This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The pimento tree, Pimenta officinalis, Lindley (N.O. Myrtaceoe), is a handsome tree indigenous to and common in the West Indies, and found also in Central America and Venezuela. It is cultivated, especially in Jamaica, in plantations known as pimento walks.
The tree bears large panicles of fragrant, white flowers with two-celled inferior ovaries, each cell containing a single ovule. The flowers are succeeded by small fruits; as soon as these have attained their full size, but before they ripen, the whole panicle is collected and dried in the sun, during which the green colour changes to a reddish brown. The stalks are then separated and the fruits are ready for packing. Had they been allowed to ripen they would have become dark purple and filled with a sweet pulp, but would have lost much of their aroma; hence they are collected whilst unripe.
Pimento berries appear to have been long known to the Mexicans, who used them, together with vanilla, for flavouring chocolate; through them the Spaniards became acquainted with the spice towards the end of the sixteenth century, and introduced it into Europe, where great quantities were consumed. It was supposed to possess the combined flavour of cloves and other spices; hence its name of ' allspice.' It is also called Jamaica pepper.
Pimento berries are small, nearly globular, reddish-brown fruits from 5 to 8 mm. in diameter. They have a rough surface, and are crowned with the remains of the calyx in the form of a raised ring, in which the four calyx-teeth are scarcely discernible; in the centre of this ring are the short remains of the style. The pericarp is thin, woody, and brittle. At the base a small scar indicates the point of attachment of the pedicel.
Cut transversely, the fruit is seen to be two-celled, each cell containing a single flattened or irregularly plano-convex, nearly black seed, within which there is a dark coiled embryo but no endosperm.
The thin pericarp contains a large number of oil-glands embedded in it; many are situated just below the outer epidermis, and elevate it at intervals, thus producing the roughness of the pericarp; these glands are just visible in a transverse section when examined with a lens. The seeds also contain oil-glands, but are much less aromatic than the pericarp.
The odour of pimento berries is agreeably aromatic; it is especially perceptible when the fruits are crushed. The taste is warm and aromatic, resembling, but distinct from, that of cloves.
The student should observe
(a) The remains of the calyx crowning the fruit,
(b) The two cells, each containing a single seed; and should compare these fruits with
(i) Cubebs, which are one-celled, dark greyish black or greyish brown in colour, and reticulated on the surface, (ii) Black pepper, which is one-celled and one-seeded.
Pimento berries contain from 3 to 4.5 per cent, of volatile oil (sp. gr. 1.040 to 1.055; O.R. = - 2°) consisting principally of eugenol (about 65 per cent.), which is also the chief constituent of oil of cloves. They contain, further, a notable quantity of tannin and yield from 2.5 to 5 per cent, of ash.
Dark (nearly ripe) fruits have been coloured with bole or brown ochre and passed off as genuine; the fraud may be detected by boiling them for a few moments with hydrochloric acid, filtering, and testing with potassium ferrocyanide, when at most a bluish green colour should be produced.
The fruits of Pimenta acris, Wight (compare p. 57), may be distinguished by their five calyx teeth. Mexican allspice, the fruits of Eugenia Tabasco, G. Don, are larger than the genuine, but neither so dark nor so aromatic. Both are of rare occurrence.
Pimento is used as a flavouring agent and as an aromatic stimulant, resembling cloves in its action.