Plant height and number of years before producing the first grains
Shade necessities
Amount of organic matter needed
A tree or frame to grow around (Bamboo, coconut or Erythrina lanceolata)
Labor intensity (pollination and harvest activities)[25]
Vanilla grows best under hot humid climate from sea level to an elevation of 1500 m. Most of its production is done 10 to 20 degrees above and below the equator. The ideal growing conditions are moderate rainfall, 150–300 cm, evenly distributed through 10 months of the year. The optimum temperatures for cultivation are 15–30 °C (59–86 °F) during the day and 15–20 °C (59–68 °F) during the night. Ideal humidity is around 80%, and under normal greenhouse conditions it can be achieved by an evaporative cooler. However, since greenhouse vanilla is grown near the equator and under polymer (HDPE) netting (shading of 50%), this humidity can be achieved by the environment.
Soils for vanilla cultivation should be loose with high organic matter content and loamy texture. They must be well drained, and a slight slope helps in this condition. Soil pH has not been well documented, but some researchers have indicated an optimum soil pH of around 5.3.[26] Mulch is very important for proper growth of the vine, and a considerable portion of mulch should be placed in the base of the vine.[27] Fertilization varies with soil conditions, but general recommendations are: 40 to 60g of N, 20 to 30g of P2O5 and 60 to 100g of K2O should be applied to each plant per year besides organic manures like vermicompost, oil cakes, poultry manure and wood ash. Foliar applications are also good for vanilla, and a solution of 1% NPK (17:17:17) can be sprayed on the plant once a month. Vanilla likes a lot of organic matter; therefore 3 to 4 applications of mulch a year are adequate for the plant.
Propagation, pre-plant preparation and type of stock
Dissemination of vanilla can be achieved either by stem cutting or by tissue culture. For stem cutting, a progeny garden needs to be established. Recommendations for establishing this garden vary, but in general trenches of 60 cm in width, 45 cm in depth and 60 cm spacing for each plant is necessary. All plants need to grow under 50% shade as well as the rest of the crop. Mulching the trenches with coconut husk and micro irrigation provide ideal micro climate for vegetative growth.[28] Cuttings between 60 and 120 cm should be selected for planting in the field or greenhouse. Cuttings below 60 cm need to be rooted and raised in a separate nursery before planting. Planting material should always come from unflowered portions of the vine. Wilting of the cuttings before planting provides better conditions for root initiation and establishment.
Before planting the cuttings, trees that will support the vine must be planted at least three months before sowing the cuttings. Pits of 30 x 30 x 30 cm are dug 30 cm away from the tree and filled with farm yard manure (FYM or Vermicompost), sand and top soil mixed well. An average of 2000 cuttings can be planted per hectare. One important consideration is that when planting the cuttings from the base 4 leaves should be pruned and the pruned basal point must be pressed into the soil in a way that the 4 nodes are in close contact with the soil, and are placed at a depth of 15 to 20 cm.[27] The top portion of the cutting is tied up to the tree using natural fibers like banana or hemp.
Tissue culture
Several methods have been proposed for vanilla tissue culture, but all of them begin from axillary buds of the vanilla vine.[29][30] In vitro multiplication has also been achieved through culture of callus masses, protocorns, root tips and stem nodes.[31] Description of any of these processes can be obtained from the references listed before, but all of them are successful in generation of new vanilla plants that first need to be grown up to a height of at least 30 cm before they can be planted in the field or greenhouse.[25]
Scheduling considerations
In the tropics, the ideal time for planting vanilla is from September to November, when the weather is neither too rainy nor too dry, but this recommendation varies with growing conditions. Cuttings take 1 to 8 weeks to establish roots, and show initial signs of growth from one of the leaf axils. A thick mulch of leaves should be provided immediately after planting as an additional source of organic matter. Three years are required for cuttings to grow enough to produce flowers and subsequent pods. As with most orchids, the blossoms grow along stems branching from the main vine. The buds, growing along the 6 to 10 inch stems, bloom and mature in sequence, each at a different interval.[28]
Pollination
Flowering normally occurs every spring, and without pollination, the blossom wilts and falls, and no vanilla bean can grow. Each flower must be hand-pollinated within 12 hours of opening. The only insect capable of pollinating the blossom is the Melipona, a bee native only to Mexico. All vanilla grown today is pollinated by hand. A small splinter of wood or a grass stem is used to lift the rostellum or move the flap upward, so that the overhanging anther can be pressed against the stigma and self pollinate the vine. Generally one flower per raceme opens per day, and therefore the raceme may be in flowering for over 20 days. A healthy vine should produce about 50 to 100 beans per year; however growers are careful to pollinate only 5 to 6 flowers from the 20 on each raceme. The first 5 to 6 flowers that open per vine should be pollinated, so that the beans are similar in age. These agronomic practices facilitate harvest and increases bean quality. It takes the fruits 5 to 6 weeks to develop, but it takes around 9 months for the bean to mature. Over-pollination will result in diseased and inferior bean quality.[27] A vine remains productive between 12 and 14 years.
