Proteomic analysis of archaeological ceramics from Tell Khaiber, southern Iraq

Archaeological ceramics are a rich source of ancient biomolecules and their analysis provides valuable information with regard to ancient diet. Traditionally, biomolecular analyses on archaeological ceramics have focused on lipid analysis, with milk, ruminant and non-ruminant adipose fats, plant resins, as well as both marine fish and marine mammals among the resources successfully identified. However, lipidomic analyses can underestimate the presence of lipid-poor resources (e.g. cereals and grains) and are usually less specific at tissue and taxonomic levels. Proteomic analysis can be complementary, allowing for the identification of a greater variety of resources and with increased specificity. Here, we analyse eight ceramic sherds from Tell Khaiber, a Sealand Dynasty (mid-2nd millennium BCE) settlement in modern day southern Iraq, using LC-MS/MS based shotgun proteomics. Our results provide the first proteomic evidence of soybeans from archaeological ceramics and confirmation of the early appearance of soybean products in the Middle East by the mid-second millennium BCE.