278 AGRICULTURAL CHEMISTRY 



usually contain more nitrogen and gluten than large, 

 rotund kernels. The size of the germ, the proportion of 

 aleurone to endosperm, and the nitrogen content of the 

 endosperm or floury portion are the three factors which 

 determine the relation of the nitrogen in the wheat to the 

 nitrogen in the flour. Ordinarily, the germ makes up 

 about 7 per cent, of the weight of the kernel, and the 

 endosperm from 82 to 86 per cent. When the amount of 

 endosperm is increased, there is proportionally less germ, 

 and aleurone, and a larger amount of flour is secured. 

 The size of the wheat kernel together with the size of the 

 indentation marking the germ area indicate approxi- 

 mately the amount of germ in the kernel. The larger 

 the amount of germ and aleurone, the smaller the amount 

 of flour recovered when the wheat is milled. As a general 

 rule, wheats which contain the largest amount of nitro- 

 gen produce the most nitrogenous flours, but the total 

 nitrogen in the wheat cannot always be taken as an index 

 of that in the flour. Two wheats frequently contain 

 about the same total nitrogen but the nitrogen is distrib- 

 uted differently in each ; in one a larger portion is present in 

 the germ and aleurone, and in the other a larger amount 

 is in the endosperm and hence recovered as flour. In the 

 following table, the per cent, of protein in the grain and 

 that in the patent flour recovered by the modern roller 

 process of milling are given. These tests were made 

 under the supervision of the author in two of the large 

 flour mills of Minneapolis, Minn. The percentage 

 amounts of wheat recovered as patent flour were about 

 the same in all of the tests. 



