Foods and Their Adulteration: Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and RegulationsWiley, Harvey Washington
Science
Foods and Their Adulteration: Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and Regulations
Wiley, Harvey Washington
Food; Food adulteration and inspection
-------------------------+--------+--------+-------
| STARCH | |
| N × | |
| 5.70. | CRUDE | CALO-
NAME OF FLOUR. | [26] | FIBER. | RIES.
-------------------------+--------+--------+-------
|_Perct._|_Perct._|
Patent flour, | 76.14 | 0.21 |3,858.0
Bakers’ and family flour,| 74.98 | 0.22 |3,929.6
Common market flour, | 76.53 | 0.28 |3,882.5
Miscellaneous flour, | 76.15 | 0.25 |3,846.3
Self-raising flour, | 74.51 | 0.21 |3,719.3
Gluten flour, | 73.28 | 0.32 |3,891.1
-------------------------+--------+--------+-------
[26] 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.
=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 centimeters of water, knead, and allow to stand
for an hour. Work into a ball, being careful that none of the material
adheres to the dish. Holding the mass in the hand knead it in a slow
stream of cold water until the starch and all soluble 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.
[Illustration: FIG. 34.--KEDZIE’S FARINOMETER SHOWING THE
PARTS.--(_Bulletin 13, U. S. Dept. of Agriculture._)]
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