconut (Cocos nucifera) is a traditional food ingredient processed in agro-industries in many parts of Tamilnadu. Drying of coconut kernels at industrial level is currently done in open sun drying, which has problems of hygiene. While drying, the endosperm of coconut is exposed and it is susceptible for contamination due to dirt. The coconut kernel having initial moisture content of 50-55 per cent is reduced to 6 per cent during drying operation for safe storage and to maintain food quality. In order to solve the problem of hygiene and to effect faster drying rate, the MPUAT design solar tunnel dryer was installed at M/s Supa Farms, Chinniyampalayam, Coimbatore, Tamilnadu. Solar tunnel dryer is semicylindrical tunnel shaped structure covered with UV stabilized polyethylene sheet. The floor area (18.0x3.75 m) of the tunnel dryer is black coated to attain the maximum drying efficiency. The results showed that the temperature inside the solar tunnel dryer gets boosted up by 15-20 degrees C more than the ambient. The results also revealed that the coconut kernels being dried in the solar tunnel dryer was completely protected from rain, insects and dust and the dried coconut kernels were high quality compared to open sun dried product.