Organic residue analysis in China: an overview, progress and prospects

ARCHAEOLOGY: USES OF CHROMATOGRAPHY IN

Because they hold information about cultural identity, foodways have been the focus of a variety of disciplines in archaeology. However, each approach documents different stages of culinary preparation and is constrained by the preservation specificities of each type of artefact and ecofact. Difficulties in achieving an interdisciplinary approach may explain the scarcity of such studies. In this paper, we propose a methodology that combines archaeozoological, carpological and microbotanical analysis of ecofacts retrieved in the sediment, with use-alteration, organic residue and microbotanical analysis carried out on pottery vessels, recovered during the excavation of a XXth century archaeological dump site in Lower Casamance (Senegal). The results demonstrate the strength of this multiproxy approach in reconstructing past foodways by characterising the importance of aquatic, terrestrial animals and plant products in the Diola Kassa diet. In addition, this study questions the modalities of food transformation by assessing the preparation techniques of animal and vegetal products (cutting marks, heating processes etc.) and the function of pottery vessels (transport, storage, cooking etc.). Aquatic products and rice were a significant part of the diet of the users of the dump (from archaeozoology, carpology, phytoliths and organic residue analysis) and wet cooking (boiling?), salty and acidic foods seem to have been particularly prevalent (from use-alteration). The absence of specific animal and plant parts in the archaeological record, as well as some pottery function, is also questioned. Beyond gathering the results of each approach, this study focuses on the interweaving of different research methods to depict past foodscape.

Archaeological organic residue analysis (ORA), the recovery of biomolecules from pottery and other archaeological materials to reconstruct past pottery-based activities, has been used for decades to investigate ancient food practices in the Mediterranean. This article posits that taking an ‘assemblage’ approach might enable archaeologists to realize the potential of ORA more fully by treating organic residues as both molecular-scale members of broader archaeological assemblages and as assemblages of biomolecules. Approaching ORA as ‘curating the biomolecular assemblage’ brings into view both quality-control considerations advocated by the broader field of ORA as well as specific regional considerations for archaeology in the Mediterranean, such as distinct disciplinary trajectories in the archaeologies of prehistory versus ‘text-based’ archaeologies; unique Mediterranean environmental contexts and resulting effects on organic resources; and frequent periods of cultural, political and economic connectivity. Key topics for ORA in Mediterranean archaeology include understanding how Mediterranean environments impact residue preservation, protecting residues from contamination, ensuring inter-comparability of datasets to enable broader regional or temporal comparisons and adapting to challenges and opportunities in investigating wine and olive oil using ORA.

Often treated as an accessory science, organic residue analysis (ORA) has the capacity to illuminate otherwise hidden aspects of ancient technology, culture, and economy, and therein can play a central role in archaeological inquiry. Through ORA, both the intact vessel freshly excavated from a tomb and the sherd tucked away in a museum storage closet can offer insights into their contents, their histories, and the cultures that created them—provided the results can be carefully calibrated to account for their treatment during and after excavation. The case study below presents ORA data obtained from a range of artifacts from Late Bronze Age Crete, setting results from freshly-excavated and legacy objects alongside one another. Although legacy objects do tend to yield diminished results from both a quantitative and qualitative perspective, our comparative work has demonstrated both their value and untapped potential when their object biographies are carefully considered. It also sheds light on biomarker degradation processes, which have implications for methodologies of extraction and interpretation of legacy objects. Comparative studies such as these broaden the pool of viable ORA candidates, and therein amplify ORA’s ability to reveal patterns of consumption as well as ecological and environmental change. They also highlight the role and value of data-sharing in collaborative environments such as the OpenARCHEM archaeometric database.

A call for caution in the analysis of lipids and other small biomolecules from archaeological contexts

While oxidation products of unsaturated fatty acids, for example dicarboxylic acids (hereafter diacids), must form during the use of unglazed ceramic vessels for the processing of animal and plant products, such components have never been observed during studies of absorbed lipids. Their absence from the extractable lipid fraction is presumed to be the result of their loss from potsherds through groundwater leaching. Lipid oxidation products including short-chain dicarboxylic acids, ω-hydroxy acids and longer-chain hydroxy and dihydroxy acids have now been observed as components probably covalently bound into solvent insoluble residues of potsherds recovered from waterlogged deposits. These components were only revealed following alkaline treatment of the insoluble residues. A similar mixture of diacids was observed in high abundance in the free lipid fraction of vessels recovered from an exceptionally arid deposit where groundwater leaching would never have occurred. These results confirm the formation of oxidation and probable polymerization products of unsaturated fatty acids during vessel use and burial.

Organic residues analysis is an important tool in archaeological research because it sheds light on aspects of the daily life of the past. In particular, it allows us to obtain information on food production, consumption and trade. In this paper we present the results of residue analysis performed on ceramic vessels from the archaeological site of Placa Major-Horts de Can Torras (Castellar del Valles, Barcelona, Spain), a long lasting site, of which we studied the Late Antique occupation. The site is a rural settlement located in the northeast of Catalonia and it was characterized by structures made of perishable material and by the presence of silos, above which probably the living structures were placed. Analyses were carried out on twelve cooking and storage ceramic forms that were the most representative of the Late Antique phase. In particular pots, jugs, pans and dolia were analyzed, in order to investigate the food consumed at the site. Analyses were conducted by gas chromatography-mass spectrometry (GC-MS). The results show the cooking of animal and vegetal products in the cooking vessels (pots and pan) and the storage of wine in the dolia . Pinaceae products are particularly abundant in some vessels, which suggests the use of this substance at the site. In general, the analyses carried out provide the first case study of residue analysis of ceramic material of this period in Catalonia and allowed us to recover information both on food habits and on the use of different ceramic forms during Late Antiquity in this area.

