- Avocados, like apples, turn brown when exposed to air. It’s actually a chemical reaction and not a sign of spoiled avocado.
- Compounds in the flesh are reacting with oxygen, with the help of enzymes, to produce brown pigments called melanin.
- The brown part of an avocado might look unappetizing and can taste bitter, but it’s still safe to eat.
- You’d have to leave an avocado out for a few days before it spoiled from oxidation.
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Following is a transcript of the video.
If an avocado is brown on the inside, it might not look pretty and might taste bitter. It’s still safe to eat, but the less browning there is, the better.
Narrator: Would you eat this avocado? How about this one? They’re actually the same, just one’s been sitting out for a few hours. And sure, one doesn’t look as good, but that doesn’t mean you should just throw it out. In 1989, the average American ate about one pound of avocados a year. By 2017, that amount had increased sevenfold.
But as much as we like to eat them, the struggle with browning avocados is real. Some people might try to prevent it by putting the avocado pit in the bowl, but it does not work that way. Just like with apples, bananas, and potatoes, the flesh of an avocado browns when it’s exposed to oxygen in the air. It’s a process called oxidation, and it happens when the oxygen reacts with compounds called polyphenols with the help of enzymes called polyphenol oxidase. This damages the tissue of the flesh, in the process turning it brown. But the brown color is not a sign that it’s spoiling. You’d have to leave it out for a few days before it spoiled from oxidation. That brown color is actually from a nontoxic chemical called melanin. It shows up in everything from fruit to the iris in your eyes.
Needless to say, that bowl of brown avocado won’t hurt you. However, the more oxidation that takes place, the more tissues it damages. For example, bruising or chilling an avocado for too long can lead to significant oxidation, which actually damages so much tissue that it changes the texture and flavor of the fruit so that it’s mushy and bitter. But a little browning won’t make a difference. To prove it, we did an experiment. We served green avocados and avocados that were left to brown for a few hours.
Gina Echevarria: “Okay, tastes like a normal avocado, I think.”
Abby Tang: “I don’t like that one. I don’t know why. I just like, it tastes a little bad.”
Clancy Morgan: “Pretty strong taste, I would say. Pretty strong avocado, earthy taste. But yeah, it tastes very ripe.”
Echevarria: “Yeah, pretty standard avocado.”
Tang: “It tastes like a regular avocado but rotten. Why did you feed me a rotten avocado?”
Echevarria: “I feel like that one actually tastes a little bit better.”
Morgan: “Oh. Oof.”
Tang: “This one doesn’t taste rotten, so that’s good.”
Morgan: “Okay, that is much more ripe, super mushy.”
Echevarria: “The other one kind of just tasted like wet paper, and this one actually tasted like something.”
Tang: “This one’s fine, I like it enough. It’s an avocado. They taste the same other than one tasted older.”
Cameraperson: “And that’s the first one?”
Tang: “The first one tasted older. It was, like, sour. And the second one tasted like a regular avocado.”
Narrator: How fast your avocado browns depends on the environment, like how much oxygen is in the air, what the temperature is, and how acidic it is. Warmer temperatures accelerate the chemical reaction, turning your avocado brown faster. But if you squirt some citrus on the top, the acidity prevents oxidation, and you can keep it looking fresher for longer. Either way, even though we couldn’t agree on which tasted better, both were perfectly edible. So next time you have some old avocado, don’t just throw it out. And if the unsightly brown ruins you’re appetite, just give it a quick stir, and voila.
EDITOR’S NOTE: This video was originally published in January 2019.