Ethylene (C2 H4) is a naturally occurring hormone, that- is produced by climacteric fruits when they are mature.
As fruits are harvested immature to enable them to be transported over long distances, the ripening cycle has to be initiated by dosing them with an external stimulus.
Over the last twenty years this has been done with Calcium Carbide, which gives off Acetylene on absorbing atmospheric moisture. Though not being the actual hormone Acetylene being of the same chemical group has a similar effect on the fruits, but not in totality. Among other biological processes in ripening Starch to sugar conversion is catalyzed by ethylene to the maximum. Only ethylene-ripened fruits can develop flavor as all the natural biological processes are mimicked, as they would have been when the fruit was being tree ripened.

System for Ethylene Ripening of Mangoes

Room:
An insulated airtight room, which can hold the produce, allowing 30 % free volume is required.

Temperature:
Different fruits need different temperatures to get optimum ripening, the rough thumb rule is that the temperature for ripening will be the lowest possible temperature the fruit can withstand without injury. Generally all fruit ripening temperatures fall between 15 deg cent. to 36 deg. cent. A refrigeration system capable of removing the respiratory heat is required.

Humidity:
Humidity plays a major role in the ripening process of the fruits. Low humidity gives the fruit a dry look, which is because of moisture loss. The fruit color deteriorates causing market price losses.
We maintain humidity by keeping the Delta temperature between the Evaporator and the room air as low as possible so that the water from the air does not condense thus keeping the humidity as high as possible. This is brought about by a microprocessor controller and secondary coolant systems.
A ultrasonic transducer based humidifier capable of converting 600 ml.of water to fine mist below 10 micron per hour is supplied where humidity is difficult to maintain.

Ethylene:
A catalytic Ethylene generator capable of bringing ethylene levels to 400 ppm in closed rooms of 200 cu. meters is provided. This can be optionally controlled from the central microprocessor unit.

Carbon dioxide:
Carbon dioxide above 1 % is detrimental to the ripening process.
The central microprocessor unit controls Ventillation. This ventilates the rooms on a time-based basis or optionally by actual values monitored by sensors.
A carbon dioxide sensor is used in an automatic closed loop system as an option.

Ventilation:
Every fruit respires and from time to time air changes are necessary as oxygen levels drop and co2 levels increase. In order to decrease co2 levels air changes are effected by a
specially designed valve, which closes tight, shut when not ventilating.

 

Inputs Courtsey Reena Farms