Page:Foods and their adulteration; origin, manufacture, and composition of food products; description of common adulterations, food standards, and national food laws and regulations (IA foodstheiradulte02wile).pdf/447

 in flaxseed oil, namely, linolein. When prepared for edible purposes it contains only a small quantity of free acid, is free from rancidity, clear, and brilliant in appearance and has a sweet agreeable taste. The specific gravity of sesamé oil at 15 degrees C. varies from .9225 to .9237. It absorbs from 103 to 108 percent of its weight of iodin and has a refractive index at 15 degrees of about 1.4748.

Adulteration of Sesamé Oil.—Some of the other vegetable oils are cheaper than sesamé and are added to it for the purpose of adulteration and cheapening the product. Among the most common oils used for the adulteration of sesamé are poppyseed oil, cottonseed oil, and rape oil. The presence of cottonseed oil in sesamé oil is easily distinguished by the Halphen test already given. The presence of poppyseed oil is revealed by the high iodin number and the high degree of heat produced when mixed with sulfuric acid.

Only the best variety of cold-drawn sesamé oil is used for edible purposes and for making oleomargarine. The inferior qualities are used in soap making, the making of perfumes, etc., and the lowest quality of oil is used for burning purposes.

Characteristic Reaction.—A test which is known as Baudouin's is extremely delicate and reliable and is easily applied. It consists in the development of a red color when a small quantity of sesamé oil is treated with hydrochloric acid in the presence of furfural. The test is easily carried out as follows: Place a few drops of a two percent solution of furfural in a test-tube with 10 cubic centimeters of sesamé oil or the oil to be tested for sesamé and 10 cubic centimeters of hydrochloric acid of 1.19 specific gravity, and shake the mixture well for half a minute. When the tube is left at rest, if sesamé oil be present the aqueous acid layer which forms will have a distinct crimson color. Any coloration which is produced by other oils is entirely distinct from this one and therefore can be easily distinguished.

Geographical Distribution.—The sesamé plant is grown chiefly for commercial purposes in India, China, Japan, and West Africa. The technical preparation of the oil, in so far as is known, is not practiced in the United States. It is pressed and prepared for commerce chiefly in France. The seeds are rich in oil, yielding a larger percentage by pressure or extraction than most of the oil-bearing seeds.

Sunflower Oil.—The oil extracted from the seed of the sunflower is of high quality for edible purposes. Although not in general use in this country, it is very extensively used in Russia and some other parts of Europe. There is every reason to believe that a profitable industry could be established in the preparation of edible oils from sunflower seeds. The plant grows in the greatest luxuriance in nearly all parts of the country, and the yield is sufficiently great to make it an object of more interest to our agricultural population than it is at the present time.