Optimization of the supercritical fluid extraction of triterpenic acids from Eucalyptus globulus bark using experimental design

• Published in: The Journal of supercritical fluids Vol. 74; pp. 105 - 114
• Main Authors: Domingues, Rui M.A., de Melo, Marcelo M.R., Oliveira, Eduardo L.G., Neto, Carlos P., Silvestre, Armando J.D., Silva, Carlos M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2013
• Subjects: Bark; Design of experiments; Ethanol; Ethyl alcohol; Eucalyptus; Eucalyptus globulus; Extraction; Optimization; Recovery; Response surface method; Supercritical fluid extraction; Supercritical fluids; Triterpenic acids; Triterpenic acids; Response surface method; Supercritical fluid extraction; Design of experiments; Eucalyptus globulus; Bark
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2012.12.005

[Display omitted] ► SFE of triterpenic acids (TTAs) from Eucalyptus globulus bark with pure/modified CO2. ► Experimental conditions tested: 40–60°C, 100–200bar, 0–5% ethanol. ► Optimization of the SFE performed following DOE and RSM approaches. ► SFE yields (total, free TTAs, acetylated TTAs) and TTAs concentration were measured. ► The behaviors of the SFE of free and acetylated TTAs are very different. The supercritical CO2 extraction of E. globulus deciduous bark was carried out at different temperatures (40–60°C), pressures (100–200bar), and ethanol contents (0.0–5.0wt.%) to study triterpenic acids (TTAs) recovery. A factorial design of experiments and response surface methodology were implemented to analyze the influence of these variables upon extraction and perform its optimization. The best conditions were 200bar, 40°C and 5% ethanol, for which the statistically validated regression models provided: extraction yield of 1.2% (wt.), TTAs concentration of 50%, which corresponds to TTAs yield of 5.1g/kg of bark and a recovery of 79.2% in comparison to the Soxhlet value. The trends of the free and acetylated TTAs were very different, due to their distinct CO2-philic character caused by dissimilar polarities: the acetyl derivatives approached a plateau near 200bar and 5% ethanol, while the free TTAs extraction always increased in the range of conditions studied.