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should be applied to all flour made from well grained wheat, ground, and unbolted. Most of the flours however, which are sold nowadays as graham flours are produced by a more or less perfect bolting process. From the above it is seen that true graham flour will contain practically the same constituents as the wheat kernel itself and in the same proportion and have the same composition as wheat.
Entire Wheat Flour.-This name would naturally carry the idea of a flour corresponding to the graham flour above mentioned. It is, however, a misnamed trade-mark for a flour produced in a special manner which consists in the removal of the outer or purely branny covering of the grain. "Entire wheat" flour, therefore, contains all the ingredients of wheat grains, save those which are found in the outer branny covering.
Gluten Flour. This is a name applied to a flour which is produced by removing the greater part of the starch from ordinary flour. It is especially recommended for the use of diabetic patients. Unfortunately, the name is very commonly applied to flours made from wheat containing a little higher percentage of protein than the ordinary and sometimes even to an ordinary wheat flour. Its use with such a product is purely fraudulent.
Mixed Flour. The act of Congress of June 13, 1898, defines mixed flour and imposes a tax upon the manufacture, sale, importation, and exportation of that article. The maximum tax laid upon mixed flour is 4 cents on a barrel of 196 pounds. The total number of barrels of mixed flour returned for taxation for the fiscal year ending June 30, 1905, was 362; half barrels, 59,443; quarter barrels, 6,265; eighth barrels, 24,974. The total quantity of mixed flour returned for taxation during the year is 5,495,937 pounds. The above data show that the amount of mixed flour offered for sale is a very small part of the total flour manufactured in the United States. It may be that there is a great deal of flour mixed and sold in violation of the law since it is quite impossible in the inspection of the stores to supervise all the transactions of business deals in flour; especially is it believed that rye flour and buckwheat flour are often adulterated by mixing with them the flour of other cereals. This adulteration is not one which is at all injurious to health but is simply practiced for the purpose of making a rye or buckwheat flour look whiter or because the added flours are cheaper than the real rye or buckwheat.
Properties Affecting the Commercial Value of Flour.-Aside from its nutritive properties wheat flour has a commercial value depending upon its color and texture and upon the gluten which it contains. The character of gluten also varies largely in different varieties of wheat and in wheat grown in different localities. A chemical examination will not always tell the bread making properties of a flour, and the character of the bread itself depends often quite as much upon the skill of the baker as upon the flour which is used.
In cases where loaves are sold by weight, a flour with a high percentage of
SEPARATION OF GLUTEN.
tenacious gluten is often preferred, since it permits of the forming of loaves containing a maximum percentage of water. With a flour rich in gluten it is not difficult to make a palatable loaf which does not bear any evidence of an excess of water, containing as much as 40 percent of moisture. The baking of bread is an art which is most successfully practiced by professionals, and the American method of home bread making does not always lead to the happiest results.
The ideal flour for bread making is one which contains a sufficient quantity of gluten to make a porous and spongy loaf, but not one which permits an excessive quantity of moisture to be incorporated in the loaf itself.
Average Composition of Different Varieties of Flour.-Analyses of a great number of samples of different varieties of flours lead to the following data, which may be accepted as a very close approximation of the average variety of different grades of flour offered upon the American market:
Bakers' and family flour,
Perct. Perct. Perct. Perct. Perct. Perct. Perct. Perct. Perct. Perct.
Separation of Gluten.-The character of a wheat flour, as has already been intimated, is measured largely by the quantity of gluten which it may contain. The separation of gluten may be accomplished by any one, even without a chemical training, by a little practice. It is, therefore, one of the tests for the value of a wheat flour which can be easily and generally applied. The principle of separation of the gluten rests upon the fact that when wheat flour is moistened and kneaded into a sticky mass it may be washed with pure water with constant kneading until nearly all the starch has been removed from the mass. Meanwhile only that portion of the protein is removed which is soluble in the water and the gluten which is formed by the process of kneading remains as a sticky mass. When this moist mass is kneaded and rolled until all the moisture is taken out of it that can be removed in this way, it may be weighed and the proportion of moist gluten in the sample determined. It may then be placed in an oven and dried, and then the proportion of dry gluten secured. The following method is one which is easily applied. Place 10 grams of the sample in a porcelain dish and moisten with from 6 to 7 cubic centi
* In the first of these columns the starch is calculated by difference, assuming the protein to be the quantity of nitrogen present multiplied by 6.25. and in the second column the figure is obtained in the same way, using 5.70 as the protein factor.
