Threshing Methods, Dryers and Dehuskers Suitable for Brown Rice Production - A Review

Abstract

The importance of choosing whole grains such as brown rice rather than refined grain, i.e., white rice, to maintain a healthy body weight, prevention of cardiovascular diseases, phyto-nutrient qualities associated with health promoting activity equal to or even higher than that of vegetables and fruits, etc is well established. In India, generally after harvesting of paddy crop, it is left in the field for drying and the crop is threshed for removal of grains from the panicles.  The paddy grains are again dried and milled for the production of brown rice. During this process, lots of middle men are involved by which the cost of brown rice becomes very high and thus, unaffordable to common people.  Hence, it was thought that if equipment like thresher cum drier cum dehusker is made available, then brown rice can be produced in the farm itself which will be very cheap.  Thus, to fabricate a paddy thresher cum drier cum dehusker, a review was conducted to identify the most suitable threshing method, a drying method which can instantly dry the grains after threshing and the most appropriate dehusker which can remove the husk of the paddy grain efficiently.  From the review, it is concluded that a paddy thresher cum drier cum dehusker can be fabricated by having axial-flow threshing mechanism with  co-axial split-rotor threshing drum (suitable for high moisture paddy crop), a drier with infrared emitters for instant drying of paddy grains and rubber roll dehusker for removal of husks with high milling efficiency.