One of the steps in human development that has long been recognized as critical is the invention of cooking. Led by the University of Bristol, an international team of archeologists has uncovered the earliest direct evidence of humans cooking plants for food found anywhere in the world.
A team at the Organic Geochemistry Unit in the University of Bristol’s School of Chemistry worked with colleagues from the Universities of Milan and Modena, and Sapienza, University of Rome. Unglazed pottery from two sites in the Libyan Sahara, dating from more than 10,000 years ago, was studied. Ancient cooking would originally have involved the use of fires or pits. The subsequent invention of ceramic cooking vessels led to an increase in food preparation methods.
Cooking would have increased the availability of new energy sources as it allowed the consumption of foodstuffs that were unpalatable or even toxic beforehand. Until now, there has been no evidence of plants being cooked in early prehistoric cooking vessels.
Lipid residues of foodstuffs preserved within the fabric of unglazed cooking pots was detected by the researchers. Based on the identification of plant oil and wax compounds, the team found that more than half of the vessels studied had been used for processing plants.
Researchers performed detailed studies of stable isotope and molecular compositions. This showed that a wide range of plants were processed including the leafy parts of terrestrial plants, grains and, surprisingly, aquatic plants.
Due to the arid desert environment at the sites, plentiful plant remains were preserved in remarkable condition. These remains support the interpretations of the chemical signatures obtained from the pottery. The importance of plants to the ancient people of the prehistoric Sahara was highlighted by the fact that the plant chemical signatures from the pottery show that the processing of plants was practiced for more than 4,000 years.
The lead author of the paper, Dr Julie Dunne, is a post-doctoral research associate at Bristol’s School of Chemistry. She noted that the importance of plants in prehistoric diets has not really been recognized until now. This work however, clearly shows the importance of plants as a dependable dietary resource.
Dunne added that these findings emphasize the sophistication of early hunter-gatherers in their utilization of a wide range of plant types. Their ability to boil them for long periods in ceramic vessels would have significantly improved the range of plants prehistoric people could eat.
Professor Richard Evershed, also from Bristol’s School of Chemistry, is the co-author of the paper. Evershed noted that the finding of extensive oil residues and plant wax in early prehistoric pottery shows that early pottery was used very differently in the Sahara compared to other regions in the ancient world. The new evidence fits in with theories proposing different patterns of animal and plant domestication in Europe/Eurasia and Africa.
The full study was published in the journal Nature Plants.