|
|
 |
|
The Pantry:
EGGS -
USES
Pantry: Eggs 101 |
  Eggs
have many uses in baking and cooking. They can
bind
ingredients as in meatloaves or croquettes. They can also
leaven
such baked high rises as soufflés and sponge cakes. Their
thickening
talent is seen in custards and sauces. Eggs
emulsify mayonnaise,
salad dressings and Hollandaise sauce and are frequently used as a
glaze to coat breads and cookies.
They clarify soups and
coffee. In boiled candies and frostings, eggs
retard crystallization.
They also enable coating. In
general, eggs add color and
flavor. As a finishing touch, they can be hard cooked and used
as a garnish. |
|
|
EGGS HAVE MANY USES IN BAKING
RECIPES: |
|
Recipes |
Foaming, Coagulation, Color
|
|
Candy, Eclair,
Confectionary |
Inhibition of Crystals |
|
Custards, Puddings |
Coagulation
+
Flavor
|
|
Omelets, Scrambled, Poached |
Coagulation +
Flavor |
|
Mayonnaise, Salad Dressing |
Emulsification |
|
Meringues, Soufflés |
Foaming
and Leavening |
|
Ice Cream |
Emulsification, Texture |
|
Pancakes and Waffles,
Crepes |
Flavor,
Coagulation |
|
Doughnuts,
Croissants |
Texture,
Flavor |
|
Health Foods |
Egg
whites: no fat
and protein purity of egg white
|
Eggs as Thickeners: A sauce or
custard can be thickened, called coagulation, by adding egg and heating,
critical to many recipes. A large portion of the discussion of stirred and baked
custard hinges on egg coagulation. How
Eggs Thicken
In many instances, the egg in a
recipe will serve to glue the ingredient's together. When eggs are added to a
mixture to thicken, sometimes the mixture is quite warm. If added directly, the
mixture will cook the eggs. A technique called
tempering is used when combining
the two to avoid this problem.
|
Coagulation: When
eggs are heated, the protein in the white and yolk starts to coagulate.
This means that the liquid egg becomes firmer. As heating continues the
egg eventually becomes solid.
Eggs coagulate at (as measured with
an Instant Read Thermometer):
 | Whites: 140 degrees F
|
| Yolks: 150 degrees F
|
|
Both egg yolks and
whites contain protein. They are shaped like coils or springs or complex wads
that are all separate from one another. You can see through an egg white because
the proteins are not attached!
|
Curdling is also known as synersis or
weeping. When egg mixtures such as custards or sauces are cooked too
rapidly, the protein becomes over-coagulated and separates from the liquid
leaving a mixture resembling fine curds and whey. If curdling has not
progressed too far, it may sometimes be reversed by removing the mixture
from the heat and stirring or beating vigorously.
To prevent syneresis or curdling, use a low temperature,
stir, if appropriate for the recipe, and cool quickly by setting the pan in
a bowl of ice or cold water and stirring for a few minutes.
The term curdling is usually used in connection with a
stirred mixture such as custard sauce, while weeping or syneresis are more
often used with reference to pie meringues or baked custards. aeb.org |
When eggs are heated,
their proteins unwind (called denaturing) and
break apart from their tightly bound bundles, bump up against one another, and
adhere to form loose, flat and long strands. These strands are linked together
in a three-dimensional mesh. You can see the result of this process with egg
whites because they turn from clear to opaque, forming a solid gel. Liquid gets
trapped in these strands, and this causes the mixture to thicken.
Gentle cooking, such as baking a
custard without starch in a waterbath, keeps the egg proteins loose and soft
until the mixture gets hot enough, at around 160 degrees F. The constant
stirring with a stove top recipe maintains an even temperature so the protein
bonds don't form too early, which are allowed to set undisturbed in baked
versions.
|
The usual custard proportions are 1 egg plus 2 tablespoons
sugar for each cup of milk. This is the minimum ratio of eggs to milk which
will produce a properly thickened custard, although as many as 4 eggs may be
used and the sugar may be increased to 4 tablespoons. Increasing the sugar
makes the custard less firm and lengthens the cooking time. Increasing the
eggs make the custard more firm and shortens its cooking time. |
But despite the gentle heat,
if custard is heated above 180 degrees F, the more tightly the proteins join
together. They becoming thicker, curdling and squeezing out all the water which
you see evidence of coming from little tunnels in the custard, called synersis.
The egg proteins will overcoagulate from too much heat which eventually shrinks
when cooled.
You can also see overcooking
or exposure to too much heat in a cracked cheesecake. Overheated eggs shrink
when cooled causing with a large crack running through its center or tiny cracks
all over its top.
