Uso de ultrasonidos en la extracción de plantas labiadas combinando etanol y CO2 supercrítico

Abstract

Several plants of the labiate family, such as rosemary (Rosmarinus officinalis L.), marjoram (Origanum majorana L.) and basil (Ocimum basilicum L.), contain important phenolic compounds, substances prized for its recognized antioxidant activity. The aim of the research was to combine a sonication step prior using ethanol as co-solvent, with subsequent supercritical extraction (US-SFE), to facilitate the extraction of these compounds and comparing the results obtained with supercritical extraction (SFE) with pure CO2 and co-solvent. In the SFE rosemary leaves the extraction yield increased significantly from 4,52 % to 7,99 % by using ethanol as co-solvent and 15,03 % with US-SFE. Prior sonication step got the final yield of extract obtained tripled compared to the SFE. In the extraction of marjoram leaves positive results were obtained with the US-SFE, since the increase of extraction yield was 46 % related to the yield obtained in the SFE with ethanol co-solvent. Basil leaves in the US-SFE produced no advantage over the other techniques in terms of performance or total polyphenol content. The inclusion of a previous stage of ultrasonication increased the extraction yield, reduced time, the flow of CO2 and ethanol consumption process, and a similar extract was obtained in terms of carnosic acid content.