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THE BOOK OF WHEAT 



flour and acquired from the air. It was sweet, and by no 

 means unpalatable. It is now baked like common bread. 



Gluten bread is made from strong flour and water. The 

 dough is pressed and strained under a stream of water until 

 the starch has been worked out, when it is kneaded again and 

 baked. It gives a light and elastic loaf which is often pre- 

 scribed for diabetic patients. Aerated bread, which has had 

 considerable popularity in London, is made by a method 

 invented in 1856. The water used is charged with carbon 

 dioxide gas. Another form of bread that has been made is the 

 salt-rising bread. Hot water and cornmeal are mixed into a 

 stiff batter, which is left at blood heat until it is fermented. 

 The ferments originally present or acquired from the air 

 produce fermentation, which leavens the batter. A thick 

 sponge is then made from wheat flour and warm milk in which 

 a little salt and sugar have been dissolved. This sponge and 

 the fermented batter are thoroughly kneaded together and set 

 in a warm place for several hours. 



Chemical Changes and Losses in Baking. Below is given in 

 per cents the average composition of white bread and of the 

 flour from which it was made. 



In mixing the bread, the water was added, the fat was added 

 as butter or lard, and the ash was added as salt. The protein 

 and carbohydrates which were lost went to nourish the yeast 

 plant. This feeds mainly on the sugar in the dough, and in its 

 growth gives off alcohol and carbon dioxide gas. The gas and 

 the generated steam expand with heat, force their way through 

 the dough, and thus lighten it. Yeast also acts as an agency to 

 turn starch into sugar. It is the tenacious quality of gluten 

 (wanting in other than wheat flours, however nutritive), which 

 retains the gas in its tendency to escape. Being elastic, the 

 gluten expands, and the bread becomes porous. 



"In bread making the action of the yeast and heat results 

 in: (1) The fermentation of the carbohydrates and the pro- 



