Vanilla

Vanilla fragrans
Family: Orchidaceae​

History

Vanilla is an economically important crop as it is the source of natural vanillin. It is believed that vanilla is indigenous to northeastern Mexico. It is ancient Totonaco Indians of Mexico who were the first keepers of the secrets of vanilla. When they were defeated by the Aztecs they were demanded to relinquish their exotic fruit, vanilla pods. Later Aztecs were defeated by the Spanish and Spaniard Hernando Cortez, the Spanish mariner, returned to Spain with the precious plunder vanilla beans which were combined with cacao to make an unusual and pleasing drink. For eighty years this special beverage was only enjoyed by the nobility and the very rich. Then in 1602 Hugh Morgan, Apothecary to Queen Elizabeth I, suggested that vanilla could be used as a flavoring all by itself and versatility of the exotic bean was finally uncovered. However, only in 1858, Gobley was able to isolate vanillin from vanilla pods. Today vanilla is grown by Madagascar, Indonesia, Mexico, Tahiti and few other countries including Sri Lanka as a commercial crop.

Products and Uses

Vanillin is the main product extracted from vanilla. It is used as a flavor ingredient in the confectionery industry, perfumery, and pharmaceutical industries.

Major Growing Areas

In Sri Lanka vanilla is mainly confined as a home garden crop grown in mid and low country wet zone. Total extent is less than 100ha. and the main growing areas are Kandy, Nuweraeliya, Matale, and Kegalle districts.

Varieties

No specific varieties have been identified in Sri Lanka and planting material is taken from traditionally grown vines.

Soils and Climatic needs

Soil

 High fertile well-drained loamy soils are preferable. Soils should be rich in organic matter.  

Climate

 Altitude – Vanilla performs well up to 1000m above the mean sea level. Temperature – 21-32 0C is suitable. But Vanilla performs well at 27 0C

 Rainfall – 2000-2500 mm. But 2-3 months dry spell is needed for flower initiation.

Crop establishment

Planting material

Vegetative methods are practiced. Cuttings, 3’-4.5’ (1-1.5m) in size, are obtained from selected mother vines. The lower end of the cuttings should be closer to the node and 3-4 leaves should be removed from the lower end. To induce buds cuttings should be hanged on a support for about 7 days. 

3 nodal, 4 nodal cutting could be planted in 8” X 5” polythene bag and after shoot growth vanilla plants can be used as planting material.

Field Planting

 Vanilla is a shade loving plant hence live support trees are used to provide adequate shade (50-60%). Gliricidia is the most suitable shade tree and support trees should be established at least six months before planting vanilla.

Spacing – 2.5m x 1.5 m (8’ x 5’) (2000 cuttings / ha) Planting should be done with the onset of rain. Loosen the soil around the base of support up to 8’’ deep in an area of about 2’ in diameter. Then add a 2-3 basket of organic manure. Make a furrow 10 (4’’) deep (from support tree and across the surface of planting pit.) and place the cutting horizontally in the furrow leaving 3 cm from lower cut end jutting out into the air. Cuttings should be buried firmly with upturned soil. The upper end of the cutting is tied up on to the support tree and mulching should be done up to the thickness of 7.5 – 15 cm using decayed organic matter. 

Crop management

Training of vines

When cuttings start to grow emerging axial buds should be trained to turn vines to grow upward direction. When vines reach the top of the support tree they should be allowed to droop. When reached to ground let them grow on soil further 30 -45 cm (1-1.5’) and then curl the stem upwards and allow the buds to grow up again on the support tree. This process should be repeated until vines form several loops. Ground area of loops should be covered with organic manure. 

Stimulate flowering – 

To get the maximum number of flowers flowering should be induced artificially. Usually, this practice is done in January. For that 5-7 nodes are removed from the tip of drooped matured branches. To get 70-80% sunlight shade trees too should be pruned. 

