Sidebilder
PDF
ePub

crackings, or of slight and partial crushings, alternating with sifting and sorting, is better adapted to hard wheat. There is also a mixture of the two processes called half high milling.

In general, the modern commercial process may be described as follows: The wheat is first cleaned, then passes to a series of cylindrical rolls arranged at distances so graded that when the wheat kernel passes between the first set it is merely cracked; then the fragments drop between the next set and are again cracked, and so on, each set pulverizing a little finer than the preceding one. In this way the husk is not bruised, only flattened out and loosened so that the dry starch granules drop out. The flour is not heated, since it is not subjected to friction, and since it falls through the cool air between each set of rolls. At each grinding the fine flour is removed by bolting, and finally all the different streams are blended to form different grades of flour. It is thought that the separation of the non-nutritious portion is also more complete, and hence that the flour is richer in the phosphates and nitrogenous substances which are found in the layer of cells next the husk. Since there are no particles of bran in the high-milled flour it is whiter, and since it has been ground dry it has less moisture and will keep longer.

Low milling yields about 80 per cent of flours of various grades, differing comparatively little from each other. High milling yields about 75 per cent of merchantable flour, 72 per cent being straight grade or ordinary white flour.

Flour for household use will perhaps average 70 per cent of starch and dextrin, about 7 per cent each of sugar, mineral matter, and cellulose, i per cent of fat, and about 15 per cent of albuminous or nitrogenous substances. These constituents are so proportioned as to render wheat flour a highly nutritious food, capable by itself of sustaining life and health.

The durum wheat, from which the bread of the common people is made in Southern Europe and Russia, was almost an unknown thing on our grain markets until 1900; but today it is a living question in the milling centers of the Northwest. It is a wheat for the dry lands, where the ordinary kinds grow poorly or not at all, and it yields so much more per acre and is so much surer a crop that, even if it should not bring the highest prices, it will pay better than the less drouth resistant species which Western farmers have hitherto tried to grow on the dry farm lands of the Dakotas and Nebraska.

“ Custom still fights the innovation of a new flour, and there are people who think our bread is in danger of being deteriorated by the new introduction; but they are not the well-informed who have tasted the full-flavored wheat breads of Spain or Italy, or who realize the great and growing future of macaroni as a food in this country. American-made macaroni, prepared with the best of the old American wheats, cannot be compared with the delicate products of a Gragnano factory. But with the culture of this durum wheat in America a change is coming, and the time may come when we shall ship macaroni to Italy instead of importing it at the rate of nearly $2,000,000 a year. This innovation in the great wheat industry has been the result of the efforts of Mr. M. A. Carleton, who was sent to Russia as an agricultural explorer of the Office of Plant Introduction in 1898 and in 1900. The office has distributed thousands of bushels of the durum wheat varieties gathered by him from all the Mediterranean and South Russian countries where it is

[blocks in formation]

The importance of good flour can hardly be overestimated, since upon good bread depends the health of the greater part of the human race in all temperate climates.

This is not the place to discuss physiological questions, or to take part in the war of words over graham, whole wheat, and fine flour. A discussion of the chemical side of the question will be found in the Thesis of Miss Charlotte A. Bragg, Technology Quarterly, vol. III, No. 3, 1890, from which the following extract is made:

“The following tables give in a condensed form the results of the analyses of the two samples of wheat, and the products derived from them. A balance sheet was deduced therefrom.

ST. LOUIS WINTER WHEAT

Water Phosphorus Nitrogen

Per cent Per cent Per cent
Whole Wheat 12.85 0.262 1.87
Royal Patent

13:37 0.051 1.39 10ur Plant Immigrants, by David Fairchild, in National Geographic Magazine, April, 1906.

[blocks in formation]

MINNESOTA SPRING WHEAT

Water Phosphorus Nitrogen
Per cent Per cent

Per cent
Whole

11.09 0.230 2.24
Patent

12.29 0.050 2.10 Bakers'

12.14

0.091 2.40 Low Grade 11.47 0.192 2.59 Shorts

11.27 0.560 2.78 Bran

11.23 0.830 2.55 “The balance sheet defines the position of fine white flour very clearly. It shows that hard spring wheat gives a flour rich in nitrogen, 69.5 per cent of the total being saved in the three grades of flour. Winter wheat does not show quite as well ; not only is there more bran, but it is richer in nitrogen. Nevertheless, 62.2 per cent of the total nitrogen is saved. There is, therefore, no need to eat whole wheat bread in order to obtain a food rich in nitrogen.

“Quite another story is told by a study of the proportion of phosphorus. The two varieties of wheat more nearly approach each other, but the spring wheat loses 79.6 per cent and the winter wheat 77.8 per cent of its total phosphorus. Here, then, is the bone of contention. The fine white flour is sadly deficient in phosphorus, but is the phosphorus which is contained in the bran available for human food ? According to the latest experiments of Professors Voit and Rübner in Munich, it would seem that not only is the bran quite indigestible, but that by its irritating action it causes a loss of both nitrogen and carbohydrates, which would be available in its absence.

“ It would seem, therefore, fair to conclude that the bread made from fine flour, which is most tempting to eyes and palate, may, after all, be the one best adapted to the needs and conditions of the human system.”

Since the amount of gluten in a flour often has an interest for the housewife beyond that of nutritive value, a means of estimating it is often called for.

Wiley (Agricultural Analysis, vol. III, p. 435) gives the following as a method for separating crude gluten from flour: Ten grams of flour (or one-half an ounce may be taken) are well moistened with a nearly equal weight of cool water (not over 60° F.), worked into a ball, and allowed to stand an hour. It is then kneaded in a stream of cold water until the starch and soluble matter is removed. It may be weighed moist as a rough comparison with other flours.

BUCKWHEAT

Buckwheat (Fagopyrum esculentum) a native of Central Asia, does not belong to the grasses or cereals, but to the family Polygonacea, which includes rhubarb and dock. It grows as far north as 72°, and thus stands next to barley. It matures very quickly — in one hundred days — and thrives on sandy soil. It is probably a native of Asia, and is largely grown in temperate

« ForrigeFortsett »