Flavedo and albedo changes in 'Eureka' lemons caused by static compression and impact loading

Abstract

Mature lemons (Citrus limon (L.) Burm. ‘Eureka') were subjected to increasing compression, impact and static loading, then stored at either 1C, 13C or 20C for 14 or 28 days. Following storage, fruit were assessed for cellular damage associated with the site of loading. Slow compression (1.7cm plunger driven at a loading rate of 200 mm min−1) resulted in cell damage in the mid to lower flavedo tissue. Tissue failure was characterised by cell rupture, with minor cell deformation and compression associated with damage to the oil glands. Impact loading caused relatively little lower flavedo damage, with most of the injury associated with the albedo, the upper flavedo and tissue surrounding the oil glands. Damaged albedo cells formed a distinct zone of ruptured and laterally compressed tissue which increased in area with drop height. Static loading (3.7 kg top weight) resulted in a similar mode of failure to that of impact loading, with extensive cellular damage observed in the lower albedo. Injury was distinct in that cells were not laterally compressed and flavedo damage was far more pronounced.