Fruit Ethylene Absorbent for Storage

- Sep 30, 2017 -

Ethylene gas is a harmless, odorless, colorless gas that is produced from both natural and man-made sources.  The ethylene gas molecule is very reactive and is readily oxidized into a state that will not do damage to produce.


There are several ways that may be used to remove ethylene gas from produce storage areas. One of the simplest and safest methods is to oxidize it with sodium permanganate.  This reaction can reduce ethylene gas to extremely low levels. Sodium permanganate (NaMnO4) is used in a number of familiar applications, such as in drinking water and air treatment systems. 


The carrier medium for sodium permanganate can vary, however, for the home market, a natural zeolite is used.  Zeolite is a pure form of ancient volcanic ash that has a very high crystalline surface area, providing an ideal substrate for the ethylene gas oxidation to occur.


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Natural zeolite is often used as an odor absorber and a humidity stabilizer in refrigerators, closets, and automobiles. The very high surface area traps molecules and absorbs water when humidity is too high - releasing it back into the atmosphere when it gets too dry. Of course, the zeolite serves those purposes as well, but its primary function is to remove ethylene gas from the produce bin.


The reaction between the ethylene gas and sodium permanganate oxidizes the ethylene gas away and, of course, decreases the available sodium permanganate too. The amount of sodium permanganate available will typically last at least 3 months in most home refrigerators and dry storage areas. After 3 months the sachet should be replaced with a new one. 


Consumers can also recycle the spent zeolite by sprinkling it onto plants and flowers in the household.  Zeolite is a natural soil and the MnO2 provides trace minerals to the soil, making it a very good fertilizer.