Response of cactus pear fruit to high temperature conditioning and film wrapping

First crop cactus pear cv "Gialla" fruits harvested the 15thof September were wrapped with a 19 mm thick film or left unwrapped and then divided into two lots, of whom one was immediately stored at 17°C and 60% relative humidity (RH) for 2 or 4 weeks, while the other one before being stored at the same conditions, was conditioned at 36°C and 90% RH for 36 hours. At each inspection time fruit were checked for incidence of decay, overall appearance and presence of dermatosis. High temperature conditioning, although not detrimental, had a negative effect on overall appearance and dermatosis. Dermatosis appeared in the form of brown spots on the peel similar to the symptoms of chilling injury previously described by other authors. The incidence of decay was higher in conditioned fruits than in nonconditioned ones. Plastic film had a positive effect in reducing ageing and dermatosis, while promoted microorganism development. Neither the plastic film nor the curing treatment had important influence on chemical parameters, while significant was the effect of the storage period on pH, which changed from 5.95 of harvest to 6.3 after 4 week's storage, and titratab1e acidity (% citric acid), which decreased from 0.077% of harvest to 0.045% at the end of the storage period. In conclusion, the results show a very positive contribution of the plastic film in maintaining the initial quality of the fruits, in fact at the end of the trial the wrapped fruit appeared as fresh as at harvest, while no positive influence was exerted by the cwing treatment.