Engineering properties and bruise susceptibility of peach fruits (Prunus persica)

Abstract

In order to better design and modification of peach post harvesting systems such as sorting, conveying and packaging, selected engineering properties and bruise susceptibility of two Iranian peach varieties (Elberta and Spring time) were determined.  Physical and mechanical properties such as dimensions, mass, volume, projected area, surface area, sphericity, static friction and rolling resistance coefficients on various surfaces, firmness and compressibility were measured.  Also, effect of cultivar, drop height (50, 100 and 150 mm) and contact surface material (fruit, steel and rubber) on the bruise area and volume were investigated.  Analysis of variance results indicated that cultivar had a significant effect (p<0.05) on certain engineering parameters such as dimensions, volume, mass, surface area, rolling resistance coefficient and firmness.  The effect of cultivar on the bruise volume and area was not significant.  The contact surface material and drop height had significant effect on the bruise area (p<0.01) and volume (p<0.05).  Mean comparison of data revealed that the bruise area on all three contact materials was significantly different from each other, but on the rubber surface, it showed no significant differences in bruise volume.  Also, bruise area was significantly different for 50 and 150 mm drop heights, while bruise volume had significant difference at all three drop heights. In general, results indicated that some engineering parameters are depended on cultivar and have more rules in designing of sorting and conveying systems.  Also, in sorting or packaging lines safe drop height must be considered and it is closely related to the contact surface material.

Keywords: peach, physical and mechanical properties, bruise area, bruise volume