Design of a Mechanical Oil Kneader Based on Ergonomic Studies of the Traditional Kneading Process

Abstract

The traditional groundnut oil processing is a popular commercial value addition activity, especially amongst women in Northern Nigeria. The process comprises of seven sub-processes, which include roasting, de-skinning, winnowing, milling, kneading, frying and forming of groundnut cake. Past studies have shown that the kneading sub-process was more strenuous and time consuming. To address these limitations, relevant data from ergonomics studies of the traditional kneading process were incorporated into engineering design procedure to develop a mechanical oil kneader that has similar motion with the traditional, but incorporates components that confer mechanical advantages. Comparative evaluation of the kneading process using same quantity of groundnut (i.e. 6.5kg) revealed that average percent oil extracted was 34.7% with the mechanical kneader, whilst it was 26.4% by the traditional process; and extraction efficiency for the kneader was 71.3% and 52.8% for the traditional. Time wise, the mechanical kneader required only 32% of the time used for kneading same weight with the traditional. In effect, the mechanical kneader enhances the volume of oil extraction and reduces the processing duration by 68%.