his also is
readily detected, by microscopic examination, as the corn starch and
wheat starch grains are quite different in mechanical structure. Such
flours are required to be labeled, in accord with the congressional act
of 1898, when Congress passed, in advance of the general pure food bill,
an act regulating the labeling and sale of mixed and adulterated flours.
Various statements have been made in regard to the adulteration of flour
with minerals, as chalk and barytes, but such adulteration does not
appear to be at all general.

170. Nutritive Value of Flour.--From a nutritive point of view, wheat
flour and wheat bread have a high value.[66] A larger amount of
nutrients can be secured for a given sum of money in the form of flour
than of any other food material except corn meal. According to
statistics, the average per capita consumption of wheat in the United
States is about 4-1/2 bushels, or, approximately, one barrel per year,
and from recent investigations it would appear that the amount of flour
used in the dietary is on the increase. According to the Bureau of
Labor, flour costs the average laborer about one tenth as much as all
other foods combined, although he secures from it a proportionally
larger amount of nutritive material than from any other food.

CHAPTER XI

BREAD AND BREAD MAKING

171. Leavened and Unleavened Bread.--To make unleavened bread the
flour is moistened and worked into a stiff dough, which is then rolled
thin, cut into various shapes, and baked, forming a brittle biscuit or
cracker.

The process of making raised or leavened bread consists, in brief, of
mixing the flour and water in proper proportions for a stiff dough,
together with some salt for seasoning, and yeast (or other agent) for
leavening. The moistened gluten of the flour forms a viscid, elastic,
tenacious mass, which is thoroughly kneaded to distribute the yeast. The
dough is then set in a warm place and the yeast begins to grow, or
"work," causing alcoholic fermentation, with the production of carbon
dioxid gas, which expands the dough, or causes it to "rise," thus
rendering it porous. After the yeast has grown sufficiently, the dough
is baked in a hot oven, where further fermentation is stopped because of
destruction of the yeast by the heat, which also causes the gas to
expand the loaf and, in addition, generates steam. The gas and steam
inflate the tenacious dough and finally escape into the oven. At the
sam