The Importance Of Eating Eggs
Eggs are of great importance in the diet, and to appreciate this fact fully he true nature of this food must be understood. For domestic use, the eggs of guinea hens, turkeys, ducks, and geese occasionally find favor, but as eggs laid by hens are the kind that is commonly used, it is to such eggs that this Section is devoted. A hen’s egg may really be considered as an undeveloped chicken, because it contains all the elements required to build the body of the chick and provide it with the energy it needs to pick its way into the world. When it emerges from the shell, it is fully developed, and in a short time itbegins an independent existence, seeking and finding its own food. The fact that eggs store so much nutritive material explains to some extent why they are a valuable source of food for man and why they are used so extensively. However, as in the case of milk, the elements that eggs contain are not in just therightproportion for the sole nourishment of a human being, so they must generally be used in combination with other foods.
Most persons are familiar with the appearance of eggs, but in order that satisfactory results may be obtained in their selection, care, and cooking, it will be necessary to look into the details of their composition. As is well known, an egg consists of a porous shell lined with a fine, but tough, membrane that encloses the white and the yolk and serves to protect them. The yolk is divided from the white by a delicate membrane, which permits it to be separated from the white when an egg is carefully broken. This membrane extends to each end of the shell in the form of a small cord, and it is so fastened to the shell as to hold the yolk evenly suspended. The porous nature of an egg shell is required to give air to the developing chick, but it is this characteristic that permits eggs to spoil as they grow old and are exposed to air, for through these minute pores, or openings, the water in the egg evaporates and air and bacteria enter. Of course, as the water evaporates and is replaced by air, the egg becomes lighter. Because of this fact, the freshness of eggs can be determined by placing them in water. When they are fresh, they will sink in cold water, but as they decompose they become lighter and will float. Since it is known that the spoiling of eggs is due to the entrance of air through the porous shell, it may be inferred that their decay may be prevented either by protecting the shell so that air cannot enter or by keeping the eggs at so low a temperature that bacteria cannot grow. Although stored eggs always deteriorate more or less, both of these methods of preservation have proved very satisfactory, the former being used largely in the home and the latter finding its solution in cold storage. A knowledge of how eggs can be preserved, however, is of great value, for if there were no means of preservation and eventual marketing, the price of eggs would at times rise to actual prohibitive limits.
That eggs as an article of food are growing in importance is indicated by the fact that their production has come to be a large and widely distributed industry. Owing to the private consumption and sale of eggs, an accurate statement of the number of eggs produced is difficult to give. Still, in a report, the United States Bureau of Agriculture estimated the value of the yearly egg production at something more than three million dollars, with an allowance of about 210 eggs, or 17-1/2 dozen, per capita each year, or 4 eggs a week for each person. These figures, however, are only suggestive of the production, use, and value of eggs, for as the population increases so does the use of eggs. In fact, they are proving to be almost indispensable to the cook, the baker, the manufacturers of certain foods, and many others.
With the increase in the demand for eggs has come a corresponding steady advance in the money value of this product and, consequently, an increase in its price. The housewife who would practice economy in cookery can readily see, therefore, that with reference to the number of eggs required and the ways in which they are used, she must choose carefully the recipes and methods she employs. If the eggs are always considered a part of a meal, their use is seldom an extravagance, even at such high prices as they sometimes attain. On the other hand, if a dessert that requires the use of many eggs is added to a meal that is itself sufficient in food value, it is not unreasonable to regard such use of eggs as an extravagance. A point that should be taken into consideration in the use of eggs in the diet, especially when their price seems very high, is that there is no waste matter in them, unless the shell is regarded as waste. Therefore, they are often more economical than other foods that can be bought for less money. It must not be understood, however, that eggs are used only as an article of diet. They are also a very important food ingredient, being employed in the preparation of many kinds of dishes. For instance, they are often used to thicken custards, sauces, etc.; to clarify soups and jellies; to lighten cakes, puddings, hot breads, and other baked mixtures; to form the basis for salad dressings; and to combine or hold together many varieties of food.
Like milk, eggs are often spoken of as a perfect food. Still, as has been pointed out, they are not a perfect food for man, but they are of especial nutritive value and should be used freely in the diet just as long as their cost neither limits nor prohibits their use. An idea of how they compare with other nutritious foods can be obtained from Fig. 1, which shows that eight eggs are equal in food value to 1 quart of milk or 1 pound and 5 ounces of beefsteak. A better understanding of their food value, however, can be gained from a study of their composition.