Biorefining of industrial hemp (Cannabis sativa L.) threshing residues into cannabinoid and antioxidant fractions by supercritical carbon dioxide, pressurized liquid and enzyme-assisted extractions

•Hemp threshing residue biorefined by high pressure and enzyme assisted extractions.•Supercritical CO2 extraction optimized for lipophilic extracts and cannabinoids.•Pressurized liquid extraction effectively recovered phenolics and antioxidants.•EAE increased the yield of water-soluble fraction and monosaccharide content.•In total>50% of soluble substances were recovered from hemp threshing residues. C. sativa threshing residues were biorefined by consecutive supercritical carbon dioxide (SFE-CO2) pressurised liquid (PLE) and enzyme-assisted extractions (EAE). SFE-CO2 at optimised parameters yielded 8.3g/100g of lipophilic fraction containing 0.2 and 2.2g of cannabidiol and cannabidiolic acid per 100g of threshing residues, respectively. The recovery of cannabinoids from plant material was >93%. PLE gave 4.3 and 18.9g/100g of flavonoid-containing polar extracts, while EAE added 20.2% (w/w) of water-soluble constituents and increased the release of mono- and disaccharides by up to 94%. Antioxidant capacity of non-polar and polar fractions was in the range of 1.3–23.5mg gallic acid equivalents/g DW and 0.6–205.2mg Trolox equivalents/g DW, with the highest activities of PLE-EtOH/H2O extract. The combined SFE-CO2, PLE and EAE reduced antioxidant capacity of starting plant material by 90–99%, showing that suggested multistep fractionation procedure is efficient in the recovery of a major part of the antioxidatively active constituents from hemp threshing residues.