Lemonade Is The Secret Ingredient That Keeps Apples From Browning

We've all witnessed how apples turn brown after being cut open and exposed to air. Fortunately, there are a number of ways to prepare sliced apples to slow the browning process. One way to keep your apples from turning brown after cutting them, for instance, is to soak them in salt water. That being said, if salty apples aren't your thing — and we can't blame you — we have a slightly more appealing method that entails soaking your apple in a classic lemonade recipe. The lemonade (both liquid and the powdered pre-fix kind) essentially serves as a barrier between the apple and the air, keeping it from oxidizing.

Of course, if you opt to use the lemonade-soak method, it's worth noting that your apple slices will carry a citrusy flavor that can change the overall taste of the apple. You can also spritz the slices with lemon juice for similar (hopefully milder) results. All in all, though, these methods are arguably better than eating an apple that's gone brown and mushy.

The science behind using lemon juice to preserve apple slices

We know that lemon juice and lemonade keep apples from browning, but how exactly does this work? First, let's look at what causes apples to brown at all. Apples contain an enzyme called polyphenol oxidase or PPO, and compounds called polyphenols, with the two ideally separated by membranes. Cutting into an apple exposes these two to each other, as well as to the outside air. Through a chain of chemical reactions, this combo creates melanin, which — as you might guess — gives the apple a brown color.

Here's where the lemon of it all comes into play. Lemon juice contains ascorbic acid, perhaps better known as vitamin C. The acid protects the PPO from reacting with the air, and as a result, the apple doesn't turn brown. In fact, a calcium/vitamin C combo is precisely why McDonald's apple slices don't turn brown despite being exposed to air for who knows how long. Who would've thought there was so much behind the lemonade/lemon juice method?