abstract
This work encompasses a comparison of the extraction of Quercus cerris cork with methanol, ethanol, dichloromethane, and petroleum ether by Soxhlet and room temperature batch solid-liquid extraction (SLE) and with supercritical carbon dioxide modified with ethanol. The maximum total extraction yield (eta(Total)) was attained by Soxhlet extraction with methanol (eta(Total) = 13.8 wt.%) and the minimum for batch SLE with petroleum ether (eta(Total) = 0.35 wt.%). For the supercritical fluid extraction (SFE) runs eta(Total) ranged from 1.2 to 1.7 wt.%. In terms of friedelin extraction yields (eta(Friedelin)) the results ranged from 0.12 wt.% (batch SLE with petroleum ether) to 1.68 wt.% (Soxhlet with methanol). The best performing assays in terms of friedelin concentration in the extracts (C-Friedelin) were those involving weakly polar or nonpolar solvents. Batch extractions at room temperature reached C-Friedelin values significantly lower than Soxhlet extractions with the same solvent due to the unfavourable effect of temperature on the solubilisation of friedelin. The extracts were analysed by FTIR-ATR and GC-MS and the data used for similarity analysis using multidimensional scaling (MDS). The results unveil that more than the extraction method (Soxhlet, Batch, or SFE) it is the intrinsic polarity of the solvent that defines the ensuing chemical composition of the extracts. For this reason, this study contributes for the selection of solvents and extraction methods of future industrial applications targeting Q. cerris cork valorization.
keywords
SUPERCRITICAL-FLUID EXTRACTION; FTIR SPECTROSCOPY; TRITERPENIC ACIDS; CLUSTER-ANALYSIS; IONIC LIQUID; SUBER L.; CORK; GREEN; KINETICS; BARK
subject category
Engineering
authors
Vieira, PG; de Melo, MMR; Sen, A; Simoes, MMQ; Portugal, I; Pereira, H; Silva, CM
our authors
Carlos Manuel Silva
Associate Professor
Inês Portugal
Assistant Professor
Marcelo Morais Rodrigues de Melo
Post-Doc Fellowshipacknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. Authors want to thank the funding from Project AgroForWealth (CENTRO-01-0145-FEDER000001), funded by Centro2020, through FEDER and PT2020.