102 



THE: PROTEINS OF THE: WHEAT 



and no practicable method of purification existed which could be carried out 

 without great loss of substance, the nitrogen in each was determined and 

 the protein calculated by multiplying the result obtained by 6.25. The 

 spring- wheat preparation was thus found to contain 3.07 per cent of nitro- 

 gen, equal to 19.19 per cent of protein, and the winter-wheat preparation 

 5.15 per cent nitrogen, equivalent to 32.18 per cent. The amount of pro- 

 teose and peptone thus found in the extract from the spring wheat was 

 J -3 2 97 grams, which equals 0.213 per cent of the flour, and in the winter- 

 wheat extract 2.8063 grams, equal to 0.432 per cent of the flour. 



The sodium chloride extract contained, therefore, the following amounts 

 of protein : 



The remainder of the protein matter of the seed forms the gluten. The 

 proportion of gliadin and glutenin in this gluten was determined in the fol- 

 lowing manner : 



200 grams of spring-wheat flour made from the entire seed and a like 

 quantity of a similar winter- wheat flour were each made into a dough and 

 thoroughly washed with water as long as starch was removed. The gluten 

 thus obtained, after freeing from loosely adhering moisture, was weighed 

 and exactly one-half dried at 1 10 to constant weight. The spring wheat 

 was thus found to yield 12.685 P er cent dry gluten, the winter- wheat flour 

 11.858 per cent. 



The other half of the gluten was cut up very fine and extracted as thor- 

 oughly as possible with alcohol of 0.90 sp. gr. The alcoholic extract was 

 then evaporated to small volume, cooled, and the solution decanted from the 

 precipitated protein. This precipitate was then extracted with ether and 

 dried at 110. From the spring-wheat gluten 4.3379 per cent and from the 

 winter wheat 4.2454 per cent of alcohol-soluble protein were obtained. 



The residue extracted with alcohol was then dried at 110 and weighed. 

 The spring- wheat gluten contained 7.80 per cent insoluble in alcohol, the 

 winter wheat 7.504 per cent, reckoned on the wheat. Nitrogen was then 

 determined in these residues dried at 110, as well as in the dried gluten 



