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32 BULLETIN -1463, U. S. DEPARTMENT OF AGRICULTURE 
The siftings of intermediate fineness produced, as a general rule, 
the bread of the brownest and smoothest crust. The crust of the 
bread from the finest siftings usually tended toward paleness and 
roughness. 
The siftings requiring the longest proofing time in the pan were of 
intermediate fineness. ‘The fine ‘siftings absorbed water more slowly 
than did those of intermediate or coarse granulation and usually 
produced a sticky sponge. These finer <iftings also showed other 
indications of inferi jority as a bread flour over “the coarse and inter- 
mediate siftings, such as a dead and weak dough during mixing and 
at the time of panning and a broken and ragged top on the proofed 
loaf. 
The findings in connection with this form of treatment are in 
general agreement with those of Le Clere and his coworkers. 
SUMMARY 
The results obtained from these investigations do not differ in any 
marked way from those of previous investigations. They do, how- 
ever, shed light on certain phases of the subject on which no in- 
formation was previously available, and they clarify and strengthen 
certain conclusions of previous investigations. 
The results obtained were similar for the two methods of excessive 
grinding employed. They indicate that the chemical composition 
and baking quality of flour may be affected by excessive grinding. 
fn noting the effect produced, however, full consideration should be 
given to the excessiveness of the grinding required to produce this 
effect, otherwise improper importance may be attached to it. Study 
of the results in this light indicates that such a considerable amount 
of excessive grinding was required to bring about any appreciable 
effect in most of the factors examined that it is very improbable that 
any very marked change in the flour, except in its fineness and white- 
ness, would occur under commercial conditions unless all, or nearly 
all, of the milling reductions were accomplished under excessive 
roll pressure. Even then there is some doubt as to whether the degree 
of effect would be appreciable enough to make any material differ- 
ence in bread-baking quality. 
In the preceding pages it has been definitely shown that. as a result 
of grinding flour excessively, certain chemical changes take place 
that alter the quality of the gluten proteins, and change the physical 
condition of the starch oramules. The extent of these changes ; is varl- 
able and depends somewhat upon the class of flour under consider- 
ation. 
In baking results, the most marked effect from excessive grinding 
was the increase in water absorption and the deterioration in color 
of crumb. As for the other baking factors, the effect was more or 
less variable in degree and somewhat inconsistent as to tendency, but 
usually when any marked change occurred it was in those samples” 
which were most excessively ground. 
With respect to the various sizes of particles of which flour is 
normally composed the differences noted in chemical composition 
and baking results, because of their more practical application to 
ordinary milling practice, are of greater importance than those noted 
in connection with excessive gr inding. The smaller-sized particles— 
