Caution! Contents were hot: Novel biomarkers to detect the heating of fatty acids in residues from pottery use

Abstract

Understanding exposure of pottery vessels to fire is an important question in the agenda of researchers studying how prehistoric pottery was used to prepare food and the reasons leading to its widespread adoption across the world. In the case lipid residues from cooking, making sense of the range of biochemical compounds synthesised by the application of significant amounts of heat (i.e > 100 °C) to lipid residues can reveal different use patterns in the repertoires of the earliest pottery productions. While knowledge about the thermal degradation of fats in archaeological pottery has been available since the mid-nineties, this paper presents and describes two previously unreported biomarkers detected during ongoing research on the earliest Mediterranean farming societies: the ketonic decarboxylation of saturated fatty acids and dicarboxylic acids resulting in very long chain oxo fatty acids, and, the cyclisation of monounsaturated fatty acids yielding ω-(2-alkylcyclopentyl)alkanoic acids. Therefore, combining experimentation with the analysis of several sets of Neolithic pottery, this paper aims at updating the available data on the range of known biomarkers for lipid thermal alteration by characterising said unreported compounds and facilitating their detection in further studies.