Organic residue analysis from the surface and edges of lithic artifacts is a useful technique to determine stone tool function. This study reports the results of organic residue analysis from 55 stone tools excavated from Hinds Cave in the lower Pecos region of southwestern Texas. Organic residue analysis is combined with stone tool edge-angle and use-wear analysis to determine correlations between tool type and tool function, and types of material used for hafting tools to handles. Although a wide variety of organic residue was observed on the tools, rodent hair and plant debris, mainly of rhaphid phytoliths and various epidermal fiber fragments, were the most prevalent. The study indicates that the stone tools were multipurpose, used for slicing or cutting both plant and animal remains. The most common hafting material was from yucca and agave fiber.

Organic residues include a broad range of materials that can be analyzed at a macro-, micro- or molecular level. They represent the carbon-based remains (in combination with H, N, O, P and S) of fungi, plants, animals and humans. Organic residue analysis is a relatively new technique to archaeology. The chapters of this volume bring together scholars from across the globe and attest to the diverse range of analytical methods, material types, spatio-temporal cultural units and research questions to which organic residue analysis has been applied.

This thesis investigates the function of early Holocene hunter-gatherer ceramic vessels in northern Eurasia. It presents the first systematic application of organic residue analysis (ORA) to Early Neolithic pottery from European Russia and Siberia. During the early Holocene (ca. 9,700 to 5,000 cal BC) pottery was widely produced by hunter-gatherers across Eurasia. One existing theory suggests that the advent of pottery was linked to an intensification of aquatic resource exploitation; the so-called “Aquatic” Neolithic (Gibbs et al. 2017). This theory is supported by recent ORA of early pottery from eastern Asia and northern Europe, where lipid markers derived from aquatic resources were frequently encountered, absorbed in the pots themselves. One area neglected by ORA is the vast territory of what is now Russia where the arrival of pottery marks the start of the Neolithic period, predating agriculture by several thousand years. Despite its importance in defining the Neolithic in this region, little is known about how early pottery was used and what drove its adoption during the early Holocene. Here, ORA was applied to 417 samples, representing 314 ceramic vessels, recovered from three important early Neolithic sites: the East Siberian site of Gorelyi Les, and Rakushechny Yar and Zamostje 2 in the southern and northern part of European Russia respectively. Overall, the results generated by this thesis indicate much greater diversity in the use of early pottery than predicted from the “Aquatic” Neolithic theory. While aquatic products were indeed prevalent at many sites, lipids derived from terrestrial plants and animals were also common and, overall, the initial use of pottery seems to have varied according to the regional context. These results challenge the idea that the widespread adoption of pottery by Holocene Eurasian foragers was driven primarily by the need to process aquatic resources.

Organic residue analysis has become one of the major and rapidly developing fields in archaeological sciences. The analyses of lipid residues have produced several fruitful studies allowing a better understanding of past life-ways and economy, pottery function and agricultural practices. One potentially fruitful, yet under-utilized analytical method for the identification of archaeological lipid residues is MALDI-FT-ICR-MS. In this Perspective Special Feature, Ester Oras and colleagues demonstrate the suitability of MALDIFT- ICR-MS for archaeological organic residue analysis with four different archaeological samples and highlight its capability of identifying different intact, degraded and oxidized triacylglycerols from food residues. The article describes the analysis of samples of both food-crust and ceramic powder from vessels discovered from the 12th–13th century AD cemetery at Kukruse, Estonia. Dr. Oras is a Research fellow of, Analytical Chemistry, Institute of Chemistry, University of Tartu (Tartu, Estonia). Her research interests are organic residue analysis of prehistoric and early medieval material with her main focus on food residues, but she has also worked on adhesives, embalming resins, and isotope based migration studies.

LC–MS method development and comparison of sampling materials for the analysis of organic gunshot residues

The analysis of organic residues from archaeological materials has become increasingly important to our understanding of ancient diet, trade and technology. Residues from diverse contexts have been retrieved and analysed from the remains of food, medicine and cosmetics to hafting material on stone arrowheads, pitch and tar from shipwrecks, and ancient manure from soils. Research has brought many advances in our understanding of archaeological, organic residues over the past two decades. Some have enabled very specific and detailed interpretations of materials preserved in the archaeological record. However there are still areas where we know very little, like the mechanisms at work during the formation and preservation of residues, and areas where each advance produces more questions rather than answers, as in the identification of degraded fats. This chapter will discuss some of the significant achievements in the field over the past decade and the ongoing challenges for research in this area.

Fit for purpose? Organic residue analysis and vessel specialisation: The perfectly utilitarian medieval pottery assemblage from West Cotton, Raunds

Production and exchange of goods in Early Byzantine Hierapolis of Phrygia (Turkey): Organic residue analyses on local/regional ovoid amphorae