Vanilla. Vanilla bean. Vanilla planifolia.
Vanilla. N. F. IV (U. S. P. VIII). Vanilla Bean. Vanille, Fr. Cod. Fructus Vanillae, P. G. Vanille, G.—"The cured, full-grown, unripe fruit of Vanilla planifolia Andrews (Fam. Orchidaceae)." N. F.
Vanilla planifolia is a fleshy, dark green, perennial climbing plant, with a very long, smooth, dark green stem, much branched, and furnished at the nodes with aerial roots, which cling to the tree or the wooden framework supporting the plant. The dark green, tough leaves are alternate, oval, sessile, attenuate at the apex, fleshy and veinless. The pale greenish-yellow, sessile flowers are about two inches in diameter, and occur in loose, axillary racemes of eight or ten. The fruit is a slender pod, seven or eight inches long, filled with an oily mass containing numerous small, black, shining seeds.
This plant is a native of the West Indies, Mexico and South America, but is now extensively cultivated. The plant does well from the sea-level up to two thousand feet of altitude, requiring for its perfection, however, a moist, hot climate, with an habitual dry summer spell which seems to be necessary to bring good flowering. It is propagated by means of cuttings, sometimes two or three feet in length, but preferably from ten to twelve feet long, taken from growing shoots; these are planted after the dry season is over and should produce flowers in two years. Preferably placed upon trees, but sometimes on long stakes, trellises, wire supports, etc., the slip is placed with one end on the ground, covered with leaves or some light top dressing. In many cases the vines are planted so closely as scarcely to leave room for cultivators to pass, but it has been found that under these circumstances the vanilleries are especially liable to destructive fungous diseases. As the flower does not fertilize itself, fertilization (pollination) by hand is necessary; it is usually performed by women and children. It is said that a fairly trained workman can fecundate over one hundred flowers per hour. In most localities not more than thirty fertilized flowers should be left to a plant. The pods reach their full size in from five weeks to eight months, according to the altitude of the locality and to the amount of shade. The first indication of ripening is a slight yellowing of the whole pod; as soon as this occurs the pods should be picked, and sorted, and the curing process commenced. If left to ripen further the pods are prone to split and otherwise deteriorate. For the purpose of curing them the pods are kept in a heated room for some days (about 110° F.), then transferred to a cooler one (90° F.), and finished at ordinary temperature. During the process, which lasts some months, there is a loss of 70 to 80 per cent. of weight. For details as to culture, see Bulletin 21, 1898, U. S. Department of Agriculture, Division of Botany. The practice of curing the beans by placing them under blankets in the sun is still in vogue, but that of using a regulated artificial heat is more certain, and it is the modern method.
When thoroughly cured the beans are sorted and tied into bundles, which are wrapped in sheet lead or placed in small metallic boxes. In doing this it is essential that the bundle be wrapped in a thin vegetable parchment paper, as chemical action occurs when the beans come in contact with the metal.
Fruits which have not been picked early enough are inferior and are frequently cut into short pieces and sold as "cuts." If by chance the fruit should be picked too early the quality of the resulting product is distinctly inferior. The fruit as first picked has no aroma, the vanillin during the process of curing being produced from the glucoside coniferin in the interior of the fruit. This was shown to be converted into coniferyl alcohol and glucose, and the former of these subsequently changed into vanillin.
The cultivation of vanilla has extended from South America throughout the tropics, so that at present, although the wild plant is abundant in the Mexican States of Vera Cruz and Oaxaca the vanilla of the markets comes almost exclusively from vanilleries. Holland is supplied from Java plantations; France from Tahiti, Madagascar, Reunion, Guadeloupe, and other of her colonies. From Mauritius and the Seychelles the product goes to London. In the markets most of the varieties are known by the name of the country in which they are produced. The finest of the varieties is the Mexican, although of recent years the Bourbon beans have so improved that they almost rival it in strength and flavor. At present the Mexican bean is sold at somewhat less than double the price of the Bourbon; the Bourbon at almost double the price of the Tahiti, the latter bean being commonly much injured by carelessness in the process of curing.
Of Mexican vanilla, the first quality occurs in pods from 15 to 20 cm., long, flattened, 6 to 8 mm. in diameter, with the lower end slightly attenuated, the upper end gradually tapering for about a quarter of the length of the pod, usually curved and slightly twisted near the point. The color is dark brown, the pods fairly plump, the surface ridged longitudinally, and with an incrustation of fine crystals beginning at the ends, gradually extending; when fresh somewhat viscid, but always roughish to the touch. For an interesting account of the Mexican vanilla plant by Charles E. Hires, see A. J. P., 1893, 576.
