changes the appearance and flavor of beef, alters nutritional value,
makes it safer, and extends its shelf life.
meat after you cook it does not "seal in the juices," but it does
change the flavor 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 contain
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.)
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.
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 characteristic warmed-over flavor.
Cooking and storing meat under a blanket of antioxidantsócatsup or a
gravy made of tomatoes, peppers, and other vitamin CĖrich
vegetablesóreduces the oxidation of fats and the intensity of
warmed-over flavor. Meat reheated in a microwave oven also has less
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
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.
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
Other Kinds of Processing Affect Beef
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 proteins, "tenderizing" the
Canning. Canned beef does not develop a warmed-over flavor because
the high temperatures in canning food and the long cooking process
alter proteins in the meat so that they act as antioxidants. Once the
can is open, however, the meat should be protected from oxygen that
will change the flavor of the beef.
Curing. Salt-curing preserves meat through osmosis, the physical
reaction in which liquids flow across a membrane, such as the wall of
a cell, from a less dense to a more dense solution. The salt or sugar
used in curing dissolves in the liquid on the surface of the meat to
make a solution that is more dense than the liquid inside the cells of
the meat. Water flows out of the meat and out of the cells of any
microorganisms living on the meat, killing the microorganisms and
protecting the meat from bacterial damage. Salt-cured meat is much
higher in sodium than fresh meat.
Freezing. When you freeze beef, the water inside its cells freezes
into sharp ice crystals that can puncture cell membranes. When the
beef thaws, moisture (and some of the B vitamins) will leak out
through these torn cell walls. The loss of moisture is irreversible,
but some of the vitamins can be saved by using the drippings when the
meat is cooked. Freezing may also cause freezer bumódry spots left
when moisture evaporates from the surface of the meat. Waxed freezer
paper is designed specifically to hold the moisture in meat; plastic
wrap and aluminum foil are less effective. NOTE: Commercially prepared
beef, which is frozen very quickly at very low temperatures, is less
likely to show changes in texture.
Irradiation. Irradiation makes meat safer by exposing it to gamma
rays, the kind of high-energy ionizing radiation that kills living
cells, including bacteria. Irradiation does not change the way meat
looks, feels or tastes, or make the food radioactive, but it does
alter the structure of some naturally occurring chemicals in beef,
breaking molecules apart to form new compounds called radiolytic
products (RP). About 90 percent of RPs are also found in nonirradiated
foods. The rest, called unique radiolytic products (URP), are found
only in irradiated foods. There is currently no evidence to suggest
that URPs are harmful; irradiation is an approved technique in more
than 37 countries around the world, including the United States.
Smoking. Hanging cured or salted meat over an open fire slowly
dries the meat, kills microorganisms on its surface, and gives the
meat a rich, "smoky" flavor that varies with the wood used in the
fire. Meats smoked over an open fire are exposed to carcinogenic
chemicals in the smoke, including a-benzopyrene. Meats treated with
"artificial smoke flavoring" are not, since the flavoring is
commercially treated to remove tar and a-benzopyrene.