Contrary to popular opinion, there is no law that says one must have eggs or cereal or pancakes or pastries for breakfast and must not have shrimp curry or chili or spaghetti and meatballs.Although most of us would think these last suggestions rather strange for the morning meal, there is probably no food that someone, somewhere, does not enjoy for breakfast.
No doubt many Japanese, who have soybean soup, sour pickles, and rice for their first meal of the day, think Western breakfast habits are strange.
However, the egg remains a favorite breakfast food, even as we become more adventurous and explore ethnic cuisines. For such apparently simple items, eggs are used in many ways in the kitchen and require special study. We examine not only the usual breakfast preparation but other egg dishes as well,such as soufflés and custards.
COMPOSITION
A whole egg consists primarily of a yolk, a white, and a shell. In addition, it contains a membrane that lines the shell and forms an air cell at the large end, and two white strands called chalazae that hold the yolk centered.
1. The yolk is high in both fat and protein, and it contains iron and several vitamins. Its color ranges from light to dark yellow, depending on the diet of the chicken.
2. The white is primarily albumin protein, which is clear and soluble when raw but white and firm when coagulated.The white also contains sulfur.
The white has two parts: a thick portion that surrounds the yolk, and a thinner, more liquid portion outside of this.
3. The shell is not the perfect package ,in spite of what you may have heard.Not only is it fragile but it is also porous, allowing odors and flavors to be absorbed by the egg and allowing the egg to lose moisture even if unbroken.
GRADES AND QUALITY
Grades
In the United States, eggs are graded for quality by the U.S.Department of Agriculture.The three grades are AA, A,and B.
The best grade (AA) has a firm yolk and white that stand up high when broken onto a flat surface and do not spread over a large area. In the shell, the yolk is well centered, and the air sac is small.
As eggs age,they lose density.The thin part of the white becomes larger, and the egg spreads over a larger area when broken. Also,the air sac becomes larger as the egg loses moisture through the shell.
Maintaining Quality
Proper storage is essential for maintaining quality. Eggs keep for weeks if held at 36°F (2°C) but lose quality quickly if held at room temperature. In fact, they can lose a full grade in one day at warm kitchen temperatures. There’s no point in paying for Grade AA eggs if they are Grade B by the time you use them. Store eggs away from foods that might pass on undesirable flavors or odors.
Grades and Use
Grade AA is the best to use for fried or poached eggs. Lower grades spread out too much to produce a high-quality product. For hard-cooked eggs, use either Grade A eggs or Grade AA that have been held a few days in the refrigerator. Very fresh eggs are difficult to peel when cooked in the shell.
Grade B eggs are suitable for use in baking. If you are certain they have developed no strong flavors, they may be used for scrambled eggs, where the firmness of the whole egg is less important.
MARKET FORMS
1. Fresh eggs or shell eggs.
These are most often used for breakfast cookery .
2. Frozen eggs.
- Whole eggs
- Whites
- Yolks
- Whole eggs with extra yolks
Frozen eggs are usually made from high-quality fresh eggs and are excellent for use in scrambled eggs, omelets, French toast, and in baking. They are pasteurized and are usually purchased in 30-pound (13.6-kg) cans. These take at least two days to thaw at refrigerator temperatures.
3. Dried eggs.
- Whole eggs
- Yolks
- Whites
Dried eggs are used primarily for baking. They are not suggested for use in breakfast cookery.
Unlike most dehydrated products, dried eggs are not shelf-stable and must be kept refrigerated or frozen,tightly sealed.
Sanitation
In recent years, cases of salmonella food poisoning have been caused by raw or undercooked eggs. As a result, cooks have been made more aware of egg-related sanitation concerns. Pasteurized egg products are used in more operations.
EGG SUBSTITUTES
Egg yolks, in addition to being high in fat, are also high in cholesterol. Efforts to reduce cholesterol in the diet have led to the development of commercial egg substitutes.
These are of two types:
1. Egg substitutes that can be used to make such dishes as scrambled eggs, omelets, and custards are made of pasteurized egg whites with the addition of a blend of ingredients to substitute for the yolks, such as vegetable oil, milk solids, vegetable gums, salt, emulsifiers, and vitamin additives. They are sold in bulk liquid form,usually frozen,and can be substituted, ounce for ounce,for whole liquid eggs in most egg preparations.
2. Eggless egg substitutes contain no egg product. They are made of flours or other starches, plus vegetable gums and stabilizers, and, sometimes, soy protein. They are intended for use in baked goods only and are not suitable for use in breakfast egg preparations or custards. If they contain no milk products (read ingredient lists on individual products),they may be used in vegan diets.
GENERAL COOKING PRINCIPLES
The most important rule of egg cookery is simple:Avoid high temperatures and long cooking times.In other words,do not overcook.This should be a familiar rule by now. Overcooking produces tough eggs,causes discoloration,and affects flavor.
Coagulation
Eggs are largely protein,so the principle of coagulation is important to consider.
Eggs coagulate at the following temperatures:
Whole eggs,beaten about 156°F (69°C)
Whites 140° to 149°F (60° to 65°C)
Yolks 144° to 158°F (62° to 70°C)
Custard (whole eggs plus liquid) 175° to 185°F (79° to 85°C)
Note that whites coagulate or cook before yolks do. This is why it is possible to cook eggs with firm whites but soft yolks. Note also that when eggs are mixed with a liquid, they become firm at a higher
temperature.However,185°F (85°C) is still much lower than the temperature of a sauté pan or skillet over high heat.
As the temperature of coagulation is reached, the eggs change from semiliquid to solid,and they become opaque.If their temperature continues to rise, they become even firmer. An overcooked egg is tough and rubbery. Low temperatures produce the best-cooked eggs.
If egg-liquid mixtures such as custards and scrambled eggs are overcooked,the egg solids separate from the liquids, or curdle.This is often seen as tough, watery scrambled eggs.
Sulfur
The familiar green ring you often see in hard-cooked eggs is caused by cooking at high temperatures or cooking too long.The same green color appears in scrambled eggs that are overcooked or held too long in the steam table.
This ring results when the sulfur in the egg whites reacts with the iron in the yolk to form iron sulfide, a compound that has a green color and a strong odor and flavor. The best way to avoid green eggs is to use low temperatures and short cooking and holding times.
Foams
Beaten egg whites are used to give lightness and rising power to soufflés, puffy omelets, cakes, some pancakes and waffles, and other products.The following guidelines will help you handle beaten egg whites properly
1. Fat inhibits foaming.
When separating eggs, be careful not to get any yolk in the whites. Yolks contain fats. Use very clean equipment when beating whites.
2. Mild acids help foaming.
A small amount of lemon juice or cream of tartar gives more volume and stability to beaten egg whites. Use about 2 teaspoons cream of tartar per pound of egg whites (20 mL per kg).
3. Egg whites foam better at room temperature.
Remove them from the cooler 1 hour before beating.
4. Do not overbeat.
Beaten egg whites should look moist and shiny. Overbeaten eggs look dry and curdled and have lost much of their ability to raise soufflés and cakes.
5. Sugar makes foams more stable.
When making sweet puffed omelets and dessert soufflés,add some of the sugar to the partially beaten whites and continue to beat to proper stiffness.(This will take longer than when no sugar is added.) The soufflé will be more stable before and after baking.