41. As has been previously stated, the substance in eggs that requires
special care in the cooking process is the protein, which occurs in this
food in the form of albumen. Because of this, certain points concerning
the treatment that the albumen requires should be kept in mind. In a raw
egg, the albumen occurs in a semiliquid form, but it coagulates at a
lower temperature than does the yolk, which contains a high percentage
of fat. After coagulation, the consistency of the two parts is very
different. The white is elastic and more or less tough, while the yolk,
upon being thoroughly cooked, becomes powdery, or mealy, and breaks up
into minute particles. The egg white begins to coagulate at 134 degrees
Fahrenheit, and it becomes white and jellylike at 160 degrees. Bringing
an egg to such a temperature produces a more desirable result than
cooking it at a high temperature--boiling point, for instance--because
the albumen, instead of becoming tough, as it does at a high
temperature, acquires a soft, tender consistency that exists throughout
the entire egg. An egg cooked in this way is more digestible and
appetizing than one that is boiled until it becomes hard and tough.
42. The low temperature at which eggs will cook in the shell applies
also to eggs when they are combined with other foods. Sometimes,
however, a mixture in which eggs are one of the ingredients must be
cooked at a high temperature because the materials mixed with them
require it. This difficulty can be overcome when eggs are combined with
starchy foods, such as corn starch, rice, and tapioca, that require long
cooking. In such a case, all the ingredients except the eggs may be
cooked the length of time they require, after which the eggs may be
added so that they will cook just long enough to become coagulated.
Longer cooking is liable to spoil the texture. Often the starchy mixture
retains sufficient heat to set the eggs without further cooking after
they are added.
43. A very nutritious way in which to prepare eggs when they are to be
used for a dessert is to combine them with milk to form a custard,
which, after being sweetened and flavored, is baked. The proportion that
has been accepted as ideal to produce a dessert of the right thickness
is one egg to each cupful of milk; however, an entire egg is not always
required, as one yolk is often sufficient to thicken 1 cupful of milk.
Care should be taken in the cooking of such custards, for if they are
cooked too long or at too high a temperature they will curdle and whey;
whereas, a properly cooked custard--that is, one cooked slowly at a low
temperature and for the required length of time--will have a smooth,
jellylike consistency. A slight variation in a dish of this kind is
secured by reducing the number of eggs and thickening it with corn
starch or some other starchy material. While such a mixture is not a
true custard, it makes an excellent dessert.
44. In the cooking of mixtures containing eggs, no utensil proves quite
so satisfactory as the double boiler, which has already been explained
and illustrated. In fact, it is almost impossible to cook an egg mixture
directly over the flame on account of the difficulty encountered in
preventing the eggs from curdling. The low temperature at which cooking
is possible in the double boiler makes it a comparatively simple matter
to bring a mixture to the proper consistency without the formation of
curds. Still, a certain amount of precaution must be taken even with a
double boiler. If the degree of heat that is reached in this utensil is
applied too long, the result will be no more satisfactory than when
mixtures are exposed directly to the heat and cooked at a high
temperature. While every effort should be made to cook mixtures
containing eggs, such as custards or mayonnaise, so as to prevent curds
from forming, occasionally they will form in spite of all that can be
done. However, it is sometimes possible to remedy the matter by placing
the vessel at once in cold water and beating the mixture rapidly with a
Dover egg beater until the curds disappear. The cold water cools the
mixture and prevents the formation of more curds, and the beating breaks
up those which have already formed, provided they are not too hard.
45. In addition to the uses already mentioned, eggs have numerous other
uses in cooking with which the housewife should be familiar. For
instance, slightly beaten egg is used to a great extent to make crumbs
or meal adhere to the surface of croquettes, meat, oysters, etc. that
are to be sauted or fried in deep fat, a coating of this kind preventing
the food from becoming soaked with grease. In addition, egg is used to
stick flour together for certain kinds of dough, such as noodles. Then,
again, it is much used to puff up mixtures and produce a hollow space in
them, as in popovers and cream puffs. While such mixtures do not require
beating, spongy mixtures, such as omelets and sponge cakes, do. In
these, eggs are an important factor, and they must be thoroughly beaten
in order to incorporate the air in small bubbles and thus produce the
desired texture.