abstract
Supercritical fluid extraction (SFE) was applied for the first time to Quercus cerris cork, and compared with Soxhlet with dichloromethane (DCM). Novel triterpenes, viz. betulin and squalene, and beta-sitosterol were identified for the first time in the lipophilic extracts. The SFE at 300 bar and 40-80 degrees C provided extracts much richer in friedelin-the major compound from both SFE and DCM extracts - with concentrations up to 40.6 wt%, against 26.0 wt% for DCM. The SFE yields ranged between 0.97 and 1.81 wt% with pure CO2, and attained 2.83 wt% when ethanol was introduced as cosolvent (10 wt%). In this case, however, the friedelin concentration dropped significantly due to the additional removal of non-target compounds. In general, the experimental data and their trends were in accordance with the theoretical predictions of kinetic and equilibrium properties estimated in this work for the friedelin/SC-CO2 system. This study demonstrates that the SFE of Q cerris cork arises as a prospective pathway for a green and enhanced friedelin production process under the biorefinery concept. (C) 2014 Elsevier B.V. All rights reserved.
keywords
EUCALYPTUS-GLOBULUS BARK; RESPONSE-SURFACE METHODOLOGY; TRITERPENIC ACIDS; CHEMICAL-COMPOSITION; CARBON-DIOXIDE; BY-PRODUCTS; EXPERIMENTAL-DESIGN; SUBER L.; CO2; OPTIMIZATION
subject category
Chemistry; Engineering
authors
Sen, A; de Melo, MMR; Silvestre, AJD; Pereira, H; Silva, CM
our authors
Armando Jorge Domingues Silvestre
Full professor
Carlos Manuel Silva
Associate Professor
Marcelo Morais Rodrigues de Melo
Post-Doc FellowshipProjects
acknowledgements
Authors thank funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. CP-IP 228589 AFORE, and Fundacao para a Ciencia e a Tecnologia (Portugal) for funding Associate Laboratory CICECO (Pest-C/CTM/LA0011/2013), CEF Research Center (Pest-OE/AGR/UI0239/2014) and the post doc scholarship of Ali Sen.