Annatto. Orleana. Annotta. Arnotta. Terre de la Nouvelle-Orleans, Fr. Orellana, Orlean, G.—The coloring substance called annatto, arnotta or roucou, is the reddish pulp surrounding the seeds in the fruit of Bixa orellana L. (Fam. Bixaceae), a middle-sized tree native to Northern South America, but widely cultivated in tropical Asia and Africa. The pulp is separated by bruising the fruit, mixing it with water, then straining through a sieve, and allowing the liquid to settle. The mass which remains is dried and formed into flat cakes or cylindrical rolls. Another mode is to bruise the seeds, mix them with water, and allow the mixture to ferment. The coloring matter is deposited during the fermentation, after which it is removed and dried. In commerce there are two kinds of annatto, the Spanish or Brazilian, and the French, the former coming in baskets from Brazil, the latter in casks from French Guiana. The French, which is also called flag annatto, has a disagreeable odor, probably from having been prepared by the fermenting process in which urine is sometimes used; but is superior, as a dye stuff, to the Spanish, which is without any disagreeable odor. Annatto is of a brownish-red color, usually rather soft, but hard and brittle when dry, of a dull fracture, of a sweetish peculiar odor, and a disagreeable, saline, bitterish taste. It is inflammable, but does not melt with heat. It softens in water, to which it imparts a yellow color, but does not dissolve. Alcohol, ether, the oils, and alkaline solutions dissolve the greater part of it. The South American Indians are said to produce directly from the annatto seeds, without fermentation, a color similar to and almost as brilliant as carmine. (P. J., April, 1903.) For a proximate analysis of the leaves see Ap. Ztg., 1899, p. 35. It contains a peculiar coloring principle, to which Preisser, its discoverer, gave the name of bixin. This has the formula C28H34O5, and when pure is a dark, red, somewhat crystalline substance. According to Van Hasselt, bixin has the composition C29H34O5, but Heiduschka and Eiffart believe that the correct formula is C29H34O5. (A. Pharm., 1911, No. 1, 39.) It is accompanied by a yellow coloring matter, orellin. A coloring matter found in the root of Escobedia scabrifolia, a plant growing in tropical America, is used by the Mexicans in coloring fats and butter yellow. (S. W. P., 1912, No. 18, 260.) The chief uses to which annatto is applied are for dyeing silk and cotton orange-yellow, and for coloring cheese and butter. The color, however, which it imparts to cloth ia fugitive. It has been given internally as a medicine; but is not now used, and probably exercises little influence upon the system. In pharmacy it is employed to color ointments and plasters, and has occasionally been substituted for saffron. It is frequently adulterated with red ochre, powdered bricks, colcothar, farinaceous substances, chalk, calcium sulphate, turmeric, etc. The mineral substances, if present, will be left behind when the annatto is burned. Tincture of annatto is made by extracting 100 parts of annatto with 100 parts of water containing 1 1/2 per cent. of potassium carbonate, and evaporating to 60 parts, mixing with 12 parts of alcohol and filtering.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.