apples are red inside
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Apples Are Red Inside (What’s the Cause & Are They Safe to Eat?)

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Apples come in a multitude of colors ranging from yellow, green, and pink to red. The difference in their skin color is due to the natural pigments they contain that develop as the apple matures.

But did you know that the flesh of apples can have varying shades as well? It’s not always white, as most people would assume. The colors cover the full spectrum ranging from light pink, all the way to deep purple and even black!

A relative newcomer in the fruit world, red-fleshed apples are still a rare sight; however, we’re sure that apple lovers and aficionados have heard of and tried this interesting new variety. 

So, why are apples red inside, and are they safe to eat? Apples are red inside because they either belong to a variant that has naturally red flesh or because it has reacted with the air and the oxidation process has turned the inside of the apple reddish-brown.

Regardless of the reason, you don’t have to worry about your apple having red skin. As long as it looks and smells alright, it should be good to eat.

Read on to find out more about what causes red flesh in apples, whether they are safe to eat, and how to tell if an apple has gone bad!

Apples Are Red Inside – What Causes Red Flesh in Apples?

Red flesh in apples can be caused by a variety of factors. While some varieties are specially cultivated for this unique flesh color, others have it exclusively due to environmental factors such as temperature and light intensity.

That being said, apples aren’t the only fruit that features high levels of pigmentation. Several varieties of berries, peaches, and plums are great examples, in addition to vegetables such as red cabbage.

Let’s discuss in detail the two main causes of red flesh in apples:

Cause #1: Naturally Red Variants

One reason why some apples have red flesh is that they are naturally cultivated to have this unique pigmentation.

red flesh in apples

Found in some regions of Central Asia and East Europe, they have been brought to the US where they are being bred to form more varieties.

The flesh of these apples ranges from bright pink to bright red and even orange. They also have different colored blooms as compared to the white blooms found in regular apple trees.

Depending on the tree, you may have light pink to bright pink blossoms on red-fleshed apple trees.

Most varieties of red-fleshed apples, however, tend to be too bitter and not the best for consumption.

For this reason, breeders decided to cross bitter-tasting red-fleshed apples with sweet and scrumptious white-fleshed apples to produce marketable apples with red flesh inside.

As a result, some varieties of red-fleshed apples are sweet while some may be a bit tart, as with other white-fleshed apples. Some even have subtle hints of berry and citrus flavors, while others taste like fruit punch!

Sweet-tasting red-fleshed apples are not only a novelty to cultivate but may also have antioxidant properties. They can easily be identified by cutting them open.

You will see that they are mostly colored completely through, either a deep red or a nice pink, instead of just on the surface.

If you are not familiar with them, they might seem odd to you and you might assume that something is wrong with them, but don’t worry, the coloring is 100% natural and edible.

Some common varieties of red-fleshed apples include:

Cause #2: Oxidation Process

The reason why your apples may sometimes turn reddish-brown from the inside is due to the oxidation process wherein the apple reacts with oxygen in the air and changes its color.

It mostly happens when you cut an apple and leave it for a while. As soon as the fleshy part of the apple is exposed to air, it will start to oxidize and change its color from yellow-white to pink and then eventually reddish-brown.

This can happen with any type of apple and is not limited to white or red-fleshed ones. Depending on how old the apple is and the environmental conditions that it has been exposed to, the process may be faster or slower.

The reason this happens is due to the presence of phenol inside the apples, which easily oxidizes and gradually changes the color of the apple from white to brown.

This effect may also sometimes result in deep red streaks on the flesh, which mostly only occur if the skin of the apple was damaged before being cut.

Some of the red color from the damaged skin may seep into the flesh and result in red or pink streaks inside.

While these may look weird, a slight color change shouldn’t be anything to worry about and you can still eat them without an issue.

Is It Safe to Eat Oxidized Apples?

As mentioned above, apples contain an enzyme called polyphenol oxidase that acts as an oxidizing agent for the polyphenol molecules that give apples their pigmentation.

Normally, the enzyme and the molecules are stored in separate areas of the fruit’s cells. However, once sliced or bitten into, the cells become damaged and the two come into contact with each other.

apples are red inside

Add oxygen into the mix and you have a chemical reaction known as oxidation that changes the polyphenols and produces a brown color. It starts with light pink, which slowly transitions to reddish-brown, and then ultimately brown.

Simply put, the insides of an apple turn brown when exposed to air, altering its color, flavor, and smell, and in some cases, its nutritional value as well. The longer it is exposed to air, the browner it will become, and fast.

Despite their off-putting color, oxidized apples are perfectly fine to munch on, unless you notice unusual growths or smells.

How to Slow Down Oxidation

Although perfectly okay to eat, oxidized apples look unappealing. Thankfully, there are a few easy ways to slow down the browning process and preserve their sweet flavor and crunchy texture:

Lemon/Citrus Juice

Squeezing a bit of lemon juice, or any liquid containing citric acid, will stop the enzyme and prevent browning by bringing down the apple’s pH levels

This will, however, change the apple’s flavor profile and give it a tart flavor. For a sweeter option, you may also opt for pineapple juice.

