BREAD. 393 



What is said 984 FLOUR. Fine flour makes less 



of the nutri- nutritious bread than the coarser varieties. 



tious proper- .!**>* 



ties of fine because it contains a smaller proportion of 

 gluten. Gluten being tougher than the 

 starch, is not reduced to so fine a powder, and is par- 

 tially separated in the process of bolting. All grains 

 contain sugar in small proportion. Sugar is therefore 

 one of the constituents of flour. 



Whatchemi- ^85. BREAD. The " raising" of bread 

 cat principles i s a process of fermentation. The yeast 



are involved 



in making employed in the process converts a portion 

 of the starch of the flour into sugar, and 

 subsequently into alcohol and carbonic acid. The 

 sponge is made light and porous, by the gas bubbles 

 which become entangled within it. A large part of 

 the alcohol produced in the process escapes into the 

 oven, and thence into the exterior air. It may be 

 condensed and converted into spirits by the proper 

 apparatus. This has been successfully done in large 

 bakeries in Europe, but the process has not been found 

 to be of any considerable economical importance. In 

 the process of baking a portion of starch is converted 

 into gum. By moistening the baked loaf with water 

 the gum is dissolved, and by a new heating, hardens 

 into the shining surface which is often observed on 

 bakers' bread. 



What materi- 986 - YEAST POWDERS. The gas which 

 ais are some- i s needed to make bread lia:ht, may be 



times substi- 

 tuted for produced by other means than the process 



yeast / of fermentation. If carbonate of soda, for 



example, is kneaded into the dough, and tartaric acid 

 17* 



