hich part of the
gliadin had been extracted, the bread was only slightly improved. In
flour of the highest bread-making properties the two constituents,
gliadin and glutenin, are present in such proportions as to form a
well-balanced gluten.

The proteids of wheat flour are mainly in an insoluble form, although
there are small amounts of albumins and globulins; these are coagulated
by the action of heat during the bread-making process, and rendered
insoluble. A portion of the acid that is developed unites with the
gliadin and glutenin, forming acid proteids, which change the physical
properties of the dough. Both gliadin and glutenin take important parts
in bread making. The removal of gliadin from flour causes complete loss
of bread-making properties. Ordinarily from 45 to 65 per cent of the
total nitrogen of the flour is present in alcohol soluble or gliadin
form. Proteids also undergo hydration during mixing, some water being
chemically united with them, changing their physical properties. This
hydration change is necessary for the full development of the physical
properties of the gluten. The water and salt soluble proteids appear to
take no important part in the bread-making process, as their removal in
no way affects the size of the loaf or general character of the bread.
Because of the action of the acids upon the gliadin, bread contains a
larger amount of alcohol soluble nitrogen or gliadin than the flour from
which the bread was made. It is believed that this action changes the
molecular structure of the protein so that it is more readily separated
into its component parts when it undergoes digestion and assimilation.

182. Production of Volatile Nitrogenous Compounds.--When fermentation
is unnecessarily prolonged, an appreciable amount of nitrogen is
volatilized in the form of ammonia and allied bodies, as amids. During
the process of bread making, the yeast appears to act upon the protein,
as well as upon the carbohydrates, and, as previously stated, losses of
dry matter fall alike upon these two classes of compounds, nitrogenous
and non-nitrogenous. Analyses of the flours and materials used in bread
making, and of the bread, show that ordinarily about 1.5 per cent of the
total nitrogen is liberated in the form of gas during the bread-making
process, and analyses of the gases dispelled in baking show
approximately the same per cent of nitrogen. When bread is dried, as in
a drying oven, a small amount of vola