Integrated green-based processes using supercritical CO₂ and pressurized ethanol applied to recover antioxidant compouds from cocoa (Theobroma cacao) bean hulls

A customised multi-task equipment, combining supercritical carbon dioxide (sc-CO₂) and pressurized liquid extraction (PLE) with ethanol, was developed to selectively recover antioxidant compounds from cocoa bean hulls, praising this agro-industrial by-product. Total phenolic content of the extracts was determined by Folin-Ciocalteu method, while the in vitro antioxidant activity was obtained by DPPH and by β-carotene bleaching methods, whereas the chemical profile of selected extracts was carried out by gas-chromatography-mass spectrometry (GC–MS) analysis. PLE extracts from sc-CO₂ residue showed higher total phenol content and antioxidant performance, compared to extracts from separated methods, providing TPC values from 35 to 51 mg GAE g⁻¹ and EC₅₀ values from 115 to 177 μg mL⁻¹, respectively. The combined application of sc-CO₂ and PLE to selectively recover bioactive extracts from cocoa bean hulls, representing green methods, is a promising alternative to provide supplies for cosmetic and food industries, performed at a costumised low cost multi-task unit.