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
