A medium-throughput approach for improved taxonomic identification of lipids preserved in ancient pottery

Organic residue analysis (ORA) is a valuable tool for the study of ancient diets, but conventional methods remain limited in terms of taxonomic identification or to resolve mixtures. Here, we propose a method to further explore a class of compounds—triacylglycerols (TAGs)—using high-resolution mass spectrometry to overcome these limitations in an attempt to better characterise culinary practices. Over 70 medieval Sicilian pots and a wide range of authentic fresh products were studied by matrix-assisted laser desorption/ionisation– mass spectrometry (MALDI-MS and MALDI-MS/ MS). MALDI-MS analysis can distinguish fresh foodstuffs but provides little additional information regarding the contents of archaeological pottery compared to conventional ORA methods. In contrast, product ion analyses were able to deconvolute a range of animal carcass fat mixtures. In addition, detailed analysis of the composition of saturated T44 and unsaturated T50– T54 TAGs was able to provide greater taxonomic resolution regarding dairy products and plant oils.