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Amount of Sugar Lost in Fermentation.—The total quantity of sugar and other carbohydrates lost in fermentation amounts to about 2 percent of the weight of flour used. Sometimes it is much greater and sometimes less than this. The nutritive value of the product is diminished in proportion to the extent of the loss of sugar. The carbon dioxid produced during fermentation has no food value, and the alcohol is largely lost in the form of vapor during the process of baking. About half the loss is due to carbon dioxid and half to alcohol. The alcohol, although lost mostly during the baking, serves a useful purpose,—in the expansion of the vapor it aids the carbon dioxid in making the bread more porous. The hydrolysis which takes place in baking converts some of the starch to dextrinoid or saccharoid conditions. It is evident that from 6 to 8 percent of total starch present in the flour is changed during the fermentation and baking into more or less soluble forms.

Fig. 36.—Comparative Appearance of Breads of Different Kinds.

Texture and Size of Loaves Made from Different Kinds Of Flour.—The variations in bread and size of loaves made from different kinds of flour when the conditions of fermentation and baking are the same depends upon the texture and quantity of the gluten material in the flour. The difference in the appearance and size of loaves is shown by a photograph of the cross-sections of three loaves of bread in Fig. 36.

It is seen that the loaves made from graham flour and entire wheat flour are somewhat coarser in structure and are less in size than those made from the same quantity of standard patent flour.