Testing Chili Peppers

Chemists Heat Things Up with New Model to Determine Heat of a Pepper

January 1, 2010

Chemists developed a mathematical model to quickly and easily test the level of 'heat' in a chili pepper. To determine how hot a pepper is, scientists traditionally measure capsaicinoids- chemicals that make a pepper hot via a method that is time consuming and expensive. The new method uses a multivariate regression analysis of known capsaicinoid content data from several pepper samples. A computer program uses this data to hone in on the aspects of the heat spectrum that correlate with the capsaicinoid concentrations in the pepper. The computer can then recognize various components of heat in an extract and use the information to compare unknown peppers to what it already knows.

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HOT STUFF: Capsaicinoids are the compounds that give chile peppers their spicy taste. They bond with pain receptors in the mouth and throat, producing a burning sensation in the tissue. Then the receptors send a message to the brain, which triggers increases in heart rate and perspiration, as well as the release of endorphins (which are also released in other situations that play with the sensations of pleasure and pain, such as the runner's high). The units used to describe the heat of a pepper are called Scoville heat units (SHU). Bell peppers rank 0 SHU, jalapenos 3,000-6,000, habaneros 300,000, and the naga jolokia (a pepper from India) ranks the highest, with over 1,000,000 SHU.

WHAT IS SPECTROSCOPY? Spectroscopy is a technique used by astronomers and physicists to study the make-up of an object based on the light it emits. Anything that produces light or radiates energy, whether a light bulb or a star, is telling us about itself and anything between us and the source. This is possible because each chemical element has a unique signature, emitting or absorbing radiation at specific wavelengths. For example, sodium, used in street lights, emits primarily orange light. Oxygen, used in neon lights, emits green light. By passing the light from a star or other object through a special instrument, called a spectrograph, the light is "spread" into a spectrum in much the same way visible light is spread into its colors by a prism. By carefully studying how the spectrum becomes brighter or darker at each wavelength, scientists can tell what chemical elements are present.

The American Mathematical Society and the Mathematical Association of America contributed to the information contained in the TV portion of this report.This report has also been produced thanks to a generous grant from the Camille and Henry Dreyfus Foundation, Inc.

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Dr. Kenneth W. Busch
Baylor University
Waco, Texas 76798
Kenneth_Busch@baylor.edu
254-710-3311

Mike Breen and Annette Emerson
American Mathematical Society
Providence, RI 02904-2294
paoffice@ams.org
1-800-321-4267

Ivars Peterson
Mathematical Association of America
Washington, DC 20036-1358
ipeterson@maa.org
1-800-741-9415