Some Biochemical Factors Underlying the Differential

Development of internal browning and some associated biochemical and physicochemical changes were investigated in the pineapple cultivar Mauritius (syn. Queen) and compared with those of a lesser susceptible cultivar Kew (syn. Smooth Cayenne). The study was expected to identify the major factors underlying the cultivar resistance to the disorder. Three-week long storage trials were conducted simulating the sea freight export conditions at 10C and 85% RH. In Mauritius, the internal browning symptoms began within a week of storage at 10C initially in the marginal core tissue which subsequently spread to the surrounding flesh, whereas in Kew, the symptoms commenced only after 2-3 weeks of storage as isolated, smaller patches in the tissue surrounding the core. There was a clear difference in the time of incidence and the pattern of internal browning symptom development between the two cultivars. The cv. Mauritius showed comparatively faster ripening and respiration rates and greater accumulation of acids during cold storage, than the cv. Kew. In both cultivars the tissues undergoing browning displayed greater PPO and peroxidase activity and electrolyte leakage than their respective controls. Harvesting fruit early at 100% green stage reduced the incidence and severity of internal browning in both cultivars.