INFLUENCE OF GRANULATION ON QUALITY. OF FLOUR 33 
those passing through 20xx and 25xx sieves—were found to contain 
less protein and wet and dry gluten, than the coarser particles. The 
quality of the gluten was likewise poorer in the smaller-sized sepa- 
rates. 
With the soft red winter wheat materials the smaller-sized particles 
were characterized by low ash contents. The reverse of this was 
true of the separates sieved from the hard wheat materials. The 
active acidity of the separates of all sizes was practically the same. 
The smaller-sized particles usually contained the least amount of 
gasoline soluble pigments. 
In regard to the baking quality of the various-sized particles of 
which flour is normally composed the particles of intermediate size 
gave the best appearing loaf of bread. ‘The flour particles sifted 
through the 20xx and 25xx sieves in many instances acted weakly | 
in the doughing and proofing and produced a loaf of inferior 
quality. It therefore follows that if these fine particles were sep- 
arated from flour as ordinarily milled the bread-baking qualities 
of the remaining flour would be improved. This would not be 
advisable, however, unless the resultant flours could be marketed 
at a net gain to the miller. It is probable that some day the miller 
may find it to his advantage to do something of this sort as it is 
possible that the fine particles may be of particular value for some 
other purpose than bread making. This statement is induced by 
results obtained from some pastry experiments conducted in con- 
nection with these investigations, in which it was found that these 
fine flour particles produced a very satisfactory pie crust with the 
use of considerably less shortening than was required by the coarser 
flour particles. This latter fact is due, no doubt, to the lower 
quantity and inferior quality of the gluten contained in the flour 
particles of finest size. 
EXCESSIVE GRINDING 
The more excessively the materials were ground the whiter they 
became and the more difficult it was to bolt them. 
Excessive grinding reduced the moisture content of the materials 
but did not affect their crude protein and ash contents. 
A tendency was shown for the color pigments extractable in 
gasoline to be increased where grinding was very excessive. A 
definite but not considerable tendency was shown for the hydrogen- 
ion concentration to increase with excessive grinding. 
For the particular form of excessive grinding employed in which 
the materials were ground various numbers of times a gradual de- 
crease in the wet and dry gluten content of the soft red winter 
wheat middlings seemed to have taken place. No decrease in quan- 
tity or quality of gluten was experienced in the hard wheat mid- 
dlings or in the first clear flour. In the soft red winter wheat 
straight and the hard wheat patent flours only the samples ground 
twenty times showed any injury to the gluten. . 
In the samples ground to a definite degree of fineness the results 
obtained for gluten quantity and quality were similar to those ob- 
tained from the samples ground various numbers of times. 
