CHAPTER VII._Public School Domestic Science

Carbohydrate Foods.

The idea of starchy foods is usually connected with such substances as

laundry starch, cornstarch, arrow root, etc. These are, of course,

more concentrated forms of starch than potatoes, rice, etc. Many

starchy foods contain other ingredients, and some are especially rich

in proteids.

The following table may help to make this clear (Atwater):--

PERCENTAGE OF STARCH IN VEGETABLE FOODS.

-----------------+-----------

| Per Cent.

-----------------+-----------

Wheat bread | 55.5

Wheat flour | 75.6

Graham flour | 71.8

Rye flour | 78.7

Buckwheat flour | 77.6

Beans | 57.4

Oatmeal | 68.1

Cornmeal | 71.0

Rice | 79.4

Potatoes | 21.3

Sweet Potatoes | 21.1

Turnips | 6.9

Carrots | 10.1

Cabbage | 6.2

Melons | 2.5

Apples | 14.3

Pears | 16.3

Bananas | 23.3

-----------------+-----------

It is estimated that starch composes one-half of peas, beans, wheat,

oats and rye, three-fourths of corn and rice, one-fifth of potatoes.

Vegetable proteids, as already stated, are less easily digested than

those belonging to the animal kingdom, therefore it must be remembered

that a purely vegetable diet, even though it may be so arranged as to

provide the necessary protein, is apt to over-tax the digestive

organs more than a mixed diet from both the animal and vegetable

kingdoms. Much depends upon the cooking of the starchy foods in order

to render them digestible. (Study chapter on Digestion in the Public

School Physiology.)

STARCH.

The digestion of starch--which is insoluble in cold water--really

begins with the cooking, which by softening the outer coating or fibre

of the grains, causes them to swell and burst, thereby preparing them

for the chemical change which is caused by the action of the saliva in

converting the starch into a species of sugar before it enters the

stomach. Substances which are insoluble in cold water cannot be

absorbed into the blood, therefore are not of any value as food until

they have become changed, and made soluble, which overtaxes the

digestive organs and causes trouble. The temperature of the saliva is

too low to dissolve the starch fibre unaided. Each of the digestive

juices has its own work to do, and the saliva acts directly upon the

starchy food; hence the importance of thoroughly masticating such food

as bread, potatoes, rice, cereals, etc. The action of heat, in baking,

which causes the vapor to rise, and forms the crust of starchy food,

produces what is called dextrine, or partially digested starch.

Dextrine is soluble in cold water, hence the ease with which crust and

toast--when properly made--are digested. It is more important to

thoroughly chew starchy food than meat, as it is mixed with another

digestive juice, which acts upon it in the stomach.

Sugars.

SUGAR.

There are many varieties of sugar in common use, viz.: cane sugar,

grape sugar or glucose, and sugar of milk (lactose). As food, sugars

have practically the same use as starch; sugar, owing to its

solubility, taxes the digestive organs very little. Over-indulgence in

sugar, however, tends to cause various disorders of assimilation and

nutrition. Sugar is also very fattening, it is a force producer, and

can be used with greater safety by those engaged in active muscular

work. Cane sugar is the clarified and crystallized juice of the sugar

cane. Nearly half the sugar used in the world comes from sugar cane,

the other half from beet roots. The latter is not quite so sweet as

the cane sugar. Sugar is also made from the sap of the maple tree, but

this is considered more of a luxury; consequently, not generally used

for cooking purposes.

MOLASSES AND TREACLE.

Molasses and treacle are formed in the process of crystallizing and

refining sugar. Treacle is the waste drained from moulds used in

refining sugar, and usually contains more or less dirt.

GLUCOSE.

Glucose, or grape sugar, is commonly manufactured from starch. It is

found in almost all the sweeter varieties of fruit. It is not so

desirable for general use as cane sugar.

HONEY.

Honey is a form of sugar gathered by bees from the nectar of flowering

plants, and stored by them in cells. Honey contains water 16.13,

fruit sugar 78.74, cane sugar 2.69, nitrogenous matter 1.29, mineral

matter 0.12 per cent. (Konig.)

Grains.

While the grains contain less proteid than the legumes, they are more

valuable on account of the variety of the nutrients contained in them,

and are more easily adapted to the demands of the appetite. They,

however, require long, slow cooking in order to soften the fibre and

render the starch more soluble. Among the most important we may place:

WHEAT.

