Supercritical fluid extraction method for multi class bioactives: a sustainable approach to Olea europaea pruning residue valorization

Olive pruning residues represent a promising source of bioactive compounds. This study presents the first single-step supercritical fluid extraction (SFE) approach for the simultaneous recovery of phenols, carotenoids, and tocopherols from Olea europaea leaves and branches. Using bio-ethanol-modified CO 2 , the optimized method achieved recoveries of 76% for oleuropein, 84% for α-tocopherol, 88% for lutein, and 90% for β-carotene. Compared to ultrasound-assisted extraction (UAE), SFE yielded lower absolute amounts than the exhaustive UAE reference methods, while maintaining high recovery efficiencies and offering advantages in terms of automation, solvent safety, and sustainability. HPLC-PDA/MS and FLD analyses confirmed that leaves were richer than branches, with oleuropein as the predominant phenolic compound. Greenness evaluation (AGREEprep) yielded higher scores for SFE (0.44) than UAE (0.15). These results establish SFE as a scalable and environmentally sustainable strategy for valorizing olive pruning residues into functional food ingredients, supporting circular economy models.