Oleum Palmae.—Palm Oil.
The fixed oil from the fruit of Elaeis guineensis, Jacquin.
SYNONYMS: Palmöl, Palm butter.
Botanical Source.—The oil palm is a native of western Africa, and is found growing in other tropical sections. It is a very handsome, graceful tree, growing to a great height, and supports on its spine-armed petioles, large, pinnately-divided leaves, the leaflets of which are narrow, long, and linear. The fruit is a drupe, yellow, mottled, and about an inch in length. Its leathery sarcocarp contains much oil; the seed kernel is likewise oily.
Preparation and History.—Palm oil, or fat is obtained either by pressure of the oily sarcocarp, or by boiling it in water. It is produced in western Africa, West Indies, Brazil, and Cayenne. The best varieties are those known as Lagos prima and Lagos secunda, the bulk of the oil being shipped from that port and from Palmas.
Description.—Palm oil is of a butyraceous consistence, of a reddish-yellow or orange-yellow color, and a pleasant odor. It melts at 27° C. (80.6° F.). By exposure and age the fat becomes whitish and rancid, a large portion of it being decomposed into glycerin and fatty acids; this change is not objectionable to its use in soap-making. Such changes are accompanied by rise of melting point, which reaches occasionally as high as 42° C. (107.60 F.). When fresh it will melt by the heat of the hand. Its specific gravity is 0.945. Ether completely dissolves it, while it is but partially soluble in alcohol.
The kernels also yield an oil (palm-kernel oil, or palm-nut oil), which has a white or pink color and an agreeable, orris-like, or violaceous odor. Palm oil is largely employed in the making of soaps, which retain the agreeable odor of the fat. To prepare a white soap, the oil is first bleached by means of potassium dichromate solution. It is the most easily saponified of the fixed oils.
Chemical Composition.—Palm oil consists of palmitin, olein, and free palmitic acid. Palm-kernel oil differs from palm oil in containing a considerable quantity of glycerin esters of lower fatty acids. According to Oudemans (see A. H. Allen, Com. Org. Anal., Vol. II, Part I, 3d ed., 1899, p. 164), one sample of palm-kernel oil consisted of olein (26.6 per cent); stearin, palmitin, and myristin (33 per cent), and laurin, caprin, caprylin, and caproin (40.4 per cent). All fatty acids here represented contain an even number of carbon atoms.
Action, Medical Uses, and Dosage.—This is an agreeable emollient, useful as an application to bruises, sprains, and like injuries. It is less drying than most of the vegetable oils used for this purpose.
Related Oils.—(Compare Oleum Cocos.) TUCUM OIL. A bright-red, pleasantly fragrant oil obtained from the fruit of the South American Astrocaryum vulgare of Martius.
MACAJA BUTTER.—A yellowish, butyraceous oil, having an agreeable, violaceous odor, prepared from the seeds of the Cocos aculeata, Jacquin, of the American tropical belt.