When apple season rolls around, it always feels that the kitchen fruit bowl goes from holding three or four apples to one million. Whether you’re baking some into a pie or crisp, or packing them into a lunchbox, invariably the sight of browned insides will make an appearance.
So what’s the best way to keep apples from turning brown? We did our homework—and ate through even more apples than usual—to find out.
In terms of the quality and duration of preservation, we found a clear winner. Hint: it involves salted water.
But when you factor in the ease—like how realistic it is that you’ll actually use that method—the results somewhat depend on the situation, namely whether or not you’ll have a sink (and grownup) handy to rinse those slices. Stay tuned.
Why Do Apples Turn Brown?
When exposed to oxygen, enzymes known as polyphenol oxidase (PPO) in an apple’s flesh will oxidize, or combine with the oxygen, which causes discoloration. If you’ve noticed that some apples brown faster than others, that might be because they have a higher concentration of PPO.
Methods We Tested
- Apple slices submerged in salted water for 10 minutes, then removed and sealed in a Ziploc. We used ½ teaspoon of salt in one cup of water, and we laid a paper towel over the slices to keep them from floating up to the surface.
- Apple slices submerged in unsalted water, then removed and sealed in a Ziploc. Here we also used the paper towel, which prevented the slices from hitting the air.
- Apple slices rubbed with a lemon half and sealed in a Ziploc.
- Apple slices reassembled into their original orb and secured with a rubber band.
- We had a control apple, where we didn’t interfere at all, so that we could compare the results to the methods above. We sliced the apple and left it in a bowl, exposed to air.
The Best Method to Prevent Apples from Browning
The winner? Apple slices soaked in salted water for 10 minutes, removed, and then sealed. In terms of appearance, texture, and stamina, keeping apples in salted water was the clear winner. The slices didn’t brown at all after sitting in the salted water for 10 minutes, after 30 minutes of being in the Ziploc or even an hour. After three hours, there was a hint of browning, but the slices remained impressively white. This method works well. The catch here is that when you’re ready to eat your apple, you must rinse it off, and even then, you still might taste a lingering hint of salt. It’s well worth it if you want an extra white apple.
Citrus-rubbed, sealed apple slices: Second place goes to preserving the apples with lemon juice, sealed in a ziploc bag or airtight container. Do this and your apples will brown ever so slightly after 30 minutes and a little more after an hour. They brown more but stay edible after three hours. The texture does not deteriorate at all. Here, again, you may need to rinse your apples if you don’t want to taste a hint of lemon.
Rubber-banded apple slices, the easiest way: Tied for second place, perhaps surprisingly, was keeping the apples rubber-banded together. The slices retain almost equal brightness and firmness to the lemon-rubbed and air-tight sealed apples, but the beauty of this method is that no rinsing is required. Packing apples for lunch? This method is the way to go.
Apple slices soaked in water for 10 minutes, removed, and sealed: By comparison, slices sitting in unsalted water for 10 minutes deteriorated in texture and browned a little after 30 minutes in the Ziploc. They also browned significantly after an hour. Soaking apples in unsalted water may be fine if you plan to cook the apples right away, but if you’re packing them to go, we wouldn’t recommend it.
We tested each method for keeping apples from browning, plus one control, where we simply left a cut, uncovered apple out in the air. We used the same type of apple, a Gala, and they were all around the same size. We sliced each apple down the middle, into quarters and then into eights.
Then we applied the respective method and waited 10 minutes. Next we removed the slices from the water and sealed them in a zip-top bag and compared them to the slices rubbed with lemon in a zip-top bag, and the apple held by a rubber band to prevent air exposure. We checked for browning after 30 minutes, one hour and three hours, checking the brownness and texture of the slices at each interval.
We chose this test because we figured that most people looking to prevent browning need to slice and pack an apple for a lunch or picnic, which means they need to “treat” the apple (e.g. soak in salted or unsalted water, rub with lemon juice, or just put back together) and then pack up the slices. After the initial 10 minutes, we started observing results of apple slices not exposed to air, because we know air is the number one cause of browning, and if you’re packing apples to go, it’s simple to keep them wrapped or bagged tightly.