34 BULLETIN 1463, U. S. DEPARTMENT OF AGRICULTURE 
The viscosity measurements for gluten quality bear out in a 
general way the findings obtained for the washed gluten tests. The 
glutenin content was not altered to any noticeable extent. Only 
in the soft red winter wheat straight flour was there any reduction 
in the percentage of water soluble | nitrogen, and in only one or two 
instances did there appear to be any increase in the protein content 
of the gluten proteins. 
The diastatic activity of the resultant flours was materially in- 
creased by excessive grinding. 
In the baking tests conducted on the middlngs stock and flour 
treated to excessive grinding the results for water absorption showed 
a very marked and consistent tendency to increase. Increases in 
weight of loaf corresponding fairly closely to the increases in water 
absorption also were shown. 
The size of the loaf showed a slight tendency to decrease with the 
increase in the number of times of grinding. On the other hand, in 
grinding to a definite degree of fineness the only tendency apparent 
was that the greatest volumes resulted from the materials of inter- 
mediate fineness. 
The effect of the number of grindings on color and grain of crumb 
was that the best scores were mostly from the original materials or 
the portions ground only once, and the poorest scores from the por- 
tions ground twenty times. This tendency was not apparent for 
these factors when the form of excessive grinding used was that of 
erinding to a definite degree of fineness. The general appearance 
and texture of crumb were little affected and indicated no very 
pronounced tendencies as to direction. 
In such factors as pertain to the mixing and handling of the dough 
excessive grinding showed some tendency to slow up the rate at which 
flour absorbed water, to increase the time required for proofing, and 
to result in a sticky and weak dough. 
DIFFERENT-SIZED PARTICLES OF WHICH FLOUR IS NORMALLY COMPOSED 
With respect to the different sizes of particles of which flour is 
normally composed, the ash content of the particles of the soft red 
winter wheat flours were, in- most instances, progressively lower as 
the size of the particle decreased. The reverse of this was the case 
with the hard wheat flours. The protein content of the finer flour 
particles passing through the 25xx sieve was considerably lower than 
that of the coarser sizes, as was also the quantity and quality of the 
gluten. 
In general, a fairly close parallelism existed between titratable 
acidity and ash content. In hydrogen-ion eoncentration there was no 
appreciable difference for the various sizes of flour particles. 
The finest flour particles were whitest in color according to the 
gasoline test. This also was true with respect to appearance. 
As in the case of protein content the finest particles contained the 
least percentage of wet and dry gluten, but if the quality of gluten 
is judged from the standpoint of the water absorbed per gram of 
dry gluten the quality factors seem to have been fairly constant for 
all sizes of particles. 
The diastatic activity of the different-sized particles varied in ten- 
dency but was fairly consistent in that the flours which passed 
