^i6 Journal of Agricultural Research voi. xm, no. s 



factors show that even at the isoelectric point there would be wide 

 differences in their physical properties. It appears extremely probable 

 that the actual cause of the physico-chemical differences between strong 

 and weak glutens may be due to the form in which the protein is laid 

 down in the endosperm. It is entirely within reason to suppose that 

 the gluten may, under certain environmental conditions, be deposited as 

 uniformly-sized particles with the characteristics of true emulsoids, 

 while under different environmental conditions a part of the gluten may 

 be deposited in this form and another part in a semicrystalloidal form. 

 In other words, we postulate that the particles in a weak gluten are on 

 the average nearer the boundary line which separates the crystalloidal 

 state of matter from the colloidal state than are the particles comprising 

 a strong gluten. It is the intention of one of us to test this hypothesis in 

 the near future. 



SUMMARY » 



In this paper are presented data showing the increase or decrease of 

 water imbibition caused by immersing weighed disks of gluten from five 

 selected flours in solutions of lactic, acetic, boric, phosphoric, hydro- 

 chloric, and oxalic acids of various concentrations, both with and without 

 the addition of 0.005 molar concentrations of certain salts. 



Data have also been presented showing different flour analyses such 

 as ash on dry flour, soluble ash, specific conductivity of flour extract, 

 percentage of moist gluten, percentage of dry gluten, percentage of ash 

 in dry gluten, and baking tests. 



From a study of these data, the following conclusions have been drawn : 



'(i) Although the moist glutens from these flours differ widely in 

 "quality" and in physical properties, they are hydrated to almost 

 exactly the same extent. 



(2) Gluten from a weak flour has a much lower rate of hydration than 

 gluten from a strong flour. 



(3) Gluten from a weak flour has a much lower maximum hydration 

 capacity than gluten from a strong flour, changing from a gel to a sol at 

 a much lower degree of hydration. 



(4) Two types of imbibition curves were observed. Dilute solutions 

 of hydrochloric acid and of oxalic acid cause the gluten to rapidly imbibe 

 water, while at slightly stronger concentrations of acid water is actually 

 extracted from the moist gluten. Dilute solutions of lactic, acetic and 

 phosphoric acids cause the gluten to strongly imbibe water but stronger 

 acid solutions only slightly diminish the imbibition. The hydrogen-ion 

 concentration of the acid is not the only factor influencing imbibition, 

 but it is pointed out that the anion and the undissociated molecules, as 

 well as their relative adsorption by the protein, must in all probability be 

 taken into consideration. 



