Molecular studies of organic residues preserved in ancient vessels

This study is aimed at the molecular characterisation of solid organic (food) residues preserved in an assemblage of vessels recovered from an indigenous settlement dating back to the Iron Age and Roman period at Uitgeest – Groot Dorregeest (The Netherlands). Analytical thermal-fragmentation techniques such as Curie-point pyrolysis Mass Spectrometry and Direct Temperature-resolved Mass Spectrometry gave information about a wide range of compound classes as diverse as lipids, waxes, polynuclear aromatic compounds, oligosaccharides, small peptides and protein fragments, and a variety of thermally stable (more or less condensed) polymeric char structures. Multivariate analysis identified different chemotypes: groups of residues with comparable chemical characteristics. The biomolecular origin of these chemotypes was identified by comparison with experimentally charred reference materials and the application of complementary analytical techniques such as FTIR and 13C CP/MAS NMR. The chemotypes A1 and A2 consist of charred residues identified as starch-rich foods (mixed with either animal or plant products), chemotype C consists of protein-rich charred animal products without starch, chemotype B contains smoke condensates from wood fires, and chemotype D consists of special protein-rich and lipid-free foods or non-food products. Although many molecular characteristics of the original foods have been lost as a result of extensive thermal degradation and interpretation remains limited to general food groups, the results give valuable direct evidence of ancient diet and vessel-use