Evaluation of Some Physical and Mechanical Properties of Hazelnut

In this study, several physical and mechanical properties of hazelnut and its kernels were evaluated as a function of moisture content in 5-20% (w.b.) ranges. The physical properties of nuts and kernel such as dimensional characteristics (length, width and thickness), unit mass and geometrical properties (the geometric mean diameter, volume, surface area and projected area) increased with increasing moisture content. The sphericity of nuts and kernels decreased with increasing moisture content. The average of length, width, thickness, unit mass, the geometric mean diameter, volume, surface area and projected area and sphericity of nuts were 16.92, 17.51, 15.33, 16.55 mm, 1.95 g, 2.40 cm3, 8.63 cm2, 2.16 cm2, 93.52%, the respected value for kernels were 13.55, 13.59, 11.89, 13.00 mm, 0.92 g, 1.16 cm3, 5.02 cm2, 1.26 cm2, 92.85%. The shell ratio percent obtained 52.81%. In the mechanical test, hazelnut and its kernel were loaded between two parallel plates to determine the rupture force and specific deformation required to initiate shell and kernel rupture. These tests were carried out at two moisture contents of 5% and 10 % (w.b.) for nuts and 5% (w.b.) for kernel, and three axes (X, Y, Z) directions. The results showed that moisture content and loading direction have significant effects (P < 0.01) on the rupture force and specific deformation. By increasing the moisture content, rupture force decreased, while the specific deformation increased in magnitude. The maximum force for nut cracking occurred in the x-axis, while rupture force for kernel was in the z-axis loading directions. The average of rupture force at all loading directions for nuts was very higher than for kernels.