186 BAKING. 



immediately begins to act on the sugar, causing its 

 decomposition into alcohol and carbonic acid ; but at 

 the same time it also acts upon the starch, and pro- 

 duces in it a change analogous to that which diastase 

 effects in the germination of a seed. It consequently 

 happens, that though the sugar which originally ex- 

 isted in the flour is almost entirely decomposed, yet 

 a quantity of sugar, nearly equal in amount, is pro- 

 duced or generated from the starch (360). 



453. In baking the bread a further portion of the 

 starch is decomposed; more gum and sugar are formed, 

 the azotized matters uniting with them and the modi- 

 fied starch, make a uniform substance, which is far 

 more digestible than flour or unbaked bread. At the 

 same time that these chemical changes are effected, 

 the fermentation is altogether stopped, a considerable 

 quantity of w^ater and the alcohol formed during the 

 rising of the bread are driven off, and the bread is at 

 the same time expanded and rendered still lighter, 

 by the action of the heat of the oven on the gas con- 

 tained in its cavities (62). 



454. The necessity of attending to the proportions 

 in which the several ingredients of bread are mixed, 

 as well as the need of mixing them very thoroughly, 

 is evident. If the dough is badly mixed, the car- 

 bonic acid, in place of being regularly diffused 

 throughout the substance of the dough, will be col- 

 lected into large irregular bubbles, and then the bread 

 will be full of large holes and cavities, in place of 

 being uniformly light and spongy ; and the loaf, 



