It’s no secret that when you cut an apple, they start to turn brown on the surface. This is due to oxidation. After testing several methods to keep apples from changing color right away, the best solution may surprise you!
A fresh apple is a delicious snack. It’s also a popular fruit to slice or dice and add to baked goods like cakes, pies, and muffins. When cutting an apple, a dark hue usually appears on the white flesh. This is common when making an apple pie. The color change can happen within 15 minutes!
Apple slices that have turned brown on the surface are safe to eat. However, it’s unattractive, especially when the fruit is the star of the dish. If you’re not eating or using the apples right away, a few simple tricks can slow and reduce color change. Below are the results of the four tested methods: plain water, acidulated water, honey water, and salt water.
Why do apples brown once cut?
When you cut the apple, the cell walls rupture and release an enzyme called polyphenol oxidase. When the flesh is exposed to oxygen, the enzyme reacts with polyphenols in the apple, causing a chemical reaction. This creates visible brown pigments called melanins. Browning cannot be reversed, but oxidation can be slowed.
How to keep sliced apples from browning
Several methods can stop the oxidation process. You can create a protective barrier between the exposed flesh and the air or add an ingredient to slow down browning. After testing different levels of ingredients and soak times to reduce browning, I recommend these simple anti-browning methods:
- Submerge in water: Add cut apples to a bowl of cold water, then place a paper towel on top to reduce oxygen exposure.
- Acidulated water: Combine 1 teaspoon of lemon juice with 1 cup of cold water. Submerge the apples for 5 minutes, then drain and rinse well.
- Sweetened water: Combine 1 tablespoon of honey with 1 cup of cold water, and stir to dissolve. Submerge the apples for 5 minutes, then drain and rinse well.
- Salted water: Combine ½ teaspoon salt with 1 cup cold water, and stir to dissolve. Submerge the apples for 10 minutes, then drain and rinse well.
Watch how to pick, cut, core, and more!
Apple treatments
Several types of apples are available at the store, but I used a red apple to test the anti-browning methods for consistency. It browns faster than other varieties because it has a lower level of malic acid. I sliced them 1/2-inch thick for the tests.
I included a control, observed the color change at room temperature for 24 hours, and refrigerated immediately after treatment for five days. Below are my findings.
Untreated
Apples left on the counter at room temperature start to change color around the 15-minute mark. This simulates how long a home cook typically takes to prepare the ingredient for a recipe. After an hour, they turned an intense, unappealing brown.
Even after storing them covered in the refrigerator, the apples were unattractive. Unless you’re ready to eat for a snack with peanut butter (my kid’s favorite!), you’ll need another method to stop browning.
Water Treatment
Covering the apples with tap water immediately after slicing greatly protects against oxidation. Pair that with placing a paper towel on top of the water, which prevents the slices from floating on the surface and coming into contact with the air.
I recommend doing this method when cutting a pound or more of apples. The water-covered apples also did well when stored in the refrigerator, compared to no treatment.
Acidulated water treatment
I tested levels from 1 teaspoon to 1 tablespoon of lemon juice in 1 cup of cold water, soaking for 5 minutes. The sour taste became much more noticeable as the amount increased. Although the ascorbic acid in the lemon acts as an antioxidant and the citric acid in the juice creates a low-pH environment that slows enzyme activity, too much is not always better.
At 1 tablespoon, the apples softened too much and turned even browner than the control. The cell walls broke down and got mushy from too much acid. I found that just a tiny amount, 1 teaspoon, was ideal for keeping the apple from browning and retaining texture.
Honey water treatment
You will love this method if you like a hint of sweet, floral taste to your apples. Honey contains a peptide compound that deactivates the polyphenol oxidase enzyme and prevents browning. I tested 1 to 2 tablespoons of honey in 1 cup of cold water, soaking for 5 minutes.
The 1 tablespoon amount keeps the flesh brighter white, whereas double the amount lets the golden hue soak into and transfer to the fruit. Honey is not cheap. I recommend using the lower amount for better results.
Salt water treatment
Salt is a known preservative, so it made for an exciting choice to prevent browning. The sodium inhibits the activity of the browning enzyme, and it worked! I added a small amount, ½ teaspoon, to 1 cup of cold water. I soaked them for 5 to 10 minutes and found that the longer time prevented browning longer.
Don’t soak longer than 10 minutes, or the apples will start to taste briny. Rinse and drain before storing in the refrigerator. This method kept the apples freshest, with no noticeable flavor or texture change.
