Composition, Structure, and Basic
Quality Factors
Composition of
Meat
Muscle tissue consists of these major
components:
Water (about 75% of muscle
tissue)
With such a high percentage of water
in meat, you can see why shrinkage can be a big problem in cooking
meat.
Protein (20% of muscle
tissue)
Protein is an important nutrient and
the most abundant solid material in meat.
Protein coagulates when it is
heated. This means it becomes firmer and loses moisture. Coagulation is
related
to doneness: when protein has coagulated to the desired degree,
the meat is said to be "done."
Too high heat toughens
protein.
Fat (up to 5% of muscle
tissue)
Of course, there can be more fat surrounding the
muscles. A beef carcass can be as much as 30 % , fat.
A certain amount of fat is desirable for three
reasons:
1.
Juiciness
Marbling is fat that is deposited within the
muscle tissue. The juiciness we enjoy in well-marbled beef is due more to
fat than to moisture.
Surface fat protects the
meat-especially roasts-from drying out during cooking as well as in
storage. Adding surface fats where they are lacking is called
barding.
2.Tenderness
Marbling separates muscle fibers, making them
easier to chew.
3. Flavor
Fat is perhaps the main source of flavor in meat. A
well-marbled Prime (top grade) steak tastes "beefier" than the same cut of
a lower grade.
Carbohydrate
Meat contains a very small amount of carbohydrate.
When you brown meat, you are, in part, caramelizing the
carbohydrate.
Structure
Muscle fibers
Lean meat is composed of long, thin muscle fibers
bound together in bundles. These determine the texture or grain of
a piece of meat. Fine-grained meat is composed of small fibers bound in
small bundles. Coarse-textured meat has larger fibers.
Connective tissue
Muscle fibers are bound together in a network of
proteins called connective tissues. Also, each muscle fiber is
covered
in a sheath of connective tissue.
It is very important for the cook to understand
connective tissue for one basic reason: connective tissue is
tough.
To cook meats successfully, you should
know:
Which meats are high in connective tissue and which
are low.
What are the best ways to make tough meats
tender.
1. Meats are highest in connective tissue
if:
a. They come from muscles that are
more exercised. Muscles in the legs, for example, have more connective
tissue than muscles in the back.
b. They come from older animals. Veal is
tenderer than meat from a young steer, which in turn is tenderer than
meat from an old bull or COW. (Young animals have connective tissue,
too, but it becomes harder to break down as the animal
ages.)
2. Meats high in connective tissue can be made more
tender by using proper cooking techniques.
There are two kinds of connective tissue:
collagen, which is white in color, and elastin, which is
yellow.
Collagen
Moist heat turns collagen into gelatin and water.
Moist heat at low temperatures for a longertime is most effective
in
creating a tender, juicy finished product.
Other factors also help tenderize
collagen:
Acid helps dissolve collagen.
Marinating meat in an acid mixture, or adding an acid such as tomato or
wine to the
cooking liquid, helps tenderize.
Enzymes are naturally present in
meat. They break down some connective tissue and other proteins as meat
ages.
Tenderizers are enzymes such as
papain (extracted from papaya), which are added to meats by the cook. Too
long
an exposure at room temperature can make the meat undesirably
mushy.
Elastin
Older animals have a higher
proportion of elastin than younger animals.
Elastin is not broken down in
cooking.
Tenderizing can only be accomplished by removing the elastin
(cutting away any tendons) and by mechanically
breaking up the
fibers, as in:
Pounding and cubing (cubed
steaks).
Grinding (hamburger).
Slicing the cooked meat very thin
against the grain (as in London broil).
