Controlled Atmosphere Ripening – Part 3 – All about Ethylene Gassing

All about Ethylene…

How much ethylene gas is enough?  Can you use too much ethylene?  For how long do you gas?  Can you / should you use fresh air ventilation while gassing?

If you ask five different people, you might get 10 different answers <g>.

We have a number of installations, where the ripening rooms are equipped with ethylene sensor gassing control.  These rooms also have carbon dioxide sensors, to control fresh air ventilation automatically to a chosen setpoint.

Through working in partnership with our ripeners, we have been able to learn some interesting things about ethylene gas control.

First, when a room starts to gas, if the gas is working, the carbon dioxide (CO2) level in the room will rise.  This is a natural result of the increased respiration of the fruit, as it begins to ripen.  Higher CO2 levels, create a “modified atmosphere”, displacing oxygen, and can slow the ripening process.

So, we recommend using fresh air ventilation during gassing, to maintain consistent levels of oxygen and CO2 at all times.

Does this use more ethylene gas?  Yes.  But if we use the ethylene sensor to control the ethylene gas level, to 50 ppm, or some other low level, we actually use less gas than uncontrolled ethylene generators can use.

Second, for how long do we need to gas the fruit?  The primary contributing factor, for how long we need to gas, to ensure that all fruit in the room is initiated into ripening, is the temperature of the fruit.  At higher temperatures, the gassing duration can be shorter, not more than 24 hours.  At lower temperatures, we might need to gas for 36 or 48 hours.

Pressurized ripening rooms help to ensure that all fruit in a room gets uniform temperature, airflow, and exposure to ethylene gas.

Third, if you want to slow down ripening, set a colder fruit temperature, and turn up your CO2 control to a higher level, such as 2% or 3%.

If you have any more questions, feel free to posts your questions or comments here, or contact me:  [email protected].

Or check us out here:  www.GlobalRipening.com or www.NE-Postharvest.com.