New Insights Into the World’s Oldest Bottle of Olive Oil

Summary

New research has con­firmed that a 2,000-year-old bot­tle found in Herculaneum con­tains olive oil and has revealed the mol­e­c­u­lar changes in the oil over time. Magnetic res­o­nance and mass spec­tropho­tom­e­try test­ing, as well as radio­car­bon dat­ing, con­firmed the age of the oil, which showed chem­i­cal mod­i­fi­ca­tions due to high tem­per­a­tures and long-term stor­age.

New research has con­firmed that a 2,000-year-old bot­tle found in the ancient Roman town of Herculaneum, near mod­ern-day Naples, is olive oil and has shed light on the mol­e­c­u­lar trans­for­ma­tion of the oil over the past two mil­len­nia.

“We are very sat­is­fied with the insights obtained [from the stud­ies],” said Raffaele Sacchi, the chair of the food sci­ence and tech­nol­ogy unit of the University of Naples Federico II depart­ment of agri­science (DIA).

Working with col­leagues at the National Research Council and the University of Campania Luigi Vanvitelli, Sacchi came to this con­clu­sion after car­ry­ing out mag­netic res­o­nance and mass spec­tropho­tom­e­try test­ing on the bot­tle, as well as radio­car­bon dat­ing the organic residue.

“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.”

Due to both the high tem­per­a­tures caused by the erup­tion of Mount Vesuvius in 79 A.D. and an almost two-mil­len­nia stor­age period in uncon­trolled con­di­tions, the remains of the oil still bear the traces of the chem­i­cal mod­i­fi­ca­tions typ­i­cal of altered dietary fats.

“In fact, very lit­tle of the mol­e­cules com­monly found in olive oil sur­vived,” Sacchi said. ​“The triglyc­erides, which rep­re­sent 98 per­cent of the oil, broke down into the con­stituent fatty acids; the unsat­u­rated fatty acids are com­pletely oxi­dized, gen­er­at­ing hydroxy acids, which, in turn, with a slow kinet­ics, reacted with each other form­ing con­den­sa­tion prod­ucts, estolides, which have never been observed before in con­ven­tional processes of nat­ural alter­ation of olive oil.”

Furthermore, the olive oil residue pro­duced a num­ber of dif­fer­ent volatile sub­stances, which are the same as those found in highly ran­cid oil and formed as the result of the decom­po­si­tion of oleic and linoleic acids.

The sat­u­rated fatty acids and phy­tos­terols pro­files also made it pos­si­ble to estab­lish with cer­tainty that the residue found in the bot­tle does not con­tain ani­mal fat, which was widely used by the pop­u­la­tion of the time, and that it is unequiv­o­cally olive oil.

“The rel­a­tive enrich­ment of sat­u­rated fatty acids and the for­ma­tion of estolides have con­tributed to solid­ify the olive oil in situ,” Sacchi said, clar­i­fy­ing that the oil is lean­ing to one side, because the bot­tle laid in an inclined posi­tion from the erup­tion until its exca­va­tion.

“The iden­ti­fi­ca­tion of the nature of this archae­o­log­i­cal bot­tle of olive oil gives us irrefutable proof of the impor­tance this prod­uct had in the daily diet of the pop­u­la­tions of the Mediterranean basin, in par­tic­u­lar to the ancient Romans in Campania Felix,” he said.

“Also, this has a major impact on cul­ture and on the image of Italian olive oil, since we obtained a ​‘cer­ti­fied’ glass bot­tle of olive oil stored for as many as 2,000 years,” Sacchi added, clar­i­fy­ing that the oil most likely had solid­i­fied because the bot­tle laid in an inclined posi­tion.

• Nature