Crackability and chemical composition of pre-treated cashew nuts using a hand-operated knife cutter

Abstract

The crackability and chemical composition of pre-treated cashew nuts were investigated considering three nut grades (large, medium and small) and two methods of pre-shelling treatment (hot-oil roasting and steam–boiling).  The pre-treated nuts were shelled using a hand operated knife cutter.  Crackability was calculated as a ratio of the weight of completely shelled nuts to the total weight of nuts fed into the machine.  Whole kernels out-turn was calculated as the ratio of the weight of whole kernels to the total weight of kernels recovered after shelling.  Chemical analyses were carried out following standard methods in literatures.  The average values of crackability for raw, roasted and steam-boiled nuts were 76%, 100% and 99% respectively.  For roasted nuts, crackability was higher than that of steam-boiled nuts and pre-shelling treatments affected whole kernels out-turn significantly (p<0.05).  Large and medium roasted nuts exhibited the highest whole kernels out-turn (99.6% and 99.5% respectively).  Raw nuts gave the least values of whole kernels out-turn (62%, 33.9%, and 44.7% for large, medium and small respectively).  Pre- shelling treatment made cashew nuts more amenable to fracture; but the whole kernels out-turn of large nuts was generally higher than that of medium and small nuts.  The pre-treatments showed no significant difference in the chemical composition and energy content of cashew kernels; but for crude fiber and carbohydrates wherein the differences were significant (p<0.05).

Keywords: cashew nut, pre-shelling treatment, crackability, whole kernels, chemical composition