Oxford chemists determine honey providing in a 2,500-year-old shrine

This analysis is a reminder that archaeological collections maintain untapped scientific potential and the way new info could be revealed when fashionable analytical methods and multidisciplinary collaborations are mixed.

Project co-lead Dr Luciana da Costa Carvalho, Department of Chemistry

The underground shrine, about an hour and a half’s drive away from Pompeii, was initially found in 1954 and included a number of bronze jars containing an orange-brown sticky substance. At the time, archaeologists assumed the residue was honey, since this was an necessary substance within the historical world, typically left in shrines as choices to the gods or buried alongside the lifeless. However, over the course of 30 years, three completely different groups analysed the residue however failed to substantiate the presence of honey. Instead, they concluded that the jars contained some type of animal or vegetable fats contaminated with pollen and bug elements.

In this new research, the researchers used a collection of contemporary analytical methods, together with mass spectrometry for proteins and small molecule compositional evaluation, to find out its molecular make-up. This built-in strategy enabled the identification of sugars, natural acids, and royal jelly proteins that will have remained undetected utilizing a single technique. The outcomes demonstrated that the traditional residue had a near-identical chemical fingerprint to fashionable beeswax and much like fashionable honey.

Further insights got here from evaluating the outcomes obtained for the residue with the outcomes from analyses of contemporary honeycomb samples, and experimental simulations of degraded honeycomb.

Professor James McCullagh, Director of Oxford’s Mass Spectrometry Research Facility within the Department of Chemistry who co-led the mission, stated: ‘The application of multiple analytical techniques was key to the success of this study. By applying several mass spectrometry and spectroscopic approaches we were able to reveal a comprehensive picture of the residue’s molecular composition — enabling us to differentiate between contaminants, degradation merchandise, and authentic biomarkers.’

‘We used X-ray photoelectron spectroscopy to analyse the surface of the residue and found copper corrosion products closely associated with it,’ added lead writer Dr Luciana da Costa Carvalho, a postdoctoral researcher within the Department of Chemistry. ‘Copper ions are naturally biocidal, and we believe their presence may have helped protect the sugar markers in this area from microbial decay.’

The research was made attainable as a result of a close partnership between the University of Oxford’s Ashmolean Museum and the Archaeological Park of Pompeii. Dr Kelly Domoney, Heritage Science Manager on the Ashmolean Museum who co-led the research, defined: ‘In preparation for the exhibition “Last Supper in Pompeii” at the Ashmolean Museum in 2019, our colleagues at the Archaeological Park of Paestum and Veila generously made several important and high-profile loans, including a Greek bronze hydria from the Heroon and its organic contents. We were permitted a unique opportunity to re-analyse those contents using modern instrumentation at the University.’

Dr Luciana da Costa Carvalho describes the outcomes of the research.

For the exhibition, 37 objects have been rigorously assessed, with methods that included microscopy and X-radiography, to tell their future conservation. In many instances, this revealed new details about how the objects have been made and used. For occasion, some vessels retained soot from cooking hearths on the underside of the bottom, while others confirmed thick accumulation of limescale on the inside, demonstrating that they have been used as kettles for heating water.

The turning level within the mission got here with the identification of main royal jelly proteins all particular to honeybee secretions. Our outcomes reveal the ability of bottom-up proteomics mixed with metabolomics within the investigation of archaeological samples.

Co-author Elisabete Pires, Department of Chemistry

Co-author Dr Gabriel Zuchtriegel, Director of the Archaeological Park of Pompeii and former Director of the Archaeological Park of Paestum & Velia, stated: ‘The application of chemical and scientific analyses to extract new and detailed information from existing artefacts allows us to adopt a more informed and nuanced approach to understanding the lives and rituals of past societies, and all from material that already lines the shelves of every archaeological museum collection.’

The authors hope this work will encourage additional re-analysis of legacy supplies, particularly these held in museum collections the place sampling is proscribed and earlier assessments proved inconclusive.

The research ‘A Symbol of Immortality: Evidence of Honey in Bronze Jars Found in a Paestum Shrine Dating to 530-510 BCE’ has been printed within the Journal of the American Chemical Society.