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When Good Bananas Go Bad

Have you ever wonder why bananas seem to go bad so quickly?

a collection of bananas, some with brown spots

Photo: Fernando Stankuns (Flickr)

Why do bananas get those ugly brown spots?

On this Moment of Science, When Good Bananas Go Bad.

Have you ever wonder why bananas seem to go bad so quickly? And why do they develop those brown spots?

Well, those spots are a natural part of the ripening process. You see, just like all fresh produce, your bananas are alive. They’re taking in oxygen to help them convert sugars into energy, and releasing carbon dioxide. This process is called respiration.

The quicker a fruit or vegetable respires, the quicker it ripens. For most fruits, the respiration rate slows down after the initial growth stage and the fruit ripens slowly. The growth and ripening process of bananas, however, is different. Although at first the banana’s respiration slows down too, when it’s ready to ripen, the banana’s pulp releases a chemical that increases respiration. This converts the starches in the banana to sugars and gives it its fabulous taste.

With all this respiration, the banana eventually processes all the starches available. And that’s when it begins to die. Those brown spots are rot and decay.

  • aj_doge

    Yah, the brown is rot and decay, however; it is also small monosaccharide sugar molecules, which means it tastes' good AND is healthy. Humans use these molecules as energy. The Process of Respiration breaks the fruits normally long polysaccharide chains down into it's smaller monosaccharide sugars. It is just condensed mono saccharide molecules Mmmmm sugar …

  • Robert H. Pike

    So here’s two solutions that work for me to slow “banana respiration”.
    1. Zip lock ‘em; and suck the air out of the bag.
    2. Keep the zipped bag in the warmest part of the fridge; the skins will get brown, but the flesh stays sweet a LOT longer.

  • bobbi

    wow so smart

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