CONSUMERS LIKE TO BUY RIPE MANGOES
SCIENTIFIC NAME: Mangifera indica
FAMILY: Anacardiaceae
With the demand from consumers for fruit that is ready-to-eat escalating, the need to accelerate the ripening process for many products has grown accordingly.
Consumer confidence gained through satisfaction with fruit that has sprung and coloured evenly, has seen them absolutely reject, for example, mangoes with motley colouring and green background colour.
Set out below is a procedure for ripening mangoes following work done in this area by Scott Ledger and John Bagshaw of the Horticultural Postharvest Group, QDPI.
MATURITY
Mangoes must be mature when picked to ensure that they ripen to an acceptable eating quality and skin colour.
Immature fruit have poor eating quality and do not develop an attractive yellow skin colour.
Ethylene will not colour immature fruit.
The current minimum maturity standard for mangoes is 15 per cent dry matter for Kensington Pride types, and 14 per cent for common mangoes.
ETHYLENE
Ethylene triggers the ripening of mature mangoes. One day under ethylene is sufficient to start the ripening process.
Ethylene can be injected into the ripening room using the shot method at a concentration of 100 ppm, or continuously injected using the trickle method at a concentration of 10 ppm. With the shot method, the room must be ventilated three times during the day for five to ten minutes with the doors open and then re-injected with ethylene. The main benefit of ethylene is a more even rate of ripening within each box.
TEMPERATURE
Temperatures above 25 degrees celsius must be avoided. At high temperatures, the flesh will soften but the skin colour will not change completely to yellow. Some green skin colour is retained and the mangoes appear a motley yellow/green colour. Fruit rots are also more severe at high temperatures.
Ripening below 18 degrees celsius is not recommended, as even though the skin colour will change to yellow, flavour development is reduced.
Mangoes must be held at 20 to 22 degrees celsius following the ethylene treatment until the fruit has reached the stage of ripeness ready for sale. The total time from placing the fruit under the ethylene to eating ripe fruit, ranges from six to ten days.
Depending on maturity, flesh will start to soften and the skin show the first sign of yellowing after one to three days following the ethylene treatment. The fruit will then take another four to six days to reach eating ripe and develop full yellow skin colour.
Once mangoes have reached the stage of ripeness ready for sale, the fruit can be stored at 13 degrees celsius to slow down further ripening.
HUMIDITY
A relative humidity of 90 per cent is recommended during and following the ethylene treatment. Relative humidities below 90 per cent may lead to moisture loss and shrivelling.
The current cost runs at around 25 cents per package to use the ripening room, so it is quite economical.
DATE: November 1991
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