What Causes Fruit To Ripen?
Posted: 15/11/2017
Updated: 15/11/2017
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Have you ever wonder why all of a sudden, all your fruits are rotting faster than expected?
One bad apple can actually spoil the (whole) bushel. You might be storing all the wrong fruits and vegetables together.
Most fruits and vegetables produce a natural plant hormone called ethylene naturally throughout their life cycle and also in response to a variety of stresses such as being damaged mechanically or by disease, drought, flooding and so on (1).
Ethylene released in the form of gas influences the growth, development, and ageing (senescence) of all plants. It acts as a natural ripening agent to help make fruits to softer and sweeter and ready for consumption (2).
How to Control Ethylene to Prevent Quick Spoilage
However, high ethylene exposure can cause fruits and vegetables to turn yellow or brown and the riper it is, the more ethylene gas it produces.
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Thereby, if a fruit is going off, you should remove it from other fruits and vegetables so that it does not accelerate the ageing (rotting) process for others.
Not all fruits and vegetables produce the same amount of ethylene gas. In general, fruits tend to produce more than vegetables do. In addition, some fruits are more sensitive to these gases meaning it would take a shorter time to ripe than others. A list will be provided below.
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Keep ethylene-producing fruits and vegetables separated from ethylene sensitive fruits and vegetables
Additional response to ethylene gas (3)
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Browning and russet spotting of fresh produce
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Yellowing of cucumbers, broccoli and Brussel sprouts
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Loss of crunchiness in apples
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Citrus fruits rind breakdown
How to Use Ethylene to Speed up Ripening
On the other hand, if your bananas are green and avocados are hard but you wish to eat them soon, ethylene can come to the rescue.
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By placing an unripe fruit in a container or paper bag, it concentrates ethylene which speeds up the ripening process
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Add another high ethylene producing fruit such as a ripe banana in the bag can also speed this up
Safety
Ethylene is considered safe unless at high concentrations (>1000 ppm) which can cause dizziness and can be highly explosive.
In contrast, calcium carbide that is used in some countries is NOT. When it comes into contact with moisture in the air, it produces acetylene gas which is an artificial ripening agent. Industrial-grade calcium carbide may contain traces of arsenic and phosphorus which is highly toxic to human health making it illegal in most countries (4, 5).
List of Fruit and Vegetables
Fruit & Vegetables
Ethylene sensitivity
Ethylene production
Very High
High
High
High
Very Low
Moderate
High
Very High
Moderate
Moderate
Low
Low
Low
Low
Very Low
High
Very Low
High
Very Low
High
High
Moderate
Very Low
High
Very Low
High
Low
High
Low
Moderate
Very Low
Moderate
Moderate
Low
Very Low
Very Low
Low
Low
Low
Moderate
Low
Moderate
Very Low
Moderate
Low
High
Very Low
High
Very Low
Moderate
Very Low
High
Moderate
Moderate
High
High
Very Low
High
Very Low
Low
Very Low
Moderate
High
High
High
High
High
High
Low
Low
Low
High
Moderate
Very High
Very Low
Moderate
Moderate
High
Low
High
Low
Low
Low
Moderate
Low
Low
Very Low
Low
High
Low
Very Low
Very High
List of ethylene producing and ethylene sensitive fruits and vegetables (6, 7, 8, 9).