Development and Assessment of Coffea arabica and Coffea canephora Dehulling Machine

Abstract

This work was aimed at the development and assessment of Coffea arabica and Coffea canephora dehulling machine. Two units (dehuller and brusher) were incorporated in a single machine in order to remove the drudgery and constraints associated with the traditional dehulling and separating method of both varieties of coffee seed before it is processed into food condiment and flavouring agent. The moisture content of the seeds (MC) was determined according to the ASAE S410.1 Method.The response surface methodology (RSM) was employed to point out the relationship between the response functions and the process variables, of the dehulling system for Coffea arabica and coffeacanephora. The performance of the machine was evaluated by varying the speed of rotation of the dehulling shaft of the machine; 300rpm, 400rpm and 500rpm respectively and moisture content; 10%(db), 15%(db) and 20%(db). Based on this conditions, they worked optimally at the rate of 240kg/hr. The result showed that the performance of the machine for Coffea arabica and Coffea canephora were 65.17% (at 10%d.b, 300rpm) 62.13% (at 15%d.b, 300rpm), 59.67% (at 20%d.b, 300rpm), 58.43% (at 10%d.b, 400rpm), 58.9% (at 15%d.b, 400rpm), 55.5% (at 20%d.b, 400rpm), 57.07% (at 10%d.b, 500rpm), 56.67% (at 15%d.b, 500rpm), 56.23%(at 20%d.b, 500rpm) and 57.62% (at 10%d.b, 300rpm) 54.3% (at 15%d.b, 300rpm), 52.41% (at 20%d.b, 300rpm), 54.11% (at 10%d.b, 400rpm), 53.39% (at 15%d.b, 400rpm), 51.47% (at 20%d.b, 400rpm), 53.97% (at 10%d.b, 500rpm), 52.43% (at 15%d.b, 500rpm), 52.19%(at 20%d.b, 500rpm) respectively. Therefore, the machine is recommended for small and medium scale farmers that are involved in coffee cultivation and processing.