Determining some physical properties of walnut kernel (Kaghazi Cultivar) for quality separation

Walnut usually classified in different quality groups due to its high economic price and therefore it is required to determine physical properties of it, especially obtaining the necessary information for designing sorting and grading machines. In this research, the physical properties of Kaghazi cultivar of walnut, including dimensional properties: length, width, thickness, arithmetic mean diameter, geometric mean diameter, roundness, surface area, and also gravitational properties: mass, volume and true density and their variations were determined in three quality groups of white sound, dark sound and damaged kernels. The results indicated that the mean values of length, width, thickness, arithmetic mean diameter, geometric mean diameter, roundness, surface area, mass, volume and true density were equal to 27.74mm, 26.32mm, 10.78mm, 21.61mm, 19.85mm, 0.72, 1243.68mm2, 2.90gr, 2850mm3 and 1.03gr/mm3 in white sound kernels, respectively. In addition, the results of ANOVA showed a significant difference between quality groups based these physical quantities. In this relation, it is possible to distinguish between sound and damaged kernels according to their mass, volume and density. However, according to frequency diagrams of physical properties, it is not possible to reach the 100% of separation. Therefore, it is necessary to use a series of separating units, in which every unit use a specific property.