Document Type : Research Paper
Gain of enough knowledge on how to reduce mechanical damages is indispensable in developing fresh fruit handling as well as post harvest systems. This research was performed to determine and compare the susceptibility of five apple varieties to impact loads in KHORASAN region. Five apple varieties of KHORASAN region (AROOS, ABBASI, yellow LOBNANI, red Lobnani and Golshahi) were loaded by two impact tools (flat vs. round shaped) along with three impact energy levels (0.976, 0.590 and 0.276 J) in five replications using pendulum apparatus arrangement. For each sample, depth and diameter levels of bruise were measured. The volume as well as susceptibility to bruise were evaluated using defined equations. Statistical factorial experiments in the form of completely randomized design (5×3×2) of five replications were employed. The results indicated that the depth and diameter of bruise were significantly affected by variety, impact energy and as well by the shape of impact tool. Maximum mean bruise diameter (25 mm) and depth (11 mm) belonged to AROOS and GOLSHAHI varieties, respectively. The average bruise volume caused by the flat shaped impact tool was more pronounced than that for the circle shaped one. The results of variance analysis of susceptibility to bruise showed that variety, impact energy and the shape of impact tool exerted significant effects on bruise susceptibility (P<0.01). A comparison of mean bruise susceptibility in the different studied varieties of apple indicated that there is no significant difference observed among ABBASI, red LOBNANI and golden LOBNANI (3.71, 3.95 and 4.12 ml/J, respectively) while GOLSHAHI and AROOS (5.29 and 6.23 ml/J, respectively) exhibited more susceptibility. Further investigations showed that the resulted bruise for ABBASI and red LOBNANI varieties with an impact energy of 0.276 J was in the accepted range of grade No. 1 (on the basis of American standard for apple grading), while the bruise in other varieties facing this impact energy was out of the standard value of bruise.