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Archeobiology Reveals Chili Peppers Older than Originally Thought

There has never been a complete reconstruction of the origin, domestication, and dispersal of the chili pepper, the fruit of the genus Capsicum (Solanaceae).1 Remains of this fruit have been difficult if not impossible to find at archeological digs because they were eaten whole, which means there were no seeds or husks left behind.2 This lack of evidence has kept the history of chili peppers shrouded in mystery.

This mystery started to unravel when a variant group of 15 scientists recently published the paper, “Starch Fossils and Domestication and Dispersal of Chili Peppers (Capsicum spp., Solanaceae) in the Americas.”1 This paper has led to two groundbreaking discoveries: (1) chili peppers contain starch, and (2) starch microfossils can be extracted from food residues left on ancient food implements, allowing archeobiologists to date and identify its plant source. A combination of archaeology and biology, archeobiology involves the interpretation of ancient human interaction with plants and animals. Foods that contain starches, like yams (Dioscorea spp., Dioscoreaceae), potatoes (Solanum tuberosum, Solanaceae), and cassava (Manihot esculenta, Euphorbiaceae), can now be traced through the analysis of microscopic starch grains.

In 1982 Scott Raymond, PhD, coauthor of the recent paper and archeologist at the University of Calgary, unearthed some pottery in Loma Alto, Ecuador, with some carbonized food particle residues. Knowing the technology he needed to date them was not yet available, he and his colleagues pragmatically and wisely “wrapped [the pottery shards] in foil in the hope that someday it would be possible to analyze the residues,” said Dr. Raymond (e-mail, May 29, 2007).

Fortunately, Sonia Zarrillo, a doctoral student under Dr. Raymond’s supervision from the University of Calgary, developed a technique to isolate starch grains from carbonized residue. These residues are usually found on pottery and cooking implements used to grind up food. “Previously no one thought that starch could be recovered from cooking residues, believing that they would be gelatinized or completely destroyed,” said Dr. Raymond. “Sonia was able to recover many starch granules from the residues.” However, there was one starch Zarrillo was unable to identify, and it kept turning up. The origin of this starch was a mystery.

Later in 2005 Zarrillo organized a symposium on starch and phytolith at the 28th Annual Chacmool Conference: “Archaeology into the New Millennium” in Calgary, Alberta, Canada, a conference hosted by the Chacmool Archaeology Association and the University of Calgary’s department of archaeology. In attendance were Linda Perry, PhD, Ruth Dickau, PhD, and Deborah Pears-all, PhD, who found they had more in common than they could have hoped: they were all chasing the same mystery starch. “They gathered together in Sonia’s lab after the symposium to look at images of starch granules and found that there was one they had all discovered in their research but were unable to identify,” said Dr. Raymond.

It later occurred to Dr. Perry that chili peppers can cause gas and diarrhea in people, which is something that is often attributed to undigested starches.3 Then on a hunch, she attempted to solve two mysteries with one microscope. She examined a typical pepper and found starch granules—the elusive mystery starch. Next, she discovered that “all five species of domesticated chili peppers produce large, flattened lenticular starch grains with a shallow central depression, not unlike a red blood cell in appearance.”1

Teamed with this new knowledge of the pepper and this new technique to extract starch from food particles, the scientists found the now-identified starch on cooking implements at 7 archeological sites ranging from the Bahamas to southern Peru. It is now known that chili peppers were present in the following places and dates:

  • In Peru dating back to 4000 YBP (years before present),

  • In Zapotal and Aguadulce, Panama, possibly dating back 5600 YBP,

  • In Venezuela dating back to 1000

  • In the Bahamas tracing back to 1000 YPB, and

  • In Loma Alta and Real Alto, southwestern Ecuador, a place not thought to be a center of chili domestication, as far back as 6100 YBP.1

Through a combination of plant biogeography, archeological data, genetic data, and ethnographic data, researchers have determined that C. annuum was initially domesticated in Mexico or northern Central America, C. frutescens in the Caribbean, C. baccatum in Bolivia, C. chinense (despite its name) in northern Amazonia, and C. pubescens in the southern Andes. The new starch discovery raises the question of how these chili peppers were able to travel to Ecuador.

“Up until this point, the earliest evidence for domesticated peppers was 6000 YBP in Mexico where Capsicum annuum was domesticated. Because no chili peppers were domesticated in Ecuador, we know they must have been domesticated elsewhere at an earlier date, and then moved into the area through migration or trade,” said Dr. Perry (e-mail, April 30, 2007). These previously unknown dates and locations suggest cultural contact of groups that were thought to have never connected, as well as a wide geographical spread. “This pushes back the date for the earliest chili peppers by a considerable period,” said Dr. Pearsall, fellow coauthor (e-mail, April 30, 2007). “The domesticated chilies were carried or traded possibly from the Amazon region.”

These illuminations place chili as one of the oldest domesticated food sources in the world. It also suggests that the traditional chili cook-out was happening among distant neighbors long before the invention of the suburb.

  1. Perry L, Dickau R, Zarrillo et al. Starch fossils and the domestication and dispersal of chili peppers (Capsicum spp. L.) in the Americas. Science Magazine. February 16, 2007;(315)986.

  2. University of Missouri-Columbia. Researchers find 6,000-year-old fossil evidence of one of the oldest food sources in the Americas. College of Arts and Science News page. Available at pearsall-chiles.html. Accessed October 31, 2007.

  3. Brown D. One hot archaeological find: chili peppers spiced up life 6,100 years ago. Washington Post. February 16, 2007;A01.