Page:Foods and their adulteration; origin, manufacture, and composition of food products; description of common adulterations, food standards, and national food laws and regulations (IA foodstheiradulte02wile).pdf/290

 bread itself or in greasing the pan in which it is baked. There is great difficulty in extracting a fatty body which has been mixed with a glutinous material like flour. The analytical data, therefore, do not represent in the ether extract all the fat naturally present in the flour plus that added in the making of dough or in baking.

The quantity of moisture in bread may also be determined largely by the time of baking and the temperature of the oven. A bread baked for a long while at a low temperature will be much drier than a bread baked quickly at a high temperature. The high temperature solidifies the exterior of the loaf so as to make it difficult for the interior moisture to escape. By quickly baking the bread the temperature of the interior does not reach so high a temperature as in an oven with a low temperature and a long-continued heat.

Standard for Moisture.—The quantity of moisture in bread of standard quality in the District of Columbia may not exceed 31 percent.

The average temperature of the baking oven is about 240° C. (464° F.).

Quantity of Sugar in Bread.—The quantity of sugar found in fermented bread is always less than that present in the flour, added in milk, or otherwise introduced in the preparation of the dough. The sugar disappears largely under the influence of the fermentation due to the yeast.

Quantity of Ash.—The quantity of ash in bread is uniformly higher than the content of mineral matter in the flour. This is due to the addition of common salt which is uniformly employed in all bread, and in the case of bread made from baking powder the retention of the mineral residues in the loaf increases to that extent the content of ash. With the exception of the ash, the ether extract or fat, the sugar, and the dry material of bread correspond in quantity to the same materials in the flour from which it is made, except the loss due to the caramelization of the crust.

Acidity of Bread.—The development of the lactic acid ferments is important in regard to hygienic conditions and to palatability. Flour contains practically no acid in a free state, and the acidity of bread is itself due to the changes which take place in its preparation under the influence of the ferments therein. Bread baked in the usual manner after the yeast ferments have exerted their activity shows the presence of acetic acid, lactic acid, and other acids and salts. The acidity of bread adds to its palatability and also, doubtless, to its digestibility. Bread, containing, as it does, a large percentage of protein, is digested in an acid medium. The natural acidity of bread, therefore, must be regarded as beneficial.

Comparative Nutritive Properties of Indian Corn Bread and Wheat Bread.—There is a widespread opinion that the products of Indian corn are less digestible and less nutritious than those of wheat. This opinion amounts to a conviction in most European countries, where the products obtained by the milling of Indian corn are not regarded as fit for human