Chapter 2

17. CARBOHYDRATES.--Like fats, the food substances included in the term carbohydrates supply the body with energy. However, fats and carbohydrates differ in the forms in which they supply energy, the former producing it in the most concentrated form and the latter in the most economical form.

So that the term _carbohydrate_ may be clearly understood and firmly fixed in the mind, it is deemed advisable to discuss briefly the composition of the body and the food that enters it. Of course, in a lesson on cookery, not so much attention need be given to this matter as in a lesson on _dietetics_, which is a branch of hygiene that treats of diet; nevertheless, it is important that every person who prepares food for the table be familiar with the fact that the body, as well as food, is made up of a certain number of chemical elements, of which nitrogen, carbon, hydrogen, and oxygen form a large part. Protein owes its importance to the fact that of the various food substances it alone contains the element nitrogen, which is absolutely essential to the formation of any plant or animal tissue. The other three elements, carbon, hydrogen, and oxygen, go to make up the carbohydrates; in fact, it is from the names of these three elements that the term carbohydrate is derived. The carbohydrates include the starches and sugars that are used and eaten in so many forms, and these contain the three elements mentioned, the hydrogen and oxygen contained in them being in the proportion that produces water. Thus, as will readily be seen, by separating the name into its parts--_carbo_ (carbon) and _hydrate_ (hydrogen and oxygen in the proportion of two parts of hydrogen and one of oxygen, that is, in the form of water)--carbohydrate is simply carbon united with water. While the facts just brought out have much to do with food economy, they are of interest here chiefly because they help to make clear the term carbohydrate, which, as will be admitted, is the only correct name for the food substance it represents.

18. STARCH, one of the chief forms of carbohydrates, is found in only the vegetable kingdom. It is present in large quantities in the grains and in potatoes; in fact, nearly all vegetables contain large or small amounts of it. It is stored in the plant in the form of granules that lie within the plant cells.

Cooking applied to starch changes it into a form that is digestible. Moist heat cooks the granules until they expand and burst and thus thicken the mass. Dry heat changes starch first into a soluble form and finally into what is called _dextrine_, this being the intermediate step in the changing of starch into sugar.

19. SUGAR, another important form of carbohydrate, is mainly of vegetable origin, except that which is found in milk and called _lactose_. This, together with the fat found in milk, supplies the child with energy before it is able to digest a variety of foods. The sap of various plants contains such large quantities of sugar that it can be crystalized out and secured in dry form. The liquid that remains is valuable as food, for, by boiling it down, it forms molasses. Sugar is also present in considerable amounts in all fruits, and much of it is in a form that can be assimilated, or taken up by the body, quickly. A sugar very similar to this natural fruit sugar is made from the starch of corn and is called _glucose_. Much of the carbohydrate found in vegetables, especially young, tender vegetables, is in the form of sugar, which, as the vegetables grow older, changes to starch.

Sugar melts upon the application of heat or, if it is in a melted condition, as sirup or molasses, it boils down and gives off water. When all the water has boiled away, the sugar begins to caramelize or become brown, and develops a characteristic flavor. If the cooking is continued too long, a dark-brown color and a bitter taste are developed. Because the sugar in fruits and vegetables is in solution, some of it is lost when they are boiled, unless, of course, the water in which they are cooked is utilized.

20. CELLULOSE is a form of carbohydrate closely related to starch. It helps to form the structure of plants and vegetables. Very little cellulose is digested, but it should not be ignored, because it gives the necessary bulk to the food in which it occurs and because strict attention must be paid to the cooking of it. As cellulose usually surrounds nutritive material of vegetable origin, it must be softened and loosened sufficiently by cooking to permit the nutritive material to be dissolved by the digestive juices. Then, too, in old vegetables, there is more starch and the cellulose is harder and tougher, just as an old tree is much harder than a sapling. This, then, accounts for the fact that rapid cooking is needed for some vegetables and slow cooking for others, the method and the time of cooking depending on the presence and the consistency of the cellulose that occurs in the food.

21. IMPORTANCE OF A VARIETY OF FOODS.--Every one of the five food substances just considered must be included in a person's diet; yet, with the exception of milk, no single food yields the right amounts of material necessary for tissue building and repair and for heat and energy. Even milk is in the right proportion, as far as its food substances are concerned, only for babies and very young children. It will thus be seen that to provide the body with the right foods, the diet must be such as to include all the food substances. In food selection, therefore, the characteristics of the various food substances must be considered well. Fats yield the most heat, but are the most slowly digested. Proteins and carbohydrates are more quickly digested than fats, but, in equal amounts, have less than half as much food value. Water and mineral salts do not yield heat, but are required to build tissue and to keep the body in a healthy condition. In addition, it is well to note that a well-balanced diet is one that contains all of the five food substances in just the right proportion in which the individual needs them to build up the body, repair it, and supply it with energy. What this proportion should be, however, cannot be stated offhand, because the quantity and kind of food substances necessarily vary with the size, age, and activity of each person.

