What Happens When You Cook This Food
Cooking changes the appearance and flavor of beef, alters nutritional value, makes it safer,
and extends its shelf life.
Browning meat after you cook it does not “seal in the juices,” but it does change the fla-
vor by caramelizing sugars on the surface. Because beef’s only sugars are the small amounts
of glycogen in the muscles, we add sugars in marinades or basting liquids that may also con-
tain acids (vinegar, lemon juice, wine) to break down muscle fibers and tenderize the meat.
(Browning has one minor nutritional drawback. It breaks amino acids on the surface of the
meat into smaller compounds that are no longer useful proteins.)
When beef is cooked, it loses water and shrinks. Its pigments, which combine with
oxygen, are denatured (broken into fragments) by the heat and turn brown, the natural color
of well-done meat.
At the same time, the fats in the beef are oxidized. Oxidized fats, whether formed in
cooking or when the cooked meat is stored in the refrigerator, give cooked meat a character-
istic warmed-over flavor. Cooking and storing meat under a blanket of antioxidants—catsup
or a gravy made of tomatoes, peppers, and other vitamin C-rich vegetables—reduces the
oxidation of fats and the intensity of warmed-over flavor. Meat reheated in a microwave
oven also has less warmed-over flavor.
An obvious nutritional benefit of cooking is the fact that heat lowers the fat content of
beef by liquifying the fat so it can run off the meat. One concrete example of how well this
works comes from a comparison of the fat content in regular and extra-lean ground beef.
According to research at the University of Missouri in 1985, both kinds of beef lose mass
when cooked, but the lean beef loses water and the regular beef loses fat and cholesterol.
Thus, while regular raw ground beef has about three times as much fat (by weight) as raw
ground extra-lean beef, their fat varies by only 5 percent after broiling.
To reduce the amount of fat in ground beef, heat the beef in a pan until it browns. Then
put the beef in a colander, and pour one cup of warm water over the beef. Repeat with a
second cup of warm water to rinse away fat melted by heating the beef. Use the ground beef
in sauce and other dishes that do not require it to hold together.
Finally, cooking makes beef safer by killing Salmonella and other organisms in the
meat. As a result, cooking also serves as a natural preservative. According to the USDA, large
pieces of fresh beef can be refrigerated for two or three days, then cooked and held safely for
another day or two because the heat of cooking has reduced the number of bacteria on the
surface of the meat and temporarily interrupted the natural cycle of deterioration.
How Other Kinds of Processing Affect This Food
Aging. Hanging fresh meat exposed to the air, in a refrigerated room, reduces the moisture
content and shrinks the meat slightly. As the meat ages enzymes break down muscle pro-
teins, “tenderizing” the beef.
Canning. Canned beef does not develop a warmed-over flavor because the high tempera-
tures in canning food and the long cooking process alter proteins in the meat so that they act
Beef