Valorization by compressed fluids of Arctium lappa seeds and roots as a sustainable source of valuable compounds

An example of a sustainable and renewable but highly underused biomass with considerable potential as a source of a wide spectrum of valuable compounds is Arctium lappa, also known as burdock. In this work the feasibility and efficiency of advanced techniques applying compressed fluids to recover value from burdock seeds and roots was examined, and the influence of operating conditions and solvents on the yield, quality and composition of the extracts obtained was studied. For the seeds, compressed propane at two temperatures and pressures (6–20) MPa, and either neat supercritical CO2 (scCO2) or scCO2 with a co-solvent were tested. For the roots, extractions with scCO2 and different polarities co-solvents were performed at two temperatures and pressure 20 MPa. Pressurized liquid extractions with ethanol, methanol, water and methanol/water at 15 MPa and 353.15 K were also tested. The extracts obtained were evaluated by extraction yield, total phenolic content and antioxidant activity, and compared with Soxhlet with organic solvents. The rich spectrum of valuables - fatty acids and phenolics of different chemical complexities was identified and quantified applying GC-FID, GC–MS, LC – MS/MS. The results of this extensive study demonstrate that compressed fluids techniques are effective for value added product generation from burdock seeds and roots biomass.