Oh wow, I didn’t know this

January 29, 2026 by Youssef

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What Is Myoglobin and Its Role in Meat

Myoglobin is a heme protein responsible for transporting oxygen in the muscle cells of animals. Structurally similar to hemoglobin in blood, myoglobin binds oxygen molecules and stores them in muscle tissue, aiding in muscle metabolism and endurance. This protein is also the key factor behind the redness seen in meat.

The Source and Function of Myoglobin in Muscles

Myoglobin’s primary function in muscle tissues is to store and release oxygen when needed, especially during periods of muscular exertion. Its concentration varies with the type of muscle and the animal’s activity level, meaning muscles used more frequently for movement tend to have higher myoglobin levels, contributing to darker meat.

Debunking the Myth: Why It’s Not Blood

Contrary to popular belief, the red juice in a rare steak is not blood. Most of the blood is removed during the slaughter and processing of meat. The red liquid that pools in rare steak is actually a mixture of water and myoglobin, released from the muscle fibers during cooking. This fluid is completely safe and a natural part of the meat’s composition.

The Cooking Process: Changes in Myoglobin

As steak cooks, myoglobin undergoes several transformations. In raw meat, myoglobin is in its natural state, appearing red. As the meat reaches medium levels of doneness, the myoglobin’s iron atoms oxidize, turning brownish, which is why well-done meat has a more browned appearance. Rare steak, being cooked to a lower temperature, retains its reddish myoglobin-rich juices.