Abstract
Rosemary oil was extracted by supercritical carbon dioxide (CO2) as a solvent. The parameters of pressure, temperature, and ethanol as co-solvent were evaluated through a Taguchi experimental design. Extraction yield of rosemary oil increased with high pressure (350 bar) and mid-range temperature (40 degrees C), while the addition of ethanol as co-solvent did not improve the extraction yield. Palmitic, alpha-linolenic, linoleic, oleic, and stearic acid were the main fatty acids detected (3.96% w/w) in the extracted oil. The major volatile compounds found in the oil (75.74% w/w) included d-camphor, eicosane, 1,8-cineole, tetracosane, borneol, and beta-caryophyllene. The extracted oils showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, while Escherichia coli was less sensitive to inhibition. Antioxidant activities on DPPH and TEAC assays were higher at 60 degrees C, 100 bar without ethanol, while antioxidant activity on FRAP assay was improved at 40 degrees C, 100 bar, and ethanol as co-solvent. Operational conditions used in the present extraction process (a variation in temperature, pressure, and co-solvent) are described.
[GRAPHICS]