How humans in middle-late Neolithic China process plant food

Over the span of human history, tools to process plant food have been ever-changing.

Recently, researchers discovered that the combination of grinding slabs and rollers in the middle and lower Yellow River reaches declined gradually after 7,000 years BP. In the meantime, more efficient mortars and pestles were frequently used by prehistoric humans with the rapid development of agriculture and a transitional lifestyle from hunting and gathering to farming.  

In a study published in Archaeometry, Prof. YANG Yuzhang's team from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences made an investigation into the plant food processing tools in the Shuangdun site. The team conducted damage characteristics analysis of excavated artefacts dated back to the middle-late Neolithic period and for the first time provided solid evidence for the rise of mortar and pestle for their high processing efficiency in that period.

Researchers extracted plant starch grains from six stone artefacts, including two grinding slabs, two pestles, one mortar, and one special cake-shaped artefact, which were made of sandstone, diabase and crystal tuff. A widely used micro-remain analysis method was adopted to probe into the similarities and differences between two sets of food processing tools: slabs and rollers, as well as mortars and pestles.

The results indicated that based on their morphology and size, various plants such as Triticeae, Job’s tears, lotus root, and bean were found in both types of grinding tools. However, starch grains of rice (Oryza sativa) only appeared in mortars and pestles, suggesting this set of tools was particularly adopted to process rice in middle-late Neolithic China.

The damage type analysis of a variety of starches showed that mortars and pestles were also used for grinding plant foods in the same way as grinding slabs, while some roughly made slabs might not be used for grinding but only for pounding specific plant food.

All statistics demonstrated that with the rise of mortars and pestles, they were frequently used to hull plant seeds and to process plant foods into small pieces or powder. Grinding slabs and rollers, however, were gradually replaced, and began to decline in human economic life.

This study pioneered the research of mortars and pestles in prehistoric China. It not only deepens the understanding of the processing approaches of grinding tools, but also advances exploration into prehistoric plant food processing tools. Additionally, it provides a full picture of the evolution of food processing tools and reflects abundant details of lifestyles in prehistoric Eastern China.