Work into a ball, Holding the mass starch and all solu
meters of water, knead, and allow to stand for an hour. being careful that none of the material adheres to the dish. in the hand knead it in a slow stream of cold water until the ble matter are washed out. Place the ball of gluten thus formed in cold water and allow to stand for one hour; remove from water, press as dry as possible between the hands, roll into a ball, and weigh in a flat-bottomed dish. After weighing, place the ball of moist gluten in the drying oven for twenty hours; cool and weigh.
Gluten Tester.-A simple test for determining the approximate per
FIG. 34.-KEDZIE'S FARINOMETER SHOWING THE PARTS.—(Bulletin 13, U. S. Dept. of Agriculture.)
centage of gluten in flour may be used, based upon the principle that the viscosity of dough is a measure of its practical gluten content. The name applied to a gluten tester is farinometer.
A convenient form of farinometer devised by Kedzie is shown in the accompanying figure. It is patterned somewhat upon the plan of Jago's viscometer. The instrument is shown in parts in Fig. 34. The instrument as in use is exhibited in Fig. 35. Parts shown in Fig. 34 are as follows: No. I is the stand or support of the parts. No. 2 is the cap of
No. 1, and discloses the half-inch opening (half closed by the slide) through which the dough is forced by the pressure of the rod No. 4. The slide by which this opening is closed is plainly shown; also the socket for holding No. 3. No. 3 is a brass tube 3 inches high and 1 inch internal diameter, with a small knob to fit into the notched opening in the side of the socket seen in No. 2, to hold No. 3 firmly in place. No. 4 is a steel rod inch in diameter and 12 inches long, with a thin brass cap 1 inch in diameter, beveled slightly so that the front edge fills the barrel of No. 3 without friction, and is yet dough-tight. Near the top the rod is marked into inch spaces.
In using the farinometer two points are considered:
1. The water-absorbing power of a flour, or the percentage of water it will take up to form a dough of a certain consistency.
2. The viscosity of such dough, or its resistance to change of form under a uniform force; e. g., the length of time in seconds required to force a cylinder of dough 1 inch high through a hole one-half inch in diameter under the pressure of a vertical steel rod 13 inches long and weighing 2 pounds avoirdupois.
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.
FIG. 35.-KEDZIE'S FARINOMETER IN USE.(Bulletin 13, U. S. Dept. of Agriculture.)
Adulterations of Flour.-The adulteration of wheat flour is not prac
ticed 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.
Age of Flour.-The freshly ground flour is most highly esteemed by many consumers on account of palatability and freedom from all danger of mold and ferments. Older flours are likely to lose flavor, become moldy and infested with weavil and other insect pests. The last-named evils are avoided by the use of wheat containing no fungus, none of the eggs of the weavil, nor of other insects, and enclosing the freshly ground flour in packages not accessible to infection. Even then it is advisable to consume the flour as soon as convenient after the milling process. Many manufacturers and experts contend that flour is improved by keeping for a certain length of time, and this contention is based on the assumption that the flour assumes a lighter color and improves in flavor on keeping. There is of course a certain limit to improvements of this kind.
Substitutes for Flour.-Wholesome ingredients are used in part instead of flour in bread making, and when that fact is clearly made known the admixture of these substances with flour is not considered an adulteration. Bread which is made of an admixture of Indian corn meal with flour or rye flour with flour or other cereal products is well liked by many people. Potatoes are also used very often in bread making. Acorns, buckwheat, and other farinacious and oily substances are also employed. The admixture of inert substances with flour merely to increase the bulk and weight of the loaf, even if notified, cannot be regarded as other than an adulteration.