Determination of pear bruises due to a thin edge compression load by CT scan method

In this research via CT scan, the relationship between physical properties of pears and storage times with bruise due to loading force was investigated. Before loading and storing, 50 pears were examined using CT scan and 27 pears with zero bruise percentage were selected. Dimensions of pears (length, width, thickness) were measured, then properties such as the equivalent diameter, geometric mean diameter, spherical coefficient, surface area and aspect ratio of calculus were calculated, then selected pears were subjected to quasi-static loading with a thin edge pressure with three forces of 15, 20 and 25 N and 5, 10 and 15 days storage was used to investigate the effect of forces on pears. Then, after loading and storing, using the CT scan in each period of storage, the rate of pear bruise was calculated. The results of the experiments showed that there is an inverse relation between geometric diameter, arithmetic and equivalent diameter, spherical coefficient and aspect ratio with the bruise percentage. Also, a direct and unreasonable relationship between the level of the surface area and the percentage of bruising was obtained. Also, according to the obtained results, during the 5-day storage period, the amount of geometric diameter, arithmetic and equivalent diameter, spherical and aspect ratio on the percentage of bruising were not significantly affected and percentage of bruising can be almost zero and with increasing storage, the above parameter's will affect the percentage of bruising.