WHEAT 275 



of thin, transparent flakes which resemble gelatin. In 

 fact, gliadin was called by the earlier investigators, plant 

 gelatin. When moistened, the gliadin expands and forms 

 a mucilagenous mass. When more water is added, a 

 small amount is dissolved. Gliadin is soluble in dilute 

 acid and alkali solutions ; in many wheats, particularly 

 those which have undergone slight fermentation, there is 

 sufficient acid developed to combine with and render solu- 

 ble appreciable amounts. Gliadin, like all of the wheat 

 proteids, is characterized by a high per cent, of nitrogen. 

 Gliadin takes a very important part in bread-making, and 

 is the material which binds together the flour to form 

 dough and enables the mass to expand, retaining the gas 

 generated by the yeast. Wheat gluten contains from 60 

 to 70 per cent, of gliadin and from 30 to 40 per cent, of 

 glutenin. 



Glutenin is the proteid which remains after extracting 

 the gliadin from the gluten. When dry and pure, it 

 forms a light gray mass which may be reduced to a fine 

 powder. Glutenin is insoluble in dilute alcohol and salt 

 solutions and is only sparingly soluble in water, but is 

 readily soluble in dilute acid and alkali solutions. This 

 proteid also takes an.important part in bread-making. It 

 combines mechanically with the gliadin and, "serving as 

 a nucleus to which the gliadin adheres," prevents the 

 dough from becoming too soft and sticky. When these 

 two proteids are present in the proportion of about 65 per 

 cent, of gliadin to 35 per cent, of glutenin, a much better 

 quality of bread can be produced than from flour contain- 

 ing the same amount of total proteids but of which 75 per 



