Gordon Ramsay's Top Tip For Prepping Vibrant Avocados

It's a truth universally acknowledged that food tastes better when it looks good. For instance, bright green avocado is just more appetizing than an avocado that has turned a dull greenish-brown.

Avocado turns brown as it oxidizes. As soon as the green flesh hits the air after you cut into it, the process starts. The more air it is exposed to, the more brown it becomes. Once you dice it or mash an avocado, you've exposed even more of the flesh to oxygen, and it will brown all the more rapidly — unless you can stop the process. On TikTok, chef Gordon Ramsay shows an easy way to keep avocados bright as you cook the remainder of your meal: drizzle lime juice on the cut side.

By slicing into the avocado, he starts the oxidizing process. But by hitting the fruit with a little lime juice, he dramatically slows that process, meaning the avocado will stay vibrant as he finishes his farmer's eggs and serves his dish. The reason comes down to chemistry: The citric acid in the lime juice delays the oxidation that causes browning. With just a light coating of citrus juice, your avocado will stay green and beautiful until you're ready to eat it.

Avocados contain compounds called phenols. Different phenolic compounds are responsible for a variety of aromas, flavors, and colors in plant foods. As per a 2020 study published in Biomolecules, many phenolic compounds may even have a cancer-fighting effect. In avocados, a phenol called polyphenol oxidase is an enzyme that, when exposed to oxygen, turns phenolic compounds into quinones, which are responsible for browning. Quinones are also toxic to bacteria, so their formation helps fight back against diseases that could hurt the fruit (browning is a side effect). This is the same reaction that causes other fruits, like apples, to brown after they're cut.

Browning can be slowed down by making those enzymes react, well, more slowly. The citric acid in many citrus juices makes the polymerization that causes browning to happen more slowly. By cutting into the avocado and then immediately hitting it with lime juice, Gordon Ramsay delays browning long enough to keep the avocado bright and ready for the meal.

The two main ways to keep a cut avocado from browning are to slow the enzymatic conversion into quinones or to cut off oxygen. This is why leaving the pit in was thought to keep avocado from browning. However, no known property of the avocado pit prevents browning except that the avocado flesh under it isn't exposed to air. This means that the random pit in the bowl of guac simply isn't going to work.

The idea of cutting off oxygen does work, however. This is the idea behind putting cut avocado in a bowl of water, which cuts off oxygen. However, this move also creates an environment where bacteria can thrive, increasing the risk of contracting a food-borne disease. It's safer to not store avocados in water, especially after they've been cut.

Onion extracts, chili pepper extracts, and unripe grape juice have been shown to inhibit browning, though they might change the taste of your avocado. If you don't have those ingredients, or lemons or limes, the best way to store avocado is to tightly wrap it in plastic wrap and stick it in the fridge. The cling film will cut off contact with the air, while the cold environment of the refrigerator will slow down the enzymatic process responsible for browning.