Vanilla is one of the most popular flavorings in the world. Its extract is used in food, beverages, pharmaceutical, and perfumes. Vanilla flavoring is obtained from the beans of the vanilla orchid (Vanilla planifolia). Vanilla is particularly popular in beverages, desserts, ice cream, dairy products, pastries, confectionery, and chocolates. In culinary applications, it can be added by adding vanilla extract or vanilla beans to a liquid preparation. Depending on the concentration, natural vanilla gives preparations a yellow or brown color.
Vanilla fruit matures in about 6 months and grows quickly on the vine. Because vanilla fruits ripen at varying rates, daily harvesting is required to ensure that each fruit has the best flavor. Individual pods are hand-picked as the end begins to split. Overripe fruits are more likely to split, lowering their market value.
The length and appearance of the pod determine the commercial value of vanilla beans. If the fruit is longer than 15 cm (5.9 in), it is of high quality. The largest fruits (those measuring 16-21 cm in length) are reserved for the gourmet vanilla market. Fruits between 10 and 15 cm long, pods, and fruits less than 10 cm long are classified as second-quality, and fruits less than 10 cm long are classified as third-quality. Good quality vanilla has a strong aromatic flavor. But foods containing small amounts of low-quality vanilla or artificial vanilla-like flavorings are far more common.
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Until the 19th century, the bulk of vanilla flavor was obtained naturally from vanilla plant. A major change in the vanilla industry occurred in 1874 when German chemists developed a synthetic alternative to natural flavor. Today, it is estimated that 97% vanilla-flavored foods are produced with synthetic vanillin.
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Table of Contents
ORIGIN AND HISTORY OF VANILLA FLAVORING
The origin of vanilla can be traced back to 1,000 years ago when the Totonac people of Mexico’s eastern coast first cultivated vanilla for its fragrance. But the first recorded use of vanilla as a flavoring agent was during the 15th century CE when the Aztecs conquered the Totonac and used vanilla to flavor their drinks made from ground corn, honey, and powdered cocoa beans.
Then in 1519, the Aztec king served vanilla-flavored cacao drink to the Spanish conquistador Hernan Cortés, who returned to Spain with cacao beans and vanilla pods.
Early to mid-1800s saw the spread of vanilla cultivars due to the plant’s high culinary value, including to Réunion (previously known as Bourbon)., a West Indian island where the vine would grow, but the pod would not develop. Mexico continued to hold a monopoly because only native orchid bees could pollinate the pods and cause them to develop. That is, until 1837 when Charles Morren, a Belgian botanist, solved the riddle and realized the importance of the Melipona bee for pollination.
After his discovery, he devised a method of artificial pollination, but unfortunately this was not feasible commercially. 5 years later, Edmond Albius, a 12-years old slave in the West Indies, discovered and developed a method of hand pollinating the vanilla flower. Even now, this technique is employed, which has allowed vanilla to be grown in various tropical regions of the world. Albius won his freedom for the invention of this process.
Today, the biggest producers of vanilla in the world are Madagascar, Indonesia, and Mexico. In 2021, Madagascar produced 3070 tons, Indonesia produced 1456 tons, and Mexico produced 609 tons of vanilla. Bourbon or Madagascar vanilla is produced on the West Indian island of Réunion
VANILLA CHEMISTRY
Among spices, vanilla is special because it requires a lot more processing to create the culinary form. Fresh vanilla beans have very little to no flavor. The main component of aroma and flavor of vanillla is vanillin (4-hydroxy-3-methoxybenzaldehyde).
Vanillin is only found in the conjugated form as glucovanillin in the green pods of orchids. Vanilla’s distinctive aroma develops after fermentation. Usually between 2.5% and 3.0% of fermented pods contain vanillin. Along with vanillin, low-quality vanilla species also contain the aromatic aldehyde piperonal.
There are over 250 other compounds that contribute to the flavor of vanilla. These compounds produce floral, spicy, woody, and fruity aromas. Though lesser, they differentiate vanilla pods from the synthetic vanillin flavoring. Aromatic carbonyls, aromatic acids, aromatic esters, aromatic alcohols, phenols and phenol ethers, aliphatic alcohols, acids, carbonyls, lactones and esters, are among the other aroma compounds found in vanilla.
