Design And Fabrication Of A Prototype Decorticator To Remove Seed Coat Of Black Cumin (Nigella Sativa)

Abstract

Black cumin (Nigella sativa) seed is very important and widely used seed in traditional medicine. Since, black cumin seeds have been enveloped with a thick seed coat in black color, potential for commercial applications has been restricted. Hence, a prototype decorticator was designed and developed to remove the seed coat by applying abrasion and friction principle. The machine consists with a cylinder, axle and flat bars. Four flat bars have been welded 150mm apart in symmetrical manner on the axle. Distance between two flat bars are 25mm at an angle of 600, however, the angle of two flat bars should be in counter directions as well as in non-geometric way. Therefore, this mechanism imparts adequate push with necessary energy to the watery black cumin seeds in counter current manner when axle is rotating at the speed of 821rmp. Thus, watery seeds are pushing as a counter current streams from opposition directions and smashing each other with an adequate energy, resulting to create friction and abrasion actions between black cumin and black cumin seeds as well as between seeds and inside surface of the cylinder. Due to acting upon these two forces over the seed coat, end result was detaching the seed coat from the cotyledons. Results revealed that decortications machine was capable to remove 85% of the seeds coat of the seeds by applying friction and abrasion principle. Best results were obtained when seeds were soaked in cold water for 5 minutes prior to ingestion them into the decorticator