Of the Mexican vanillas the most valuable variety, called ley, or vainilla mansa, by the Spaniards, consists of cylindrical, somewhat flattened pods, six or eight inches long, three or four lines, thick, nearly straight, narrowing towards the extremities, bent at the base, shining and dark brown externally, wrinkled longitudinally, soft and flexible, and containing within their tough shell a soft black pulp, in which numerous minute, black, glossy seeds are embedded. It has a peculiar, strong, agreeable odor, and a warm, aromatic, sweetish taste. The interior pulp portion is most aromatic. In it are more or less numerous, minute crystals. Another variety, called vainilla simarona by the Spaniards, is smaller, of a lighter color, and less aromatic. The pods are said to be very dry and to contain no vanillin. (Nueva Farmacopea Mexicana.) According to Schiede, it is yielded by a distinct species, the Vanilla sylvestris Schiede. A third variety is the vainilla pompona of the Spaniards (boba vainilla, or platano vainilla). In this, the pods are from 12 to 18 cm. long, from 12 to 18 mm. broad, shaped somewhat like a plantain, almost always open, very dark brown or nearly black, soft, viscid, and of a strong odor. Schiede states that it is the product of the Vanilla Pompona Schiede. The variety vainilla vezacate is said to be derived from pods gathered long before maturity. (Nueva Farmacopea Mexicana.) The vainilla pompona of the Spaniard is evidently the vanillons of European commerce, which are usually from 10 to 13 cm. long and from 15 to 25 mm. in diameter, frequently sharply angled, brown to red-brown in color, usually split open and free from efflorescence. Owing to the transverse markings by twine with which they have been wrapped during the process of curing, the beans have a peculiar twisted appearance. Their odor, which resembles that of heliotrope, is due to the presence in them of heliotropin, in lieu of vanillin.
Bourbon vanilla, produced in the Isle of Reunion to the amount of 200,000 pounds a year, resembles Mexican vanilla, but is scarcely so long in the tapering portions, ia of a dark-brown almost black color, is not so firm as the Mexican, has the surface smooth and waxy, and soon becomes covered with a coating of acicular crystals known as "frost." The odor of this vanilla is said to resemble that of Tonka bean rather than that of Mexican vanilla.
The Seychelles and Mauritius vanilla (inferior Bourbon of the trade) has the pods about six inches in length, not over a quarter of an inch in width, and characterized by the pale color, the faint odor, and a smooth but not waxy surface.
South American or Guadeloupe vanilla resembles the Mexican bean, but is usually recognizable, when the bean is entire, by the latter being broad and flattened, usually half an inch or more wide, slightly tapering at the lower end, and at the upper sharply attenuated an inch or so at the point. It has a reddish brown color, and is of a rank odor. It is very pulpy, with a surface intermediate in feel between the Bourbon and the Mexican, and having but few crystals. One variety of this vanilla, sold under the name of vanillons, has the odor of heliotrope and is much used by perfumers and tobacco manufacturers.
Tahiti vanilla, "transplanted Mexican vanilla," has its pods from six to seven inches long, flat, from three-eighths to half an inch wide, with a reddish-brown color. They are almost destitute of vanilla flavor, and have an odor suggesting heliotrope. It is said they contain piperonal and also vanillin. (Ph. Cb., 45.)
Java vanilla, which is almost exclusively consumed in Holland, has a pod from four to six inches long, with a flavor as fine as that of the Mexican bean, and a much stronger odor.
