Development of walnut dehulling machine and assessment of its performance using Ethephon and Tween-80 as pre-treatments for hull loosening.

A power- driven walnut dehulling machine was developed and tested. The machine was evaluated for dehulling after applying Ethephon and Tween-80 to green walnuts by dip and spray methods. The results showed that with the increase in dipping time and post dipping/spraying time, the effective throughput capacity, dehulling efficiency and fully dehulled walnut percentage increased, whereas partially dehulled walnut percentage and labour requirement decreased in both manual and mechanical dehulling. Maximum effective throughput capacity, dehulling efficiency and fully dehulled walnut percentage were observed, when green walnuts were subjected to dehulling after 4 days of Ethephon spray treatment (0.3 %). The effective throughput capacity, dehulling efficiency and fully dehulled walnut percentage were found significantly higher in mechanical dehulling than in manual dehulling.