Effect of moisture content and impact energy on the cracking of conophor nut

The cracking of conophor nut using an impact test apparatus was carried out at different moisture contents (14.9% - 50.3% (d.b.)) and impact energy levels (0.05 - 0.19J) under lateral and longitudinal loading orientations, in order to explore the possibility of developing an effective and appropriate technology equipment for cracking the nut.  The data obtained on the quantity of fully cracked nuts with unbroken kernels, fully cracked nuts with broken kernels, partially cracked and uncracked nuts were subjected to statistical analysis.  Results showed that moisture content, impact energy and loading orientation as well as their interactions significantly affected the crackability of conophor nut at 1% level of significance.  The moisture content at which a combination of high whole kernel yield and minimum kernel damage was obtained ranged from 14.9% to 31.9% (d.b.).  The impact energy range of 0.05 to 0.11 J gave the best combination of high whole kernel yield and minimum kernel damage at both lateral and longitudinal orientations.  The study shows that the development of a spinning disc cracker, which uses impact to crack conophor nut is possible.  It suggests that the radius and speed of the spinning disc should be such that would ensure that the impact energy generated and imparted on the nuts will not exceed 0.11J and nuts should be conditioned to the dry basis moisture content that does not exceed 31.9% (d.b.) prior to cracking for optimum efficiency. Keywords: crackability, impact energy, moisture content, conophor nut, kernel, cracker, cro