The best method to keep apples from turning brown after cutting them
For short-term storage (within 12 hours): Submerge in water with a paper towel on top. It’s easy and economical. Under the water, the apples aren’t exposed to air, and the paper covering the surface creates a physical barrier. I use this method when slicing pounds of apples that I will cook or bake the same day, like for apple crisp, apple crumble, or Dutch apple pie.
For long-term storage (12 hours to several days): I recommend the salt water method. This is great for refrigerator storage, especially if you are prepping ahead of time for a spiralized apple salad or packing school lunches. Salt is a preservative; even a tiny amount helps to interfere with oxidation. The flesh was a lovely bright off-white, even after 24-plus hours, with little effect on the taste or texture.
Antioxidants in the Kitchen: Other Foods That Turn Brown
The same browning reaction happens in other produce that contains polyphenol oxidase, like avocados, pears, bananas, and potatoes. In cooking, an antioxidant is anything that slows that reaction down. Ascorbic acid (vitamin C) in lemon and lime juice is the most common, which is why so many recipes call for a squeeze of citrus.
- Avocados: Toss cut avocado with a little lime or lemon juice, and press plastic wrap directly onto the surface of guacamole to keep the air out. Here’s how to cut an avocado without making a mess.
- Pears: Pears brown just like apples, so the same plain water, lemon water, or salt water soak works well.
- Bananas: Sliced bananas darken quickly. A light toss with lemon or pineapple juice helps in a fruit salad or tropical fruit salad, and freezing bananas is the best way to save them for later.
- Potatoes: Cut raw potatoes turn gray or brown when exposed to air. Keep them submerged in cold water until you’re ready to cook.
Apple Recipes to Try
Frequently Asked Questions
Yes! It’s best to submerge the apples in a saltwater solution for 10 minutes, then rinse them with water before storing them in the refrigerator. This prevents browning for at least 24 hours, and up to several days.
Soak sliced apples before storing them. Mix ½ teaspoon salt with 1 cup water, soak for 10 minutes, then rinse with water. Alternatively, use 1 tablespoon of honey and 1 cup cold water, soak for 5 minutes, then rinse. Portion the slices, and place them in an airtight container or resealable bag, pressing out as much air as possible for 3 to 5 days. Sliced apples are also perfect for apple nachos, or bake them into crispy apple chips.
Soaking apples in water, lemon juice and water, honey diluted with water, or lightly salted water for at least 5 minutes helps prevent browning. Rinse, cover, and store in the refrigerator as soon as possible to reduce oxidation.
Enzymes like polyphenol oxidase are proteins that denature when exposed to extreme conditions like low pH or high temperature. That is why citric acid or acidic lemon juice is added to store-bought apple products to reduce enzyme activity. Blanching sliced or diced apples for a few minutes in boiling water stops the browning reaction. Unfortunately, it will soften slightly. If you go the cooking route, plunge them immediately into an ice water bath.
How to Keep Sliced Apples from Turning Brown
Ingredients
- 1 apple, sliced or diced
- 1 cup cold water
- 1 tablespoon honey, optional
- 1 teaspoon lemon juice, optional
- ½ teaspoon table salt, sea salt, or kosher salt, optional
Instructions
- Water Method – In a medium bowl, add water and apples. Place a piece of paper towel on top of the water to create a protective barrier. Drain when ready to use or store.
- Lemon Juice Method – In a medium bowl, add water and lemon juice, stir to combine. Submerge the apples for no more than 5 minutes. Rinse with cold water and drain.
- Honey Method – In a medium bowl, add water and honey, and stir to combine. Submerge the apples for no more than 5 minutes. Rinse with cold water and drain.
- Salt Method – In a medium bowl, add water and salt and stir to combine. Submerge the apples for no more than 10 minutes. Rinse with cold water and drain.
Notes
- Serving Size: Based on a large apple (approximately 3.25″), about 2 cups slices.
- Storing: Place sliced or diced apples in an airtight container or plastic bag with the air removed for 3 to 5 days.
- Freezing: Store in a single layer in a large resealable bag. Fruit can be frozen for up to 6 to 9 months.
Nutrition Facts
Percent Daily Values are based on a 2000-calorie diet. All nutritional information is based on estimated third-party calculations. Each recipe and nutritional value will vary depending on the brands you use, measuring methods, and portion sizes per household.
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