Vanilla

A choice flavoring obtained from a climbing orchid,
Vanilla fragrans, a native of tropical American
forests. The vanilla plant belongs to the orchid family
and is indigenous to southeastern Mexico, where it
was used by the Aztecs to flavor their cocoa. In 1510
vagnuila first appeared in Spain. Its fruits are pods
called vanilla beans (see illus.). These are picked at
the proper time before they have fully matured.
Vanillin (4-hydroxy-3-methoxybenzaldehyde) is
the principal component of vanilla, although other
components contribute to the distinctive flavor of
the extract compared to synthetic vanilla. When they
are harvested, the beans contain no free vanillin; it
develops during the curing period from glucosides
that break down during the fermentation and sweating
of the beans. The sweating process consists of alternately
drying the beans in sunlight and bunching
them so that they heat and ferment. Sweating boxes
are used in Mexico, whereas the shorter Madagascar
method starts out by wilting green pods in hot
water and uses blankets on which the beans can first
be spread out and later rolled up for the enzymatic

reactions and fermentation to take place. Further curing
and dehydration occur in a warehouse. Periods
of 4 weeks to 4 months may be required to develop
the proper flavor and reduce the moisture content
of the beans sufficiently to prevent molding. Beans
can be artificially dried in ovens, but frequently an
inferior-quality product results. See FERMENTATION;
FOOD ENGINEERING.
After curing, the pods are sorted into grades based
on quality. The best cured beans are 8–10 in. (20–
25 cm) long, with drawn-out ends and curved bases.
They are soapy or waxy to the touch, dark brown,
and coated with fine crystals of vanillin, termed frost.
Vanillin constitutes 1.2–3.5% of the bean, but other
compounds contribute also to the aroma. In addition
to the flavoring materials, vanilla beans contain
fat, wax, sugar, gum, resin, and tannin. Vanilla
is used in cookery, confectionery, and beverages.
Vanilla extract, most used, is prepared by extracting
the crushed beans with alcohol. A synthetic vanillin
is made from eugenol occurring in clove oil, but the
natural product is preferred. Several plants have been
used as substitutes for true vanilla but these are of
little value. See ORCHIDALES; SPICE AND FLAVORING.
Perry D. Strausbaugh; Earl L. Core
The principal types of commercially used vanilla
beans are the Mexican, Bourbon [Bourbon comes
mainly from Madagascar, but was named after the
island of Bourbon (now Island of R´eunion) in the
Indian Ocean, where the French started the cultivation
of vanilla], South American, Javan, and
Tahitian.
Vanilla extract is prepared from vanilla beans with
or without one or more of the following added: sugar,
dextrose, glycerol. Vanilla extract contains the soluble
matters from not less than 3.3 oz of vanilla
beans in 1 qt (10 g/100 ml). To be legally called
vanilla extract, 1 U.S. gal (3.785 liters) of vanilla extract
must contain the soluble matter from not less
than 13.35 oz (378.5 g) of vanilla beans. The finished
flavoring should contain at least 35% alcohol
by volume to keep the solubles in solution.
In the alcoholic extraction of the vanilla flavor, the
color of the extract is influenced by the quality of
the beans, the strength of the alcoholic menstruum,
the duration of the extraction, and the presence of
glycerin, which is added to retard evaporation and
to retain the flavor of the extract. Best results are
obtained with three consecutive extractions at room
temperature, each requiring a minimum of 5 days.
The first should have a maximum alcohol content
of 65%; the second, 35%; the third, 15%. To improve
aroma, extracts are aged, using stainless steel or glass
containers.
A standard vanilla extract is equivalent in flavoring
strength, though not in quality, to a 0.7%
vanillin solution. The vanillin content of pure extracts
range from 0.04 to 0.12 oz/qt (0.11 to
0.35 g/100 ml), with the average at about 0.06 oz/qt
(0.19 g/100 ml). Ash content, soluble ash, lead number,
total acidity, and acidity other than vanillin are
among the conventional indices used to detect adulteration.

 

Denatonium Benzoate

Denatonium benzoate (de-an-TOE-nee-um BEN-zoh-ate) is generally regarded as having the most bitter taste of any compound known to science. It is sold under the trade name of Bitrex. Although denatonium benzoate has a powerful taste, it is colorless and odorless. The taste is so strong, however, that most people cannot tolerate a concentration of more than 30 parts per million of denatonium benzoate. Solutions of denatonium benzoate in alcohol or water are very stable and retain their bitter taste for many years. Exposure to light does not lessen the compound’s bitter taste.

Denatonium benzoate compound was discovered in 1958 by a scientist named W. Barnes, who was working for the chemical firm of T. & H. Smith, in Edinburgh, Scotland. Barnes was interested in developing a new anesthetic, more powerful than those already available to physicians. He
decided to focus his research on lidocaine, a very popular anesthetic, and compounds chemically related to it. In one line of his experiments, Barnes added a single benzoyl group (benzoic acid with a hydrogen removed: C6H5COO) to a nitrogen atom in lidocaine. The resulting compound was
denatonium benzoate. Although the compound had little effectiveness as an anesthetic, Barnes noted that it had a peculiar odor and taste. The Smith company decided to exploit this unusual property of denatonium benzoate, and obtained a patent for it under the name of Bitrex. Today, the primary manufacturer of Britex in the world is the Macfarlan Smith corporation of Edinburgh.

The process by which denatonium benzoate is made is a proprietary secret of the Macfarlan Smith corporation. A proprietary secret is a method of making a product for which a company holds a patent and the details of which it does not disclose to the general public.

One of the first and most important uses of denatonium benzoate was as an additive to methanol (methyl alcohol; wood alcohol). Although ethanol (ethyl alcohol; grain alcohol) has some harmful effects on humans, especially if taken in excess, it is relatively safe to drink in beer, wine, and other alcoholic drinks. By contrast, methanol is highly toxic. Anyone who accidentally or intentionally consumes methanol is likely to experience serious health effects, including death. By adding a small amount of denatonium benzoate to methanol, consumers are discouraged—and usually prevented—from drinking the substance.

Denatonium benzoate has many other applications. For example, it can be used in a dilute solution to brush on the fingernails of people who are compulsive fingernail-biters. Some parents use a similar solution on the thumbs of children who suck their thumbs more than they should. Denatonium benzoate is also used as an animal repellent. Products containing denatonium benzoate can be sprayed on trees, brushes, crops, and other material to prevent deer from grazing on those products. One of the product’s first applications was as a treatment on pig’s tails to prevent pigs from biting each other. The coatings on electric cables are sometimes
impregnated with a denatonium benzoate solution to discourage rats from chewing on them.

Some of the other applications in which denatonium benzoate has been used include the following:

• In liquid laundry detergents;
• In fabric conditioners;
• In toilet cleaners;
• In disinfectants;
• In household antiseptics;
• In kitchen, bathroom, and floor cleaners;
• In paint products and paint brush cleaners;
• In personal care products, including bath foam, soaps, perfume and after shave lotions, nail polish remover,
shampoo, and shower gel;
• In pesticides, such as insecticides, rodenticides, slug
bait, and ant bait;
• In herbicides; and
• In a wide variety of automotive care products, such as
antifreezes, coolants, and car cleaning materials.

In all of these cases, the purpose of adding denatonium benzoate is to change the taste of the product just enough to prevent someone, especially children, from eating a substance that could cause them harm.

Despite its bitter taste, denatonium benzoate appears to pose little or no hazard to human health. Exposure to the pure compound may cause respiratory discomfort, but only people working with the substance directly are likely to encounter this problem.