Just How Hot Is That Red Hot Chili Pepper?

Capsaicinoids are the family of chemicals that give a pepper its spiciness. Capsaicin and dihydrocapsaicin are two members of the group that make up to 90 percent of the total capsaicinoid content found in the pepper. The exact amount of capsaicinoid content varies from pepper to pepper, giving each individual pepper a different degree of spiciness.

“Capsaicinoids are the active ingredient in pepper spray, tear gas and some arthritis medications, not to mention spices and foods like salsa, so a wide range of industries could find this new approach useful,” said Dr. Kenneth Busch, professor of chemistry and co-director of the Center for Analytical Spectroscopy at Baylor and a lead investigator on the project.

The current industry standard to test the heat of a pepper is through a process called high-performance liquid chromatography, but the process can be expensive and time consuming because scientists must first chemically separate the capsaicinoids in the extract from other interfering molecules that also are present.

Rather than try to chemically separate the capsaicinoids, Baylor researchers used a mathematical approach based on multivariate regression modeling. The new approach takes known capsaicinoid content numbers from a series of pepper extracts and plugs them into a computer program. Those base numbers “train” the computer to focus on the subtle features present in the spectrum that correlate with the capsaicinoid concentration, allowing the computer to recognize the hotness components in the extract even in the presence of the other interfering molecules. Once the computer has been “trained” to recognize those components, it can then be used to determine the heat of other unknown peppers.

While methods for testing the heat of a pepper have dramatically improved over the years, Baylor researchers believe their cheminformatics approach is less expensive and quicker than other modern techniques, potentially saving time for the busy food preparation industry.

“Like all fundamental research, application will come over time,” Busch said.