Water! Water! Chili peppers can blister your tongue and make your eyes gush with tears, but some people can't get enough of them. And chefs from Mexico to Thailand know that just a dash of chili can turn a bland dish into a piquant pleasure. Now scientists have found that this fiery plant has been a culinary staple for at least 6000 years.
Based on previous archaeological and genetic research, researchers believe that the five most common species of chili peppers were domesticated in Central and South America several thousand years ago. They then spread around the world after the European conquest of the Americas. But unlike other domesticated plants such as maize and wheat, chilis leave very few visible traces at archaeological sites, making it very difficult to determine exactly when and where they were first cultivated.
An international team led by archaeobiologist Linda Perry of the Smithsonian National Museum of Natural History in Washington, D.C., employed a relatively new technique called starch analysis to look for chili remains at archaeological sites in the Americas. The researchers found that all five chili pepper species produce microscopic starch grains that look something like red blood cells. These grains were present in milling stones, pottery shards, and sediments from seven archaeological sites in Venezuela, Peru, Panama, Ecuador, and the Bahamas, the team reports today in Science. The oldest sites containing the grains were two prehistoric villages in Ecuador occupied 6100 years ago. That means chilis were routinely used as a condiment in prehistoric cuisine during the early days of farming in the Americas, the team concludes.
"Ancient Americans clearly knew a good thing when they tasted it," says archaeobotanist Andrew Fairbairn of the University of Queensland in Brisbane, Australia. "The spread of domestic plants was driven as much by taste and culinary value as the search for calories," he argues. And Eve Emshwiller, an ethnobotanist at the University of Wisconsin, Madison, says that the identification of chili peppers in Ecuador 6000 years ago suggests that they were domesticated even earlier elsewhere in the Americas, because other evidence--including genetic studies--points to areas further north, such as Mexico, as the sites of the plant's first cultivation.