Design and Development of Walnut Dehuller-cum-washer

Traditional manual practices of walnut dehulling and washing are tedious, laborious, and time consuming. Power-operated and manual-operated walnut dehuller-cum-washers were designed, developed, and evaluated in comparison to existing manual methods. The performance parameters evaluated in the present study differed significantly (p<0.05) in all three tested methods. Highest throughput capacity (340 kg.h-1) was observed for power-operated walnut dehuller-cum-washer (M1), followed by 16.25 kg.h-1 by manual-operated walnut dehuller-cum-washer (M2), and12.54 kg.h-1 by manual dehulling and washing (M3). Labour requirement was lowest in M1 (2.94 man.h.t-1), followed by M2 (61.53 man.h.t-1), and M3 (79.74 man.h.t-1). Highest dehulling and washing efficiency was in case of M1 (96.82%), followed by M3 (85.17%), and M2 (82.60%). Furthermore, M1, M2, and M3 yielded fully dehulled walnut percentages of 97.20, 81.20, and 94.56; partially dehulled walnut percentages of 1.87, 7.80, and 4.74%; and un-hulled walnut percentages of 0.9, 9.5, and 0.5%, respectively. Broken walnut percentage was least (0.02%) in case of M1, followed by M3 (0.20%), and M2 (0.50%). Hardness of walnut was highest with M1, and lowest for M3. Peroxide value and free fatty acid content were lowest in case of walnut processed by M1, followed by M2, and M3. Brightness (L*) of un-shelled walnut as well as kernel were highest for M1; whereas redness (a*) and yellowness (b*) were minimum in walnut processed by M1. Adoption of the developed prototypes in walnut dehulling and washing can significantly enhance the throughput capacity with drastic reduction of labour requirement, besides improving the quality of whole walnut as well as its kernel.