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to the composition of the hulls or chaff. The fat or oil comes chiefly from the germ.
Composition of Hulled Oats.-Inasmuch as the chaff is always separated from the oat flour when the latter is to be used for human food, the composition of the oat in the hulled state is of greater importance to the present purpose than in the unhulled condition. The means of 179 analyses show the hulled oats to have the following compositions:
The removal of the hulls, as is seen, and the partially dried condition of the grain in the above analysis increases the percentage of other ingredients. The protein and fat are especially large in quantity. Oatmeals may be regarded as the richest of the cereal flours, both in protein and in oil.
The Protein of Oat Kernels.-There are three principal products in the oat kernels characterized by their different degrees of solubility, namely, protein soluble in alcohol, protein soluble in dilute salt solution, and protein soluble in alkali. The protein soluble in alcohol constitutes about 1.25 percent of the whole grain, the protein soluble in dilute salt solution about 1.5 percent, and the protein soluble in alkali the remainder, viz., 11.25 percent. The protein of oats has very little agglutinating power and, therefore, oat flour is not suitable for making bread, or rather it is very little used for that purpose.
Oat Products.-As has been intimated before, the principal oat products, as far as food is concerned, are the various forms of oatmeal commonly classed as breakfast foods. These products are prepared in various forms of agglutination and physical texture but if made from genuine oats, as there is little cause for doubt, they have essentially the same composition and nutritive power. It is doubtful if there is any preparation of oatmeal any more nutritious or palatable than the plain oat grain properly cooked. The forms in which the oat products are offered to the public are perhaps more convenient for use and in some cases by reason of heating and preparation require less trouble, but otherwise they apparently have no advantage over the simple product.
The mean composition of a number of oat flour products is shown in the following table:
It is evident from the above average analysis that the products examined are made from the whole kernel without the removal of the germ but with a very careful removal of the hull and bran. The composition of these products compares very favorably with the typical composition of the kernel itself.
FIG. 29.-OAT STARCH. X 200.-(Courtesy of Bureau of Chemistry.)
These data show the high nutritive value of these oat products, both in respect of fat and protein.
Adulterations.-There are very few adulterations of oatmeal. Fortunately the price of this cereal is such that the admixture of other cereals would not be profitable. Doubtless such admixtures have often been made but evidently, from the examination of the products upon the open market, they are not very frequent. The characteristic appearance of oat starch is shown in Fig. 29.
Oat starch grains average about 10 microns in diameter. There are usually present some grains of somewhat oval shape, which assist in identi
fying oat products when present. The starch granules also have a tendency to agglutinate into masses of varying size, as shown in the photograph.
Detection of Adulterations.-The adulteration of qatmeal with the flour of other cereals can easily be detected by the use of the microscope. Oat starch when highly magnified presents a peculiar cellular structure of pentagonal character which might be compared to the effect produced by grinding a large number of faces upon a precious stone. This peculiar appearance is caused by the tendency of the starch granules in oats to become compacted in large masses. The appearance of the separate granules and also the compact aggregate are shown in the figure on the preceding page. The large aggregated masses are of different sizes, ranging from .02 to 1.2 millimeters in length. These masses are usually broken up by grinding or pressure and, therefore, are not found in very great abundance in the commercial oatmeal. When separated into single granules these are found to be irregular in outline, due to the compression to which they have been subjected, more or less pentagonal in structure, and from .015 to .02 millimeter in diameter. The starch granules do not show any very marked characteristics under polarized light and have neither lines nor hilum. The above statements can easily be verified by any one who can operate an ordinary microscope, but before attempting to detect adulteration a careful examination of starch granules, prepared by the investigator himself, should be made.
RICE (Oryza sativa).
Rice is one of the most important food cereals. It furnishes a large part of the food of the inhabitants of China and Japan. It is a food rich in starch and poor in protein, and furnishes, therefore, heat and energy, and is well adapted for the nourishment of those engaged in hard labor or who undergo extreme physical exertion. The cultivation of rice is rapidly extending in the United States, especially in Louisiana and Texas. The statistical data relating to the rice crop for 1906 are as follows:
The adulteration of rice is confined to coating it with talc, paraffin, and glucose. The object of this treatment is to give a better appearance to the grain and to protect it from the ravages of insects. The use of indigestible substances such as talc and paraffin is scarcely justifiable. The starch granules of rice have distinctive properties which enable them to be readily recognized under the microscope, as shown in Fig. 30.
The rice starch grains are polygonal in form and have sharp angles. The
grains vary in size from 2 to 10 microns, though the latter size is seldom reached, the most of the grains being about 6 microns. The hilum is seldom visible. The grains occur in the rice kernels mostly in groups of a considerable number of the individual grains forming starch masses of ovoid or angular form.
This is the source of the principal supply of bread in many European countries, but is not extensively used in the United States except among our citizens of foreign birth. It is also extensively used for making whisky. Rye belongs
FIG. 30.-RICE STARCH. X 200.-(Courtesy of Bureau of Chemistry.)
to the genus Secale. Only one species (Secale cereale L.) is commonly cultivated, but this species has a great many different varieties or races. According to the time of sowing there are two great classes of rye, namely, that planted in the autumn or early winter and that planted in the early spring, generally known respectively as winter and spring rye. This is one of the hardiest of cereals, and grows well in all locations where wheat and other common cereals flourish. The area planted in rye in the United States in 1906 and the quantity harvested are given in the following table:
Price per bushel,.
58.9 cents 19,671,243 dollars
Composition of Rye.-From a study of many hundreds of analyses of rye of American origin the following table may be given as approximating the composition of a typical American rye:
The percentage of moisture in American grown rye is usually less than that of European origin. The American rye, also, has smaller kernels as a rule
FIG. 31.-RYE STARCH. X 200.-(Courtesy of Bureau of Chemistry.)
than that of foreign growth. In the content of protein the American samples of rye are fully equivalent to those of foreign origin, and in their mean composition, except as noted above, do not differ greatly from that of standard. varieties collected abroad.
Protein of Rye.-As is the case with other cereals more than one nitrogenous constituent exists in the rye. Three of the principal ones have been separated and named as follows: leucosin, gliadin, and edestin. Other proteins belonging to the globulin, albumin, and proteose family are also found in small proportions. The gliadin of rye resembles in its chemical and physical