Keeping Quality and Storage

Keeping Quality and Storage

Washing the fruits immediately after harvest is essential, as the sap which leaks from the stem bums the skin of the fruit making black lesions which lead to rotting.

Some cultivars, especially ‘Bangalora’, ‘Alphonso’, and ‘Neelum’ in India, have much better keeping quality than others. In Bombay, ‘Alphonso’ has kept well for 4 weeks at 52° F (11.11° C); 6 to 7 weeks at 45° F (7.22° C). Storage at lower temperatures is detrimental inasmuch as mangos are very susceptible to chilling injury. Any temperature below 55.4° F (13° C) is damaging to ‘Kent’. In Florida, this is regarded as the optimum for 2 to 3 weeks storage. The best ripening temperatures are 70° to 75° F (21.11°-23.89° C).

Experiments in Florida have demonstrated that ‘Irwin’, ‘Tommy Atkins’ and ‘Kent’ mangos, held for 3 weeks at storage temperature of 55.4° F (13° C), 98% to 100% relative humidity and atmospheric pressure of 76 or 152 mmHg, ripened thereafter with less decay at 69.8° F (21° C) under normal atmospheric pressure, as compared with fruits stored at the same temperature with normal atmospheric pressure. Those stored at 152 mmHg took 3 to 5 days longer to ripen than those stored at 76 mmHg. Decay rates were 20% for ‘Tommy Atkins’ and 40% for ‘Irwin’. Spoilage from anthracnose has been reduced by immersion for 15 min in water at 125° F (51.67° C) or for 5 min at 132° F (55.56° C). Dipping in 500 ppm maleic hydrazide for 1 min and storing at 89.6° F (32° C) also retards decay but not loss of moisture. In South Africa, mangos are submerged immediately after picking in a suspension of benomyl for 5 min at 131° F (55° C) to control soft brown rot.

In Australia, mature-green ‘Kensington Pride’ mangos have been dipped in a 4% solution of calcium chloride under reduced pressure (250 mm Hg) and then stored in containers at 77° F (25° C) in ethylene-free atmosphere. Ripening was retarded by a week; that is, the treated fruits ripened in 20 to 22 days whereas controls ripened in 12 to 14 days. Eating quality was equal except that the calcium-treated fruits were found slightly higher in ascorbic acid.

Wrapping fruits individually in heat-shrinkable plastic film has not retarded decay in storage. The only benefit has been 3% less weight loss. Coating with paraffin wax or fungicidal wax and storing at 68° to 89.6° F (20° -32° C) delays ripening 1 to 2 weeks and prevents shriveling but interferes with full development of color.

Gamma irradiation (30 Krad) causes ripening delay of 7 days in mangos stored at room temperature. The irradiated fruits ripen normally and show no adverse effect on quality. Irradiation has not yet been approved for this purpose.

In India, large quantities of mangos are transported to distant markets by rail. To avoid excessive heat buildup and consequent spoilage, the fruits, padded with paper shavings, are packed in ventilated wooden crates and loaded into ventilated wooden boxcars. Relative humidity varies from 24% to 85% and temperature from 88° to 115° F (31.6°-46.6° C). These improved conditions have proved superior to the conventional packing of the fruits in Phoenix-palm-midrib or bamboo, or the newer pigeonpea-stem, baskets padded with rice straw and mango leaves and transported in steel boxcars, which has resulted in 20% to 30% losses from shriveling, unshapeliness and spoilage.

Green seedling mangos, harvested in India for commercial preparation of chutneys and pickles as well as for table use, are stored for as long as 40 days at 42° to 45° F (5.56°-7.22° C) with relative humidity of 85% to 99%. Some of these may be diverted for table use after a 2-week ripening period at 62° to 65° F (16.67° -18.13° C).

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