FOOD VALUE

22. Nearly all foods are complex substances, and they differ from one another in what is known as their _value_, which is measured by the work the food does in the body either as a tissue builder or as a producer of energy. However, in considering food value, the person who prepares food must not lose sight of the fact that the individual appetite must be appealed to by a sufficient variety of appetizing foods. There would be neither economy nor advantage in serving food that does not please those who are to eat it.

While all foods supply the body with energy, they differ very much in the quantity they yield. If certain ones were chosen solely for that purpose, it would be necessary for any ordinary person to consume a larger quantity of them than could be eaten at any one time. For instance, green vegetables furnish the body with a certain amount of energy, but they cannot be eaten to the exclusion of other things, because no person could eat in a day a sufficient amount of them to give the body all the energy it would need for that day's work. On the other hand, certain foods produce principally building material, and if they were taken for the purpose of yielding only energy, they would be much too expensive. Meats, for example, build up the body, but a person's diet would cost too much if meat alone were depended on to provide the body with all the energy it requires. Many foods, too, contain mineral salts, which, as has been pointed out, are needed for building tissue and keeping the body in a healthy condition.

23. To come to a correct appreciation of the value of different foods, it is necessary to understand the unit employed to measure the amount of work that foods do in the body. This unit is the CALORIE, or _calory_, and it is used to measure foods just as the inch, the yard, the pound, the pint, and the quart are the units used to measure materials and liquids; however, instead of measuring the food itself, it determines its food value, or fuel value. To illustrate what is meant, consider, for instance, 1/2 ounce of sugar and 1/2 ounce of butter. As far as the actual weight of these two foods is concerned, they are equal; but with regard to the work they do in the body they differ considerably. Their relative value in the body, however, can be determined if they are measured by some unit that can be applied to both. It is definitely known that both of them produce heat when they are oxidized, that is, when they are combined with oxygen; thus, the logical way of measuring them is to determine the quantity of heat that will be produced when they are eaten and united with oxygen, a process that causes the liberation of heat. The calorie is the unit by which this heat can be measured, it being the quantity of heat required to raise the temperature of 1 pint of water 4 degrees Fahrenheit, which is the name of the thermometer commonly used in the home. When burned as fuel, a square of butter weighing 1/2 ounce produces enough heat to raise 1 pint of water 400 degrees Fahrenheit, and it will yield the same amount of heat when it is eaten and goes through the slow process of oxidation in the body. On the other hand, 1/2 ounce of sugar upon being oxidized will produce only enough heat to raise the temperature of 1 pint of water about 230 degrees Fahrenheit. Thus, as will be seen, 1/2 ounce of butter has a value of approximately 100 calories, whereas 1/2 ounce of sugar contains only about 57-1/2 calories.

Other foods yield heat in varying degrees, and their food value is determined in exactly the same way as that of butter and sugar. To give an idea of the composition of various food materials, as well as the number of calories that 1 pound of these food materials will yield, food charts published by the United States Department of Agriculture are here presented. As an understanding of these charts will prove extremely profitable in the selection of food, a careful study of them at this time is urged. In addition, reference to them should be made from time to time as the various kinds of foods are taken up, as the charts will then be more easily comprehended and their contents of more value.

DIGESTION AND ABSORPTION OF FOOD

24. The third requirement in the selection of food, namely, its digestion and absorption, depends considerably on the persons who are to be fed. Food that is chosen for adults entirely would not be the same as that intended for both young persons and adults; neither would food that is to be fed to children or persons who are ill be the same as that which is to be served to robust adults who do a normal amount of work. No hard-and-fast rules can be laid down here for this phase of food selection, but as these lessons in cookery are taken up in turn, the necessary knowledge regarding digestibility will be acquired.

* * * * *

PREPARATION OF FOOD

REASONS FOR COOKING FOOD

25. The term cookery, as has been explained, means the preparation of both hot and cold dishes for use as food, as well as the selection of the materials or substances that are to be cooked. The importance of cooking foods by subjecting them to the action of heat has been recognized for ages; and while it is true that there are many foods that appeal to the appetite in their raw state and still others that can be eaten either raw or cooked, there are several reasons why it is desirable to cook food, as will be seen from the following:

1. Cooking makes foods more palatable. This is true of such foods as meat, cereals, and many vegetables, which would be very unappetizing if they were eaten raw.

