The Chemistry of Wheat Gluten. 497 



THE CHEMISTRY OF WHEAT GLUTEN. 

 By Geo. G. Nasmith, R.A. 



(Read 26th April, igo2.) 



I. — Historical . . 497 



II. — Observations 501 



III. — Properties of Gliadin 509 



IV. — Properties of Glutenin ......... 510 



V^— The Ferment Theory of Gluten Formation .... 511 



VI. — The Aleuron Layer of Wheat 513 



VII. — Conclusions 514 



VIII. — Bibliography 516 



I. — Historical. 



The first preparation of gluten from wheat flour by washing away 

 the starch from dough seems to have been made by Becari, ^ but 

 Einhof2 was the first to give special attention to its composition. He 

 extracted wheat gluten with dilute alcohol, and he found that the 

 substance which precipitated on cooling, diluting or concentrating the 

 solution was practically identical with gluten itself 



Taddei^ named the portion soluble in alcohol gliadin, the residue 

 zymom. 



Berzelius* thought that he found a second constituent in the part 

 of the gluten soluble in alcohol, which he called mucin, and which was 

 precipitated by acetic acid. He^ regarded Taddei's gliadin as identical 

 with the substance obtained by Einhof from wheat, barley and rye. 

 The insoluble residue Berzelius called plant albumin, from its great 

 similarity to animal albumin. 



De Saussure^ found that wheat gluten contained about 20 per cent, 

 plant gelatin, or glutin, as he proposed to call it, 72 per cent, insoluble 

 plant albumin, and i per cent, mucin ; the latter, although differently 

 prepared, he considered to be similar to the mucin of Berzelius, and it 

 had, as he thought, the power of transforming starch into sugar. 



Boussingault,^ like Einhof, considered that part of the gluten 

 soluble in alcohol to be identical with the entire gluten proteid. 



Liebig^ named the portion of the gluten insoluble in alcohol plant 