Pest and disease management
Most diseases come from the uncharacteristic growing conditions of vanilla. Therefore, conditions like excess water, insufficient drainage, heavy mulch, over-pollination and too much shade favor disease development. Vanilla is susceptible to many fungal and viral diseases. Fusarium sp, Sclerotium sp, Phytopthora sp and Colletrotrichum sp cause rots of root, stem, leaf, bean and shoot apex. These diseases can be controlled by spraying Bordeaux mixture (1%), Carbendazim (0.2%) and Copper oxychloride (0.2%).
Biological control of the spread of such diseases can be managed by applying to the soil Trichoderma (0.5 kg per plant in the rhizosphere) and foliar application of Pseudomonads (0.2%). Mosaic virus, leaf curl and Cymbidium mosaic potex virus are the common viral diseases. These diseases are transmitted through the sap; consequently affected plants have to be destroyed. The insect pests of vanilla include beetles and weevils that attack the flower, caterpillars, snakes and slugs that damage the tender parts of shoot, flower buds and immature beans, and grasshoppers that affect cutting shoot tips.[27][28] If organic agriculture is practiced, insecticides are avoided, and mechanical measures are adopted for pest management.[25] Most of these practices are implemented under greenhouse cultivation, since in the field such conditions are very difficult to achieve.
Artificial vanilla
Most artificial vanilla products contain vanillin, which can be produced synthetically from lignin, a natural polymer found in wood. Most synthetic vanillin is a byproduct from the pulp used in papermaking, in which the lignin is broken down using sulfites or sulfates. However, vanillin is only one of 171 identified aromatic components of real vanilla beans.[32]
Leptotes bicolor also belongs to the orchid family and is used as a natural vanilla replacement in Paraguay and southern Brazil.
Non-plant vanilla flavoring
In the United States, Castoreum, the exudate from the castor sacs of mature beavers, has been approved by the Food and Drug Administration (FDA) as a food additive,[33] often referenced simply as a "natural flavoring" in the product's list of ingredients. It is commonly used in both food and beverages, especially as vanilla and raspberry flavoring.[34] It is also used to flavor some cigarettes and in perfume-making.
Stages of production
A vanilla plantation in a forest of Réunion Island [edit] Harvest
The vanilla bean grows quickly on the vine but is not ready for harvest until maturity — approximately ten months. Harvesting vanilla beans is as labor intensive as pollinating the blossoms. Immature dark green pods are not harvested. Pale yellow discoloration that commences at the distal end of the beans is an indication of the maturity of pods. Each bean ripens at its own time, requiring a daily harvest. To ensure the finest flavor from every bean, each individual pod must be picked by hand just as it begins to split on the end. Overmatured beans are likely to split, causing a reduction in market value. Its commercial value is fixed based on the length of the pod. If the bean is more than 15 cm in length, it belongs to first-quality product. If the beans are between 10 and 15 cm long, pods are under the second-quality category, and beans less than 10 cm in length are under the third-quality category. Each of the beans has a considerable amount of seeds inside the pod, which are covered by a dark-red liquid from which the vanilla essence is extracted. Vanilla bean yield depends on the care and management given to the hanging and fruiting vines. Any practice directed to stimulate aerial root production has a direct effect on vine productivity. A five-year-old vine can produce between 1.5 and 3 kg pods, and this production can increase up to 6 kg after a few years. The harvested green beans can be commercialized as such or cured in order to get a better market price.[25][27][28]
[edit] Curing
Several methods exist in the market for curing vanilla; nevertheless, all of them consist of four basic steps: killing, sweating, slow-drying, and conditioning of the beans.[35][36]
[edit] Killing
The vegetative tissue of the vanilla pod is killed to stop the vegetative growth of the pods and disrupt the cells and tissue of the beans, which initiates enzymatic reactions responsible for the aroma. The method of killing varies, but may be accomplished by heating in hot water, freezing, or scratching, or killing by heating in an oven or exposing the beans to direct sunlight. The different methods give different profiles of enzymatic activity.[37][38]
Testing has shown that mechanical disruption of bean tissues can cause curing processes,[39] including the degeneration of glucovanillin to vanillin, so the reasoning goes that disrupting the tissues and cells of the bean allow enzymes and enzyme substrates to interact.[40]
Hot-water killing may consist of dipping the pods in hot water (63–65 °C) for three minutes, or at 80 °C for 10 seconds. In scratching killing, beans are scratched along their length.[38] Frozen or quick-frozen beans must be thawed again for the subsequent sweating stage. Tied in bundles, rolled in blankets, beans may be placed in an oven at 60° C for 36 to 48 hours. Exposing beans to sunlight until they turn brown is a method originating in Mexico that was practiced by the Aztecs.[40]
