MEAT. 237 MEAT. from 15 to 20 per cent, of (he matorial as pur- chased. Digestibility. Aeenrdinj; to the results of a number of experiments, an average of 97 per cent, of the protein and !I5 per cent, of the fat of meat is digested. Little is known of llie rela- tive digestibility of difl'erent kinds of meat, but it is probable that as regards thoroughness of digestion they do not vary greatly. Texture (Toughness) of Me.vts. Whether meats are tough or tender depends upon two things: the character of the walls of the muscle tubes and the eliaraeter of the connective tissues which bind the tubes and muscles together. In young and well -nourished animals the tube walls are thin and delicate, and the connective tissue is small in amount. As the animals grow older or are made to work (and this is particularly true in the case of poorly nourished animals) the walls of the muscle tubes and the connective tissues become thick and hard. This is the reason wliy the flesli of young, well-fed animals is tender and easily masticated, while the llesh of old, hard-worked, or poorly fed animals is often so tough that prolonged boiling or roasting seems to have but little eti'ect on it. After slauglitering, meats iMidergo marked changes in texture. These changes can be grouped under three classes or stages. In the first stage, when the meat is just slaugh- tered, the tlesh is soft, juicy, and quite tender. In the next stage tlie tlesh stilt'ens and the meat becomes hard and tough. This condition is known as rifior mortis and continues until the third stage, when the tirst changes of decomposition set in. In hot climates the meat is commonly eaten in either the first or second .stage. In cold climates it is seldom eaten before the second stage, and generally, in order to lessen the toughness, it is allowed to enter the third stage, when it becomes soft and tender, and acquires added flavor. The softening is due in part to the formation of lactic acid, which acts upon the connective tissue. The same eti'ect may be pro- duced, though more rapidly, by macerating the meat with weak vinegar. Meat is sometimes made tender by cutting the flesh into thin slices and jiounding it across the cut ends until the fibres are broken. The flavor depends largely upon the kinds and amounts of 'nitrogenous extractives' which the nuisde fibres or tubes contain. Pork and nuitton are deficient in extractives, and what flavor they possess is due largely to the fats contained in them. The flesh of birds and of most game is very rich in extractives, which accounts for its high flavor. In general, the flavor of any par- ticilar meat is largely modified by the condition of the animal when slaughtered, and by its food. age, breed, etc. The flesh of young animals is more tender than but not so highly flavored as that of more raatui-e animals. It is often said that the flesh of males is more highly flavored than that of females. There are at least two excep- tions to this rule, since the flesh of the goose is more highly flavored than that of the gander, and in the case of pork there is little dillerenee between the flesh of the male and that of the female. Castration, as illustrated in the familiar Fia. 6. DKlisSED SIDE OF MUTTON OB Fig. 7. DIAGRAM OF CDT8 OF PORK. 1. Head; '2. shoulder: 3, back; 4, middle cut; 5, belly; 6, ham ; 7. ribs : 8, loin. example of the capon, tends to make the flesh more tender, fatter, and better flavored. The flesh of the animals which feed exclusively upon fish or flesh has a strong, disagreeable taste, and is eaten only by uncivilized people or those in great need. Fish is an exception to the rule, however. Jleat which is allowed to hang and ripen develops added flavors. In the first stages of decomposition compounds quite similar to the nitrogenous extractives are formed, and it is to these that the improved flavors are due. Cooking. Meat is not often eaten raw by civilized people. For the most part it is either roasted, broiled, fried, stewed, or boiled. Among the chief objects of cooking are the loo.sening and softening of the tissues, which facilitates di- gestion by exposing them more fully to the action of the digestive juices. Another important ob- ject is to kill parasites and microiirganisms it present, and thus destroy organisms that might otherwise expose the eater to great risks. Minor, but by no means un- important, objects are the coagulation of the albumen and blood so as to render the meat more acceptable to the sight, and the develop- ment and improvement of the natural flavor, which is often accomplished in part by the addition of condi- ments. If meat in cooking is placed in cold water and heated gi'adually, jjart of the organic salts, the soluble al- bumen, and the extractives or flavoring matters will be dissolved out. The broth or soup obtained will be rich, but the meat will be eorre- s])ondingly tasteless. This tasteless material has been found to be as easily and completely digested as the same weight of ordi- nary roast. It contains nearly all the protein of the meat, and, if it is properly <'ombined w'ith vegetables, salt, and flavoring materials, makes an agreeable as well as nutritious food. If a piece of meat is plunged into boiling water, the Fig. 8. DRESSED SIDE or PORK.
