resumo
Supercritical fluid extraction of Eucalyptus globulus leaves was accomplished using carbon dioxide at different pressures (200, 250 and 300 bar) and ethanol contents (0.0, 2.5 and 5.0 wt%), with and without biomass pretreatment (grinding or dewaxing), with the objective to study total (eta(Total)) and triterpenic acids (eta(TTA)) extraction yields. A factorial design of experiments and response surface methodology was performed to assess and optimize the impact of both operating conditions at 40 degrees C and 12 g(CO2) min(-1). The best results were obtained for 250 bar and 5.0 wt% ethanol, for which eta(Total) = 3.95% and eta(TTA) = 0.67%. Three kinetic extraction curves were measured and modeled, in order to quantify the influence of both biomass pretreatments, being concluded that grinding favors the total extraction yield while dewaxing enhances the TTAs concentration in the extract. The Broken plus Intact Cells model disclosed kinetic and structural differences between the three biomass samples (natural, ground and dewaxed leaves), being able to explain the distinct trends of the various removal curves.
palavras-chave
TRITERPENIC ACIDS; OIL; OPTIMIZATION; SOLUBILITY; CO2
categoria
Engineering
autores
Rodrigues, VH; de Melo, MMR; Portugal, I; Silva, CM
nossos autores
Carlos Manuel Silva
Professor associado
Inês Portugal
Professor Auxiliar
Marcelo Morais Rodrigues de Melo
Bolseiro de pós-Doutoramento
Vitor Hugo dos Louros Rodrigues
Estudante de doutoramentoagradecimentos
This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID /CTM /50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement.