THE COLLOIDAL SWELLING OF WHEAT 
GLUTEN IN RELATION TO MILLING 
AND BAKING. 
BY FRED W. UPSON AND JOHN W. CALVIN. 
Aside from its theoretical interest in connection with the 
general problem of water absorption by animal and plant tissues, 
the colloidal swelling of gluten is of great practical importance in 
its relation to certain problems of milling and baking. In a 
former paper^ the authors have presented experiments on the 
colloidal hydration of moist wheat gluten and discussed the 
subject of water absorption in its theoretical aspects. This 
subject has also been dealt with in papers by Wood^ and by 
Wood and Hardy.^ 
A review of the literature on wheat and flour chemistry shows 
that, excepting the work of the authors named, the colloidal 
properties of gluten have not been taken into account in previous 
investigations in this field. This subject is far too important to 
be overlooked. 
The experiments by Wood and by Wood and Hardy were 
carried out by immersing small bits of gluten, suspended over 
glass rods, in beakers containing solutions of varying concentra- 
tions of different acids both with and without the presence of 
salts, and noting the effect of the different solutions in bringing 
about ''disintegration" and ''loss of cohesiveness" of the gluten. 
Our experiments deal with the changes in hydration capacity of 
gluten under different conditions and were carried out by de- 
termining accurately the amount of water absorbed by gluten 
from solutions of varying concentrations of different acids, both 
with and without the presence of salts. 
EXPERIMENTS ON THE SWELLING OF WHEAT GLUTEN.^ 
The gluten for the following experiments was prepared by 
washing the starch from flour under a stream of distilled water. 
lUpson and Calvin, Jour. Amer. Chem. Soc. 37, 1295 (1915). 
2Wood, Jour. Agr. Sci. 2, 267 (1907). 
3Wood and Hardy, Proc. Roy. Soc. London, (B) 81, 38 (1909). 
^For a brief bibliography of work on the colloidal swelling of proteins 
see article by the authors, Jour. Amer. Chem. Soc. 37, 1295 (1915). 
For a detailed account of experiments on the swelling of animal proteins 
see Fischer, Oedema and Nephritis, Sec. Ed. N. Y. (1915). 
