Even some die-hard steak lovers get a little squeamish when they see that red liquid oozing out of their meat as they cut into it. And that same blood-like fluid is in the package when you buy the meat and it doesn’t look any more appealing in there. But while a lot of us assume it’s blood, we’re wrong.
The red liquid is actually myoglobin - “a protein that’s only found in muscle tissue.” It carries oxygen through the muscle and it’s red, that’s where muscle tissue gets it’s color. And when a steak is cooked, the myoglobin gets darker, so the meat looks more gray as it gets more well done.
And here’s a little trivia: some commercial meat packers treat raw steaks with carbon monoxide to “lock in the myoglobin” so it keeps that fresh-looking red color. Now you know!
Source: New York Post