EXAMINATION OF GRAHAM FLOUB. 27 



DISCUSSION OF RESULTS OF ANALYSES. 

 SAMPLES GROUND IN THE BUREAU OF CHEMISTRY (TABLE l). 



Table 1 shows that when the sample of soft winter wheat is ground 

 five times between the corrugated rolls, a greater amount of mid- 

 dlings and flour is obtained and a less amount of bran and shorts than 

 when it is passed only three times over the rolls. The nitrogen/ ash, 

 fiber, and pentosan content and the gliadin ratio of the Graham 

 flour produced are essentially the same in both samples. It is seen, 

 however, that No. 9904 has a higher gliadin ratio of the bran, shorts, 

 and middlings than No. 9910. This is because these products of the 

 coarsely ground Graham flour have adhering to them a larger amount 

 of flour than when the Graham flour has been more finely ground. 

 Another point of interest is that there is a gradual decrease in nitro- 

 gen content and a gradual increase in gliadin number from the bran 

 to the flour. 



In the case of the hard winter wheat and durum wheat Grahams, 

 it is noted that the nitrogen content of the flour is about equal to or 

 greater than that of the fine, or even of the coarse, middlings. This 

 fact leads one to infer that in the process of grinding hard wheats a 

 relatively large amount of break flour is produced. Break flour 

 from hard wheats is often higher in nitrogen than is the bran. 2 



Samples 9922 and 9928 contain normal amounts of "ash, fiber, and 

 pentosans. The gliadin ratio gradually increases from the bran to 

 the flour. On the other hand the nitrogen content of the middlings 

 is lower than that of the flour. The amount of flour passing through 

 the 109 sieve is extremely low, being only 9.5 and 16 per cent, respec- 

 tively, whereas in the case of soft winter wheat the corresponding 

 amount was 15 and 28.8 per cent. No. 9934, which was ground on 

 burrstones, shows a larger amount of flour material (40.3 per cent) 

 than the samples ground by means of corrugated rolls. The nitrogen, 

 ash, fiber, and pentosans agree fairly well with the two samples 

 passed through the rolls. The gliadin ratio of the bran especially is 

 much lower than that of the bran from Nos. 9922 and 9928, due to the 

 fact that the bran of No. 9934 contained less flour and middlings. 

 The gliadin ratio of the other portions separated is also lower than 

 the corresponding portions of the two samples ground on rolls, prob- 

 ably because these contained more particles of bran which had been 

 finely ground between the burrs. For the same reason (namely, 

 high bran content) the percentage of ash is higher in the flour from 

 No. 9934. 



i The nitrogen determinations were all made in the Nitrogen Laboratory, T. C. Trescot, chief. 

 * Analyses made of bran and of flour from wheat milled in this bureau showed that the nitrogen of the 

 flour is sometimes 1 per cent more than that of the bran. 



