Application of chromatography and mass spectrometry techniques to characterise lipid residues in vessels from a cooking context in the archaeological site of El Colorado, Catamarca, Argentina

Abstract

The study of lipid residues in archaeological ceramic artefacts provides insight on past culinarypractices and foodways. The application of both gas chromatography-mass spectrometry (GC-MS) andhigh performance liquid chromatography-electrospray ionisation mass spectrometry (HPLC-ESI) allow thecharacterisations of FAME, sterol and acylglyceride profiles and more thorough searches of biomarkers,that together help better determine potential lipid origins in complex mixtures. In this study we carried outGC-MS and HPLC-ESI analyses on lipid residues recovered from a set of four ceramic containers that wereunearthed in situ in an intact domestic cooking context dating from the 14th century AD, in the archaeologicalsite of El Colorado, Catamarca province, Argentina [1, 2]. We studied two Santa María style vessels, oneSanta María style bowl and one ordinary cooking pot. In addition, we studied sediment samples from thehearth and activity area, as well as a sediment sample outside of the cooking area as a means of control.Results from GC-MS analyses from the ceramic containers indicated mixtures of plant and animallipids. Most of the recovered fatty acids were saturated (C12:0 to C26:0), although dicarboxylic acids (C6 toC10) were also found in some samples, which could indicate the degradation of unsaturated fatty acids [2].One sample showed small amounts of oleic acid (C18:1). The presence of ruminant animal lipids ? possiblyfrom llama ? is suspected given the presence of odd carbon linear and branched fatty acids. It is interestingthat the sediment samples from the hearth and the kitchen activity area yielded lipids, although the FAMEprofiles did not match any of the ceramic containers. We propose that these lipids were the product of foodprocessing and/or spills during cooking activities. The sample taken outside of the cooking area did notshow significant presence of lipids. Sterol analysis showed presence of cholesterol in three ceramiccontainers, as well as plant sterols (stigmasterol, sitosterol) in two containers. With HPLC-ESI we identifiedintact mono-, di- and triacylglycerides (MAG, DAG, TAG) in the archaeological samples.The characterisation of the lipid profiles and the identification of biomarkers in these samplesprovided insight on the culinary use of these archaeological utensils in the kitchen context from El Colorado.We plan to compare these results to our acylglycerides and FAME database from plants and animals nativeto the area under study, which is currently under construction.