Beyond rice: Preliminary investigation of encrusted organic residues in a pottery vessel reveals diverse food resources at the Neolithic Hemudu Settlement, China

A type of black foodcrust was found adhering to several pottery fu pots from the early stratum of the Hemudu archaeological site (c. 7000–6500 cal. BP), China. These residues have long been described as cooked rice crusts, but specific analysis has been lacking. To clarify the nature of these crusts and explore potential clues to ancient diets, we conducted botanical and chemical analyses on one sample. Various starch granules and a phytolith particle were recovered, including those from rice (Oryza sp.), Triticeae tribe, oak acorn (Quercus sp.), Papilionoideae beans, and lily bulbs (Lilium sp.). SEM examination confirmed the presence of rice. FTIR and GC–MS tests revealed lipids, proteins, and carbohydrates. Stable isotope analysis indicated C₃ plant dominance with minor animal components. Radiocarbon dating revealed a freshwater reservoir effect, suggesting aquatic ingredients. GC–MS and GC-c-IRMS measurements provided information on rice cooking and multiple terrestrial and aquatic animal sources. These comprehensive analyses prove that the Hemudu fu pot crusts were food-derived but not purely rice. The findings reveal the diversity of food resources utilized by the Hemudu people, reflecting a subsistence strategy that combined low-level food production and foraging in early sedentary settlements. They also provide new evidence for the fu pot's cooking function.