Vanilla pods are described by the N. F. as:
"Pods linear, flattened, from 15 to 35 cm. in length and from 5 to 9 mm. in breadth: summits terminating in flat circular scars; gradually tapering, more or less bent and curved or hooked at the bases, or in the Tahiti variety, broad in the middle and tapering towards either end, the base closely resembling the summit; externally blackish-brown, longitudinally wrinkled, moist-glossy; occasionally with an efflorescence of vanillin in the form of acicular crystals or mono-clinic prisms; frequently with narrow, elliptical or irregular, more or less wrinkled, dark-brown patches of cork; occasionally split into three parts near the tip, flexible and tough, one-celled, containing a blackish-brown pulp and numerous blackish-brown seeds; the latter being flattened, irregularly triangulate or nearly circular in outline, reticulate and varying from 0.25 to 0.3 mm. in diameter. Odor and taste characteristic and very agreeable. Under the microscope, transverse sections of the pods of Vanilla show an epidermis with a somewhat thickened outer cuticularized layer having occasionally rounded or conical masses of an excretion of a gum-like substance; a layer of collenchyma of one or two rows of cells; a thick sarcocarp composed of parenchyma cells in which are imbedded an interrupted circle of fibrovascular bundles; the parenchyma cells are deeply undulate in outline and usually contain a thin protoplasmic layer enclosing numerous oily globules or may contain bundles of raphides of calcium oxalate; the individual crystals varying from 0.2 to 0.4 mm. in length; some of the parenchyma cells are specially modified and distinguished by their somewhat thickened walls with long, oblique, slit-like pores or the thickening may extend in the form of broad, spiral bands; in the fibrovascular bundles the phloem is central, being more or less surrounded by a few tracheae, the walls possessing; slit-like pores or spiral thickenings, and at the outside of the bundle is a closed circle of sclerenchymatous fibers, the walls being thin, strongly lignified, provided with numerous, transverse, simple pores, the outer wall of the outer row of fibers being irregular or sinuate; from the inner walls of the endocarp arise the placentae bearing numerous brownish-red or blackish seeds, and from the cells of the endocarp also arise numerous long, nearly straight hairs, the ends being rounded, the hairs being more or less matted together by a gummy or resinous mass in which some of the seeds are held; in mounts ma,de in hydrated chloral T.S. or potassium hydroxide T.S., the immature, brownish-red seeds show a deeply reticulate seed-coat, with cells of an oblong-polygonal form in surface view. Place a few of the crystals, occurring as an emorescence on the fruit, on a microscope slide or watch crystal and add a drop of phloroglucinol T.S. and hydrochloric acid; the solution immediately acquires a carmine-red color (distinction from benzoic acid). The amount of extractive yielded to dilute alcohol should not be less than 12 per cent. Vanilla yields not more than 6 per cent. of ash." N. F.
Transverse sections of the pods of vanilla show an epidermis with a somewhat thickened outer cuticularized layer having occasionally rounded or conical masses of an excretion of a gum-like substance; a layer of collenchyma of one or two rows of cells; a thick sarcocarp composed of parenchyma cells in which are imbedded an interrupted circle of fibrovascular bundles; the parenchyma cells are deeply undulate in outline and usually contain a thin protoplasmic layer enclosing numerous oily globules or may contain bundles of raphides of calcium oxalate; the individual crystals varying from 0.2 to 0.4 mm. in length; some of the parenchyma cells are specially modified and distinguished by their somewhat thickened walls with long, oblique, slit-like pores or the thickening may extend in the form of broad, spiral bands; in the fibrovascular bundles the phloem is central, being more or less surrounded by a few tracheae, the walls possessing slit-like pores or spiral thickenings, and at the outside of the bundle is a closed circle of sclerenchymatous fibers, the walls being thin, strongly lignified, provided with numerous, transverse, simple pores, the outer wall of the outer row of fibers being irregular or sinuate; from the inner walls of the endocarp arise the placentae bearing numerous brownish-red or blackish seeds and from the cells of the endocarp also arise numerous long, nearly straight hairs, the ends being rounded, the hairs being more or less matted together by a gummy or resinous mass in which some of the seeds are held; in mounts made in hydrated chloral T.S. or potassium hydroxide T.S., the immature, brownish-red seeds show a deeply reticulate seed-coat, with cells of an oblong-polygonal form in surface view.
A characteristic test for the vanillin crystals which occur as an efflorescence on the fruit is as follows: On a microscope slide or watch crystal, place a few crystals and add a drop of phloro-glucinol T.S. and hydrochloric acid; the solution immediately acquires a carmine-red color (distinction from benzoic acid). The amount of extractive which vanilla of good quality yields to dilute alcohol should not be less than 12 per cent. Nor should it yield more than 6 per cent. of ash.
Vanilla beans from which the vanillin has been removed by means of a solvent are sometimes offered for sale. The fraud is to be detected by the absence of flavor and odor. Such beans, and also beans of an inferior quality, are sometimes "improved" in appearance and in odor by the use of benzoic acid. For the detection of this fraud the pharmacist should avail himself of the fact that while the crystals of benzoic acid are flattened and rhomboidal and generally lie upon the bean, those of vanillin are usually acicular and stand out at right angles from the surface of the fruit. The absence of the crystalline coating on the vanilla beans seems to be no proof of inferiority, for Henri Lecomte affirms that it is not rarely absent in the best Mexican bean. (B. Sc. Pharm., 1901.)
