THE DIGESTION OF FOODS.

It is important that the cook not only understand the nature and composition of foods, but they should also know something of their digestive properties, since food, to be serviceable, must be not only nutritious, but easily digested. Digestion is the process by which food rendered soluble, and capable of being absorbed for use in carrying on the various vital processes.

The digestive apparatus consists of a long and tortuous tube called the alimentary canal, varying in length from twenty-five to thirty feet, along which are arranged the various digestive organs,—the mouth, the stomach, the liver, and the pancreas,—each of which, together with the intestines, has an important function to perform. In these various organs nature manufactures five wonderful fluids for changing and dissolving the several food elements. The mouth supplies the saliva; in the walls of the stomach are little glands which produce the gastric juice; the pancreatic juice is made by the pancreas; the liver secretes bile; while scattered along the small intestines are minute glands which make the intestinal juice. Each of these fluids has a particular work to do in transforming some part of the food into suitable material for use in the body. The saliva acts upon the starch of the food, changing it into sugar; the gastric juice digests albumen and other nitrogenous elements; the bile digests fat, and aids in the absorption of other food elements after they are digested; the pancreatic juice is not confined in its action to a single element, but digests starch, fats, and the albuminous elements after they have been acted upon by the gastric juice.


The first act of the digestive process is mastication, or chewing the food, the purpose of which is to crush the food and divide it into small particles, so that the various digestive fluids may easily and promptly come into contact with every part of it.
"Salivary Digestion.—During the mastication of the food, the salivary glands are actively pouring out the saliva, which mingles with the food, and by softening it, aids in its division and prepares it for the action of the other digestive fluids. It also acts upon the starch, converting a portion of it into grape-sugar.

After receiving the food, the stomach soon begins to pour out the gastric juices, which first makes its appearance in little drops, like beads of sweat upon the face when the perspiration starts. As the quantity increases, the drops run together, trickle down the side of the stomach, and mingle with the food. The muscular walls of the stomach contract upon the food, moving it about with a sort of crushing action, thoroughly mixing the gastric juice with the food. During this process both the openings of the stomach are closed tightly. The gastric juice softens the food, digests albumen, and coagulates milk. The saliva continues its action upon starch for sometime after the food reaches the stomach.

"After the food has remained in the stomach from one to three hours, or even longer, if the digestion is slow, or indigestible foods have been eaten, the contractions of the stomach become so vigorous that the more fluid portions of the food are squeezed out through the pylorus, the lower orifice of the stomach, thus escaping into the intestine. The pylorus does not exercise any sort of intelligence in the selection of food, as was once supposed. The increasing acidity of the contents of the stomach causes its muscular walls to contract with increasing vigour, until finally those portions of the food which may be less perfectly broken up, but which the stomach has been unable to digest, are forced through the pylorus.


Time Required for Digestion.—The length of time required for stomach digestion varies with different food substances. The following table shows the time necessary for the stomach digestion of some of the more commonly used foods:—

hrs
min
Rice
1
0
Sago
1
45
Tapioca
2
0
Barley
2
0
Beans, pod, boiled
2
30
Bread, wheaten
3
30
Bread, corn
3
15
Apples, sour and raw
2
0
Apples, sweet and raw
1
30
Parsnips, boiled
2
30
Beets, boiled
3
45
Potatoes, Irish, boiled
3
30
Potatoes, Irish, baked
2
30
Cabbage, raw
2
30
Cabbage, boiled
4
30
Milk, boiled
2
0
Milk, raw
2
15
Eggs, hard boiled
3
30
Eggs, soft boiled
3
0
Eggs, fried
3
30
Eggs, raw
2
0
Eggs, whipped
1
30
Salmon, salted, boiled
4
0
Oysters, raw
2
55
Oysters, stewed
3
30
Beef, lean, rare roasted
3
0
Beefsteak, boiled
3
0
Beef, lean, fried
4
0
Beef, salted, boiled
4
15
Pork, roasted
5
15
Pork, salted, fried
4
15
Mutton, roasted
3
15
Mutton, broiled
3
0
Veal, broiled
4
0
Veal, fried
4
30
Fowls, boiled
4
0
Duck, roasted
4
30
Butter, melted
3
30
Cheese
3
30
Soup, marrowbone
4
15
Soup, bean
3
0
Soup, mutton
3
30
Chicken, boiled
3
0


Food combinations.
—Some persons, especially those of weak digestive powers, often experience inconvenience in the use of certain foods, owing to their improper combinations with other articles. Many foods which are digested easily when partaken of alone or in harmonious combinations, create much disturbance when eaten at the same meal with several different articles of food, or with some particular article with which they are especially incompatible. The following food combinations are among the best, the relative excellence of each being indicated by the order in which they are named: Milk and grains; grains and eggs; grains and vegetables or meats; grains and fruits.

Persons with sound stomachs and vigorous digestion will seldom experience inconvenience in making use of other and more varied combinations, but dyspeptics and persons troubled with slow digestion will find it to their advantage to select from the bill of fare such articles as best accord with each other, and to avoid such combinations as fruits and vegetables, milk and vegetables, milk and meats, sugar and milk, meat or vegetables, fats with fruits, meats, or vegetables, or cooked with grains.

Comments

Popular posts from this blog

4 Easy French Apple Recipes

French food terminology

5 French Menu Ideas to try out