270 
70 per cent., the result is a heavy, sour bread. 
The difference in chemical composition be- 
tween barley gluten is scarcely sufficient to 
account for the difference in behavior of the 
two flours to yeast (Plimmer) : 
Wheat Barley 
Total protein ...... 10.00 11.00 
Gliadingsseecee rere 4.25 4.00 
Glutening eee. 4.00 4.5 
Accordingly, it seemed that physical chem- 
ical factors might enter into the question. 
With some colloids at least, the viscosity is 
increased by raising the content of inorganic 
salt (Loeb) and this is apparently what is 
desired in the case of barley gluten.1 At the 
same time, it seemed desirable to determine 
the optimum hydrogen ion concentration of 
some of the flours in the presence of yeast. 
Accordingly, the following experiments were 
performed : 
Wheat, barley, rice and potato flours were 
used. When prepared without wheat, rice and 
potato flours failed to rise, owing to the lack 
of a protein similar to gluten, whose physical 
characters permitted the holding of the gases, - 
CO, especially, to “lighten” the dough. 
When used with distilled water, barley flour 
alone gave practically the same sort of bread 
as that when wheat flour is used in amounts 
smaller than 70 per cent., the heaviness and 
sourness rendering its use impossible. An 
attempt was made to mix barley and rice, 
barley and potato, etc., but the results were 
even worse than with barley alone. 
The influence of various degrees of alkalin- 
ity and of acidity were then examined. By 
the aid of the chart of Sgrensen, mixtures of 
KH,PO, and Na,HPO, were made. Twenty- 
five grams of barley flour were weighed into 
an evaporating dish and 35 c.c. of one of the 
various solutions were added, together with 
one gram of Fleishman’s compressed yeast. 
The whole was then intimately mixed, trans- 
ferred to a cylinder and left to rise at 35° OC. 
for one half hour, in the constant temperature 
room. Solutions of phosphates were used as 
follows: Ph= 8.0, 7.6, 7.4, 7.0, 6.4, 6.0, 5.2, 4.6. 
1Cf. Upson’s work. 
SCIENCE 
[N. S. Von. XLVIII. No. 1237 
The optimum rise was obtained at 5.2 and 
later it was determined that with solutions at 
Ph=5.0, the best results were obtained. Con- 
trols were conducted with wheat flour, using 
distilled water. 
In passing it may be remarked that similar 
experiments with wheat flour have the op- 
timum at a lower acidity than that given here 
for barley flour. 
Tt has been supposed that there is a specific 
chemical effect in the phosphates, owing to the 
difference in phosphate composition in wheat 
and other gluten-bearing flours. Inasmuch as 
we are able to use lactic and acetie acids at 
Ph=5.0, it seems that the effect is rather one 
concerned with reaction. 
After the dough had risen, the preparation 
was removed and mixed with ten grams of 
fresh barley flour, the whole kneaded well and 
transferred to a pyrex beaker which was placed 
in an electric baking oven for one hour at 220° 
C. Besides barley flour, we also used rice and 
potato flours, separately, but without im- 
proving the resulting bread. 
The bread thus made is fairly good and 
greatly superior to that made from water 
preparations. 
We repeated the experiment just described 
with barley, this time using 2 per cent. NaCl 
(introduced dry) in the dough. A much 
lighter loaf was obtained, the initial rise being 
greater and the subsequent dough on the 
second rising being more similar to that of 
wheat preparations. A good crust is formed 
and there is less sourness, characteristic of all 
barley breads. 
It is apparent, then, that by maintaining a 
reaction approximating Ph—5 and a sodium 
chlorid content (added) of 2 per cent., barley 
flour may be utilized by itself to make a pass- 
ing war bread. By suitable manipulation, we 
have little doubt that an experienced baker 
can derive a formula whereby an excellent 
bread can be produced at will. 
Lorraine L. LANDENBERGER, 
Wirsrow Morse 
MicHArL Reese Hospitat, 
CHICAGO 
