504 
production of carbon dioxide, or, in other 
words, before the rise ceases. Such doughs 
are “ripe” for the oven. The baker says 
their “proof” is complete. 
The less elastic and tenacious doughs of the 
present emergency have little “ spring ” in the 
oven and if ripe are very liable to fall during 
the early stages of the baking. To guard 
against this it is a common practise to shorten 
the fermentation, which involves baking at a 
lower acidity. 
“ Overproved”’ doughs usually fall in the 
oven before the crust is formed by drying and 
coagulation of the proteins of the dough. In 
them the loss of carbon dioxide is not even 
compensated by the expansion of the gas at 
the higher temperature of the oven. Doughs 
that are not “ripe” for the oven are in the 
opposite condition and are termed “ under- 
proved.” The leakage of carbon dioxide from 
such doughs is not sufficient to permit the 
escape of the expanded gas and the loaf is 
“ tipped.” 
WHEAT SUBSTITUTES 
Although corn, barley and wheat flour con- 
tain nearly equal amounts of similar proteins, 
the properties of their doughs are markedly 
different. Rye is more tenacious than barley, 
and barley than corn, but in comparison with 
doughs made of wheat flour all others are 
“short.” They do not hold together and are 
not distensible. Therefore—with the possible 
exception of rye—they can not retain the 
carbon dioxide that is produced within them. 
To whatever extent such flours are substituted 
for wheat the same effects are observed in due 
proportion. For the “body” of the dough is 
supplied by the wheat gluten alone. The de- 
gree to which the dough can be distended 
therefore depends upon the amount and the 
hydration of the gluten. But in the presence 
of substitutes the hydration of gluten is com- 
plicated in two ways: first because water is ab- 
sorbed by the proteins of corn and of barley 
as well as by the proteins of wheat, but never- 
theless without the resulting elasticity ;17 sec- 
17 Unpublished observations. 
SCIENCE 
[N. S. Vou. XLVIII. No. 1247 
ondly because corn and barley combine with 
larger quantities of acid than does wheat.18 
The increasing acidity of the fermenting 
dough is thus partially neutralized. As a re- 
sult neither the activity of the yeast nor the 
elasticity of the dough increases so rapidly in 
the presence of substitutes. If the smaller 
amount of gluten that is present is to swell 
to the same extent as in ordinary bread the 
same acidity must be reached. Therefore if 
the amount of yeast or the length of the fer- 
mentation is not to be increased, acid must be 
added to the dough. 
But if the volume of the loaf is in this way 
increased, other dangers beset the baker when 
using a high percentage of substitute flours, 
for the leakage of carbon dioxide from the 
dough is also increased. As above mentioned 
the dough has little “spring” and falls more 
easily in the oven. This is another reason 
why the cautious baker has made his bread 
less acid during war time. He prefers baking 
dough that is “younger.” The frequent oc- 
eurrence of “ripped” bread is in this way ac- 
counted for. 
Moreover, the popularity of starch in the 
larger bake shops of the country during the 
last year, and the facility with which it was 
used, depend upon the fact that unlike all 
flours, starch absorbs only about half its 
weight of water and combines with acid to 
an inappreciable extent. 
SERUM PROTEINS 
Although skillful control of the fermenta- 
tion and of the acidity of dough (and some- 
times the addition of salts like calcium sul- 
phate) can improve leavened bread of any 
kind, it can not make up for the lack of 
gluten in wheat substitutes. Therefore, when 
wheat substitutes are employed it is desirable 
to add a small amount of a substitute for 
gluten. 
The proteins of serum are such a substitute. 
The addition to flour containing 20 to 25 per 
cent. wheat substitutes of two or three per 
cent. of dry powdered serum (which must be 
18 Unpublished observations. 
