Physical and Mechanical Properties of Some Walnut (Juglans regia L.) Cultivars

The physical properties of nuts and kernels of three Turkish walnut varieties (Juglans regia L.) such as dimensions, weight of nuts and kernels, sphericity, bulk density, volume, and coefficient of friction were determined. The resistance of the nut and kernel of walnut varieties to damage was determined by measuring the average rupture force, deformation and rupture energy along the X-, Y- and Z-axes at different compression speeds (30 and 60 mm/min). Both the static and dynamic coefficient of friction values were greater for the sheet iron surface than the galvanized one for all walnut varieties. The highest nut rupture force, deformation and rupture energy among the three walnut varieties occurred for Kaman loaded on the Y-axis. The results indicated that when testing the effects of compression axes the rupture force is highly dependent on walnut varieties. The lowest force needed to rupture the nut or kernel was found in walnut varieties with Sebin that were tested at a compression speed of 60 mm/min.