"Before our research, there wasn't much archaeological evidence to show that prehistoric people in Central and South America were eating domesticated chili peppers," said Deborah Pearsall, professor of anthropology in MU's College of Arts and Science. "Chili peppers don't preserve well because when you cook with them, you eat most of them; you don't have husks or shells that are thrown away and preserved. That's why we used a technique that involved analyzing microscopic starch grains on cooking and grinding tools to find this new evidence."
Pearsall, who studied tools from sites in Ecuador and the Bahamas, teamed with a group of scientists doing research in various locations in Central and South America; the project was led by Linda Perry, a research associate at the Smithsonian National Museum of Nature History's Archaeobiology Program. Perry discovered an unknown microfossil starch grain while doing research in Venezuela, and when the other researchers compared notes, they realized that their work in the Bahamas, Panama, Ecuador and Peru also revealed the same unknown starch grain. After studying the starches of many domesticated and wild plants, Perry determined that the mystery starch was a chili pepper.
"We knew from historic and ethnographic records that people were eating domesticated chili peppers, but this archaeological evidence confirms those findings. It also shows us that chili peppers are one of the oldest domesticated food sources in the Americas and that people in distant areas all ate them. Th is suggests that these groups might have had some type of contact with each other," Pearsall said.
Loma Alta and Real Alto, the sites in southwestern Ecuador studied by Pearsall, turned up the oldest starch of domesticated chili peppers, at approximately 6,000 years old. Starch of the peppers in other sites ranged from approximately 5,600 years to 500 years old. Under a microscope, the starch grains appeared as large, flattened disks with shallow central depressions, different from the appearance of starch grains from other foods.
This discovery enables researchers to gain a better picture of ancient diets. By analyzing the grains on cooking tools, they were able to determine that people used the same grinding stones to grind corn, chili peppers and a root crop called manioc, and they probably combined these ingredients to make soups, stews and other dishes. Pearsall found evidence of this diet on grinding stones from four ancient households at Real Alto, leading her to conclude that these foods were eaten by everyone, not just the commoners or the elites.