[edit] Sweating
Sweating is a hydrolytic and oxidative process. Traditionally, it consists of keeping beans, for seven to ten days, densely stacked and insulated in woolen or other cloth. This retains a temperature of 45–65 °C and high humidity. Daily exposure to the sun may also be used, or dipping the beans in hot water. The beans are brown and have attained much of the characteristic vanilla flavor and aroma by the end of this process, but still retain a 60-70% moisture content by weight.[40]
[edit] Drying
Reduction of the beans to 25–30% moisture by weight, to prevent rotting and to lock the aroma in the pods, is always achieved by some exposure of the beans to air, and usually (and traditionally) intermittent shade and sunlight. Beans may be laid out in the sun during the mornings and returned to their boxes in the afternoons, or spread on a wooden rack in a room for three to four weeks, sometimes with periods of sun exposure. Drying is the most problematic of the curing stages; unevenness in the drying process can lead to the loss of vanillin content of some beans by the time the others are cured.[40]
Grading vanilla beans at Sambava, Madagascar [edit] Conditioning of the bean
This step is performed by storing the pods for five to six months in closed boxes, where the fragrance develops. The processed beans are sorted, graded, bundled, and wrapped in paraffin paper and preserved for the development of desired bean qualities, especially flavor and aroma. The cured vanilla beans contain an average of 2.5% vanillin.
[edit] Grading
Once fully cured, the vanilla beans are sorted by quality and graded. Vanilla grades depend mostly on the length of the bean, since there is a correlation between length and vanillin content.[41][42] Some commonly used grades are shown in the table below.
Vanilla extract is normally made from Grade B beans.
Vanilla grades Grade A /
Grade I 15 cm and longer, 100–120 beans per pound Also called "Gourmet" or "Prime". 30–35% moisture content.
Grade B /
Grade II 10–15 cm, 140–160 beans per pound Also called "Extract beans". 15–25% moisture content.
Grade C /
Grade III 10 cm
[edit] Usage
[edit] Culinary uses
There are three main commercial preparations of natural vanilla:
whole pod
powder (ground pods, kept pure or blended with sugar, starch, or other ingredients)[43]
extract (in alcoholic or occasionally glycerol solution; both pure and imitation forms of vanilla contain at least 35% alcohol)[44]
Cook Flavoring Company's Pure Vanilla Powder Vanilla flavoring in food may be achieved by adding vanilla extract or by cooking vanilla pods in the liquid preparation. A stronger aroma may be attained if the pods are split in two, exposing more of a pod's surface area to the liquid. In this case, the pods' seeds are mixed into the preparation. Natural vanilla gives a brown or yellow color to preparations, depending on the concentration. Good-quality vanilla has a strong aromatic flavor, but food with small amounts of low-quality vanilla or artificial vanilla-like flavorings are far more common, since true vanilla is much more expensive.
A major use of vanilla is in flavoring ice cream. The most common flavor of ice cream is vanilla, and thus most people consider it to be the "default" flavor. By analogy, the term "vanilla" is sometimes used as a synonym for "plain". Although vanilla is a prized flavoring agent on its own, it is also used to enhance the flavor of other substances, to which its own flavor is often complementary, such as chocolate, custard, caramel, coffee, cakes, and others.
The cosmetics industry uses vanilla to make perfume.
The food industry uses methyl and ethyl vanillin. Ethyl vanillin is more expensive, but has a stronger note. Cook's Illustrated ran several taste tests pitting vanilla against vanillin in baked goods and other applications, and, to the consternation of the magazine editors, tasters could not differentiate the flavor of vanillin from vanilla;[45] however, for the case of vanilla ice cream, natural vanilla won out.[46]
[edit] Medicinal uses
In an in-vitro test, vanilla was able to block quorum sensing in bacteria. This is interesting because in many bacteria quorum sensing signals function as a switch for virulence. The microbes become virulent only when the signals indicate that they have the numbers to resist the host immune system response.[47] The essential oils of vanilla and vanillin are sometimes used in aromatherapy. In old medicinal literature, vanilla is described as an aphrodisiac and a remedy for fevers; these purported uses have never been scientifically proven. It has been shown that vanilla increases levels of catecholamines (including adrenaline), and as such can also be considered mildly addictive.[48]
[edit] Gallery
A vanilla plantation in open field on Réunion.
A vanilla plantation in a "shader" (ombrière) on Réunion.
Flower
Green fruits
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