INFLUENCE OF ELECTROLYTES UPON THE VISCOSITY 



OF DOUGH. 



By L. J. HENDERSON, W. O. FENN,* and EDWIN J. COHN.* 



{From the Wolcott Gibhs Memorial Laboratory, Harvard University, in Cooperation 

 with the Division of Food and Nutrition, Medical Department, U. S. Army.) 



(Received for publication, December 6, 1918.) 



The rising of bread and the quahty of the baked loaf depend upon 

 the nature of the dough and especially upon such of its properties as 

 tenacity, ductility, and elasticity. These properties are hard to 

 define theoretically in this complex colloidal system, but they are, 

 as we have found, related to viscosity or to whatever may determine 

 the resistance of dough to stirring and to flowing through a tube. 

 Accordingly, experiments have been made to measure what may pro- 

 visionally be called the viscosity of dough under conditions which 

 reveal the influence of the hydrogen ion concentration and of a variety 

 of electrolytes upon this property. The result of the experiments is 

 proof that in addition to the effect of water content and of the pres- 

 ence of substitutes lacking gluten, the viscosity of dough is much in- 

 fluenced by these two factors. Certain important points in baking 

 practice are explained by these results. 



Measurement of the Viscosity of Dough. 



The property that we shall call viscosity is quantitatively meas- 

 ured in the experiments reported by the resistance of dough to stirring. 

 12 gm. of dough are packed in the torsion viscosimeter represented, 

 full size, in Fig. L 

 . The viscosimeter is placed in a thermostat at 30° C. and the dough 

 allowed to stand 10 minutes in order to bring it to the temperature of 



C3^ * Lieutenant, Sanitary Corps, U. S. Army. 



387 



CsJ 



