Starch grain analysis of two different types of grinding stones from the Neolithic Shuangdun site (ca. 7.3–6.8 ka BP) in eastern China

Abstract

AbstractTwo different types of grinding stones, grinding slabs and rollers, as well as mortars and pestles from the Shuangdun site (ca. 7.3–6.8 ka BP) in the middle Huai River region, were subjected to starch grain analysis to investigate the evolution of plant food processing tools during the transition period from a gathering–fishing–hunting economy to farming. The results suggest that both types of grinding stones were used to process various plant species, including Triticeae, Job's tears (Coix lacryma‐jobi), lotus root (Nelumbo nucifera), and bean (Vigna spp.). However, starch grains of rice (Oryza sativa) were only discovered from mortar and pestle tools, indicating that mortars and pestles might have become a fixed combination tool for rice processing. Damage characteristics analysis for different kinds of starches indicated that mortars and pestles were also used for grinding plant foods besides dehusking rice, whereas some roughly made slabs no longer had a grinding function and were used only for pounding some specific plant foods. The functional degeneration of grinding slabs coincides with the rise of farming in Neolithic China around 7,000 BP. This study provides new evidence for understanding the evolution of prehistoric human plant food processing tools in Neolithic Eastern China.