Physical properties of almond nut and kernel Original Research Article

Several physical properties of almond nut and kernel were evaluated as functions of moisture content. The average length, width, thickness, the geometric mean diameter, unit mass and volume of nuts were 25.49, 17.03, 13.12, 18.13 mm, 2.64 g and 2.61 cm3 respectively. Corresponding values for kernel were 21.19, 14.34, 6.38, 11.42 mm, 0.69 g and 0.71 cm3 respectively. In the moisture range from 2.77 to 24.97 db, studies on re-wetted almond nut showed that the bulk density decreased from 655 to 525 kg/m3, true density increased from 1015 to 1115 kg/m3, porosity increased from 35.32% to 53.21%, projected area increased from 3.74 to 3.9 cm2, and terminal velocity increased from 5.62 to 7.98 m/s. For the kernel, the corresponding values changed from 595 to 475 kg/m3, 900 to 995 kg/m3, 34.23% to 50.29%, 1.68 to 2.39 cm2 and from 5.62 to 7.2 m/s respectively. The rupture strength of almond nut and kernel decreased with increasing moisture content. The highest rupture strength occurred when loaded along the X-axis. In the same moisture range 2.77–24.97 db the static coefficient of friction varied from 0.28 to 0.83 for almond nut and from 0.53 to 0.78 for kernel over different material surfaces.