How to Keep Avocado from Turning Brown, According to a Food Scientist

You know that moment when you cut open an avocado and it has a gorgeous hue and a perfect texture? Yep, there's nothing like it. But what feels like seconds later, every avocado lover has also experienced the fruit turning brown and losing its drool-worthy appearance.

We asked food scientist Makenzie Jackson, MS, why avocados turn brown in the first place, how to keep avocado from turning brown, and how to differentiate between a brown and rotten avocado. With her help, you'll be eating perfectly-ripe avocados for life.

Why Do Avocados Turn Brown?

You've probably noticed that soon after cutting open an avocado, it turns brown. According to Jackson, that's totally normal—and there's a scientific explanation.

"Cut avocados turn brown due to an enzyme present in the avocado called polyphenol oxidase (PPO) that oxidizes polyphenols, causing a brown color to develop. It happens on a molecular level," she says. "The PPO is present in most fruits and vegetables, and a similar reaction can be seen in sliced apples."

Now that we know why it happens, how can we keep avocados from turning brown? Good news: Jackson says it's actually pretty easy with the right tricks up your sleeve. But first, let's dive into the two different types of brown avocados.

Brown Avocados 101: The Good and the Bad

If the Avocado Turns Brown After Cutting It Open:

As previously mentioned, an avocado that turns brown after being cut open is totally normal due to the reaction that takes place. Jackson says the brown color will become noticeable over the course of an hour or more, but it begins to happen as soon as the avocado is cut.

The good news is even if the avocado turns brown, it's perfectly safe to eat: "Avocados can definitely be eaten brown if they've changed color after cutting them," she says.

If the Avocado Is Already Brown:

Now, how about avocados that are already brown when you cut them open? There are two scenarios to take note of here.

According to Jackson, if you notice that the avocado has a few brown spots, it's still totally fine to eat and enjoy—they're most likely bruises. If you can't get down with smashing bruised avocado on your toast, she recommends using them in a smoothie, brownies, or avocado chocolate pudding.

If you cut the avocado open and it's mostly brown and stringy, Jackson says it shouldn't be consumed. If it's moldy on the inside, it's also not safe to eat. If you're still not sure, give it a sniff: "The odor of an avocado should be sweet and slightly nutty," she says. "If it smells off, don’t eat it."

How to Keep Avocado from Turning Brown

So you just cut open an avocado, and you don't want your unused half to turn brown. Luckily, there are some solutions that can keep it looking fresh.

First, grab an Avocado Hugger. It's a Brightly team favorite for keeping your leftover avocado half fresher for longer. Jackson also has a hack: Grabbing some lime or lemon juice.

"In terms of science, ascorbic acid will hinder the activity of the polyphenol oxidase," she says. "Ascorbic acid is found in citrus, so lime or lemon juice squeezed over the avocado will work well."

No citrus juice on hand? No worries. Jackson says you can also submerge your leftover avocado in water. "[This] would help prevent oxygen from reaching the polyphenol oxidase and hinder the browning reaction," she says.

Any avocado that doesn't last can be composted alongside your other food scraps in a trusty kitchen compost bin. That way, your avocados either go in your belly or the bin—never in the trash. And if you need a use for your avocado pit, we have plenty—including turning it into a free houseplant!