Oil of Coconut.
Oil of Coconut. Cocoanut Oil. Cocoanut Butter. Oleum Cocos, P. G. Oleum Cocois. Beurre de Coco, Fr. Kokosnussöl, G.—This must not be confounded with the fixed oil of the chocolate nut, which is often called cocoa butter. (See Oleum Theobromatis) The substance here considered is the fixed oil of the coconut, which is the fruit of a species of palm, Cocos nucifera L., universally known as the coconut tree, or cocoa-nut tree. The oil is obtained either by expression or decoction, often by insolation—i.e., exposing the rasped nuts to the heat of the tropical sun. It is of a fine white color, of the consistence of lard at ordinary temperatures, becoming solid, like suet, between 4.4° C. (40° F.) and 10° C. (50° F.), and liquid at about 26.7° C. (80° F.), of a bland taste, and a peculiar, not disagreeable odor. It is readily dissolved by alcohol. It contains large quantities of the glycerides of myristic and lauric acids, with smaller quantities of the glycerides of palmitic and oleic acids. It has also been found to contain several volatile acids, as caproic, caprylic, and capric acids. (Lewkowitsch, Chemical Analyses of Oils, Fats, and Waxes, 2d ed., 1898, 538.)
The oil has been used for various purposes in medicine and pharmacy. It has been employed as a substitute for cod liver oil, especially in the form of a proprietary preparation, coco-olein. In Germany it has been used in pharmacy, to a considerable extent, as a substitute for lard, to which, according to Pettenkofer, it is preferable on account of its lesser tendency to rancidity, its more ready absorption when rubbed on the surface of the body, and its lesser liability to produce chemical changes in the substances with which it is associated. Thus, the ointment of potassium iodide, when it is made with lard, becomes yellow in a few days, while, if made with coconut oil, it remains unchanged for two months or more. Vegetable substances also keep better in ointments prepared with this oil than with lard. Besides, it takes up one-third more water, which is a useful quality when it is desirable to apply saline solutions externally. To prepare it for use, nothing more is ordinarily necessary than to melt it at a moderate heat, and strain it through linen. If colored, it may be digested with powdered animal charcoal, and subsequently filtered through paper. (A. J. P., xxix, 331.) When chilled and pressed, a solid residue, which is coco-stearin, is obtained. This is extensively used as a substitute and adulterant of the genuine cocoa butter in the confectionery trade. Coconut oil is employed in the manufacture of soap, particularly of the transparent varieties, and the so-called "marine soaps" and filled soaps; it is also largely used for giving firmness and lathering qualities to the ordinary soap; this property also permits of the addition of a large quantity of water to the soap. Unfortunately, coconut oil soap is very apt to contain free caprylic acid; and the persistent rancid odor, resembling that of infants' vomit, left upon the skin after washing with its soap is an effectual bar to its very extended use. The exportations of coconut oil from Ceylon amount to 15,000 tons annually, from British India to 4000 to 6000 tons, and from the Dutch Indies to 1300 tons per annum. Besides the oil itself, the dried pulp of the coconut is sent to European markets in large amounts under the name of copra. The export of copra from Ceylon amounts to 5000 tons annually, from Tahiti to 4000 tons, from Samoa to 3000 tons, and from Singapore to 4000 tons.
The importations of coconut oil into the United States for 1914 amounted to 74,386,213 pounds, valued at $6,703,942, and for 1915, 63,135,428 pounds, valued at $3,430,581.
According to Parisi, the endocarp or meat of the coconut is a powerful tenicide. The patient should drink the milk and then eat the flesh of the nut. The coconut is said to be largely used in India as a vermifuge, and the matter appears to have practical importance.
Powdered coconut shells have been largely used in America as an adulterant for spices. Their debris is readily recognized by the microscope. (See A. J. P., 1901.)
E. Millian describes the following test to determine the purity of coconut oil: 4 mils of the clean, water-free fat is introduced into a test tube with 2 mils of ethereal solution of phloroglucin and mixed by circular agitation; 2 mils of benzene solution of resorcin is then added and the whole again mixed. The tube is then immersed for a few minutes in ice-water, to bring the temperature to 10° C. (50° F.); 4 mils of nitric acid, sp. gr. 1.35, free from nitrous fumes, is then added, and the tube being closed with a rubber cork previously washed with the same acid, the whole is well shaken for five seconds. Pure coconut oil remains perfectly unaltered, negligible traces of impurities may impart a scarcely perceptible rose tint to the mixture; but the presence of any seed oil, such as cotton, sesame, arachis, etc., will at once be indicated by a distinct currant-red color if 5 per cent. of the adulterant be present. The color reactions which occur later, when the temperature of the mixtures rises to 40° C. (104° F.) are disregarded. It is important that the reagents and solvents employed should be absolutely pure, and that the temperature of the reagents and the oil should be between 10° C. (50° F.) and 12° C. (53.6° F.). (C. R. A. S., 1903, cxl, 1702.)