CONCENTRATED FOODS 



267 



they are more completely filled with starch have the highest 



weight per bushel. The average for English wheat is about 



62 Ibs. 



The more nitrogenous samples are harder and more 



translucent in appearance than those which are more starchy. 

 In the old-fashioned method of stone-grinding, the outer 

 coats, together with the aleurone layer 

 and a certain amount of adventitious 

 starchy matter, were first removed and 

 sold as bran. The remainder was 

 then ground directly into flour. The 

 innermost portion of the grain was, 

 of course, the last to be reduced ; it 

 contains the largest percentage of 

 starch and yields the finest, i.e. the 

 whitest, flour. 



G 





1 FIG. 18. Wheat grain. 

 Diagrammatic section 

 showing P, pericarp 

 with testa and nucellus 

 forming the branny en- 

 velope ; A, aleurone cell 

 layer of endosperm ; E, 

 parenchymatous cells of 

 endosperm ; G, the germ, 

 or embrvo. 



E 



1 FIG. 19. Cross-section through branny 

 envelope and outer portion of endo- 

 sperm X 100, showing P, pericarp, con- 

 sisting of (e) epicarp, (m) mesocarp, and 

 (d) endocarp ; E, endosperm consisting 

 of (a) aleurone cells and (p) parenchy- 

 matous cells ; (i) testa, () nucellus. 



In the modern mills the stones are replaced by metal rollers, 

 of which there are several sets ; elaborate methods of sifting and 

 fanning are employed and many different products are or may 

 be obtained. The grain is not directly ground to flour, but 

 is first broken into pieces which are separated as far as 

 possible from the husks and aleurone portion. 



1 L.G.B. Food Reports, No. 14 (Cd. 5831). By permission of the 

 Controller of His Majesty's Stationery Office. 



