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