Engineering properties of cashew apple and nut in relation to design of cashew apple and nut separator

Abstract

Cashew, an important tree nut crop, presents a challenge in separating the nut from the soft and fibrous cashew apple at maturity. Understanding the engineering properties of cashew apple and nut is necessary to design a machine for separating these two. The present study is aimed to determine the physical, mechanical and frictional properties of cashew apple and nut in six varieties viz., Bhaskara, Nethra Ganga, Ullal-3, Vengurla-7, Vengurla-4 and Dhana. The cashew apple and nuts’ arithmetic and geometric mean diameters were 44.58 to 52.11 mm, 43.41 to 51.41 mm and 24.96 to 28.81 mm, 23.89 to 28.11 mm, respectively. The sphericity of the cashew apple was found to be in the range of 0.76 to 0.89, whereas that of nut ranged between 0.71 and 0.80. Bulk density of cashew apple ranged from 495.15 to 581.50 kg m-3, whereas that of nuts ranged from 451.66 to 531.47 kg m-3. The static coefficient of friction of cashew apple and nuts varied on different surfaces. The mean values of the compression test in longitudinal and lateral directions were found to be in the range of 80.54 to 179.38 N and 90.92 to 139.40 N. The shearing force was found to be in the range of 20.36 to 53.08 N and 26.52 to 40.46 N in longitudinal and lateral directions, respectively. Statistically significant differences were observed in the physical properties of cashew apple and nuts among the varieties. These findings would be pertinent for designing the post-harvest machinery in cashew.