14 Nebraska Agricultural Exp. Station, Research Bui. 8. 
But for concentrations above the optimum, swelling does not 
fall off at the same rate as in the case of hydrochloric acid. The 
presence of neutral salts in the acid solution reduces water ab- 
sorption, the absorption becoming less and less as the con- 
centration of salt increases till at a concentration of approximately 
0.05 M, absorption is entirely prevented. For varying concen- 
trations of any one salt and acid, the concentration of salt neces- 
sary to prevent swelling of gluten first rises and then falls, with 
increasing concentration of the acid. Gluten which has ab- 
sorbed water in acid solution and taken on a soft, jellylike con- 
sistency loses water and regains its original physical properties 
when placed in a salt solution. 
Acids and salts therefore determine not only the physical 
properties of gluten but its water-holding capacity as well. 
Gluten prepared by washing flour in many changes of tap water 
is an elastic, rubberlike mass, possessing tenacity. When placed 
in dilute acid solutions, gluten absorbs water, at the same time 
losing its tenacity and elasticity, becoming soft and gelatinous. 
Wood and Hardy^ have arrived at the same conclusions thru a 
study of the dispersion and ''loss of cohesiveness " of gluten in 
different solutions, by methods quite different from ours. 
The relation of physical properties of gluten to ''strength" 
in flour has been considered in papers by Wood^ and Hardy. 
After showing that the properties of gluten depend on the nature 
and concentration of the acid and salts in the solution with 
which it is in contact. Wood suggests that "these properties 
have an important bearing on the shape of the loaf and that a 
knowledge of the acidity and soluble salt content of a flour gives 
a clue to the factor of strength which decides whether the flour 
will make a good shaped loaf." Hardy discusses the work of 
Wood and points out the importance of the acids and salts in 
determining the physical properties of the gluten and any other 
colloids present in the dough. 
Numerous attempts have been made in the past to correlate 
baking strength of flour with various more or less easily determined 
physical or chemical factors. Some of the factors which have 
been suggested as bearing a relation to baking strength are total 
nitrogen, total gluten, total gliadin, ratio of gliadin to glutenin, 
ratio of gliadin to total nitrogen, ratio of water soluble nitrogen 
«Wood, Jour. Agr. Sci. 2, 267 (1907). 
Wood and Hardy, Proc. Roy. Soc. London (B) 81, 38 (1909). 
^Wood, loc. cit. 
"'Hardy, Jour. Board Agr. Supp. England 17, 52. 
"For an historical account of the work on baking strength see Blish, Jour. 
Ind. Eng. Chem. 8, 138 (1916). 
