Abstract :
Several physical properties of hazel nuts and kernels were evaluated as functions of moisture content. The average length, width, thickness, the geometric mean diameter, sphericity, unit mass and volume of nuts were 18·03, 18·97, 16·58, 17·83 mm, 97·58%, 2·41 g and 1·92 cm3, respectively. Corresponding values for kernels were 14·31, 13·23, 12·68, 13·38 mm, 93·57%, 1·09 g and 1·15 cm3, respectively. In the moisture range from 2·87 to 19·98 d.b., for the rewetted nut the bulk density decreased from 383 to 305 kg/m−3, true density 727 to 674 kg m−3, porosity increased from 47·23 to 48·85%, projected area increased from 389 to 442 mm2, and terminal velocity increased from 4·21 to 5·45 m s−1. For the kernel, the corresponding values changed from 458 to 539, 887 to 948 kg m−3, 43·38 to 44·85%, 245 to 286 mm2 and from 7·22 to 8·54 ms−1, respectively. The rupture strength of nut and kernel decreased with increasing moisture content . The highest rupture strength occurred when loaded at right angles to the longitudinal axis. In the moisture range 2·77–19·98% d.b., the static coefficient of friction varied from 0·45 to 0·72 for nut and from 0·53 to 0·78 for kernel over different material surface.
