Vanilla

VANILLA, a flavouring agent largely used in the manufacture of chocolate, in confectionery and in perfumery. It consists of the fermented and dried pods of several species of orchids belonging to the genus .Vanilla. 1 The great bulk of the commercial article is the produce of V. planifolia, a native of south-eastern Mexico, but now largely cultivated in several tropical countries, especially in Bourbon, the Seychelles, Tahiti and Java. The plant has a long fleshy stem and attaches itself by its aerial rootlets to trees; the roots also penetrate the soil and derive a considerable portion of their nourishment from 1 Span, vainilla, dim. of vaina, a pod.

it. The leaves are alternate, oval-lanceolate and fleshy; the light greenish flowers form axillary spikes. The fruit is a pod Vanilla Plant (Vanilla planifolia). A, shoot with flower, leaf and aerial rootlets; B, pod or fruit.

from 6 to 10 in. long, and when mature about half an inch in diameter. The wild plant yields a smaller and less aromatic fruit, distinguished in Mexico as Baynilla cimarona, the cultivated vanilla being known as B. corriente, Vanilla was used by the Aztecs of Mexico as an ingredient in the manufacture of chocolate before the discovery of America by the Spaniards, who adopted its use. The earliest botanical notice is given in 1605 by Clusius (Exoticorum Libri Decem), who had received fruits from Hugh Morgan, apothecary to Queen Elizabeth ; but he seems to have known nothing of its native country or uses. The Mexican vanilla had been introduced to cultivation before the publication of the second edition of Philip Miller's Gardeners' Dictionary (1739). It was reintroduced by the marquis of Blandford, and in 1807 a flowering specimen was figured and described by R. A. Salisbury (Paradisus, London, t. 82). Mexican vanilla is regarded as the best. It is principally consumed in the United States. In Bourbon about 3000 acres are under cultivation ; the crop is sent to Bordeaux, the chief centre of the trade in France. Its odour is said to differ from the Mexican variety in having a suggestion of tonqua bean. The Seychelles produce large quantities of exceedingly fine quality; the produce of these islands goes chiefly to the London market. The Java vanilla, grown chiefly in Krawang and the Preanger Regencies, is shipped to Holland. The Tahiti produce is inferior in quality.

Mr Hermann Mayer Senior, in the Chemist and Druggist, June 30, 1906, gives the following figures, which approximately represent the world's output of vanilla during the seasons 1905-1906: Bourbon, TO tons; Seychelles, 45 tons ; Mauritius, 5 tons; Comores, Mayotte, Madagascar, etc., 120 tons; Guadeloupe, Java, Ceylon and Fiji, lotons; Mexica, 7ptons; Tahiti, loo tons total, about 420 tons.

The best varieties of vanilla pods are of a very dark chocolate brown or nearly black colour, and are covered with a crystalline efflorescence technically known as givre, the presence of which is taken as a criterion of quality. The peculiar fragrance of vanilla is due to vanillin, CsHgOs, which forms this efflorescence. Chemically speaking, it is the aldehyde of methyl-protocatechuic acid. It is not naturally present in the fleshy exterior of the pod, but is secreted by hair-like papillae lining its three internal angles, and ultimately becomes diffused through the viscid oily liquid surrounding the seeds. The amount of vanillin varies according to the kind : Mexican vanilla yields 1-69, Bourbon or Rdunion 1-9 to 2-48, and Java 2-75%. Besides vanillin, the pods contain vanillic acid (which is odourless), about II % of fixed oil, 2-3% of soft resin, sugar, gum and oxalate of lime.

Vanillin forms crystalline needles, fusible at 81 C., and soluble in alcohol, ether and oils, hardly soluble in cold, but more so in boiling water. Like other aldehydes, it forms a compound with the alkaline bisulphites, and can by this means be extracted from bodies containing it. Vanillin has been found in Siam benzoin and in raw sugar, and has been prepared artificially from coniferin, a glucoside found in the sapwood of fir-trees, from asafoetida, and from a constituent of oil of cloves named eugenol. It is from the last-named that vanillin is now prepared on a commercial scale, chiefly in Germany. Vanillin does not appear to have any physiological action on human beings when taken in small doses, as much as 10 to 15 grains having been administered without noxious results. On small animals, however, such as frogs, it appears to act as a convulsive. It has been suggested as a stimulant of an excitomotor character in atonic dyspepsia. It is a constituent of Gtinzburg's reagent (phloro-vanillin-glucin) for the detection of free hydrochloric acid in the gastric contents. The poisonous effects that have on several occasions followed from eating ices flavoured with vanilla are not to be attributed to the vanilja, but probably to the presence of tyrotoxicon (Pharm. Journ. [3], xvii. p. 150), a poison found in milk which has undergone certain putrefactive changes, and producing choleraic effects, or perhaps to the presence of microscopic fungi in the vanilla, the plantations being liable to the attack of Bacterium putredinis. Workmen handling the beans in the Bordeaux factories are subject to itching of the hands and face; but this is caused by an Acarus which occupies the end of the pod. In some cases, however, symptoms of dizziness, weariness and malaise, with muscular pains, have been felt, due possibly to the absorption of the oily juice by the hands of the workmen.

See also R. A. Rolfe, " Vanillas of Commerce," in Kew Bulletin (1895), p. 169, and " Revision of the Genus Vanilla," in Journal of The Linnean Society (Botany), xxxii. 439 (1896) ; also S. J. Galbraith, on " Cultivation in the Seychelles," U.S. Dept. of Agriculture, Division of Botany, Bulletin 21 (1898).