24-_' The Chemistry of the Sfrcnfff/i of Whmf Flour 



the reasons being twofold : 1 . It is not possible by grinding.' the ])roteins 

 together to effect the same intimacy of mixture as occurs naturally in 

 the flour. 2. The physical properties of the proteins themselves have 

 probably been considerably modified during the process of their isolation 

 as a result of prolonged contact witii different reagents (alcohol, ether, 

 alkali, etc.). 



The view has been put forward by Kosutany(!») that glutenine is 

 derived from gliadine by the splitting off of water. The i)uantitative 

 work of Osborne in connection with the hydrolysis of these proteins has 

 shown beyond doubt that they are two absolutely distinct substances, 

 and a comparison of the racemi.sation data for the glutenines with those 

 of the gliadines confirms Osborne's view. The gliadines exhibit distinctly 

 different optical behaviour during racemisation from that displayed by 

 the glutenines. 



Summary and Conclu.sioxs. 



The gliadine and glutenine proteins from typical strong and weak 

 wheat flours have been isolated and investigated by comparative methods. 



The gUadines from the two sources have been showTi to be identical 

 proteins. This conclusion, which is in harmony with the earlier results 

 obtained by Wood, has been arrived at on the following grounds: 



1. The identity of their optical behaviour when racemised by dilute 

 alkali at 37° C. under three different sets of conditions. 



2. The identity of their specific rotations in 70 per cent, alcohol. 



3. The identity of their combining capacities for alkali, as determined 

 by titration in 80 per cent, alcoholic solution by means of iV/10 NaOH 

 to phenolphthalein. 



The glutenines from the two types of flour have been showTi to be 

 two distinct substances, this conclusion being based on their different 

 optical behaviour during racemisation by dilute alkali. 



It is suggested that the existing ideas on flour strength require 

 modification to include the facts recorded in this investigation. It is 

 desirable to retain the dual conception of strength as put forward by 

 Wood. The factor which determines the size of the loaf is most probably 

 connected with the diastatic capacity of the flour, as was suggested by 

 this investigator. On the other hand, the factor which determines the 

 shape of the loaf and which appears to be directly related to the physical 

 properties of the gluten of the flour, is possibly dependent on the par- 

 ticular glutenine mechanism possessed by the wheat. 



The results of this investigation suggest that the strong wheat 

 synthesizes one type of glutenine and the weak wheat a different type, 