According to Bucholz, vanilla does not yield volatile oil when distilled with water, and the aroma appears to depend on chemical changes which may take place during and after the curing of the fruit. Many years since, vanilla was analyzed by Bucholz and Vogel, the former of whom found in it a disagreeable-smelling fixed oil, a soft resin having a feeble odor of vanilla when heated, a bitterish extractive resembling tannin, sugar, starch and benzoic acid. But the characteristic odorous principle was not isolated until Gobley obtained vanillin, by acting on vanilla with solvents. Although the latter substance has been largely manufactured, it does not take the place of the preparations of vanilla, the flavor and odor of the latter being greatly preferred. It passes with water in distillation. If vanilla, finely divided, be distilled with water, a turbid liquid passes, which becomes clear by agitation with ether, and the ether on evaporation yields crystals of vanillin. Vanilla, in the fresh state in which it is gathered, does not in the least possess the characteristic fragrant odor. H. Lecomte (J. P. C., 1903, 343) studied the conditions which bring about the formation of vanillin. According to his researches, there exist in the vanilla plant two ferments, which differ in a marked degree from each other in their functions. The one, an oxydase, is present in the individual organs of the plant, such as the leaves, shoots and their aqueous extracts, in the green and ripe fruit, and in the prepared commercial fruit. Lecomte detected it in the organs of plants of different origin, by means of G. Bertrand's reactions. At the same time, the presence of manganese salts was observed in all products, which renders it not impossible that they stand in some relation to the above-named ferment. The second ferment is contained in the sap of the vanilla, and acts as a hydrolyzing ferment. With regard to the mechanical treatment of vanilla, it would appear in the first instance as if it counteracted the function of the ferment. It consists, as is well known, of the immersion of the fruit during twenty seconds in water at 85° C. (185° F.), a manipulation which might bring about the destruction of the ferment. But the author has convinced himself that a temperature of about 50° C. (122° F.), such as the interior of the fruit probably only reaches during the short duration of the process, really promotes the function of the oxydase. Both ferments, the oxydase as well as the one possessing the hydrolytic action, appear to be necessary for the formation of vanillin in the plant, and their action may possibly be explained thus: During the preparation, the coniferin produced by the plant is split up into glucose and coniferyl alcohol. This process would explain also the occurrence of grape-sugar in vanilla. The oxydase then converts the coniferyl alcohol into vanillin. Tiemann and Haarmann obtained from Mexican vanilla 1.69 per cent. of vanillin, from Reunion vanilla 2.48 per cent., from Java vanilla 2.75 per cent. Stokeby found in vanilla, resin, wax, a fixed oil, a brown resinous matter, tannic acid changing the salts of iron to green, gum, sugar, phosphates and sulphates: hydrochloric acid separated from it oxalic acid, and potassium hydroxide, humic acid. (J. P. C., 4e ser., iii, 76, 1866; see also paper by Clay W. Holmes, Proc. A. Ph. A., 1887, 526.)
Vanilla is used in the N. F. IV in making the tincture of vanilla (10 per cent. with a menstruum of alcohol and water), which is used .as a flavoring agent in elixir of ammonium valerate, elixir of hops, elixir of strychnine valerate and syrup of the bromides.
Vanilla Poisoning.—Many years ago Orfila reported cases of violent gastro-intestinal irritation from eating vanilla ices, and since then others have reported similar instances of poisoning. In 1886 Vaughan in the investigation of an ice cream which had caused serious poisoning in eighteen persons found that the vanilla used to flavor it, in doses of 30 drops failed to produce any symptoms in either himself or his assistants, and he was able to separate the ptomaine tyrotoxicon, which he had previously found in other milk food (see A. J. P., xvi, p. 452). It is highly probable that many of these cases are due to ptomaine poisoning rather than vanilla poisoning; but if the one reported by Rosenthal (P. J. xv, p. 24) be accurately stated it must be allowed that in some instances the vanilla itself is at fault. In this connection the reports of Claverie (J. P. C. Supp. 1908, xxv) of violent dermatitis in workmen handling vanilla beans is of interest. He attributes the symptoms to the oily exudate of the vanilla pods.