Manuring– 

Usually, artificial fertilizer is not applied to vanilla but organic fertilizer is essential.  Compost should be applied at the beginning of each rainy season. Plants should be mulched at least once in six months with dry or fresh leaves and lopping of shade trees.    

Pollination–

 In vanilla artificial pollination is essential as the natural pollination rarely produce pods. The flower is self-fertile, but incapable of self-pollination without the aid of an outside agency to either transfer the pollen from the anther to the stigma or to lift the flap or rostellum and press the anther against the stigma. Usually, flowers come out in April-/ May period and flowers are small lily-like, greenish-yellow in color. There are about 20 flowers in a cluster. Usually, 2 or 3 flower in a raceme opens in a day, with the entire flowering period of the raceme lasting an average of 24 days. The flower opens in the morning and closes in the afternoon, never to re-open. If it is not pollinated, it will shed the next day. The optimum time for pollination is in mid-morning. (7am to 11 am)

20 to 30 flowers / cluster

100 -150 pods can be obtained from one vine.

Crop Protection

No economically important pests and diseases have been reported

Harvesting and Post Harvest practices

Harvesting

 Pods reach maturity after 8-9 months from pollination. Harvesting mainly falls in November- December.  The ideal stage is when the tip of the green pods start turning yellow and before split opened of the lower end of pods. In harvesting, only mature pods should be e harvested. To make one kg of pods 60 – 70 well-ripened pods are needed and 6 kg of raw pods are needed to make 1kg of cured pods. Pods must at least be longer than 6cm and better quality pods must be longer than 10cm. To get quality bulk of pods small pods ( Less than 10 cm long) should be removed from the plants 2 months after pollination and allow only 8-10 pods in a bunch and remove all other pods. Pods should be plucked by turning upright and should not be used a pair of scissors or knife to avoid fungus formed in cut end.

 Yield – After 3 years of planting 500 – 800 kg/ha and peak yield level at 7- 8 years Processing

 There are several methods of processing but the basic steps in each and every method are the same. Those steps are

Killing or Wilting – Initiates the onset of enzymatic reactions responsible for the production of aroma and flavor. Pods become brown in color.

Sweating – Increase the temperature to promote the enzymatic reactions and to provoke fairly rapid drying to prevent harmful fermentations, Develop deep brown coloration of pods. Drying – Slow drying. Beans reach to one-third of their original weight Conditioning – Store in closed boxes for a period of three months or longer to permit the full development of desired aroma and flavor

The aroma and flavor of the cured vanilla bean/pod are the characteristics that determine the bean’s commercial value on the world market. Processing should be done carefully to preserve the maximum aroma and flavor as well as the physical appearance. Once the mature vanilla beans have been picked, they are taken to the curing and sorted according to size and condition. Sorted beans are plunged into large vats of hot water (63 degrees Celsius) and quickly drained. The warm beans are wrapped in dark-colored cotton fabric and after a day they are laid on slatted platforms to dry in the open sun for an hour. For about a week, the beans are left for two hours a day to dry in the sun and rolled in cloth between drying session. At this stage, the vanilla beans have become quite supple. For the next two or three months, the vanilla beans are spread on racks in the shade or in well-ventilated rooms to allow their full flavor and fragrance to develop. After the curing process, vanilla beans are sorted in an open airy place and graded according to length before they are bundled for shipment. By this time, their aroma is quite remarkable. 

Standard quality specifications

 Length of pods – between 17-25cm Smell – Inherited vanilla smell

 Color – Dark brown or black color Appearance – Shiny oily surface

 Lack of insect attacks or other patches

 Cleanness – Lack of extraneous matter, animal o plant parts or insects Moisture – around 25%-30%

Medicinal and Chemical Properties

Though there are many compounds presents in the extracts of vanilla, Vanillin (4-hydroxy-3-methoxybenzaldehyde) is primarily responsible for the characteristic flavor and smell of vanilla. However, there are hundreds of minor compounds in vanilla extract. The main compound in vanilla oil is piperonal (heliotropin)