2. Cooking renders foods more digestible. For instance, the hard grains, such as wheat, and the dried vegetables, such as beans, cannot be readily digested unless they are softened by cooking. But while cooking makes such foods more digestible, it renders others more difficult of digestion, as in the case of eggs, the degree of digestibility depending somewhat on the cooking method used and the skill of the cook. An egg in an almost liquid form, or when only slightly cooked, as a soft-boiled egg, is more easily digested than when it becomes hardened by cooking. Then, too, a properly prepared hard-cooked egg is more digestible than an improperly cooked one, although the degree of hardness may be the same.

3. Cooking gives foods greater variety. The same food may be cooked by various methods and be given very different tastes and appearances; on the other hand, it may be combined with a large number of other foods, so as to increase the variety of the dishes in which it is used. The large number of recipes found in cook books show the attempts that have been made to obtain variety in cooked dishes by the combining of different foods.

4. Cooking sterilizes foods either partly or completely. Many foods need partial or complete sterilization for safety. They must be completely sterilized if the germs that produce fermentation or putrefaction and thereby spoil food would be destroyed. This is done when fruits and vegetables are canned for keeping. Foods that are exposed to dust, flies, and improper handling should be thoroughly cooked in order to destroy any pathogenic germs that might be present. By such germs are meant disease-bearing germs. They differ from germs that produce fermentation and putrefaction, or spoiling, and that must in general be considered as a help, for these play an important part in the raising of bread and the preparation of various foods, as is pointed out later.

5. Cooking develops flavor in many foods. In the case of some vegetables, the flavoring substance is given off in the air by certain methods of cooking and a better flavor is thereby developed.

* * * * *

METHODS OF COOKING

COOKING PROCESSES

26. Food is cooked by the application of heat, which may be either moist or dry. While it is true that the art of cooking includes the preparation of material that is served or eaten raw, cooking itself is impossible without heat; indeed, the part of cooking that requires the most skill and experience is that in which heat is involved. Explicit directions for carrying on the various cooking processes depend on the kind of stove, the cooking utensils, and even the atmospheric conditions. In truth, the results of some processes depend so much on the state of the atmosphere that they are not successful on a day on which it is damp and heavy; also, as is well known, the stove acts perfectly on some days, whereas on other days it seems to have a stubborn will of its own. Besides the difficulties mentioned, the heat itself sometimes presents obstacles in the cooking of foods, to regulate it in such a way as to keep it uniform being often a hard matter. Thus, a dish may be spoiled by subjecting it to heat that is too intense, by cooking it too long, or by not cooking it rapidly enough. All these points must be learned, and the best way to master them is to put into constant practice the principles that are involved in cookery.

27. Without doubt, the first step in gaining a mastery of cookery is to become familiar with the different methods and processes, the ways in which they are applied, and the reasons for applying them. There are numerous ways of cooking food, but the principal processes are boiling, stewing, steaming, dry steaming, braizing, fricasseeing, roasting, baking, broiling, pan broiling, frying, and sauteing. Which one of these to use will depend on the food that is to be cooked and the result desired. If the wrong method is employed, there will be a waste of food material or the food will be rendered less desirable in flavor or tenderness. For example, it would be both wasteful and undesirable to roast a tough old fowl or to boil a tender young broiler.

The various methods of cookery just mentioned naturally divide themselves into three groups; namely, those involving dry heat, those requiring moist heat, and those in which hot fat is the cooking medium.

COOKING WITH DRY HEAT

28. Cooking with dry heat includes broiling, pan broiling, roasting, and baking; but, whichever of these processes is used, the principle is practically the same. In these processes the food is cooked by being exposed to the source of heat or by being placed in a closed oven and subjected to heated air. When dry heat is applied, the food to be cooked is heated to a much greater temperature than when moist heat is used.

29. BROILING.--The cooking process known as broiling consists in exposing directly to the source of heat the food that is to be cooked; that is, in cooking it over or before a clear bed of coals or a gas flame. The aim in broiling is to retain the juices of food and develop flavor. As it is a quick method, foods that are not tender, as, for example, tough meats, should not be broiled, because broiling does not help to render their fibers more tender. In applying this cooking process, which is particularly suitable for tender portions of meat and for young fowl, the food should be exposed to intense heat at first in order to sear all surfaces quickly and thus retain the juices. At the beginning of the cooking, the article that is being broiled should be turned often; then, as soon as the outside is browned, the heat should be reduced if possible, as with a gas stove, and the article allowed to cook until done. If the broiling is done over coals, it is necessary to continue the turning during the entire process. While broiling produces an especially good flavor in the foods to which it is applied, provided they are not tough, it is not the most economical way of cooking.

