The Mystery of Red-Fleshed Apples: Causes and Safety Explained

Apples are red inside: What’s the Cause & Are They Safe to Eat?

Apples come in a variety of colors, from yellow and green to pink and red. While most people are familiar with the different skin colors of apples, many are surprised to learn that the apple flesh can also have different shades. It’s not always white, as most people think. In fact, the colors of apple flesh can cover the entire spectrum, from light pink to deep purple and even black.
In this article, we will explore the causes of red flesh in apples and address the question of whether they are safe to eat.

Causes of red flesh in apples

There are two main causes of red flesh in apples: naturally red varieties and the oxidation process.

Cause #1: Naturally Red Variants

Some apples are naturally bred to have red flesh. These varieties are found in regions of Central Asia and Eastern Europe and have been brought to the U.S. where they have been bred to create more varieties. The flesh of these apples ranges from bright pink to bright red and even orange. They also have different colored blossoms than regular apple trees.
While most red-fleshed apples are too bitter to eat, breeders have crossed them with sweet and delicious white-fleshed apples to produce marketable apples with red flesh inside. These sweet-tasting red-fleshed apples can be identified by their deep red or pink color throughout the flesh.
Common red-fleshed apple varieties include Pink Pearl, Hidden Rose, Mountain Rose, Scarlett Surprise, Pink Sparkle, and Thornberry.

Cause #2: Oxidation Process

Another cause of red flesh in apples is oxidation. When an apple is sliced and exposed to the air, it reacts with oxygen, causing a color change. The fleshy part of the apple turns from yellow-white to pink and finally reddish-brown. This process can happen to any type of apple, not just red-fleshed.
The presence of phenol inside the apple causes this color change. If the skin of the apple is damaged before cutting, red or pink streaks may appear inside as the red color of the damaged skin seeps into the flesh.

Are red-fleshed apples safe to eat?

Whether red-fleshed apples are safe to eat depends largely on the cause of the red color.
Naturally red varieties of apples are safe to eat, although some may be too bitter to enjoy. The red color in these apples is completely natural and edible.
Apples that turn red due to the oxidation process are also safe to eat. The oxidation process changes the color, flavor, and odor of the apple, but does not make it unsafe. However, if the apple shows signs of rot or has unusual growths or odors, it is best to avoid eating it.

How to slow oxidation

If you want to slow down the oxidation process in apples and prevent them from turning brown, there are a few simple methods you can try:

  • Lemon/Citrus Juice: Squeezing a little lemon juice or any liquid containing citric acid onto the apple slices can prevent browning by lowering the apple’s pH level. This method may give the apple a tart flavor.
  • Plain water: Soaking apple slices in plain water can prevent oxygen from reaching the flesh. Adding a little salt or honey to the water can further enhance the preservation process.
  • Antioxidants: Chemical antioxidants such as vitamin C (calcium ascorbate) can help slow the browning process. Dissolving a vitamin C tablet and calcium supplement in the water with the apple slices can help preserve their freshness.
  • Airtight container: Storing treated apple slices in an airtight container in the refrigerator can minimize exposure to air and slow oxidation.

Identifying bad apples

While red-fleshed apples are generally safe to eat, it’s important to know how to recognize signs of spoilage or decay in apples. Some indicators that an apple has gone bad include bruising, holes, soft spots, wrinkled skin, mushy texture, and unusual growths or odors.
When buying apples, check the expiration date on the package to get a general idea of their shelf life. In addition, trust your senses and avoid eating apples that appear rotten or have discolored spots. If only part of the apple is discolored or rotten, you can cut off the affected area and still eat the rest if it appears fresh and healthy.


Red-fleshed apples are a fascinating variation of this popular fruit. They can occur naturally in certain apple varieties or as a result of the oxidation process. While naturally red-fleshed apples can be enjoyed for their unique flavors and antioxidant properties, apples that turn red due to oxidation are still safe to eat.
When it comes to eating apples, it’s important to use your judgment and inspect the fruit for signs of spoilage. As long as the apple looks and smells good, it should be safe to eat, regardless of the color of the flesh.
So the next time you come across an apple with red flesh, embrace its vibrant colors and enjoy the deliciousness it has to offer!


Why are some apples red on the inside?

Some apples have naturally red flesh due to certain genetic traits or crossbreeding with red-fleshed apple varieties.

Are red-fleshed apples safe to eat?

Yes, red-fleshed apples are generally safe to eat. However, it’s important to check for signs of spoilage or decay before eating.

Can red-fleshed apples taste different from regular apples?

Yes, red-fleshed apples can have unique flavors ranging from sweet to slightly tart. Some varieties may even have hints of berry or citrus flavors.

How can I tell if a red-flesh apple has gone bad?

Signs of a bad apple include bruising, soft spots, wrinkled skin, unusual growths, and a mushy texture. If the apple smells bad or has discolored spots, it’s best not to eat it.

Are there any health benefits to eating red-fleshed apples?

Red-fleshed apples, like other types of apples, can be a good source of fiber and several vitamins. In addition, some studies suggest that red-fleshed apples may have antioxidant properties.

How do I prevent apples from browning?

To slow the oxidation process and prevent browning, you can try methods such as squeezing lemon juice on the apple slices, soaking them in plain water, using antioxidants such as vitamin C, or storing them in an airtight container in the refrigerator.