Ancient Compounds Discovered in 2500-Year-Old Containers
In an exciting discovery, scientists have identified the contents of sticky residues found inside 2,500-year-old bronze jars discovered in an underground shrine in Paestum, Italy. The residue, which was initially described as a paste-like substance with a strong wax aroma, has been chemically analysed and found to be primarily composed of honey and related bee substances.
The findings, published in a study in the Journal of the American Chemical Society, reveal that the residue contains lipids, saccharide decomposition products, hexose sugars, and major royal jelly proteins. This direct molecular evidence suggests that the jars once contained honey or honey-related substances.
Over the past 30 years, subsequent analysis by three separate teams had cast doubt on the hypothesis that the jars contained honey. However, recent advancements in biomolecular techniques have allowed for a more accurate and comprehensive analysis of the residue.
The complexity of the residue, which includes compounds characteristic of honey’s sugar content and bee secretions, had been preserved due to the anaerobic environment and chemical reactions involving copper ions from the bronze jars. The presence of saccharide decomposition products such as 5-methyl furfural and levoglucosenone correlates with the degradation of honey sugars over millennia, while proteins linked to royal jelly, a substance secreted by worker bees, confirm the jars held bee products beyond just pure honey.
This find is significant because it is the oldest direct chemical evidence of honey storage in metal containers. It reveals ancient practices related to bee product exploitation, ritual use, and possibly apiculture in the Mediterranean region. Honey was a pivotal material in ancient cultures, used as a sweetener, medicine, cosmetic, and in religious rituals, underscoring its value in Greek and Roman society where bees and honey symbolized divine nourishment and wisdom.
In addition, the study offers a more specific method for detecting bee products in ancient contexts. The researchers compared the results to samples of modern honey and honeycomb, both fresh and artificially aged with heat, from Greece and Italy. The ancient residues are considered complex chemical ecosystems, and the team's findings significantly expand the analytical toolkit available for investigating chemically complex archaeological residues.
Furthermore, the research highlights the value of reinvestigating archaeological residues in museums with advanced biomolecular techniques. In 2019, the jars were reanalyzed at the Ashmolean Museum with the help of new advanced biomolecular techniques.
Major royal jelly proteins (MRJP) were found in samples from the core of the Paestum residue, providing definitive evidence it contained bee products. MRJPs are a series of 9 homologous proteins found in insects of the order Hymenoptera, including bees. These proteins are secreted by nurse bees' cephalic glands and mixed with honey and pollen to feed larvae in the hive.
The increased acidity levels in the Paestum residue, consistent with long-term degradation of honey and beeswax, also support the findings. The residue contains intact hexose sugars at higher concentrations than in degraded beeswax, further confirming its honey-like nature.
In summary, the 2,500-year-old residue is a chemically complex mixture primarily composed of honey and related bee substances, confirming these bronze jars contained honey and bee products with important cultural and ritualistic implications in ancient Paestum, Italy. The study provides the first direct molecular evidence to support the presence of honey and likely honeycombs, and it significantly expands the analytical toolkit available for investigating chemically complex archaeological residues.
The study reveals that the ancient bronze jars contained not just honey, but also various bee products, including royal jelly, which are proteins secreted by worker bees. This discovery sheds light on the ancient practices of bee product exploitation and apiculture in the Mediterranean region.
The findings also underscore the importance of nutrition in ancient cultures, as honey was a valuable material used as a sweetener, medicine, cosmetic, and in religious rituals. Its significance is mirrored in Greek and Roman society, where bees and honey symbolized divine nourishment and wisdom.
Moreover, the research offers a method for detecting bee products in ancient contexts, expanding the analytical toolkit available for investigating chemically complex archaeological residues. This could lead to further discoveries and insights into the past practices and cultures involving beekeeping and honey production.
