Why can't bananas be put in the refrigerator?

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Why can't bananas be put in the refrigerator?

Postby dylan92 on March 17th, 2009, 11:10 am 

Many people say that banana cant be in therefrigerator, im asking if any chemical reaction will happen if banana store in refrigerator?if anybody have any answer,please tell me,thank you
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Postby BioWizard on March 17th, 2009, 12:06 pm 

I think putting them in the refrigerator causes them to turn black, and it retards the ripening process.
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Postby Paris on March 17th, 2009, 2:36 pm 

Bananas turn black in the refrigerator mainly because of the chemical reactions in their peel.

A non-ripe green banana peel contains a plant hormone called ethylene. This gaseous chemical is responsible for helping ripen the banana to yellow color. At the same time, some natural acids are also being produced which regulate the ripening process and make the banana sweet (inside the banana, the large number of enzymes of Kreb’s cycle convert citric acid, mallic acid and oxalic acid into glucose, which turn the banana sweet during the process of ripening).

When someone puts a banana in the fridge, the production of these natural acids slows down as consequence of the cold temperature and, as a result, the ripening process of its interior slows down.

However, in cold temperatures, the physical state of cell membranes in the banana peel changes causing leakage of the enzyme polyphenoloxidase which oxidize phenolic compounds that leak from the vacuoles of the cells ( this enzyme polymerises them into polyphenols similar in structure to the melanin formed in suntanned human skin), and hence producing the dark colour.

Nonetheless, bananas can be stored in the refrigerator for few days. Despite the peel of banana becoming dark, its content will remain firm and delicious. Coating the banana with organic wax to prevent contact with the oxygen of the air can also slow down the blackening of the skin.

Another solution is to peel the bananas beforehand, put them in a sealed freezer bag and then storing them in the fridge. Coating them with little bit of fresh lemon juice can help to reduce its darkening process even more.
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Postby BioWizard on March 17th, 2009, 2:52 pm 

I knew that the darkening of the skin in the fridge was due to the release of an enzyme, since it wouldn't make sense that a nonenzymatic oxidative reaction would happen at 4C but not at room temp. I didn't know what enzyme though nor what the substrates were. Thanks Paris for the info.
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Postby wolfhnd on March 17th, 2009, 10:30 pm 

The darkening serves no purpose as far as I can tell?
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Postby Paris on March 18th, 2009, 12:01 am 

BioWizard wrote:Thanks Paris for the info.


You are welcome, Bio. It is a pleasure to exchange knowledge.
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Thanks

Postby dylan92 on March 19th, 2009, 11:14 am 

Wow!thanks,u solve my question,n u are good!You give a very detail answer!thanks a lot guys!
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Re:

Postby Fainche on January 18th, 2011, 1:19 am 

BioWizard wrote:I think putting them in the refrigerator causes them to turn black, and it retards the ripening process.

Yeah, I do agree with you man putting a banana in refrigeration cause them to turn in black. And easy to over ripe then the taste is changing also. So the banana can not put in inside the refrigeration.
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Re: Why can't bananas be put in the refrigerator?

Postby linford86 on January 31st, 2011, 12:12 pm 

Well, you can certainly put bananas in the freezer for a short time. I like eating frozen bananas and therefore do this all the time. However, I eat the banana as soon as it is frozen and therefore have never seen it blacken. It's interesting that this happens.
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Re: Why can't bananas be put in the refrigerator?

Postby zetreque on June 12th, 2014, 2:39 pm 

What was the conclusion here?

The census seems to be that the peel becomes black, but does the part we care about (the inside) actually ripen slower? I say yes it does from my experience. So despite the skin turning blacker (faster?) in a refrigerator, it still seems like a good idea if you want the banana to last longer.

It is just that the cold temperature slows the ripening of the innards but not so much the peel. Maybe it's not that it speeds up the ripening of anything, it just slows the ripening of some parts even more than others.

I also have been experimenting with slicing and freezing bananas. Yum!
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Re: Why can't bananas be put in the refrigerator?

Postby Watson on June 12th, 2014, 3:39 pm 

I think it is ethylene that helps ripen tomatoes when you put them in a paper bag. Apparently if you want to ripen an avocado, you put it in a paper bag with bananas, so tomatoes with bananas might ripen even faster than just the tomatoes.
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Re: Why can't bananas be put in the refrigerator?

Postby BioWizard on June 12th, 2014, 8:11 pm 

zetreque » 12 Jun 2014 02:39 pm wrote:The census seems to be that the peel becomes black, but does the part we care about (the inside) actually ripen slower? I say yes it does from my experience. So despite the skin turning blacker (faster?) in a refrigerator, it still seems like a good idea if you want the banana to last longer.


I believe that was it.
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