Extraction of aromatic volatiles by hydrodistillation and supercritical fluid extraction with CO2 from Helichrysum italicum subsp picardii growing in Portugal

Abstract

Volatiles from Helichrysum italicum subsp. picardii growing in Portugal were extracted by supercritical fluid extraction with CO2 (SFE-CO2) under different conditions of pressure (9 and 12 MPa) and particle size (<4 mm and 4 cm), in order to analyse their influence on the extraction yield, chemical profile, organoleptic properties and antioxidant activity. Hydrodistillation was used as conventional technique for comparison purposes. The results showed that pressure and particle size influenced the yield of SFE-CO2 extraction. Chemical analysis highlighted the abundance of monoterpene hydrocarbons in the essential oil and sesquiterpene hydrocarbons in the SFE-CO2 extracts. In terms of organoleptic properties, the SFE-CO2 extraction allowed the recovery of pleasantly scented fragrances resembling the original scent of the living plant H. italicum subsp. picardii found in Portugal. The SFE-CO2 extracts isolated at 12 MPa showed free radical scavenging ability at all tested concentrations. This study allowed the extraction and identification of high-value aromatic components with pleasant fragrance properties suggesting the Portuguese coast as an exploitable source of relevant plant matrices.