Determination of physico-mechanical properties of some domestic and foreign walnut (Juglans regia L.) varieties

In this research, we examined some of the physical (fruit dimensions, geometric mean diameter sphericity and surface area) and mechanical (puncture force, deformation, energy absorption and hardness) properties on the four different domestic (Şebin, Kaman, Bilecik and Yalova-3) and two different foreign (Chandler and Fernor) walnut (Juglans regia) varieties. For this purpose, we applied puncture force on the walnuts at the direction of width orientation (x–x), length orientation (y–y) and suture orientation (z-z). According to obtained results, there are significant differences among the walnut varieties for crustacean walnut weight and walnut weight. The maximum and minimum values of crustacean walnut weight were observed as 18.27 g and 10.98 g for Kaman and Chandler, respectively. In addition to these results, Bilecik has a maximum walnut weight – 8.71 g, while the minimum walnut weight was observed for Yalova-3 – 4.57 g. Furthermore, geometric mean diameter and sphericity values ranged to 31.93–38.57 mm and 82.78–92.54%, respectively. There are statistically significant differences on the puncture force, deformation, energy absorption and hardness according to the load axes. The maximum and minimum puncture force values were determined at the Fernor (572 N) with y–y axes and Chandler (211.9 N) with z–z axes, respectively. Also, the highest hardness and the lowest deformation values were obtained for Kaman (y–y axes) and the highest deformation and the lowest hardness were determined at Bilecik (x–x axes). The energy absorption values changed as follows: 0.455–1.086 J, 0.404–0.985 J and 0.426–1.051 J for x–x, y–y and z–z axes, respectively. © by Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie