Journal of Supercritical Fluids, Vol.92, 223-230, 2014
Supercritical fluid extraction from Syzygium aromaticum buds: Phase equilibrium, mathematical modeling and antimicrobial activity
Clove essential oil is an important product to food industry because it presents a powerful antioxidant and antimicrobial potential enabling its use for the substitution of synthetic commercial products for food preservation. The objective of this paper is to study the extraction kinetics for predicting operational condition to obtain Syzygium aromaticum essential oil using CO2 as solvent by means of the introduction of thermodynamic approach into the mathematical modeling of the process. Extractions were performed at 9000 kPa/313.15 K, 10,000 kPa/313.15 K, 9000 kPa/323.15 K, and 10,000 kPa/323.15 K and the essential oil yields obtained were 14.17%, 12.32%, 13.11%, and 14.02%, respectively. To calculate the extract solubility in CO2 supercritical, the Peng-Robinson EoS coupled with three mixing rules (van der Waals 1, van der Waals 2 and Mathias-Klotz-Prausnitz) was used and a mass transfer model was employed to represent the relationship yield versus extraction time. The mathematical modeling of the process using the calculated solubility presented high concordance with experimental data. The volatile extracts were analyzed by GC/MS and the major compounds were eugenol and beta-caryophyllene. Also, minimum inhibitory concentration (MIC) of supercritical extracts was determined with respect to Escherichia coli, Staphylococcus aureus and Entero coccus faecalis by microdilution method. All samples inhibited the bacterial growth, being the extract obtained at 313.151/9000 kPa the most effective. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Syzygium aromaticum;Clove essential oil;Supercritical fluid extraction;Peng-Robinson EoS;Antimicrobial activity