Long-lasting flavor compounds of myrtle and immortelle from ancient Egyptian tombs: A study by analytical pyrolysis

Abstract

In this work, an approach based on evolved gas analysis-mass spectrometry and double-shot analytical pyrolysis-gas chromatography-mass spectrometry was employed to investigate the low and high molecular weight fractions of two aromatic plants, myrtle and immortelle. The method was used to investigate myrtle and immortelle plants from historical herbaria, as well as archaeological samples from garlands found in ancient Egyptian tombs. Analytical pyrolysis allowed us to characterize both the volatile and non-volatile fractions, by sequentially performing a thermal desorption step and a pyrolysis step on the same sample. Volatile components ascribable to the flavor of myrtle and immortelle were detected in the first-shot chromatograms of all samples. These compounds included mono/sesquiterpenoids such as pinene and eucalyptol, and small phenols such as catechol and syringol. The results show that a portion of the volatile compounds of these plants can remain trapped in the lignocellulosic matrix for long times, and that double-shot Py-GC/MS can provide information on the volatile fraction of even archaeological plant samples.