Performance evaluation of a bush mango (irvingia gabonensis) nut cracking machine

Abstract

A bush mango (Irvingia gabonensis) nut handling machine was developed to ease the tedium involved in the cracking operation and enhance the efficiency of separating the kernels from hulls. The machine consists of a hopper, cracking unit barrel, electric motor, blower, tool frame, hull outlet and kernel outlet. It operates on the principle of impact using centrifugal force from the baffles on a spinning disc. Results of performance tests carried out using nuts at four moisture levels in the range of 7.52-20.6% (d.b) showed that percent effective cracking decreased, while percentage kernel breakage increased with increase in feed rate, moisture content and resident time of nuts in the cracking chamber. Winnowing efficiency increased with feed rate and resident time, but decreased with increase in moisture content. Highest percent effective cracking and percentage kernel breakage was 92.32 and 9.71%, respectively, at 7.52% (d.b) moisture content, 8.47 kg/h feed rate and 1 and 3min respectively, resident time. Winnowing efficiency was highest (67.07%) at 10.6% (db) moisture content, feed rate of 8.47kg/h and resident time of 3 min. The capacity of the machine was dependent on the nut moisture content.