How Hot Chile Peppers are Built: What 'Spicy' Looks Like

First Posted: Feb 03, 2016 09:14 PM EST

Some peppers can be sweet, while others are super hot. Now, though, researchers have found that super-hot chile peppers are actually built differently than other peppers.

"What we were interested in finding was why super-hot chile peppers are able to get that hot," said Paul Bosland, one of the researchers, in a news release.

How "hot" a chile pepper is can be measured in Scoville Heat Units. For example, a jalapeño has a heat rating of 2,500 to 8,000 Scoville units, whereas Scotch bonnets have a heat rating of 100,000 to 350,000 Scoville units.

A chile pepper's heat comes from the chemical compound capsaicin; capsaicinoids are found in yellow-colored sacs called vesicles. In most chile peppers, the capsaicinoid vesicles are attached to the pepper's placenta, where the seeds are located.

With super-hot peppers, though, the sacs can also be found on the walls of the pepper, and in larger quantities; this gives the pepper far more surface area to pack in capsaicinoid vesicles and to turn up the heat.

In this latest study, the researchers used an electron microscope to examine the capsaicinoid sacs in jalapeño peppers and Trinidad Moruga Scorpion peppers.

"There, you could see that the jalapeño was only fluorescing on the placenta, while the super-hots would fluoresce all over the wall," said Bosland. "It's a very dramatic image to see. Right now, we're assuming this is a genetic mutation in super-hots because we've never seen this in wild chile peppers."

This new information could potentially help breeders select new chile pepper varieties that could potentially lead to chile peppers with double the heat of today's hottest peppers.

"We'll probably see someone get a three million or four million Scoville Heat Unit fruit down the road," said Bosland. "This could be particularly helpful for the extraction industry, companies that extract those heat compounds for use in medicine."

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TagsPepper, Capsaicin, Hot, Food, Chemical