What is the Middle Part of the Apple? The Anatomy of the Core

December 28, 2025 •

3 min read

According to a study published in Frontiers in Microbiology, an entire organic apple contains about 100 million bacteria, a significant portion of which resides in the core and seeds. This central region, often discarded, is a complex botanical structure with some surprising properties.

Quick Summary

The middle section of an apple, commonly known as the core, is a fibrous, five-chambered structure containing the seeds. Botanically, these chambers are called carpels, which constitute the true fruit of the apple. While traditionally discarded, the core is edible and even contains beneficial probiotics, though caution is advised with the seeds.

Key Points

Core Anatomy: The core is the tough, central fibrous part of the apple, containing the seed chambers known as carpels.
Accessory Fruit: An apple is a pome or accessory fruit, meaning the main edible flesh is an extension of the flower's receptacle, while the core is the true fruit.
Cyanide in Seeds: Apple seeds contain amygdalin, which can produce cyanide, but the amount is too small to pose a risk unless hundreds of seeds are crushed and ingested.
Beneficial Probiotics: A significant amount of beneficial bacteria is found within the core and seeds, making the entire apple a potential source of probiotics.
Edible Core: The core is edible and can be eaten for its high fiber and probiotic content, with the safest method being to cut out and discard the seeds.
Minimize Waste: Eating the entire apple, excluding the stem, is a sustainable practice that minimizes food waste and maximizes nutrient intake.

Understanding the Apple's Botanical Structure

An apple is not a simple fruit. Botanically, it is classified as an "accessory fruit" or, more specifically, a "pome". This means that the fleshy part we eat develops from the receptacle, the thickened stem of the flower, rather than just the ovary. The true fruit, containing the seeds, is the papery structure at the very center, which we know as the core.

The Core: More Than Meets the Eye

If you cut an apple in half across its width, you'll see a distinct five-pointed star shape in the center. This fibrous and often tough region is the apple's core. Inside this core, the seeds are housed in small pockets or chambers. The entire core structure is derived from the flower's ovary and is essential for the tree's reproductive cycle.

The Carpels and Seeds

The chambers within the apple core are technically called carpels. Most apple varieties contain five carpels, each capable of holding one or two small, dark seeds, or "pips". These seeds are the plant's reproductive units and contain the genetic blueprint for a new apple tree. They are enclosed by a papery layer, the endocarp, which helps protect them.

Should You Eat the Apple Core?

For decades, the standard practice has been to eat around the core and throw it away. However, some evidence suggests that eating the entire apple, excluding the stem, could be more beneficial. The core is a source of fiber and, as some studies suggest, contains a higher concentration of beneficial bacteria (probiotics) than the flesh and skin. A 2019 study, for example, found that eating the entire apple, including the core and seeds, could increase a person's intake of microbes from 10 million to 100 million. For those concerned with food waste, eating the core is also a more efficient way to consume the fruit.

The Cyanide Myth: Are Apple Seeds Dangerous?

The reason most people avoid eating the core is the seeds. Apple seeds contain a compound called amygdalin, which can release the toxic gas hydrogen cyanide when chewed and digested. This has led to the widespread belief that apple seeds are poisonous. However, experts explain that the risk is minimal for several reasons:

Protective Coating: The hard outer coating of the seeds usually prevents the release of amygdalin, allowing them to pass through the digestive system harmlessly if swallowed whole.
Quantity Needed: It would take consuming a large number of crushed seeds—likely hundreds—to be at risk of cyanide poisoning. The average apple contains only 5 to 8 seeds.
Detoxification: The human body can safely detoxify small amounts of cyanide.

While accidentally swallowing a few seeds is not a cause for concern, intentionally chewing and consuming a large quantity is not recommended. For safe consumption of the core, simply cut the apple into quarters and remove the seeds before eating the rest.

A Comparison of Apple Parts


Feature	Core (Carpels & Seeds)	Flesh (Mesocarp)	Skin (Exocarp)
Botanical Name	Endocarp & Seeds	Mesocarp	Exocarp
Primary Purpose	Seed protection & reproduction	Nutrient storage	Protection
Edibility (Taste)	Edible, but tough and fibrous	Edible, sweet, and juicy	Edible, contains most fiber and antioxidants
Nutritional Content	High in fiber, contains probiotics	Rich in water, sugars, some vitamins	Rich in antioxidants, vitamins, and fiber
Amygdalin (Cyanide)	Present in seeds; harmless if swallowed whole	Absent	Absent

Parts of an Apple

Skin (Exocarp): The thin outer layer, rich in fiber and antioxidants.
Flesh (Mesocarp): The main edible, juicy part, providing sugars and water.
Core (Carpels): The central, fibrous part containing the seeds.
Seeds (Pips): Small, dark reproductive units found inside the core's carpels.
Stem (Pedicel): Connects the apple to the tree.
Calyx: The star-shaped remnant of the flower at the bottom of the fruit.

Conclusion

The middle part of the apple, known as the core, is a fibrous structure housing the seed-containing carpels. While the seeds contain a cyanide-producing compound, the amount is negligible and not a risk unless a very large quantity is chewed and ingested. As research shows that the core also contains beneficial microbes, eating the entire apple (sans stem) is a safe and potentially beneficial practice for many people, especially for those looking to reduce food waste and boost their gut health. Whether you choose to eat around it or eat it all, the apple's core is a fascinating and misunderstood part of this popular fruit.

Understanding fruit morphology can help clarify the biological distinctions between a fruit's culinary and botanical definitions.

Frequently Asked Questions

No, the core itself is not poisonous and is safe to eat. The seeds within the core contain amygdalin, which can produce cyanide, but you would need to chew and ingest hundreds of seeds to be at risk.

The chambers holding the seeds within the core are botanically called carpels. The entire fibrous core is a protective covering for these carpels and the seeds inside.

Nothing happens. The hard outer shell of an apple seed protects the inner compound, so it will pass through your digestive system without releasing any toxins.

Some studies suggest that organic apples have a greater diversity of beneficial bacteria in their cores compared to conventionally grown apples, which may offer more gut health benefits if consumed.

Yes, the core is a good source of fiber and contains beneficial bacteria that can contribute to gut health.

The core of an apple is the plant's true fruit, developed from the flower's ovary. Its purpose is to protect the seeds inside and aid in their dispersal.

While the stem is not toxic, it is tough, fibrous, and unpalatable, and there is no nutritional benefit to eating it. Most people discard it.