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 degrees C for 24 h under saturated humidity after harvest. The two treatments were also combined before storage at 6 degrees C for 42 d plus three additional days at 20 degrees C to simulate retail conditions. Control fruit were untreated with CaCl2 and unheated. CaCl2 treatment delayed the appearance of the typical colour of ripe fruit, decreased the rate of fruit weight loss during simulated marketing and significantly inhibited pathogen development by the end of cold storage and subsequent simulated marketing period (SMP) but significantly promoted the appearance of chilling injury (CI) during SMP. Prestorage heat treatment (HT) reduced rot development during cold storage and after, reduced chilling injury incidence during storage and reduced the decline in overall appearance. The combined treatments (CaCl2 + HT) did not exhibit advantages in mould decay control as compared with HT applied separately. HT applied alone or in combination with CaCl2 significantly increased ethylene production rate by the end of SMP. The influence of treatments on respiration rate, pH of juice, titratable acidity, total soluble solids, acetaldehyde and ethanol concentrations in the juice was negligible, both during cold storage and SMP.