A case necessary to develop postharvest mechanization is to have enough information to decrease mechanical damage for each crop. This research performed to determine and compare the susceptibility of apple varieties to impact loads. Statistical factorial experiments in the form of completely randomized design (5×3×2) with five replications were used in this order. For each sample depth and diameter of bruise was measured and the volume and susceptibility of bruise was calculated using defined equations. The results showed that the depth and diameter of bruise was affected by variety, impact energy and impactor shape. The maximum of mean bruise diameter (25 mm) and bruise depth (11mm) belonged to AROS and GOLSHAHI varieties, respectively. The results of variance analysis of bruise susceptibility showed that variety, impact energy and impactor shape factors had significant effects on bruise susceptibility (P<0.01). Comparison of mean bruise susceptibility with Duncan’s method in different apple varieties indicated ABBASI, Red LOBNANI and Golden LOBNANI had no significant difference with each other but GOLSHAHI and AROS had more bruise susceptibility with 5.29 and 6.23 mJ/lit, respectively. Further investigation showed that bruise of ABBASI and red LOBNANI varieties with impact energy of 0.276 J were in the accepted range of grade No. 1, but the bruise of other varieties with this impact energy were out of standard bruise.

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