Ethylene And It’s Function In Ripening Fruits

10 minutes read. 

  

In this article:

• What’s Ethylene?
• How Common Is Ethylene Used?
• Is Ethylene Safe?
• What Range Of Ethylene Is Harmless
• Fruits you can ripe with ethylene
• Is Ethylene Explosive?
• Frequently Asked Questions
• Conclusion

What’s Ethylene?

Ethylene is an important, natural plant hormone.

It regulates the ripening and senescence (aging) of plants. Ethylene is normally produced in small quantities by most fruits and vegetables.

However, climacteric fruits, like bananas, avocados and tomatoes create larger amounts of ethylene and this release of ethylene starts several actions like increased respiration, more ethylene production, and changes in color, aroma, and flavor.

Fortunately, the onset of this internal ethylene production can be controlled.

Simply by applying the same type of ethylene that is gotten from cracking of natural gas particularly ethane.

How Common Is Ethylene Used In Ripening Fruits?

Ethylene has become the safest method of artificial fruits ripening in the world due to its resemblance nature with the fruit naturally occurring ethylene.

The ability of fresh fruits produce companies and distribution centers to apply ethylene allows the promotion of predicable ripening times and more uniform ripening the result is better quality and consumer eating experience.

Is Ethylene Safe if consumed from fruits?

Ethylene is Generally Recognized as Safe (GRAS) by the United States Food and Drug Administration (FDA).

Given the numerous amounts of food substances, the FDA does not categorize every one. Salt, pepper and vinegar are examples.

These, along with ethylene, all are within the category of food substances that, when used for the purposes indicated, in accordance with good manufacturing practice, are regarded by the FDA as generally recognized as safe (GRAS) for such uses.

What Range Of Ethylene Is Harmless For Ripening Fruits?

Ethylene has been found not harmful or toxic to humans in the concentrations found in ripening rooms (100-150 ppm).

In fact, ethylene was used medically as an anesthetic in concentrations significantly greater than that found in a ripening room.

However, ethylene is often targeted as the reason for difficulty in breathing in ripening rooms.

What can affect some people in the ripening room is usually either:

Carbon Dioxide (CO2,) levels: CO2, is produced by the ripening fruit in the room and levels increase over time.

Oxygen levels: Another thing is oxygen in the room, when loaded is taken in by the ripening fruit. This sometimes will make breathing in a ripening room difficult.

The increased CO2, and decreased oxygen levels are the main reasons for venting the ripening room.

Ethylene Action Slows At Lower Temperatures

At their minimum temperature levels, fruit is basically inactive and does not respond well to externally supplied ethylene.

Ethylene will penetrate most substances.

In fact, it will permeate through produce cardboard shipping boxes, wood and even concrete walls.

Fruits you can ripe with ethylene

Is Ethylene Used To Ripe Every Fruit?

Ethylene is harmful to many fruits, vegetables, and floral items.

While ethylene is irreplaceable due to its ability to initiate the ripening process in several fruits.

It can also be very harmful to many fruits, vegetables, flowers, and plants by accelerating the aging process and decreasing the product quality and shelf life.

The degree of damage depends upon the concentration of ethylene, length of exposure time, and product temperature.

If ethylene damage is suspected, testing for ethylene levels in the fruit should be performed. This will indicate if one of the steps below should be followed:

• Ethylene producing items (such as apples, avocados, bananas, melons, peaches, pears, and tomatoes) should be stored separately from ethylene-sensitive ones (broccoli, cabbage, cauliflower, leafy greens, lettuce, etc.).

• Also, ethylene is emitted by engines. Propane, diesel, and gasoline powered engines all produce ethylene in amounts large enough to cause damage to the ethylene-sensitive produce items mentioned.

• Ventilate the storage area, preferably to the outside of the warehouse, on a continuous or regular basis to purge the air of any ethylene

• Remove ethylene with ethylene absorbing filters. These have been proven in reducing and maintaining low ethylene levels.

Is Ethylene Explosive?

Ethylene is explosive at high concentrations.

At 27,000 ppm, just a spark can ignite ethylene and cause a deadly explosion. We have an entire section of our web site devoted to the explosions that can result from excessive ethylene: ethylene explosions.

However, when using our products as directed, reaching the explosive level is not possible. The explosive level is about 200 times greater than the level necessary to initiate ripening.

Always use our generators in ripening rooms that are 1600 ft3 or larger (45 m3).

Can Ethylene Be Used To Ripe Orange?

Ethylene is used to ‘de-green’ citrus.

This is a natural process that triggers pigment changes: the loss of green peel color by removing the chlorophyll, which allows the orange or yellow to fully cover the entire peel.

No loss of flavor is caused; this is merely a continuation of the natural plant process.

Frequently Asked Questions (FAQ)

What Is An Ethylene Generator?

Ethylene generator is small but powerful device for creating ethylene in a ripening room or chamber, the generator allows fruit to be ripened on a demand schedule. 

By introducing small, controlled amounts of natural ethylene into the room, several types of fruits, like bananas, avocados and mangos will begin a managed ripening process. 

This allows for perfectly ripened fruit to be delivered to the consumer, ready-to-eat!