When starch is present in a custard
recipe, it HELPS to prevent the unwound egg proteins from joining together too
soon, thus when heated to too high a temperature and then cooled, the custard
won't scramble or crack. When the mixture gets hot enough at around 212 degrees
F, the proteins simply join together.
However, if you undercook a
starch-based custard they won't join together and gel. Yolks have a starch
digesting enzyme called alpha-amylase. In order for a successful gelling of a
starch in the recipe, the enzyme has to be killed by cooking the custard almost
to boiling (a little under 212 degrees F). Otherwise the left-over enzymes
digest all of the nice firm starch gel and your custard is nothing but liquid.
Eggs as Binders: Whole raw egg adds
moisture to a mixture and holds the ingredients together. As the food is heated,
egg protein coagulates, thus binding ingredients together. This is a very useful
property for binding in products such as meat loaves, formed meat and poultry
products and for natural thickening of custards and pie fillings. The
temperature of coagulation can be controlled by adjusting pH, adding salts and
other ingredients.
Eggs as Glazes: Egg whites, egg yolks,
whole eggs, and egg washes brushed on breads and other baked products add a
rich, shiny glaze. The glaze is caused primarily by the protein and fat
interaction. The simple glaze is generally made by adding a "little water" to
the egg and brushing it on.
|
Type |
How Much Foam ? |
Leaven |
|
Beaten
egg whites |
Most: 6 to 8 times in volume |
Soufflés,
meringues, angel food cakes and some candies and frostings. |
|
Beaten egg
yolks |
Medium: double or triple in volume |
Important in
making chiffon and sponge cakes and omelets |
|
Beaten
whole eggs |
Least: less volume than egg yolks |
Other baked
goods |
Eggs as Leaveners: Eggs serve as
leaveners in their ability to foam. Egg whites or egg yolks can each foam
separately or together as a whole egg. Whisking egg white incorporates air and
produces a foam - a relatively stable mass of bubbles. Whole eggs incorporate
air less well, especially when beaten into a batter, but give a
sponge cakes a light texture.
If left to stand, egg white foam
will gradually collapse, but when heated the foam becomes permanent, such as
meringue. The
Angel Food Cake, a white cake, tall and light in texture, is leavened
only by beaten egg whites.
Before the invention of the egg
beater, making this heavenly delight required a deep platter, a whisk and a very
strong arm for whipping the egg whites. The electric mixer has simplified the
process. I use my handheld mixer for whipping small amounts and my stand mixer,
fitted with a whipping attachment, for larger amounts. Make sure the egg whites
reach at least 1/3 of the way up the beaters. If not, use a hand-held one.
Eggs as Clarifiers:
Eggs and egg whites have been used as a clarifier. The process is as it sounds,
the clearing of a liquid. Master chefs use it to clarify stock to produce clear
consommés.
|
Mayonnaise is made by combining lemon juice or vinegar with egg yolks.
Eggs (containing the emulsifier lecithin) bind the ingredients together and
prevent separation. Then, oil is added drop by drop as the mixture is
rapidly whisked. Adding oil too quickly (or insufficient, rapid whisking)
will keep the two liquids from combining (emulsifying). But, as the sauce
begins to thicken, oil can be added more rapidly. Seasonings are whisked in
after all of the oil has been added. |
Eggs as Emulsifiers:
Eggs and
gelatin are among the foods that contain emulsifiers.
Egg yolk contains lecithin which acts a an emulsifier. Adding egg
yolk to a mixture of oil and water prevents the two liquids from separating;
the emulsifiers in the yolks are liaisons between the two liquids and serve to
stabilize the mixture.
Emulsifying is done by slowly adding
one ingredient to another while simultaneously mixing rapidly. This disperses
and suspends tiny droplets of one liquid through another. However, the two
liquids would quickly separate again if an emulsifier were not added.
An example of this is mayonnaise which is an emulsion of oil and
vinegar, held together by egg yolk. Industrially manufactured mayonnaise uses
pasteurized egg (which has been heat treated to destroy potentially harmful
micro-organisms), rather than raw egg, to ensure safety.
Eggs Add Color and Flavor:
The yellow color of egg yolk derives from the fat-soluble
carotenoids in the lipid portion of lipoproteins. This rich color means quality
and the anticipation of good flavor in such recipes as pasta, mayonnaise and
cakes.
Over a hundred volatile components
contribute to the flavor of eggs. Egg flavor provides a rich, rounded, neutral
background against which other flavors can be highlighted. The flavor is
delicate enough that it blends well with most ingredients.
Eggs Enable Coating
such as breadcrumbs to stick to the surface a product and forms a protective
barrier during cooking.
|
| |
