184 Journal of Agricultural Research voi. xix, N0.4 



ammonia nitrogen were made on the respective samples of sound and frozen 

 wheat, as well as on straight flours milled from the wheats. The extrac- 

 tion of the nonprotein nitrogen and its quantitive separation from the 

 proteins, as well as its concentration to enable the estimation of the 

 various forms in which it exists, was satisfactorily carried out by methods 

 previously published by the writer (2). 



Table I shows the distribution of the various forms of nitrogen in 

 the two series of wheat samples described in preceding paragraphs. 



In a previous paper (2) it has been shown that while the proteins 

 themselves are completely removed in the method for determining non- 

 protein nitrogen there still remain some peptids in the solution. There- 

 fore the figures for a-amino nitrogen reported in the tables include the 

 "exposed" a-amino nitrogen of these peptids as well as the a-amino 

 nitrogen of the amino acids. By far the greater part, however, is from 

 the amino acids rather than from the peptids. 



It will be noted that the most severely frozen wheat contains two to 

 three times as much total nonprotein nitrogen as the sound wheat. 

 The increase in ammonia and amid nitrogen is proportional to the in- 

 crease in nonprotein nitrogen, the percentage of these two constituents 

 in terms of the total nonprotein nitrogen remaining practically constant 

 in each series. In the samples of frozen wheat a much larger per- 

 centage of the nonprotein nitrogen is in the a-amino form than in the 

 matured samples. In the most severely frozen sample of the 191 7 

 series nine times as much of the total nitrogen of the wheat is in the 

 a-amino form as in the sample which matured earliest. 



It is to be noted that the nitrogen in the a-amino and amid forms, 

 as well as total nonprotein nitrogen, runs higher in the mature samples 

 of the 1 91 8 series than in corresponding samples of the 191 7 series, while 

 the a-amino nitrogen runs lower in the frozen samples of the 191 8 series 

 than in the corresponding samples of the 191 7 series. There is much 

 less difference, however, in the figures for total nonprotein nitrogen in 

 the two series, there being nearly the same percentage in the most 

 severely frozen samples of both series. It is strongly suspected that 

 these differences are due to chemical changes caused by allowing the 

 wheat from the 191 8 series to stand in the field several months after 

 cutting. Such treatment frequently occurs to Montana wheat in actual 

 farming practice, and its effect on the composition of the kernel will be 

 more thoroughly investigated in the near future, as well as its influence 

 on the baking quality of the flour. 



