The effect of relative humidity on water loss and lenticel damage incidence during cold storage of apples

Lenticel breakdown is a major defect in the South African pome fruit industry and has caused severe losses. The aim of the trials was to investigate the role relative humidity (RH) during storage has on lenticel breakdown susceptibility.

‘Braeburn’ apples were stored at various RH levels for approximately 3 weeks before simulated shipping. Fruit was evaluated at the end of cold storage and after a 7-day shelf life. Fruit mass loss was recorded at each storage and evaluation stage. Air temperature and RH was monitored throughout the trial.

High incidence of lenticel disorders occurred in both seasons. No clear trend was noted between RH levels and lenticel incidence. Differences between treatments regarding moisture loss occurred, but no clear correlation with lenticel damage was detected.

Although treatment differences occurred regarding RH levels, air temperature, moisture loss and lenticel damage, no clear trend were noted across populations and seasons. There was no correlation between any of the mentioned parameters indicating the complex nature of the development of lenticel damage.

The nature of lenticel disorder development in relation to RH is unpredictable. The inconsistent results indicate that there might be a number of factors effecting the development of lenticel disorder and cannot be attributed to only one factor.