New light on the use of Theobroma cacao by Late Classic Maya

Abstract

Cacao seeds, Theobroma cacao , provide the basis for a ceremonially important Mesoamerican food. Past efforts to identify cacao in ceramics focused on highly decorative vessel forms associated with elite ceremonial contexts, creating assumptions as to how cacao was distributed and who could access it. This study examines 54 archaeological ceramic sherds from El Pilar (Belize/Guatemala) of Late Classic (600 to 900 CE) residential and civic contexts representing a cross-section of ancient Maya inhabitants. Identification of cacao in ancient sherds has depended on the general presence of theobromine; we used the discrete presence of theophylline, a unique key biomarker for cacao in the region. Analysis was done by grinding off all outside surfaces to reduce contamination, pulverizing the inner clay matrix, extracting absorbed molecules, and concentrating the extractions. In order to obtain especially high selectivity and low limits of detection, our study utilized the technique of resonance-enhanced multiphoton ionization coupled with laser-desorption jet-cooling mass spectrometry. This technique isolates molecules in the cold gas phase where they can be selectively ionized through a resonant two-photon process. Of the sherds analyzed, 30 samples (56%) were found to contain significant amounts of theophylline and thus test positive for cacao. Importantly, cacao is present in all contexts, common to all Maya residents near and far from centers.

Classic Maya Settlement Systems Reveal Differential Land Use Patterns in the Upper Belize River Valley

“…In contrast, Hoggarth's excavations suggest that the Ixim elite at Settlement Cluster C were well-integrated into the Baking Pot polity by the Early Classic period because less labor flowed into the district center at this time, instead being diverted for massive remodeling and additions to the Baking Pot epicenter [25] (pp. [40][41]. Similarly, the previously mentioned excavations at Bedran revealed an affluent intermediate elite residence with access to sumptuary wealth items, such as two cacao drinking vessels with a hieroglyphic band containing royal titles, which given their inscriptions were likely gifted through tributary networks from apical elites at the epicenter [120,121,191].…”

“…There are several good examples of commoner households on Class I soil which clearly accessed not only high proportions of portable wealth but also some sumptuary items, e.g., ground stone maces, jade jewelry, figurines, and celts, and ceramics with inscriptions bearing elite titles [1,25,26]. These items denote a high level of affluence and potentially moved down tributary networks in exchange for high-value crops such as cacao that could only be grown on the deep, well-drained soils around these households [40]. In contrast, households situated on Class II and III soils rarely have access to such elaborate statements of affluence, but often still have high proportions of less elaborate wealth items such as polychrome ceramics and shell jewelry [26] (pp.…”

“…The application of new metabolomic approaches to dental calculus can identify cacao biomarkers [199]. The combination of such an approach with chemical residue analysis of ceramics, has the potential to revolutionize our understanding of cacao consumption in the past by showing who was storing cacao in household ceramics versus actually consuming it [40,200]. When coupled with soil classification data and paleoethnobotanical analyses, such approaches could provide a solid understanding of ancient agricultural economies and tributary networks.…”

“…The 1:50,000 scale soil map used by Fedick [23], and considered in this study, suggests that 20% of the region's soil was likely suitable for cacao cultivation. Recently, Ford and colleagues [40] have employed laser mass spectrometry to detect the cacao biomarker, Theophylline, in residues on ceramics. Intriguingly, the results showed that cacao was accessed by a large percentage of households, irrespective of status, in both the alluvial valley bottoms and the surrounding uplands.…”