30. PAN BROILING.--Pan broiling is an adaptation of the broiling method. It consists in cooking food in a sissing-hot pan on top of the stove without the use of fat. In this process the surfaces of the steak, chop, or whatever the food may be, are quickly seared, after which the article is turned frequently and cooked more slowly until done. The object of pan broiling is the same as that of broiling, and it is resorted to, as a rule, when the fire is not in the right condition for broiling.

31. ROASTING.--Originally, the term _to roast_ meant to cook before a fire, because, before the time of stoves, practically all food was cooked in the fireplace. Food that was to be roasted was placed before the fire in a device that reflected heat, this device being open on the side toward the fire and closed on that toward the room. The roast was suspended in this device, slowly turned, and thus cooked by radiant heat--that is, heat given off in the form of direct rays--the principle being the same as that of broiling, but the application different. Nowadays, the term _roasting_ is almost universally applied to the action of both hot air and radiant heat. However, much of what is called roasting is in reality baking. Foods cooked in the oven of an ordinary coal or gas range are really baked, although they are said to be roasted, and a covered roasting pan is a misnomer. Food must be exposed to the air in the process of cooking if it is to be roasted in the true sense.

It may be well to note that successful roasting or broiling depends more on the shape of the article to be roasted or broiled than on its weight. For this reason, thick, compact cuts of meat are usually selected for roasting and thin cuts for broiling. Good results also depend very much on the pan selected for the roasting process. One of the great aims in cooking should be to save or conserve all the food possible; that is, if by one process less waste in cooking results, it should be chosen rather than one that will result in loss at the end of the cooking process.

32. BAKING.--By baking is meant cooking in a heated oven at temperatures ranging from 300 to 500 degrees Fahrenheit. As the term baking is frequently used in a wrong sense, the actual conditions of the process should be thoroughly understood. In both broiling and the original method of roasting, the heat is applied directly; that is, the food is exposed directly to the source of heat. Actual baking differs from these processes in that it is done in a closed oven or by means of heated air. Starchy foods, such as bread, cakes, and pastry, are nearly always baked, and gradually other foods, such as meats, fish, and vegetables are being subjected to this method of cooking. In fact, persons who are skilled in cooking use the oven more and more for things that they formerly thought had to be cooked in other ways. But the name that is applied to the process depends somewhat on custom, for while meat that is cooked in the oven is really baked, it is usually termed roasted meat. It seems strange, but it is nevertheless true, that ham cooked in the oven has always been termed baked, while turkey cooked in exactly the same way is said to be roasted.

COOKING WITH MOIST HEAT

33. The methods of cooking with moist heat, that is, through the medium of water, are boiling, simmering, steaming, dry steaming, and braizing. In every one of these processes, the effect of moist heat on food is entirely different from that of dry heat. However, the method to be selected depends to a great extent on the amount of water that the food contains. To some foods much water must be added in the cooking process; to others, only a little or none at all. If food is not placed directly in large or small quantities of water, it is cooked by contact with steam or in a utensil that is heated by being placed in another containing boiling water, as, for example, a double boiler.

As water is such an important factor in cooking with moist heat, something concerning its nature and use should be understood. Therefore, before considering the moist-heat cooking processes in detail, the function of water in the body and in cooking and also the kinds of water are discussed.

34. FUNCTION OF WATER IN THE BODY.--Water supplies no energy to the body, but it plays a very important part in nutrition. In fact, its particular function in the body is to act as a solvent and a carrier of nutritive material and waste. In doing this work, it keeps the liquids of the body properly diluted, increases the flow of the digestive juices, and helps to carry off waste material. However, its ability to perform these necessary functions in the right way depends on its quality and its safety.

35. KINDS OF WATER.--Water is either hard or soft. As it falls from the clouds, it is pure and soft until it comes in contact with gases and solids, which are dissolved by it and change its character. It is definitely known that the last of the water that falls in a shower is much better than the first, as the first cleanses not only the air, but the roofs and other things with which it comes in contact. In passing through certain kinds of soil or over rocks, water dissolves some of the minerals that are contained there and is thus changed from soft to hard water. If sewage drains into a well or water supply, the water is liable to contain bacteria, which will render it unfit and unsafe for drinking until it is sterilized by boiling. Besides rain water and distilled water, there is none that is entirely soft; all other waters hold certain salts in solution to a greater or less degree.