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The global demand and cost for vanillin far outnumber the vanilla plant’s capacity to produce the flavor. This is the reason why synthetic vanillin accounts for the majority of the vanilla flavoring market. Furthermore, it is produced at one hundredth the cost of natural vanillin. After saffron, vanilla is the most expensive spice.
HOW IT IS MADE
The primary aroma/flavor constituent, vanillin, is bound as a glycoside and is enzymatically hydrolyzed to release vanillin. The vegetative cells of the vanilla bean must be disrupted in order to begin the enzymatic hydrolysis of the vanillin glycosides. Killing disrupts the cells and tissue of the fruits, mimicking the enzymatic reactions that sets free the aromatic compounds. There are 4 ways to accomplish this:
- Immersing the beans in hot water
- Freezing
- Scratching
- Exposing the beans to direct sunlight
The various methods produce different profiles of enzymatic activity, allowing glycosidase enzymes to act on glucovanillin and release free vanillin.
Hot-water killing is achieved by immersing the vanilla beans in hot water for 3 minutes at 145°F (63°C) to 149°F (65°C) for 3 minutes or 176°F (80°C) for 10 seconds. To mimic the enzymatic reaction, the Aztecs exposed the fruits to sunlight until they turned dark brown. Fruits can also be wrapped in blankets and tied into bundles before heating them in an oven at 140°F (60°C) for 36 to 48 hours. Fruits can be frozen and thawed to initiate enzyme and substrate release, but they must be thawed for the sweating stage.
Sweating, drying, and conditioning
Sweating is the process of holding the fruits for 7-10 days at temperatures between 113°F (45°C) to 149°F (65°C) with high humidity. The fruits are brown at the end of the sweating process and have developed the distinctive vanilla flavor and aroma, and a moisture content of 60-70% by weight.
Drying is the most difficult stage to manage because uneven drying can result in vanillin loss. The drying process lowers the beans’ moisture content to between 25% and 30%. This is sufficient to keep them from rotting and maintain the aroma compounds in the pods. The beans are typically dried by being exposed to brief periods of shade and sunlight.
After drying, the pods are conditioned by storing them in closed boxes for 5 to 6 months. This phase sees the development of the scent.
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Some of the glycoside components of the seed and plant cell walls are transformed into vanillin as the bean pods age and brown. An average of 2.5% vanillin can be found in the dried vanilla fruits.
NATURAL VS. SYNTHETIC VANILLA
Natural vanilla extract is a complex mixture that contains vanillin extracted from alcohol soaked vanilla beans or processed beans that have been washed with alcohol multiple times. The aroma and flavor of pure natural vanilla extract are best described as sweet, fruity, and spicy.
Natural vanilla flavoring plant is too costly for industrial use. For this reason, the majority of vanilla flavoring is a synthetic vanillin product with added sugar and other compounds. This is still pure vanilla; it is just not produced naturally by the plant. Vanillin can be synthesized in a variety of ways. The ‘classical’ synthesis of vanillin from isoeugenol or oreugenol was developed in 1896. This was the preferred method for 50 years. Today, Vanillin is now produced in large quantities industrially via the Reimer-Tiemann reaction, which begins with guaiacol and ends with o-vanillin.
The thing is vanilla is a very volatile compound, regardless of whether the vanilla is artificial or pure vanilla extract. To avoid evaporation and loss, it is best added later in the cooking process.
Working with vanilla pod, rather than flavoring or extract, is ideal for obtaining the most complex and interesting vanilla flavor. This is because the majority of the vanilla flavor is found in the sticky material in the pod as well as the small black bean seeds.
To achieve this, scrape out the sticky black material and seeds, and include the scraped seeds and bean in the recipe. This is even better if the dish consists of cream or milk as an ingredient. The compounds that give vanilla its flavor and scent are more soluble in fat and oil than in water. And the fats in milk dissolve the vanilla flavor molecules. This leads to leading to concoctions like vanilla bean ice cream or vanilla milk.
References:
J. Valisek (2014). The Chemistry of Food. John Wiley & Sons, Ltd.
M. Wallert, K. Colabroy, B. Kelly, J. Provost (2016). The Science of Cooking: Understanding The Biology And Chemistry Behind Food And Cooking. John Wiley & Sons, Inc..
S. Farrimond (2018). The Science of Spice. Dorling Kindersley Limited.
J. deMan, J. Finley, W. Jeffrey Hurst, C. Y. Lee (2018). Principles of Food Chemistry (4th edition). Springer.
