Characterization of damages caused by impact and compression forces on apples

Mechanical injuries are defined as plastic deformations, superficial ruptures and tissue impairments caused by external forces. Injuries are separated out into damages set off by impacts, compression forces or abrasions. Mechanical injuries resulting from impacts are by far the most studied, probably because of more frequent incidence along the fresh produce handling chain and, additionally, for the reason of straight forwardly replication likelihood at laboratories. In contrast, investigations of injuries in consequence of compression forces are scarcer. The main characteristic of impacted apples is the development of lesions arising from internal tissue oxidation perceptible on the outside of fruits. That feature bestows very often the reason for discards and losses and is a rationale for research with apples and other sensitive fruit species to mechanical injuries. Reports concerning the characterization of injuries caused by mechanical damages are, as well, sporadic. Therefore, the present work proposed to describe and typify lesions set off by impacts and compression forces on apples. Injuries caused by compression forces are imperceptible on the outside of the apples. In mesocarp tissues, these damages are hardly identifiable. Impacts render internal tissue oxidations, which are perceptible on the epicarp of the apples. In injured tissues, starch hydrolysis is inhibited and the starch-iodine test might be used to evaluate lesions caused by mechanical injuries on fruit. Anatomically there are differences in between impacted and compression forces. Compression forces alter cell shape and cell walls, a feature not observed with regards to impacts.