May 20, 1918 Hydration Capacity of Gluten 391 



rather than to chemical difference in the flours. His first paper (16) 

 is devoted to a study of possible chemical differences. He determined 

 total nitrogen, total gliadin nitrogen, amid nitrogen in the gliadin, ratio 

 of gliadin to total protein, total ash, total soluble ash, acid, and carbon- 

 dioxid production in several different flours. He contends that the 

 size of the loaf is regulated to a large extent by the fermentable sugars 

 which are present, this being indicated by the carbon dioxid evolved, 

 while — 



shapeliness, and probably gas retention, are dependent on the physical properties of 

 gluten as modified by the presence of vary'ing proportions of salts. 



In later papers Wood (77) and Wood and Hardy (/<?, ig) investi- 

 gated certain of the physical properties of gluten, especially as to the 

 effect of electrolytes in solution upon its physical state. 



That the gluten which is washed from a strong flour is different in 

 character from that obtained from a weak flour is a matter of general 

 knowledge. Shutt (ij, p. 60) visualizes the differences between such 

 glutens as follows : 



In flours of high bread-making values the gluten is resilient, elastic, firm, and co- 

 hesive; in poor flours it may be flabby, nonresilient, soft, or sticky. 



Wood suspended strings of gluten about the size of a pencil across 

 V-shaped glass rods in beakers containing varying concentrations of 

 different acids and then noted the concentration at which cohesion was 

 so far reduced as to allow the gluten to fall off the rod and disperse in a 

 cloudy solution. He apparently used gluten from only one flour in 

 these experiments. 



In this manner it was found that gluten suspended in distilled water 

 retained its coherence almost indefinitely, but that in solutions of hy- 

 drochloric acid as dilute as N/ 1,000 dispersion began almost immedi- 

 ately. This action increased with an increased concentration of acid 

 up to about N/jo, and then decreased again until at a concentration of 

 approximately NI12 the gluten became — 



permanently coherent and much harder and more elastic, and less sticky than in its 

 original condition. 



Similar experiments were conducted with sulphuric, phosphoric, 

 oxalic, acetic, lactic, citric, and tartaric acids, both with and without 

 the additions of certain salts. Unfortunately Wood does not give the 

 necessary tabular data to permit exact comparisons; and in the curve 

 shown, those for "acid alone" are omitted, and only certain of those for 

 "acid -I- salt " are given. He finds, however, that the order in which the 

 acids affected the coherence of the gluten was (i) hydrochloric, (2) sul- 

 phuric, (3) phosphoric, (4) oxalic. The three remaining acids behaved 

 quite differently, for, while dilute solutions caused disintegration, this 



