Oleum Theobromatis (U. S. P.)—Oil of Theobroma.
Related entry: Theobroma.—Cacao
A fixed oil expressed from the seed of Theobroma Cacao, Linné (Nat. Ord.—Sterculiaceae)"—(U. S. P.).
SYNONYMS: Oleum theobromae (U. S. P., 1880), Butter of cacao, Oleum cacao, Butyrum cacao.
Preparation and Description.—Butter of cacao must not be confounded with cocoanut oil from Cocos nucifera; with palm oil from Elaeis guineensis; nor with coca, the dried leaves of Erythroxylon Coca; it is obtained by two or three processes, one of which is to roast the seeds, and, after removing the testa, grind the seeds, put them in canvas bags, expose them to steam, and press between hot iron plates. The butter thus expressed may be purified by melting it in hot water, by passing it through hot animal charcoal, or by the use of acids, and then running it into molds. The seeds contain about 45 per cent of this fat, 6 to 11 percent of starch, 1 to 4 per cent of theobromine, nitrogenous matter, cacao-red, ash, etc. The yield of cacao butter is about 30 to 35 per cent.
Butter of cacao is officially described as "a yellowish-white solid, having a faint, agreeable odor, and a bland, chocolate-like taste. Specific gravity, 0.970 to 0.980 at 15' (59° F.). Readily soluble in ether or chloroform, also soluble in 100 parts of cold and in 20 parts of boiling absolute alcohol, all these solutions being neutral to litmus paper. It is brittle at 15° (59° F.), and melts at 30° to 33° C. (86° to 91.4° F.), to a clear liquid"—(U. S. P.). The melted fat solidifies again at 20.5° C. (68.9° F.), accompanied by a sudden rise of temperature to about 27° C. (80.6° F.). It is not easily liable to become rancid.
Chemical Composition.—Butter of cacao consists of the glycerides stearin and olein, with small quantities of laurin, palmitin, and arachin. Kingzett's theobromic acid (C64H128O2, 1877) could not be reobtained (M. C. Traub, Archiv der Pharm., 1883, p. 19). P. Graf (Archiv der Pharm., 1883, p. 830) also found small quantities of formic, acetic, and butyric acids, and cholesterin (phytosterin).
Adulterations and Tests.—Butter of cacao may be adulterated with tallow beef suet, stearin, stearic acid, wax, spermaceti and paraffin, oils of cocoanut, almond, etc. Some of these admixtures may be recognized by determining the acid and iodine numbers and the saponification equivalent of the fat. The U. S. P. directs the following test: "If 1 Gm. of oil of theobroma be dissolved in 3 Cc. of ether, in a test-tube, at a temperature of 17° C. (63° F.), and the tube subsequently plunged into water at 0° C. (32° F.), the liquid should not become turbid, nor deposit a granular mass in less than 3 minutes; and if the mixture, after congealing, be exposed to a temperature of 15° C. (59° F.), it should gradually form a perfectly clear liquid (absence of paraffin, wax, stearin, tallow, etc.)"—(U. S. P.).
Action, Medical Uses, and Dosage.—Oil of theobroma is emollient and nutrient. It forms a good dressing for wounds and abraded or excoriated parts, and on account of its melting at the temperature of the body, furnishes a good base for suppositories for the relief of rectal, vaginal, and uterine lesions. Internally, in 5 to 30-grain doses, it has been employed in chronic bronchial and intestinal disorders.
Related Oils.—SHEA BUTTER, also known as Bambuk or Galam butter, is a light-greenish or grayish fat, mild to the taste, and having an odor like cacao butter. It fuses near 28° C. (82.4° F.). It is expressed from the seeds of Bassia Parkii, De Candolle, an African tree.
MANWAH BUTTER.—From the seeds of the Indian Bassia latifolia of Roxburgh. The oil is yellowish or greenish. Its fusing point is near 45° C. (113° F.). The flowers of this species are fleshy and said to yield 50 per cent of sugar, and are employed by the natives in the making of a spirituous beverage, and for food. (For other species of Bassia, see Monesia.)
MAFURA BUTTER.—The seeds of the Trichilia emetica, Vahl (Mafureira oleifera, Bertero) (Nat. Ord.—Meliaceae), are bitter and have the characteristic odor of cacao-beans, and yield a fat much resembling cacao-butter. It is yellow, not so soft as tallow, is mild in taste, and has the odor of cacao-butter. It fuses at 42° C. (107.6° F.). Olein and palmitin are its constituents, and when saponified it yields a large amount of palmitic acid. The oil is obtained in tropical Africa by boiling the seeds in water.