Effect of cosmetic matrices on the release and odour profiles of the supercritical CO₂ extract of Origanum majorana L.

Objective: In this study, the effect of different cosmetic matrices on the release profile and odour intensity of the fragrance O. majorana was investigated for the first time. Methods: The fragrance compounds of O. majorana were extracted by supercritical fluid extraction using carbon dioxide (SFE-CO₂) at 40°C and two operating pressures (8.5 and 10 MPa), and their chemical profiles were assessed by gas chromatography with flame ionization detector coupled with mass spectrometry (GC-FID/MS). Lastly, the fragrance compounds were incorporated into three cosmetic matrices (glycerine, dipropylene glycol and skin lotion) to assess their release and odour profiles over time using dynamic headspace (DHS)/GC-FID/MS and Odour Value concept, respectively. Results: The SFE-CO₂ enabled recovering extracts with the pleasant scent of the living plant, and the increment of pressure induced an increase on the extraction yield. GC-FID/MS analyses revealed that oxygen-containing monoterpenes was the principal group of components identified in both SFE-CO₂ extracts. The fragrance compounds were more retained in dipropylene glycol, and the major deviations from the original odour intensity (control) were observed in the presence of dipropylene glycol and skin lotion. Conclusion: The hydrophilic character of the cosmetic matrices strongly influenced the release of the fragrance compounds, thus affecting the odour profile of the studied mixtures.