Quality of mature Zill mangoes after long-term refrigerated storage as determined by pre-storage ripeness and cold-storage regime.
Oosthuyse S. A.
Author Affiliation: Merensky Technological Services, PO Box 14, Duivelskloof 0835, South Africa.
Yearbook - South African Mango Growers' Association 14 : 37-42
Abstract : Mango cv. Zill fruits picked at an advanced stage of maturation were either pre-stored (20°C for 72 h) or placed directly in cold storage. The cold-storage regimes were (1) 4 weeks at 11°, (2) 4 weeks at 8° and (3) 2 weeks at 8° followed by 2 weeks at 6°. After cold storage, the fruits were stored at 20° for a further 18 days. Firmness decreased and skin and pulp colouration increased during pre-storage. During cold storage, skin colouration increased most in regime 1 (45.8%) and least in regime 2 (4.2%), and was greater for all 3 regimes when pre-storage preceded cold storage. TSS content directly after cold storage was commensurate with prior softening. In directly stored fruits, the extent of softening during cold storage was positively related to temperature. In the pre-stored fruits, no such relationship was apparent, as these fruits all softened to the point of eating-ripeness during cold storage. Skin colouration just prior to cold storage and its increase during cold storage were directly related to the percentage of fruits showing signs of disease (soft-brown rot (Nattrassia mangiferae)) after cold-storage, and almost entirely accounted for the differences in percentage disease due to treatment 2 days after cold storage. Severe chilling injury symptoms were absent. Pre-storage reduced skin sensitivity to lenticel damage and shrivelling, but not to sap-pitting. The incidence of each of these disorders was inversely related to cold-storage temperature. The beneficial effects of pre-storage were offset by the negative effects of an increased incidence of disease and overripeness after cold-storage. Direct placement in cold storage at 8° was deemed the best storage option.