Noble Chemists and Archaeologists: Chemical Analyses of Food Residues from Ancient Maya Vessels

Abstract

<p>This study of ancient Maya foodways was undertaken in order to better understand changes in economic and social structures that took place in Maya society between Preclassic (1200 B.C. - A.D. 250 - 900) periods. Two chemical methods were used to identify archaeological food residues that have been preserved in ceramic vessels excavated from several ancient Maya settlements. A second objective of the project was to evaluate the utility of each method of residue analysis for the investigation of ancient Maya foodways in particular, and for the study of ancient foodways and related archaeological questions, generally. Stable carbon and nitrogen analysis was used to analyse 23 carbonised food residues preserved on the interior surfaces of Middle Preclassic cooking vessels from the site of Cuello Belize. Isotopically light δ13C values in all but two vessels indicate that most of the vessels were not used to prepare maize. Elevated δ15N values in all residues (n=13) with measurable amounts of nitrogen clearly indicate that freshwater fish were prepared in these vessels. Depleted δ13C values, and the thickness and location of the chars on these same vessels suggest that a starchy C3 plant was cooked along with the fish. Unambiguous evidence that the earliest Maya at Cuello made use of fish from wetland areas neat the sire is important as other lines of achaeological evidence do not or cannot demonstrate this as clearly. Moreover, these results show that isotopic analysis of charred residues can provide new and different information to investigations of past foodways. Future applications will be restricted only by the small number of carbonised residues recovered, as strong and universal theoretical principles and the long-term stability of the isotopic signals create potential for widespread utility of the method. Ancient lipid residues successfully extracted from ceramic vessels from four Lowland Maya sites were analyzed by gas chromatography. Fatty acid profiles of the residues contain a record of the former contents of the vessels. Contamination during burial or post-excavation was shown to be minimal except where vessels had been catalogued using nail polish. Direct comparision of the fatty acid profiles of archaeological residues with those of comparative cooked food standards (fresh and degraded) were made difficult by complex processes of degradeation that have greatly altered the archaeological resides. However, I suggest that a meat of plant origin can be assigned to most residues based on a ratio of medium:long chain fatty acids 2 for meats. Freshwater fish residues, in Cuello vessels that had chars, are distinguishable by relatively higher proportions of the odd-numbered fatty acids. In light of these results, and given that faunal and botanical remains are poorly preserved at Lowland sites, the analysis of lipid residues is potentially a useful analytical tool for investigating ancient Maya foodways. The fatty acid criteria suggested for the identification of lipid residues cannot be applied universally as food assemblages from different geographic regions have distinct fatty acid compositions. This fact along with the highly varied and complex processes of degradation, which are currently poorly understood, will serve to limit the development and application of this approach to archaeological studies of foodways.</p>