Starch recovery from powdered ceramic matrix

The analysis of organic residues associated with archaeological ceramic vessels has been at the forefront of the study of ancient cuisines, providing key insights into the identification of ingredients and how they were processed. Among these, starch analyses provide a unique opportunity to study the processing and consumption of starch-rich plants, offering a window into past culinary practices. When available, starch granules are analysed from charred food crusts attached to pottery vessels or from the sediment attached to the inner wall of unwashed vessels, while washed vessels are seldom sampled due to the complex (and often unknown) life history of curated artefacts. To address this issue, we designed a series of experiments with replica and archaeological ceramic vessels to assess whether it is possible to recover starch granules from powdered ceramic matrix, a sampling method commonly used when conducting chemical analyses. The results of our pilot study show that starch granules can indeed be recovered from powdered ceramic matrix, showing higher starch recovery rates than surface samples from the previously washed archaeological vessels analysed in this study. Moreover, this sampling method allows for the integrated recovery of samples for chemical and starch analyses in a single procedure, thus reducing the time and cost needed to collect these samples. In parallel, this study has identified gaps in our understanding of starch taphonomy, including the effect of lipids on the preservation and density of starch granules and the representativity of starch assemblages after multiple cooking episodes.