Stop Banana Slices From Browning With A Quick Citrus Hack
Bananas are one of America's favorite fruits. This best-selling grocery staple is affordable and boasts plenty of nutrients, from fiber and potassium to vitamins B6 and C. While you might eat bananas straight from the peel as a quick, healthy snack, you can also slice them up and add them to all kinds of meals. Preserving their freshness can be tricky, though. After all, whether you like to cut up bananas for overnight oats or a fresh fruit salad, the last thing you want is for them to turn an unappetizing, mushy brown.
Once bananas are peeled, sliced, and exposed to air, they tend to change color. This is because of a process known as oxidation, which affects fruits from apples to avocados. Fortunately, there's a simple hack that stops browning in its tracks — or at least slows it down enough that it won't ruin your breakfast or potluck dish. All you need is a bit of citrus. After cutting up a banana, just spritz the slices with the citrus juice of your choice.
A little acid goes a long way
You're probably aware that bananas bruise easily, and the insides turn brown for the same reason: Enzymatic browning and oxidation. Fruit tissue that's damaged by age, temperature, or rough handling releases a copper-rich enzyme as its cells split open. The enzyme in question, polyphenol oxidase (PPO), doesn't mix well with oxygen. In fact, when it comes into contact with the air, it breaks down completely. PPO's phenolic compounds oxidize into quinones, a different compound which then reacts to form melanin. This dark brown pigment is well-known for its role in coloring hair and skin, but it also colors bruised and browned bananas.
But how can this process be stopped? The answer lies in yet another chemical reaction. To halt oxidation in its tracks, PPO and its phenolic compounds can be denatured with acid. Since lemon juice, lime juice, and orange juice are all great sources of citric acid, they can prevent the enzyme from working properly, thus stopping banana slices from browning.
Thankfully, this trick is simple and cost-effective, especially since you likely have a citrus fruit (or at least a bottle of its juice) handy. If you don't, vinegar can also work in a pinch. If you're worried about your banana slices tasting tart, there's a sweeter solution: Mix a little simple syrup with lemon or lime juice and coat your banana slices in it.
Other ways to prevent banana slices from browning
Proper storage and timing can also keep your bananas from browning. Depending on what you're cutting up bananas for, you might be able to hold off until the last minute. Keeping the peel on for as long as possible can help preserve a banana's freshness and flavor while limiting when and how long it's exposed to oxygen. You can even slice a banana with the peel on, then individually peel each slice before eating.
If you're more concerned about saving time during meal prep, the citrus method is by far the easiest solution. Of course, how you store your citrus-coated banana slices can also affect the browning process. Slow down oxidation and discoloration even further by sealing and refrigerating slices in an airtight container, as the low temperature helps reduce enzymatic activity. That said, it's best to keep cut bananas in the door or on the top shelf where your fridge is warmest, as tropical fruits can develop "chilling injuries" (which include browning) at temperatures below 45 degrees Fahrenheit. Finding the coolest — not the coldest — spot in your fridge might make a big difference for your bananas after a few days of refrigeration.
No matter what you're cutting up bananas for, the fruit can be difficult to keep fresh once it's peeled. With some citrus juice and smart storage strategies, however, your sliced bananas will look and taste fresh for longer.