Extraction of low-molar-mass phenolics and lipophilic compounds from Pinus pinaster wood with compressed CO2

⿢Pinus pinaster wood samples were extracted with near and supercritical CO2.⿢The effect of pressure (10⿿25 MPa), temperature (30⿿50 °C) and ethanol as co-solvent was assessed.⿢Under selected conditions (25 MPa, 50 °C, 10% ethanol), 4 wt% was extracted.⿢One gram of extract contained 76 mg of GAE and was equivalent to 0.3 g Trolox.⿢Selected extracts contained 30% resin acids and 10% of the sum of flavonoids, lignans, stilbenes and juvabiones.

Near-supercritical and supercritical CO2 was used to extract low-molar-mass phenolics and lipophilic compounds from Pinus pinaster wood. Extraction of samples containing sapwood and knotwood was carried out at 10⿿25 MPa and 30⿿50 °C to assess the influence of the operational conditions on the yields of total extracts and phenolics, as well as on the radical scavenging capacity of extracts. The use of ethanol as a co-solvent increased both the extraction yields and the concentration of phenolics in extracts. Operating under selected conditions (25 MPa, 50 °C, 10% ethanol), the extraction yield accounted for 4.1 wt% of the oven-dry wood. The extracts contained up to 7.6 g of phenolic compounds (measured as gallic acid equivalents) per 100 g extract, and showed one third of the radical scavenging capacity of Trolox. Native resin acids accounted for about 24 g per 100 g extracts, whereas flavonoids, lignans, stilbenes and juvabiones were found at lower proportions.

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