Why does meat get brown on the grill? –Christina, 9, Seattle, Wash.
You know summer is just around the corner when the smell of barbecue is in the air. It’s a great question you ask and it leads us to the Meats Lab at Washington State University. That’s where I met up with my friend and animal scientist, Jan Busboom.
He’s really curious about animal nutrition and the meat we eat. Busboom explained that meat is muscle. It has a lot of different proteins. These proteins have different jobs. One of them delivers oxygen to the cells that make up muscles. It’s a protein called myoglobin.
Believe it or not, the red liquid we see in a package of meat comes primarily from myoglobin. The more myoglobin there is in a muscle cell, the redder the meat will look. Myoglobin is a big part of why meat is red in the first place—but it’s also part of the reason it turns brown on the grill, too.
Like almost everything on our planet, a hamburger is made up of atoms. As you may know, atoms get together to form molecules. These parts are arranged in ways that give things certain colors, tastes, and smells.
As is often the case when we heat up something, its atoms and molecules often start to move, or vibrate faster and faster. Then they transform.
When we heat up the hamburger meat, the myoglobin structure begins to change. Myoglobin loses its ability to bind onto oxygen. There’s also a change in one of the iron atoms at the center of the myoglobin.
These changes are happening on very small scale. But we can actually see the changes as the red meat transforms into a juicy brown hamburger patty.
It turns out color isn’t always the best sign that a burger is ready to eat. Busboom said sometimes a burger won’t brown on the grill. Even if it’s fully cooked, it will stay red.
On the flip side, sometimes a burger that is brown isn’t actually cooked. This is because there may be some other chemical factors going on here that influence color. That’s why it’s really important to use a thermometer and make sure your meat is safe to eat.
Not only does a burger’s chemistry influence color, but also its taste and smell. When we heat it up, proteins and sugars in the meat start to break down.
It was the French chemist Louis Camille Maillard (my-YAR) who discovered the way this works. When the Maillard reaction happens, it creates thousands of new chemical compounds that give meat flavor.
Yes, there’s a whole bunch of science happening right there on the grill. I suppose you might even say the grill master is a bit of a scientist.
Can you think of other kinds of science that go into building the perfect burger? Tell me about it sometime at Dr.Universe@wsu.edu.
Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at http://askDrUniverse.wsu.edu/ask.