orn | 1.7| 0.8|21.8| 0.4| 492
Rice: | | | | |
Whole rice, polished| 5.8| 0.3|78.4| 0.4| 1546
Puffed rice | 5.1| 0.5|84.0| 0.3| 1639
Crackers | 9.1| 7.9|70.5| 1.4| 1905
Macaroni |11.6| 0.8|72.2| 1.0| 1660
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CHAPTER X

WHEAT FLOUR

151. Use for Bread Making.--Wheat is particularly adapted to
bread-making purposes because of the physical properties of the gliadin,
one of its proteids. It is the gliadin which, when wet, binds together
the flour particles, enabling the gas generated during bread making to
be retained, and the loaf to expand and become porous. Wheat varies in
chemical composition between wide limits; it may contain as high as 16
per cent of protein, or as low as 8 per cent; average wheat has from 12
to 14 per cent; and with these differences in composition, the
bread-making value varies.

[Illustration: FIG. 36.--STARCHY (LIGHT-COLORED) AND
GLUTINOUS (DARK-COLORED) WHEATS.]

152. Winter and Spring Wheat Flours.--There are two general classes of
wheat: spring wheat and winter wheat. The winter varieties are seeded in
the fall, and the spring varieties, which are grown mainly in the
Northwestern states, Minnesota, and North and South Dakota, and the
Canadian Northwest, are seeded in the spring and mature in the late
summer. Winter wheat is confined to more southern latitudes and regions
of less severe winter, and matures in the early summer. There are many
varieties of both spring and winter wheat, although wheats are
popularly characterized only as hard or soft, depending upon the
physical properties. The winter wheats are, as a rule, more soft and
starchy than the spring wheats, which are usually corneous or flinty to
different degrees. There is a general tendency for wheats to become
either starchy or glutinous, owing to inherited individuality of the
seed and to environment. There are often found in the same field wheat
plants yielding hard glutinous kernels, and other plants producing
starchy kernels containing 5 per cent less proteids. Wheats of low
protein content do not make high-grade flour; neither do wheats of the
maximum protein content necessarily make the best flour. For a more
extended discussion of wheat proteids, the student is referred to
Chapter XI.

[Illustration: FIG. 37.--LONGITUDINAL SECTION OF WHEAT KERNEL:
_a_, pericarp; _b_, bran