A wheat kernel may be subdivided into three layers. The first or outer

one contains the bran; second, the gluten, fats and salts; third, the

starch. Some of the mineral matter for which wheat is so valuable is

contained in the bran, hence the value of at least a portion of that

part of the wheat being included in bread flour--not by the addition

of coarse bran (which is indigestible) to the ordinary flour, but by

the refining process employed in producing whole wheat flour. While

wheat is used in other forms, its principal use as food is in the form

of flour.

The following table, giving the composition of bread from wheat and

maize, will be of interest (Stone):--

COMPOSITION OF BREAD FROM WHEAT AND MAIZE.

-------------------------+--------------------------------------------

| In Air-Dry Material.

+------+-----+-----+-------+--------+--------

-------------------------+------+-----+-----+-------+--------+--------

|P.ct. |P.ct.|P.ct.| P.ct. | P.ct. | P.ct.

wheat | 3.07 | 2.33| 1.22| 2.86 | 15.70 | 74.82

wheat | 7.46 | 1.69| 1.24| 2.80 | 15.26 | 71.55

winter wheat |10.39 | .59| .32| .44 | 11.94 | 76.32

spring wheat | 8.00 | .43| .47| .39 | 14.41 | 76.30

maize | 3.40 | 1.88| 4.14| 2.53 | 12.88 | 75.17

-------------------------+------+-----+-----+-------+--------+--------

-------------------------+------------------------------------------

| In Dry Matter

+------+------+--------+---------+---------

-------------------------+------+------+--------+---------+---------

|P.ct. |P.ct. | P.ct. | P.ct. | P.ct.

wheat | 2.40 | 1.25 | 2.95 | 16.20 | 77.20

wheat | 1.82 | 1.34 | 3.02 | 16.49 | 77.33

winter wheat | .66 | .35 | .49 | 13.33 | 85.17

spring wheat | .47 | .51 | .42 | 15.66 | 82.94

maize | 1.95 | 4.29 | 2.62 | 13.33 | 77.81

-------------------------+------+------+--------+---------+---------

BREAD.

The most valuable food product manufactured from flour is bread.

Bread contains so many of the ingredients required to nourish the

body, viz.: fat, proteid, salts, sugar and starch, that it may well be

termed the "staff of life." As it does not contain enough fat for a

perfect food the addition of butter to it renders it more valuable as

an article of diet. Mrs. Ellen H. Richards gives the following

explanation of what constitutes ideal bread: "(1) It should retain as

much as possible of the nutritive principles of the grain from which

it is made; (2) it should be prepared in such a manner as to secure

the complete assimilation of these nutritive principles; (3) it should

be light and porous, so as to allow the digestive juices to penetrate

it quickly and thoroughly; (4) it should be nearly or quite free from

coarse bran, which causes too rapid muscular action to allow of

complete digestion. This effect is also produced when the bread is

sour." Bread is made from a combination of flour, liquid (either milk

or water), and a vegetable ferment called yeast (see yeast recipes).

The yeast acts slowly or rapidly according to the temperature to which

it is exposed. The starch has to be changed by the ferment called

diastase (diastase is a vegetable ferment which converts starchy foods

into a soluble material called maltose) into sugar, and the sugar into

alcohol and carbonic acid gas (carbon dioxide), when it makes itself

known by the bubbles which appear and the gradual swelling of the

whole mass. It is the effect of the carbonic acid gas upon the gluten,

which, when checked at the proper time before the ferment becomes

acetic (sour) by baking, produces the sweet, wholesome bread which is

the pride of all good housekeepers. The kneading of bread is to break

up the gas bubbles into small portions in order that there may be no

large holes and the fermentation be equal throughout. The loaf is

baked in order to kill the ferment, to render the starch soluble, to

expand the carbonic acid gas and drive off the alcohol, to stiffen the

gluten and to form a crust which shall have a pleasant flavor. Much of

the indigestibility of bread is owing to the imperfect baking; unless

the interior of the loaf has reached the sterilizing point, 212° F.,

the bacteria contained in the yeast will not be killed, and some of

the gas will remain in the centre of the loaf. The scientific method

of baking bread is to fix the air cells as quickly as possible at

first. This can be done better by baking the bread in small loaves in

separate pans, thereby securing a uniform heat and more crust, which

is considered to be the most easily digested part of the bread. Some

cooks consider that long, slow baking produces a more desirable flavor

and renders bread more digestible. One hundred pounds of flour will

make an average of one hundred and thirty-five pounds of bread. This

increase of weight is due to the addition of water.

