394 



VISCOSITY OF DOUGH 



sufficiently high concentration always, a later rise in viscosity. 

 Among the salts which we have studied the sulfates of sodium and 

 magnesium have the most marked efifect. In these cases it is sufficient 

 to handle the dough in order to note a certain "slackness" or dimin- 

 ished firmness. 



Efect of Salts upofi the Viscosity of Dough at Different Hydrogen Ion 



Concentrations. 



The third series of experiments concerns the simultaneous influence 

 of acid or alkali and salt upon the viscosity of dough. The effect of 

 different concentrations of a salt at two hydrogen ion concentrations 

 is illustrated in Table IV and Fig. 4; the effect of the same con- 



TABLE IV. 



Viscosity of Dough in the Presence of Different Concentrations of NaCl at Different 

 Hydrogen Ion Concentrations. {Time in Minutes.) 



centration of a salt at different hydrogen ion concentrations is 

 shown in Table V and Fig. 5. 



These experiments show that the influence of salts upon viscosity 

 is variable with the hydrogen ion concentration. Particularly im- 

 portant is the fact that at a more acid range of reaction sodium 

 chloride greatly depresses viscosity while calcium chloride has its 

 effect in a less acid range. The great effect of the sulfates, however, 

 may be recognized over a wide range of reaction. 



For the present we shall postpone a discussion of the theoretical 

 bearings of these experiments, which are often obscure, and may best 

 be taken into account in connection with observations upon the 

 properties of gluten soon to be published from this laboratory. 



