Post harvest Management of Horticultural Crops (2+1)

Typical banana ripening process

a. Batch/shot process - in which the chamber is charged with ethylene gas at once to a concentration of 20-200 µL-1. The chamber has to be ventilated after 24hours to prevent the accumulation of CO2. CO2 Concentration should not exceeds 5000 µL-1 (0.5%) to allow personal to enter the to inspect the fruits. If the chamber is poorly sealed, it may be necessary to recharge the chamber with C2H4 after 12 hours.
b. Trickle/flow process – ethylene is introduced into the room slowly in thin stream continuously. into the chamber at a rate just sufficient to maintain the required concentration. The ripening chambers should be ventilated at the rate of about one room volume each 6 hours, to prevent he accumulation of CO2. In practice it not necessary to install a ventilation system in rooms < 60 m3 because they have natural air leakage rates higher than the required minimum rates(Fig.).

When banana is placed in chamber so as to expose at least two faces to the circulating air, ensuring that fruits temperature are even. Or fruit is packed in vented cartoon, unitized on pallets, and fruit temperature is controlled by forced air temperature. A minimum air flow of about 0.34 L/sec.kg of banana is required. Regulating RH during the course of ripening is important for banana. A RH range of 85-90% has been recommended at stage 2(green, trace of yellow), but this should be reduced to 70-75% during the later colouring stages to avoid the skin splitting. If RH is high, fruits will become too soft and may split and if it is low it may cause weight loss, poorer colour and more blemishes on fruit. Regular cleaning with chlorine is require to avoid mould growth due to high RH during storage.

It is important to harvest at the correct stage of maturity otherwise quality will be inferior after ripening. At full maturity it is only necessary to hold fruit at desired temperature and RH and ethylene is not always necessary to ripen fruits, some fully developed fruits produce sufficient C2H4 to ripen itself and adjacent fruit(triggering effect).