Fractionation of phytocannabinoids from industrial hemp residues with high-pressure technologies

Abstract Cannabidiol (CBD) and cannabidiolic acid (CBDA)- rich extracts were obtained from industrial hemp threshing residues by sub- and supercritical carbon dioxide extraction. The supercritical CO2 extraction yielded 2.5 - 9.2 g/100 g of lipophilic raw extracts containing 0.2 – 1.8 g of cannabinoids per 100 g of various threshing residues. Carrying out the supercritical extraction with fractionation, the extract from the 1st separator (operated at 8 MPa and 40 °C) contained 30 times more CBD than the extract from the 2nd separator. Applying ethanol cosolvent to scCO2 in 10% (w/w) increased the extraction yield and the yield of main cannabinoids by 30%. Subcritical CO2 extraction resulted in a yield of 2.5 g/100 g dry material with high CBD content (0.9 g/100 g dry threshing residue) in an extract with less complexity and produced with 18% less solvent usage at mild conditions (8 MPa and 27 °C). The recovery of high cannabinoid-content extracts from industrial hemp residues makes this waste suitable for producing value-added extracts for either cosmetic or food industry.