Obtaining Aromatic Extracts from Portuguese Thymus mastichina L. by Hydrodistillation and Supercritical Fluid Extraction with CO2 as Potential Flavouring Additives for Food Applications
Humans often respond to sensory impulses provided by aromas, and current trends have
generated interest in natural sources of fragrances rather than the commonly used synthetic additives.
For the first time, the resulting aroma of a selected culture of Thymus mastichina L. was studied
as a potential food ingredient. In this context, dried (DR) and fresh (FR) samples were submitted
to carbon dioxide (CO2) supercritical extraction (SFE) and hydrodistillation (HD) methods. The
extracts were characterised according to their volatile composition by GC-MS, cytotoxicity against a
non-tumour cell culture, and sensory attributes (odour threshold and olfactive descriptors). The most
abundant aromas were quantified, and the analysis performed by GC-MS revealed an abundance of
terpenoids such as thymol chemotype, followed by the precursors -terpinene and p-cymene. DR
and FR extracts (EX) obtained from SFE-CO2 show the highest content of thymol, achieving 52.7%
and 72.5% of the isolated volatile fraction. The DR essential oil (EO) contained the highest amount
of terpenoids, but it was also the most cytotoxic extract. In contrast, SFE-CO2 products showed the
lowest cytotoxic potential. Regarding FR-OE, it had the lowest extraction yield and composition in
aroma volatiles. Additionally, all samples were described as having green, fresh and floral sensory
notes, with no significant statistical differences regarding the odour detection threshold (ODT) values.
Finally, FR-EX of T. mastichina obtained by SFE-CO2 presented the most promising results regarding
food application.
This research was funded by the European Regional Development Fund (ERDF) through
the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-
01-0247-FEDER-024479: ValorNatural. This work was financially supported by: LSRELCM Base-
UIDB/50020/2020 and Programmatic- UIDP/50020/2020 and CIMO UIDB/00690/2020, funded by national funds through FCT/MCTES (PIDDAC). L. Barros also thanks the national funding by FCT,
P.I. through the institutional scientific employment and individual program contract, and Júlia Cristiê
Kessler and Filipa Mandim acknowledges their Ph.D. scholarships by Fundação para a Ciência e a
Tecnologia (FCT) (2020.06656.BD and SFRH/BD/146614/2019, respectively).
