240 The Chemist ri/ of the Strength of Wheat Flour 



."5. The following data show the behaviour of the glutenines when 

 racotuised with N/i NaOH at 37° C. 



Manitoba flour glutenine 

 2 % in A74 NaOH 



English Hour glutenine 

 2 % in A74 NaOH 



The differences in optical behaviour displayed by the glutenines 

 during racemisation with Xj'2 and iV/4 NaOH point to the conclusion 

 that the glutenine of strong flour is a different protein from that con- 

 tained in weak flour. Two objections, however, may be raised against 

 the evidence on which this conclusion is based. 



1. In view of the difficulty of effecting complete separation of two 

 proteins from each other, it is possible that the samples of glutenine are 

 still associated with small amounts of gliadine. and that the high rotation 

 values obtained with Manitoba Hour glutenine as compared with English 

 flour glutenine may be explained on the grounds that the former glutenine 

 contains more of the high rotating gliadine than does the latter. 



2. It has not been demonstrated that the glutenines are extracted 

 from the glutens without change. It is possible that the 0-2 per cent. 

 KOH used in the isolation of the glutenine may cause, even at the room 

 temperature, a slow Taceinisati(m of the proteins and thus render un- 

 certain any conclusions which may be drawn as a result of the optical 

 behaviour of the final samples with dilute alkali at 37° C. 



The first objection cannot be sustained, liowever, since a study of 

 the initial rotations of the proteins in alkali shows that the Manitoba 

 flour glutenine would have to contain relatively large amounts of 

 gliadine to account for its optical behaviour on this assumption. Ex- 