Plain Water

Submerging slices of apple in plain water is one of the best and easiest methods to prevent oxygen from reaching the apple’s flesh. Also, since water has a neutral flavor, it doesn’t alter the taste of the fruit.

You may even add a little bit of salt or honey to the water before treating the apples. Salt is nature’s oldest preservative and keeps oxygen from reaching the apple’s surface.

Honey, on the other hand, contains a peptide compound that deactivates the browning enzyme.


The reason why commercially pre-packaged apples tend to stay fresher and whiter for so long is due to the presence of chemical antioxidants such as calcium ascorbate, more commonly known as Vitamin C.

You may dissolve a Vitamin C tablet and a calcium supplement in water along with your cut apple slices.

Airtight Container

Since the most important part of preventing sliced apples from turning brown is to reduce their exposure to air, once you treat the apple slices with the method of your choice, store them in an airtight container and keep them in the fridge.

How to Tell if an Apple Has Gone Bad

Although red-fleshed apples might look unusual, they are safe to eat. In fact, several red-fleshed cultivars are sweet-tasting and contain high concentrations of antioxidants and natural phenols.

Those that turn red due to oxidation are also safe for consumption unless they turn too brown and border on being rotten.

Apples, like all other types of fruit, will start to rot over time, which is why it is very important to be able to spot the signs of them beginning to go bad so that they can be removed from other apples and food items.

When you buy apples from the supermarket, they always have an expiration date printed on the packaging.

While this date isn’t an exact measure of the fruit going bad, it helps give a general idea of its shelf life so that you can be extra careful before consuming it.

The way an apple looks will help you determine whether or not it is safe to eat.

A few apparent signs of a rotten apple include bruising, holes, soft spots, wrinkled skin, and a mushy texture. If any of these signs start to show, it is best to avoid consuming them

rotten apples

You must always check for discolored spots and, although oxidized apples are safe to consume, if you feel like they are too brown and not safe to eat, it is best to trust your gut.

If only part of the apple is oxidized, you may even remove the affected part and eat the rest of the fruit.

The texture of the apple will also give away its quality. A rotting apple will be softer, its skin may turn wrinkly, and its texture may become grainy. If this is the case, although it will still be edible, it won’t be the best taste-wise.

Also, apples that are really old may become dehydrated and hard as a rock, in which case, simply throw them away.

In certain cases, you may come across apples with one or more holes in them. Most of the time, they may be made by a worm and may even contain one inside.

For obvious reasons, you wouldn’t want to eat an apple with a worm or insect in it, and in any case, its flesh may probably be rotten.

Lastly, if you see mold growth on an apple, which happens only in extreme situations, you should discard it immediately since it will be inedible and will most likely affect the other apples stored with it.

Related Questions

Now that you know all about apples that are red inside and whether they are safe to eat, here are a few additional questions we thought you might have!

What Are Pink Pearl Apples Used For?

Pink Pearl apples are a type of red-fleshed apple that have a yellow to green skin speckled with white spots and their flesh is a vivid pink to red color.

Highly aromatic with a balanced sweet-tart flavor, they contain subtle notes of raspberries and grapefruit and are a perfect ingredient for a variety of dishes.

Their vivid color stands out and they can be sliced and added to tarts, pies, and cones. Alternatively, you may cook it to make pink applesauce or sorbet.

Their sweet and tart flavor profile pairs well with savory items as well. Sauté a few slices of Pink Pearl with some fresh herbs and serve it with pork or fish.

You may even chop it up and add it to salads, serve with your choice of sweet or savory dips, or pair it with cheese.

How Long Do Apples Last?

How long apples last depend on several factors such as when they were harvested, their storage conditions, and whether they have been washed, cut, or cooked.

That being said, the approximate shelf life of apples left on the kitchen counter is 5-7 days. If stored in the pantry, they can last much longer for around 3 weeks. Refrigerating apples will help you prolong their life to 4-6 weeks.

Once cut, they last 3-5 days in the fridge and around 8 months in the freezer. Made into applesauce, they stay good for 7-10 days in the fridge and 2 months in the freezer.

How Do You Store Whole Apples?

The ideal temperature for storing whole apples is 30-35°F with around 90-95% relative humidity.

The refrigerator is a good option if you have fewer apples. Put them in a plastic bag with holes and place them in the fruit drawer. You may even cover them with a damp paper towel to increase humidity.

How Do You Store Sliced Apples?

Since sliced apples are more susceptible to oxidation, they will start turning brown as soon as the flesh is exposed to air. Therefore, they must be stored in airtight containers and kept in the refrigerator for 3-5 days.

How Should You Freeze Apples?

You can freeze both whole and sliced apples for several months; however, since it may change their texture and make them softer, frozen apples are best used in cooking, baking, and making smoothies.

For freezing whole apples, all you have to do is wash and dry them, and then freeze them in a single layer on a tray. Once they are frozen, transfer them into a resealable bag and store them in the freezer for 2-3 months.

For freezing sliced apples, peel and core them and cut them into large slices. Treat them with lemon juice or salt water and rinse them properly. 

Next, freeze the slices in a single layer on a tray. Once frozen, transfer them into a freezer-safe bag or container and put them in the freezer.

Here’s a handy video covering how to freeze and store sliced apples!

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