Development of a Low Cost Machine for Improved Sorghum Dehulling Efficiency

Abstract

A Pedal operated sorghum dehuller for dehulling tempered grain was developed and tested for its performance using two sorghum varieties (Dionje and Jumbo). The use of short tempering duration (10 – 15 minutes) followed by a short resting period (5 – 10 Minutes) to ensured that all the tempering moisture was absorbed into the grain before the grain was introduced into the dehuller thus eliminating the clogging problem usually associated with conventional abrasive dehullers. This facilitated the removal of the seed coat from the endosperm. The obtained results showed that the developed dehuller was able to achieve high dehulling efficiency (90.1% for Jumbo and 83.4 for Dionje) and high recovery levels compared to conventional abrasive dehullers (45.6 for Jumbo and 40.3% for Dionje). The quality of the dehulled grain was also much higher as indicated by the low ash content, low crude fibre content and superior colour of the flour obtained from the grain dehulled in the developed dehuller compared to flour from grain dehulled using conventional abrasive dehullers. These results demonstrate that it is possible to achieve high quality dehulled sorghum product and high dehulling efficiency by incorporating simple and cheap traditional pretreatments in the mechanical dehulling process. Accordingly, the developed pedal operated dehuller could be very appropriate for small scale sorghum farmers and consumers in the rural areas where spare parts, electrical power and competent technicians to run and maintain the conventional abrasive dehullers are limited.

Key Words: Sorghum, grain tempering, dehuller, dehulling efficiency