Is Ripening Or De-Greening With Ethylene An ‘Artificial’ Process? What Does Ethylene Do To Fruit?

Ethylene is a natural plant hormone that regulates the ripening and senescence (aging) of plants.

Ethylene is normally produced in small quantities by most fruits and vegetables.

However, climacteric fruits, like bananas, avocados and tomatoes create larger amounts of ethylene and this release of ethylene starts several actions like increased respiration, more ethylene production, and changes in color, aroma, and flavor.

Fortunately, the onset of this internal ethylene production can be controlled.

The ability of fresh produce companies and distribution centers to apply ethylene allows the promotion of predicable ripening times and more uniform ripening…the result is better quality and consumer eating experience.

The additional externally applied ethylene merely accelerates the normal ripening process.

There are no important biochemical, chemical, or physiological differences between fruit ripened with the naturally produced ethylene has been the triggering mechanism or where additionally externally applied ethylene has triggered the process in the mature but unripe fruit.

For example, tomato fruit are not and cannot be “artificially reddened” by ethylene.

The normal tomato ripening process, which includes pigment changes – the loss of green chlorophyll and conversion of carotenoids into red lycopene pigments – can be accelerated and brought about earlier by externally applied ethylene, but this is a normal process.

In fact, some of the components of nutritional quality, such as Vitamin C content benefit remain intact.

Because of the fact that the fruits will be consumed after a shorter time interval from harvest as a result of ethylene treatments and hence, the initial level will not have degraded as far as the longer, un-accelerated process.

Related: Calcium Carbide Used In Ripening Fruits Is Toxic To Your Body; Here’s How?

Is Ethylene Really Necessary For Banana Ripening? Won’t They Ripen On Their Own?

Bananas are harvested mature but very green in order to survive the trip from the growing regions to destinations across the world. 

Along with a rise in pulp temperature and control of relative humidity and ventilation of carbon dioxide, an external ethylene application will trigger the proper ripening process to begin, which includes the fruit producing internal ethylene.

This natural process results in uniform, controlled and predictable ripening. 

Without this exposure to external ethylene, bananas will eventually soften, but the change in color will not be uniform and the peel will be dull, pale yellow, and unattractive, and perhaps inedible. 

What Is The Effect Of Ethylene On Fruit Ripening?

Ethylene can promote ripening in tomatoes, bananas, citrus, pineapples, dates, persimmons, pears, apples, melons, mangos, avocados, papayas and jujubes – a clear indication that the action of ethylene is general and widespread amongst a number of fruits.

It is clear that ethylene is a ripening hormone – a chemical substance produced by fruits with the specific biological phenomenon of accelerating the normal process of fruit maturation and senescence.

What do you mean ‘promote’ the ripening process?

Using tomatoes as an example, the life of a tomato fruit begins with fertilization of the flower ovules.

After fertilization, the young fruit goes through a short period of cell division which is then followed by a rapid period of growth as these cells enlarge.

During the final stages of growth and development, the tomato fruit reaches its full size and is now mature.

This period of growth and development, from fertilization to development of the mature fruit, requires about 45-55 days, depending on the cultivar and the season.

During the growth and development period, there are many chemical and physical changes occurring that have an impact on fruit quality and ripening behavior after harvest.

Ripening is the final stage of the maturation process when the fruit changes color, and develops the flavor, texture and aroma that makes up what we define as optimum eating quality.

The biological agent that initiates this ripening process after the fruit is mature is naturally produced ethylene – this simple plant hormone described and understood over 40 years ago.

While there are other factors involved in this “triggering” of the ripening process by ethylene, it is essentially a universal ripening hormone.

When this internal concentration of naturally produced ethylene increases to about 0.1 – 1.0 ppm, the ripening process is irreversibly initiated.

The process may be slowed, but it cannot be reversed once it is truly under way.

So, here is the key point: additional and externally applied ethylene, provided prior to the time that the naturally produced internal concentration reaches the required 0.1 – 1.0 ppm level, will trigger or initiate – “promote” if you will – this natural ripening process at an earlier time.

What Are The Factors That Result In The Poor Quality Fruit Sometimes Seen At Retail?

Let’s use tomatoes as an example.

Although many factors could be listed, there are four which play the dominant role in determining the quality of tomato fruits presented to the customer in the retail store:

• Variety

• Maturity at time of harvest

• Storage temperature during shipping and handling (this is probably the most common cause; tomatoes are often shipped or stored at improper temperatures, which causes severe taste loss…never allow tomato pulp temperature to go below 55°F!)

• Physical damage

Conclusion

Ethylene is an important, natural plant hormone.

Ethylene has become the safest method of artificial fruits ripening in the world due to its resemblance nature with the fruit naturally occurring ethylene.

Ethylene is Generally Recognized as Safe (GRAS) by the United States Food and Drug Administration (FDA).

Ethylene has been studied and found not harmful or toxic to humans in the concentrations found in ripening rooms (100-150 ppm).

In fact, ethylene was used medically as an anesthetic in concentrations significantly greater than that found in a ripening room.

While ethylene is safe you must follow all the required precaution to avoid unintended harm.

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