MACARONI.

Macaroni is a flour preparation of great food value. It contains about

six per cent. more gluten than bread, and is regarded by Sir Henry

Thompson as equal to meat for flesh-forming purposes. Dieticians say

that macaroni, spaghetti and vermicelli are not used so extensively as

their value deserves.

BUCKWHEAT.

Buckwheat is the least important of the cereals.

RYE.

Rye is almost equal to wheat in nutritive value. Its treatment in

regard to bread making is similar to that of wheat.

CORN.

Corn contains fat, proteid and starch, and produces heat and energy.

It is very fattening, and when eaten as a vegetable is considered

difficult of digestion. Cornmeal is a wholesome food; it contains more

fat than wheat flour, and less mineral matter.

RICE.

Rice constitutes a staple food of a great many of the world's

inhabitants. It contains more starch than any other cereal, but when

properly cooked is very easily digested. It should be combined with

some animal food, as it contains too little nitrogen to satisfy the

demands of the system. It forms a wholesome combination with fruit,

such as apples, peaches, prunes, berries, etc.

BARLEY.

Barley is almost equal to wheat in nutritive value. It contains more

fat, mineral matter and cellulose (cellulose is often called

indigestible fibre, as it resists the solvent action of the digestive

juices, and is of no value as a nutrient), and less proteid and

digestible carbohydrates.

OATMEAL.

Oatmeal is one of the most valuable foods. Oats contain fat, proteid,

salts and cellulose, in addition to a large percentage of starch. The

nutritive value of oatmeal is great, but much depends upon the manner

of cooking. (See recipes.) People who eat much oatmeal should lead a

vigorous outdoor life. The following analysis of oatmeal is given

(Letheby):--

Nitrogenous matter 12.6 per cent.

Carbohydrates, starch, etc. 63.8 "

Fatty matter 5.6 "

Mineral matter 3.0 "

Water 15.0 "

----

Total 100.0

Vegetables.

Legumes--peas, beans and lentils--have an exceedingly leathery

envelope when old; and unless soaked for a long time in cold water--in

order to soften the woody fibre--and are then cooked slowly for some

hours, are very indigestible. Pea and bean soups are considered very

nutritious. Lentils grow in France; they are dried and split, in which

form they are used in soups.

POTATOES.

Potatoes are the most popular of all the tubers. As an article of diet

they possess little nutritive value, being about three-fourths water.

They contain some mineral matter, hence the reason why they are better

boiled and baked in their skins, so as to prevent the escape of the

salts into the water. Potatoes are more easily digested when baked

than cooked in any other form.

BEETS.

Beets contain between 85 and 90 per cent. of starch and sugar, some

salts, and a little over one per cent. of proteid matter. Young beets,

either in the form of a vegetable or a salad, are considered to be

very wholesome.

CARROTS, TURNIPS, PARSNIPS, OYSTER PLANT.

Carrots, turnips, parsnips and oyster plant, although containing a

large percentage of water, are considered valuable as nutrients, the

turnip being the least nutritious.

GREEN VEGETABLES.

Green vegetables do not contain much nutriment, and are chiefly

valuable as affording a pleasing variety in diet; also for supplying

mineral matter and some acids. In this class we may include cabbage,

cauliflower, spinach, lettuce and celery.

TOMATOES.

Tomatoes are wholesome vegetables; on account of the oxalic acid they

contain they do not always agree with people of delicate digestion.

CUCUMBERS.

Cucumbers are neither wholesome nor digestible.

ASPARAGUS.

Asparagus is a much prized vegetable. The substance called asparagin

which it contains is supposed to possess some value.

RHUBARB.

Rhubarb is a wholesome vegetable.

ONIONS, GARLIC, SHALLOTS.

Onions, garlic, and shallots are valuable both as condiments and eaten

separately. They contain more nutrients than the last vegetables

considered.