The discovery sheds light on the oil’s molecular evolution over two millennia.
Olive oil is one of the most ancient and versatile products of the Mediterranean region. It has been used for cooking, cosmetics, medicine, lighting and religious rituals for thousands of years. But how has olive oil changed over time? And what can we learn from the oldest bottle of olive oil in the world?
The oldest bottle of olive oil in the world was discovered in the ancient Roman town of Herculaneum, near Naples, Italy. Herculaneum was one of the towns that was buried by the eruption of Mount Vesuvius in 79 A.D., along with Pompeii and Stabiae. The bottle, or amphora, was found in a house that belonged to a wealthy family, and it contained about 3 liters of olive oil.
The amphora was first excavated in 1984, but it was only recently that a research team led by Raffaele Sacchi, the chair of the food science and technology unit of the University of Naples were able to confirm that the residue inside was indeed olive oil. They used a combination of techniques, such as magnetic resonance, mass spectrometry and radiocarbon dating, to analyze the molecular composition and age of the oil.
“We have been able to unequivocally confirm that what we have in our hand is the most ancient olive oil residue recovered, and currently exposed, in a significant amount, as it dates back to 79 A.D.,” Sacchi said. “Moreover, our study strikingly highlights the molecular evolution of olive oil through an almost 2,000-year-long storage period.”
The results are indeed surprising and fascinating. The researchers found that the oil had undergone a remarkable transformation over the past two millennia, due to the high temperatures caused by the volcanic eruption and the long storage period in uncontrolled conditions. The triglycerides, which make up 98% of olive oil, had broken down into fatty acids, which had then oxidized and reacted with each other to form new compounds, such as estolides. These compounds had never been observed before in conventional processes of natural alteration of olive oil.
The researchers also found traces of volatile substances that are typical of highly rancid oil, such as aldehydes and ketones. These substances are formed by the decomposition of oleic and linoleic acids, which are the main unsaturated fatty acids in olive oil. The saturated fatty acids and phytosterols profiles confirmed that the oil did not contain any animal fat, which was widely used by the ancient Romans, and that it was exclusively olive oil.
The study also revealed that the oil was probably produced from olives harvested in late autumn or early winter, when they are fully ripe and have a higher oil content. The olives were likely crushed by a stone mill and then pressed by a wooden beam press, which were the common methods of olive oil extraction at the time.
The researchers concluded that their study provided valuable insights into the molecular evolution of olive oil over a long period of time, as well as into the ancient production and consumption practices of this precious commodity. They also suggested that further studies could be done on other ancient olive oil samples from different regions and periods, to compare and contrast their characteristics and origins.
Sources: 1, 2, 3, 4