Botanical identification of oregano from the European food market and determination of their essential oils’ constituents utilizing μ-Raman and HS-GC/MS

“Oregano” is a culinary herb, widely used in everyday cooking. According to a CBI survey market (2009) [1], “oregano” is one of the top traded herbs on the European food market. It is found in supermarkets, flea markets and traditional shops, mainly in dried (crushed or ground) form.

Aims of the present study were: i) the botanical identification of crushed oregano material from European markets and ii) the assessment of the yield and quality of their essential oils, utilizing both Raman spectroscopy and headspace gas chromatography – mass spectrometry (HS-GC/MS).

HS-GC/MS is a routinely applied technique for the analysis of essential oils [2], while Raman spectroscopy offers the advantage of time efficiency, no sample preparation and non-destructiveness. It is also environmentally friendly and cost effective [3]. Eighteen commercial oreganos’ packages were purchased from 14 European countries. The botanical identification of the plant material was based on the major micro-morphological key characters. Essential oils were isolated using a Clevenger type apparatus and analysed by both Raman and HS-GC/MS methods, as previously described [4]. Two taxa of the genus Origanum, viz. O. onites and O. vulgare subsp. hirtum, were found to be sold under the commercial name oregano on the European food market, with a wide range of yields (0.99% – 6.04% v/w). The relative abundances of the six most prominent constituents were also compared, with carvacrol and thymol being the main components in all cases. Raman and GC/MS results were in very good agreement, with a deviation of less than 10%.

Funding This research has been co-financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship, and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code: T1EDK-04174).

 

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• References

• 1 CBI Market Survey The Spices and the herbs in the European Union. CBI Ministry of Foreign Affairs Market Intelligence 2009
• 2 Napoli E, Govino A, Carrubba A, Siong VHY, Rinoldo C. Nina 0, Ruberto G. Variations of Essential Oil Constituents in Oregano (Origanum vulgare subsp. viridulum (=0. heracleoticum) over Cultivation Cycles. Plants 2020; 9: 1174
• 3 Hanif MA, Nawaz H, Naz S, Mukhtar R, Rashid N, Bhatti IA, Saleem M.. Raman spectroscopy for the characterization ofdifferent fractions of hemp essential il extracted at 130 C using steam distillation method. Spectrochim. Acta A 2017; 182: 168-174
• 4 Kampasakali E, Nakas A, Mertzanidis D, Kokkini S, Assimopoulou AN, Christofilos D.. j-Raman Determination of Essential Oils’ Constituents from Distillates and Leaf Glands of Origanum Plants. Molecules 2023; 28: 1221

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Artikel online veröffentlicht:
16. November 2023