Wonder Contributors

A big Wonderopolis “Thanks!” goes out to Ethan from Wisconsin and Isabella from New York for suggesting we revisit today’s delicious Wonder of the Day!

Bananas are a sensitive bunch. Though they can withstand peeling, slicing, chipping, and frying, age is not so kind to them. At one time or another, nearly everyone has peeled back the skin of a banana to discover a mushy brown spot inside. But what makes good bananas go bad?

In order to understand banana bruising, first you must understand the banana’s ripening process. Meet ethylene. Ethylene is a hormone found in the peel of the banana.

When you buy a bunch of unripe green bananas at the grocery store, time and ethylene magically transform them into delicious, golden bananas. Unfortunately, ethylene has no stop button. When left uneaten, the ripening process will continue until the banana takes on a “bruised” appearance and eventually turns black.

You can’t prevent the ripening process from occurring, but one way to slow it down is by placing bananas in a cool location. You should also remove them from the bag when you bring them home from the market. Leaving bananas in the bag allows ethylene gasses to build up, causing the bananas to ripen very quickly.

This knowledge can work to your advantage, too! If you have a craving for a banana and the bunch is still green, placing a banana in a sealed bag will speed along the ripening process. Your sweet snack should be ready to eat in about 24 hours.

It’s important to remember to keep bananas out of the fruit bowl and away from other fruits if you want to delay ripening. If you place your bananas in a bowl with other fruits, such as apples or tomatoes (which also rely on ethylene for ripening), you may be surprised by what happens.

Ethylene released by neighboring fruits in the bowl can actually ripen your bananas! In fact, this is where the expression “one bad apple spoils the bunch” comes from. If one apple in a barrel begins to over-ripen and rot, it will cause the surrounding apples to do the same.

This is why fruit farmers pick and ship fruit when it’s still green, long before the ripening process has begun. Shipping under-ripened fruits ensures they are verging on peak ripeness when they hit the grocery shelves — and perfectly delicious by the time they finally reach your dinner plate.

19 Join the Discussion

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  1. I’m pulling those bananas out of the fruit bowl as soon as I get home! I am enjoying your wonders, and I think you ought to find a way to promote this to adults for their own enjoyment too.

  2. oh, well I like bananas!! but sometimes they are not all the way done and by that I mean they are not all the way ripe. I heard they are good for you. even if they are not im still going to eat them :)

    • That’s the spirit, jasmine monique’! Bananas ARE good for you! We think it’s great when you love to eat something AND it’s also healthy for you (you win twice)! Thanks for stopping by Wonderopolis today! :-)

  3. So now I can tell my friend that when a banana isn’t “done” she needs to leave it alone for a day. That’s really cool almost as cool as the ice cream sundae with maple syrup and bacon topping.

    • We think that kind of sundae sounds awesome, Kari! Thanks for visiting Wonderopolis today and for your comment! :-)

  4. I haven’t talked to you in a long time because of spring break I hope everyone had a good spring break. Bananas are one of my favorite fruit, do monkeys eat the bruises?

    • Welcome back to Wonderopolis, Brooke! It’s great to say hello again! We had an excellent spring break and we’re glad to know that you enjoyed your time, too! We think monkeys enjoy bananas so much that they don’t even worry about the bruises! They aren’t very picky when it comes to bananas! Thanks for sharing your comment, we’ll see you soon! :)

    • Welcome back, Corbin Is back! We like bananas too! We hope you learned more about bananas from this WONDER? What was your favorite thing you learned? Thanks for commenting! :)

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Have you ever wondered…

  • Why do bananas bruise?
  • What causes bananas to ripen?
  • How can you slow down the ripening process?

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Try It Out

We hope today’s Wonder of the Day left you feeling golden! Have even more fun with bananas when you ask a friend or family member to help you explore the following activities:

  • Are you an adventurous eater burned out on the same old grilled cheese? One of Elvis Presley’s favorite sandwiches was rumored to be the grilled peanut butter, banana, and bacon sandwich! If that sounds appetizing to you, give The Elvis a try the next time you have a craving for something toasty. It’s an easy, fun way to give an old favorite a new twist.
  • Can you get a banana inside a bottle without using your hands? You can if you use science! Check out the Banana Split science experiment online. You’ll need just a few simple supplies and a sense of WONDER! Have fun amazing your family members and friends with your scientific prowess!
  • Up for a challenge? See for yourself how time and ethylene affect the ripening process in groups of bananas. You’ll need an adult friend or family member to help you get four bunches of bananas from the store. You’ll also need a few other fruits, such as apples. Put one bunch of bananas uncovered in a bowl with the apples. Put another bunch of bananas uncovered by themselves on the kitchen counter. Keep one bunch of bananas inside a bag on the kitchen counter. Finally, put one bunch of bananas uncovered inside the refrigerator. Keep track of the different bunches over the next couple of days. Which bananas tend to ripen most quickly? Why? Share what you learned from today’s Wonder of the Day with your friends and family members, helping them to understand why the different bunches of bananas ripen at different rates.

Still Wondering

Who loves bananas? Monkeys, of course! In Science NetLinks’ Monkey Pay-Per-View Science Update, you’ll hear about an experiment in which monkeys were given a carefully measured amount of juice when they looked at, or away from, various pictures.

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Tomorrow’s chilly Wonder of the Day will have you learning more about the science of winter!

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