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A Little Chile Chemistry For
The Visiting Rocket Scientist
Chiles are members of the Capsicum
family. Heat range is diverse, ranging from very mild to extremely
wild. The particular class of substances that determine their
disposition is known, by those who study such things, as
Capsaicinoids. The two most common component of this class are
Capsaicin and Di-Hydrocapsaicin they looks something like this.
Capsaicin
H3CO
\____ O CH3
/ \ | |
HO-< >-C-N-C-(CH2)4-C=C-C-CH3
\____/ | | | | |
H2 H H H H
Di-Hydrocapsaicin
H3CO
\____ O CH3
/ \ | |
HO-< >-C-N-C-(CH2)6-C-CH3
\____/ | |
H2 H
Capsaicin and Di-hydrocapsaicin
together make up 80-90% of the Capsaicinoids found in Chile
peppers. In the Capsicum annum species, the total Capsaicinoid
content ranges from 0.1 to 1.0%, and the Capsaicin to
Dihydrocapsaicin ratio is about 1:1. In Capsicum frutescens the
total content ranges from 0.4-1.0% with the ratio around 2:1.
The minor Capsaicinoids include Nordihydrocapsaicin
[Dihydrocapsaicin with a (CH2)5 instead of (CH2)6], Homocapsaicin
[Capsaicin with a (CH2)5 instead of (CH2)4, and
Homodihydrocapsaicin [Dihydrocapsaicin with a (CH2)7 instead of
(CH2)6].
The different capsaicin-like compounds found in Chiles have slight
structural variations in the hydrocarbon tail, changing their
ability to bind to the nerve receptors and their ability to
penetrate layers of receptors on the tongue, mouth, and throat.
This may explain why some Chiles burn in the mouth, while others
burn deep in the throat.
Capsaicinoids are not soluble in water, but very soluble in fats,
oils and alcohol. This is why drinking water after accepting a dare
to eat an extra hot Habanero Chile won't stop the burning. Downing
a cold beer is the traditional remedy, but the small percentage of
alcohol will not wash away much capsaicin. To get some relief from
a chile burn (can't think of a good reason not to "Enjoy the
heat"), drink milk or eat ice-cream. Milk contains casein, a
lipophilic (fat-loving) substance that surrounds and washes away
the fatty capsaicin molecules in much the same way that soap washes
away grease.
The perception that peppers are "hot" is not an accident. The
capsaicin key opens a door in the cell membrane that allows calcium
ions to flood into the cell. That ultimately triggers a pain signal
that is transmitted to the next cell. When the cells are exposed to
heat, the same events occur. Chile burns and heat burns are similar
at the molecular, cellular, and sensory levels.
Paradoxically, capsaicin's ability to cause pain makes it useful in
alleviating pain. Exposure to capsaicin lowers sensitivity to pain,
and it is applied as a counter irritant in the treatment of
arthritis and other chronically painful conditions.
The capsaicinoids are unique compared to other spicy substances,
such as piperine (black pepper) and gingerol (ginger) in that
capsaicin causes a long-lasting selective desensitization to the
pain and discomfort, as a result of repeated doses. The result is
an increasing ability to tolerate ever hotter foods and permits one
to assume the title of "Chile-Head" or "CH" for
short.
People that eat lots of spicy capsaicin-rich foods build up a
tolerance to it. The incentive: Once a person has become somewhat
desensitized to the extreme heat of the "hotter" Chiles, he or she
can starts on a new culinary journey. Not being over powered by the
heat factor, the palate now has the ability to explore the many
diverse flavors offered by the myriad of different Chiles that are
currently available from around the world. Also for some
Chile-Heads a good jolt of capsaicin excites the nervous system
into producing endorphins, which promote a pleasant sense of
well-being that can last several hours. The endorphin lift or
"high", makes spicy foods mildly addictive and for some, an
obsession.
I offer the below information and pictures for folks that are
really into the science of Chiles.
Date: Mon, 26 Feb 2001
Uncle Steve,
Here are the images as promised. I included structures of some of
the minor capsaicinoids as well.
There are two versions (a and b) of each structure, corresponding
to different conventions of drawing. They're equally correct and
unequivocal, and you're free to choose whichever version you
prefer. The 'a' convention is most commonly used by chemists, but
the 'b' convention might be a bit easier to understand for
non-chemists.
Best regards,
John Henninge
Capsaicin-a
Capsaicin-b
Dihydrocapsaicin-a
Dihydrocapsaicin-b
Homocapsaicin-a
Homocapsaicin-b
Homodihydrocapsaicin-a
Homodihydrocapsaicin-b
Nordihydrocapsaicin-a
Nordihydrocapsaicin-b
Last but not least (Just in case you
want to know all about Capsaicinoids)
Melting point: 65°C
Boiling point: 210°-220°C at 0.01 torr pressure
Sorce: The Merck Index. 12th Edition. Merck & Co., Inc.
Whitehouse Station, NJ. 1996.
Still need more HOT Chile Pepper information?
Check out the "Pepper History"
page.
Who was Wilbur
Scoville?
What is The World's Hottest Chile?
Hot Chile Pepper Medical Uses
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