STORAGE RESPONSE OF CACTUS PEAR FRUIT TO CACL2 PREHARVEST SPRAY AND POSTHARVEST HEAT TREATMENT

Cactus pear fruit (Opuntia ficus-indica Mill. cv. Gialla) were treated ten weeks after full bloom with 2% CaCl2 solution and heated at 38 de grees C for 24 h under saturated humidity after harvest. The two treat ments were also combined before storage at 6 degrees C for 42 d plus t hree additional days at 20 degrees C to simulate retail conditions. Co ntrol fruit were untreated with CaCl2 and unheated. CaCl2 treatment de layed the appearance of the typical colour of ripe fruit, decreased th e rate of fruit weight loss during simulated marketing and significant ly inhibited pathogen development by the end of cold storage and subse quent simulated marketing period (SMP) but significantly promoted the appearance of chilling injury (CI) during SMP. Prestorage heat treatme nt (HT) reduced rot development during cold storage and after, reduced chilling injury incidence during storage and reduced the decline in o verall appearance. The combined treatments (CaCl2 + HT) did not exhibi t advantages in mould decay control as compared with HT applied separa tely. HT applied alone or in combination with CaCl2 significantly incr eased ethylene production rate by the end of SMP. The influence of tre atments on respiration rate, pH of juice, titratable acidity, total so luble solids, acetaldehyde and ethanol concentrations in the juice was negligible, both during cold storage and SMP.