Why the skin of a banana turns black in the refrigerator?

Bananas have become a staple in many people’s kitchens. It would not be easy to imagine the time when this delicious yellow fruit was still regarded as exotic now that we can see them everywhere we go, be it from the convenience store, coffee shop, or supermarket.

A song was even created for it entitled ‘Chiquita Banana,’ which helped people determine when bananas are perfectly ripe. One line though, tells not to put bananas in the fridge. Yet some people didn’t mind the warning and did so, only to find out that the fruit turned black inside the refrigerator. But what makes it happen? Why does a banana’s skin become black once inside the fridge?

The skin of a banana is composed of plant cells and tissue. Its tissue possesses a compound called phenolic, responsible for the distinctive yellow color of the banana. The fruit produces natural acids that instigate its ripening process. However, when placed in cold temperatures, the creation of these natural acids takes a downturn, so is the ripening process.

Now, the cold temperature, be it from the environment or through refrigeration, causes the cell walls to break down, turning the banana peel to turn black. Cell membranes begin to weaken and become vulnerable to leaking. When that happens, the phenolic compounds present in the banana combine with polyphenol oxidase. As a result, the former oxidizes and releases a melanin product, which turns the banana’s skin entirely black.

With the said process occurring in bananas, most selling companies advise refrigerating the banana only when it has reached its peak ripping stage. That way, you can preserve the banana longer as placing it in the refrigerator dramatically slows the transformation of starch into sugars, and even halting the entire ripening process.

While the banana’s skin will begin to look rotten due to reaction with the phenolic compounds and the polyphenol oxidase, it won’t have much impact on the flesh itself. A black peel may seem unappealing but remove it, and you will notice that the banana has the same sweet taste you love.

But, never pop a green banana or one that hasn’t reached your desired level of ripeness. Doing so will put a halt on the ripening process of the fruit. It would be able to continue ripening even if you place it back to room temperature, affecting the banana’s sweetness.

If you have a ripe banana, place it in a fridge, and you may keep it for around a week. Expect that its skin will turn black, though. However, it will last remarkably longer compared when it is under average room temperature. But, if you really find black-skinned bananas unappetizing, there are other options you can try to keep your bananas fresh. One way is by placing the banana from other fruits or even other bananas. Bananas tend to release huge amounts of ethylene, which activates and speeds up the ripening process drastically.

On the other hand, if you want to get your green bananas ripe sooner, place them with fruits and vegetables. Then, leave them overnight in a paper bag. That will allow ethylene to accumulate with the container without any escape room, causing the ripening process to accelerate.

Lastly, if you’re going to the supermarket to purchase bananas good for a week, a great tip is buying bananas from different hands. Through that, you can have varying ripeness, and you can eat ones that are ripe enough and store the others for the next few days. Make sure to keep them separately to avoid speeding up the ripening process, leaving you with indelible bananas.

More Readings:

Banana (Wikipedia)

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