Bleaching of Flour.
—At the present time flour is extensively bleached for the purpose of making an inferior article resemble a superior one. By this means a greater percentage of the flour produced can be rated as of first quality. Ozone and oxids of nitrogen developed by electrical discharges are the principal bleaching agents employed. Bleached flour should bear a label indicating to the purchaser the character of the manipulation to which it has been subjected.
Adulterations of Flour.
—The adulteration of wheat flour is not practiced to any extent in this country. The most common adulteration arises from grinding with wheat foreign seeds and other foreign matter, rust, smut, etc., which may be present in the grain. Other adulterations are the mixture with wheat flour of the starch or flour of maize and other cereals. The adulteration with any form of terra alba or white powdered earthy substance is exceedingly rare. Although some attempts have been made to introduce such adulterations in this country they have not reached any commercial success. The adulterations, with the exception of those with white earthy powders, are most readily ascertained by microscopic examination for foreign matters and other varieties of starch than grow naturally in the wheat.
Standard.
—The United States standard for flour is as follows:
Flour is the fine, sound product made by bolting wheat meal and contains not more than thirteen and one-half (13.5) percent of moisture, not less than one and twenty-five hundredths (1.25) percent of nitrogen, not more than one (1.0) percent of ash, and not more than fifty hundredths (0.50) percent of fiber.
Graham flour is unbolted wheat meal.
Whole wheat flour, entire wheat flour, improperly so called, is fine wheat meal from which a part of the bran has been removed.
Gluten flour is the product made from flour by the removal of starch, and contains not less than five and six-tenths (5.6) percent of nitrogen and not more than ten (10) percent of moisture.