Characterization of pottery foodcrusts through lipid and proteomic analyses: A case study from the Xiawan site in Yixing city, East China

Foodcrusts are often discovered inside archaeological pottery and other containers, and they can provide abundant information about vessel function, diet, cuisine activities and human subsistence strategies. Lipid analysis has been used for decades to characterize foodcrusts, indicating their composition and biological sources. Recently, proteomics has also been applied to foodcrusts, providing more specific information about the tissues and species origins. In this study, lipid and proteomic analyses were combined to analyze foodcrusts in pottery from the Xiawan site of the Taihu Lake region, East China. These pottery sherds are mainly attributed to the Songze cultural period (ca. 5800–5300 BP). The results show that these foodcrusts contain interpretable concentrations of lipid compounds, including a series of common medium- and long-chain fatty acids, dicarboxylic acids, aliphatic alcohols, sterols and their derivatives, isoprenoid fatty acids and long-chain ketones, as well as proteins of terrestrial mammals and aquatic products. This study provides direct evidence for the function of pottery and the exploitation of animal and plant resources at that time, especially freshwater products, marine fish, rice and millet. Therefore, the combination of lipid and proteomic analyses has great potential in organic residue analysis for foodcrusts.