Chocolate: study traces the complex origins of cocoa – 03/07/2024 – Science

Scientists are getting an extra taste of the early history of the domestication and use of cocoa — the raw material for chocolate — thanks to residues detected in a batch of ancient ceramics from South and Central America.

Using evidence from these artifacts, researchers have traced the rapid spread of cacao through trade routes after its initial domestication more than five millennia ago in Ecuador. They showed the dispersal of cocoa to the Pacific Northwest coast of South America and then to Central America until it reached Mexico 1,500 years later.

An evergreen tropical tree called Theobroma cocoa it produces large, oval pods that contain cocoa beans, similar to beans — which today are roasted and transformed into cocoa and a multitude of chocolate confections. In ancient times, cocoa was consumed as a drink or as an ingredient in other foods.

Researchers tested more than 300 pre-Columbian ceramics, spanning a period of nearly 6,000 years, for traces of cocoa DNA and three chemical compounds associated with it, including caffeine. They found evidence of cocoa in about 30% of them. The find indicates that cocoa products were used more widely among these ancient cultures than previously known.

The ceramics themselves offer an artistic glimpse into the cultures, some with wonderful anthropomorphic designs.

A study published in 2018 had revealed that the domestication and use of cacao began about 5,300 years ago in Ecuador, based on ceramic evidence at the Santa Ana-La Florida archaeological site.

The new study builds on this point by tracking the spread of cocoa in 19 pre-Columbian cultures. Some of the first uses were detected in ceramics from the Valdivia culture, in Ecuador, and the Puerto Hormiga culture, in Colombia.

Ancient DNA found in the ceramics also indicated that several cultures interbred cacao trees to adapt to new environments.

“The first stages of cocoa domestication correspond to a more complex process than we had previously assumed,” said molecular geneticist Claire Lanaud, from the AGAP unit at CIRAD, the French agricultural research center for international development, and lead author of the study. published this Thursday (7) in the journal Scientific Reports.

“We had no knowledge of such an important domestication of cacao trees along the entire Pacific coast of South America in pre-Columbian times, and so early. The significant genetic mixing observed attests to the countless interactions that may have occurred between the peoples of Amazon and the Pacific coast”, added Lanaud.

The dispersion of cocoa from Ecuador to Mesoamerica may have occurred through vast and interconnected political-economic networks, the researchers assess.

“Firstly, we can state with conviction that the origin of cocoa and its domestication was the upper Amazon and not the tropics of Mesoamerica —Mexico and Central America. The dispersal process was quite rapid and involved close and long-distance interaction of Amerindian peoples,” said archaeologist and study co-author Francisco Valdez, from the PALOC unit of France’s IRD research institution and the National Museum of Natural History in Paris.

“Maritime contacts must have been involved, as well as land contacts. Previously, the common belief was that cacao was domesticated in the Mesoamerican plains and that it dispersed from there to the south,” Valdez said.

The study provides information on the first transactions of what today ranks as one of the most important commercial crops in the world.

Today’s sugary chocolate confections differ greatly from the earliest uses of cocoa. Before Europeans arrived in the Americas five centuries ago, cultures such as the Aztecs and Mayans prepared cocoa as a drink, mixed with various spices and other ingredients.

“Cocoa, as a plant, is a food source of energy and also a medicinal product,” said Valdez.

“The Amerindian people used it in various ways. Raw, the pulp was sucked. [semente de cacau] it could be cooked, roasted, ground and transformed into liquid and solid foods. The bark, branches and cob can be burned, and the ashes are an antiseptic. And it is also used to relieve inflammation and wounds in the skin or muscles.”