A. Class Experiment.
1. Place a two-inch cube of beef in a third of a cup of cold water. Let it soak half an hour, then heat slowly to boiling, noting (1) the temperature at which coagulation takes place and (2) that at which the color changes. Continue heating ten minutes.
2. Cook a second cube of exactly the same size as in (1), but do not soak it.
3. Take a third cube like the others, grind or chop it into very small pieces, and cook as in (1).
Compare the resulting broths.
B. Prepare Soup.
Allow a pint and a half of water for each pound of meat and bone. Remove the fat by passing a small piece of ice, wrapped in a cloth, around on the surface of the soup. Divide into two portions.
1. Clear the first portion with the white of an egg. Beat the egg slightly and crush the shell, allowing one egg white and shell to each two quarts of soup. Add to the soup, bring slowly to the boiling point, and skim, or strain through cloth.
C. Class Experiment. The Use of Bones in Soup.
Examine the structure of a piece of bone. Put two pieces as nearly alike as possible to soak, one in dilute hydrochloric acid, the other in water. Let them stand in a cool place for several days. Compare the results. On what has the acid acted? Examine the ossein which is left. Now cook each bone separately in just enough water to cover and until the water is boiled down to one-half the amount. Let cool. Compare the consistency.
Liebig, who is sometimes called the father of organic chemistry, taught that protein was the sole source of muscular energy, and that meat extracts were of great nutritive value. Even Liebig afterwards realized that this last was wrong, that the meat extract was a stimulant instead of a food. But notwithstanding, the notion was held in popular opinion for a long time, and some people to-day still believe the meat extract gives strength to invalids. True meat extracts are mainly composed of the flavoring matter of meat with some mineral salts. Practically no fat, no gelatine, or other proteins are present. We can see readily that this means no real food value. The extracts may have their place, however, as stimulants. They are often fed to invalids under special conditions, or used to flavor soups or sauces.
Only slightly more nutritious are the home-made meat broths and beef tea. They contain some protein, partly gelatine, and a little fat, but are, after all, mostly water. A pint of beef broth made from a pound of beef and a half pound of veal bone shows less than one and a half per cent of protein, and about one and a half per cent of fat, and although a strong soup, it contains over ninety-five per cent of water. As soups may contain even ninety-eight per cent of water, it is quite evident that anyone fed on beef broth would not be getting much food.
Meat juices, both home-made and preserved, contain more nutriment. The home-made juices differ according to the cut of beef used and the method of extraction. They average about five per cent of coagulable protein. But Hutchison calculates that about three pints of such juice would be necessary to feed an invalid for a day. While the commercial beef juices run higher in protein than those extracted at home, their cost is very great. Hutchison suggests, therefore, the substitution of egg white with water flavored with beef extract, when beef juice is especially called for.
It is evident that meat broths, extract, tea, and the like, are all low in food value. Nevertheless they may have a place in the diet. They are used sometimes with other food to stimulate the flow of the digestive juices and to act as appetizers. This is their logical use at the beginning of a dinner. Because they are really light food, they are better before a hearty meal than a thickened cream soup, or a puree. Sometimes they are used when it is better for the patient not to have much to eat, to satisfy his desire for food. Suppose, for example, that a person has broken a leg and is laid up for a while. It is difficult to make such a person, not sick and with a normal appetite, realize that he is better off with less food than he needs when he is more active. Here, broths and soups and beverages are an aid in adding bulk to the diet, without furnishing too much food.
If meat broths contain so little nutriment, evidently the meat used to make them is almost as nutritious as before it was used. It has lost flavor and needs to be made palatable, but with proper treatment is still valuable as food.
U. S. Dept. of Agriculture. Bulletin No. 27. "Bouillon Cubes: Their Contents and Food Value Compared with Meat Extracts and Home-made Preparations of Meat."
1. Why is bone added to soup? Should it be split into pieces?
2. Consult cook books and make lists of herbs and of vegetables which may be used in meat soups.
3. Would you allow more water to meat in making soup with vegetables than without?
4. Devise ways for utilizing the meat which has been used in soup making. Is such use worth while?