Spruce Bark-A Source of Polyphenolic Compounds: Optimizing the Operating Conditions of Supercritical Carbon Dioxide Extraction

• Published in: Molecules (Basel, Switzerland) Switzerland), 2019-11, Vol.24 (22), p.4049
• Main Authors: Strižincová, Petra, Ház, Aleš, Burčová, Zuzana, Feranc, Jozef, Kreps, František, Šurina, Igor, Jablonský, Michal
• Format: Article
• Language: English
• Subjects: Antioxidants; Antioxidants - chemistry; Bark; Carbon dioxide; Carbon Dioxide - chemistry; Carbon Dioxide - isolation & purification; Chemical Fractionation; Cytotoxicity; Design of experiments; Ethanol; experimental design optimization; extractives; Factorial design; Gallic acid; Investigations; Models, Chemical; Molecular Structure; Optimization; Particle size; Phenols; Phytochemicals; Picea - chemistry; Picea abies; Pine trees; Plant Bark - chemistry; Plant extracts; polyphenolic compounds; Polyphenols; Polyphenols - chemistry; Pressure; Softwoods; Solvent extraction processes; spruce bark; supercritical extraction; Temperature; Trees; Variance analysis; Yield
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules24224049

The present study described the optimization of the extraction process with carbon dioxide in supercritical state for obtaining extractives, especially polyphenols from softwood bark, Norway spruce ( (L.) Karst.). Using a full 2 factorial design of experiments, the effect of varying the working parameters on the yield of extractives was studied for the following ranges: temperature 40-100 °C, pressure 1050-9000 psi (7.2-62 MPa), and concentration of EtOH/water co-solvent mixture 40-96.6%. In addition, total phenolics content and the antioxidant capacity of the spruce bark extract were determined. The optimum operating conditions for the yield of extractives were identified as 73 °C, 6465 psi (44.5 MPa), and 58% EtOH/water cosolvent concentration for a yield of 8.92%. The optimum conditions for achieving a total phenolics content of 13.89 mg gallic acid equivalent (GAE)/g dry extract were determined as: 45 °C, 1050 psi (7.2 MPa), and 96.6% EtOH/water mixture.