/^(?/^. 



24 



RELATION OF THE CON- 

 SISTENCY OF THE 

 WHEAT KERNEL TO 

 THE RATE OF RESPI- 

 RATION 



Reference has already 

 been made to the differ- 

 ence in the relative 

 water-imbibing capacity 

 of the various organic col- 

 loids of the wheat kernel. 

 Since starch and gluten 

 constitute a large propor- 

 tion of the endosperm, 

 their differences in this 

 regard are of principal 

 interest. Simple tests in- 

 dicate that the water-im- 

 bibing capacity of gluten 

 is materially greater than 

 that of starch. In con- 

 sequence it follov\rs that, 

 as a general rule, those 

 kernels which contain a 

 high percentage of gluten 

 will, at any particular 

 moisture content, be more 

 viscous than will kernels 

 containing a lower per- 

 centage of gluten. 



The gluten content is also related to the relative consistency or hard- 

 ness of the wheat berry. In general, the hard, vitreous grains contain 

 a higher percentage of gluten than do the soft, starchy grains. Accord- 

 ingly we may expect exactly what we find — viz, that the soft wheats 

 are "tougher" and of a lower viscosity at any given moisture content 

 (within the limits found in ordinary commercial grain) than the hard, 

 vitreous wheats. 



/2 



/3 Af /s /e /7 



Fig. 2.— Graphs showing the comparative rate of respiration 

 hard spring, soft red winter, and soft white winter wheat. 



