Abrasive-disk dehullers in Africa: From research to dissemination

RESUME— RESUMEN Abstract — Recent droughts in the Sahel and in eastern and southern Africa have increased the urgency with which national policymakers are considering drought-resistant crops. National systems for agricultural research in many African countries have strengthened their programs to improve sorghum and pearl millets. A food crop, however, only becomes food when it is actually consumed. Efforts to increase food production must, therefore, be matched by corresponding research on food after harvest. The absence of appropriate dehulling equipment, especially for small grains, has often been cited as a reason for past national neglect of these cereals. Recent droughts in the Sahel and in eastern and southern Africa have increased the urgency with which national policymakers are considering drought-resistant crops. National systems for agricultural research in many African countries have strengthened their programs to improve sorghum and pearl millets. A food crop, however, only becomes food when it is actually consumed. Efforts to increase food production must, therefore, be matched by corresponding research on food after harvest. The absence of appropriate dehulling equipment, especially for small grains, has often been cited as a reason for past national neglect of these cereals. This publication reviews the development of small-scale, inexpensive, versatile abrasive-disk dehullers in Africa. The rural deployment of mechanical dehullers offers an opportunity to eniiance national cereal self-sufficiency and to increase use of the productive capacity of the low-rainfall areas of Africa. The topics discussed in detail include the need to understand traditional food habits and preferences; the scope for applying small dehullers in Africa; detailed technical descriptions of various dehuller designs and criteria to be considered in a design process; important grain characteristics as they relate to dehulling and the effect of the dehuller's abrasive agent on the grain; installation and operation of some typical, rural, small-scale milling systems; and the process of introducing technology as one moves from applied research to applying the results. Resume — Par suite des recentes secheresses au Sahel et en Afrique orientale et australe, il est devenu encore plus urgent que les auteurs de politiques nationales se penchent sur la question des cultures resistant a la secheresse. Les syst'emes nationaux de recherche agricole de nombreux pays africains ont renforcd leurs programmes visant a ameliorer les cultures de sorgho et de millet a chandelle ou millet d'Afrique. Une recolte ne pout cependant etre dite alimentaire qu'a partir du moment ou elle est reellement consornmee. Les mesures ayant pour but d'accroItre Ia production de nourriture doivent donc s'accompagner de recherches correspondantes sur les aliments apres les recoltes. On cite souvent l'absence d'equipement de decorticage approprie, particulierement pour les cCrCales de plus petites dimensions, comme l'une des raisons expliquant que l'on ait neglige ces cultures dans le passe. Cette publication fait l'historique de la misc au point de dCcortiqueurs a disques abrasifs de petites dimensions, peu couteux et polyvalents en Afrique. Leur utilisation en milieu rural donne aux pays concernCs l'occasion d'accroItre leur autosuffisance en matiere de cereales et d'exploiter davantage la capacite de production des regions a faible pluviosite en Afrique. Voici les sujets qui sont abordCs en detail dans la publication: l'importance de comprendre les habitudes et prCfCrences alimentaires traditionnellcs; les possibilites d'utilisation des petits decortiqueurs en Afrique; la description technique detaillec de divers modeles de decortiqueurs et les criteres a prendre en consideration dans leur conception ; les caracteristiques importantes des cerCales aux fms de decorticage et les effets des agents abrasifs sur les cereales ; l'installation et le fonctionnement de certaines meuneries de petite typique des milieux ruraux ; et la transition ernie Ia recherche appliquee et l'introduction de la technologie qui en decoule.