abstract
- Rising demand for natural products is propelling the creation of selective, sustainable extraction methods. This work explores recovering bioactive constituents from Berberis microphylla G. Forst. (calafate) berries using supercritical CO¿ modified with aqueous ethanol. Two substrate delivery approaches packed bed and suspension were assessed under biphasic conditions featuring a CO¿-rich gaseous phase in equilibrium with a water-rich liquid phase. Extractions were performed at 40 or 70 °C and 20 or 30 MPa, with the liquid phase containing 35, 45, or 85 wt% water on a CO2-free basis (cfb). The packed-bed setup gave the highest total solids recovery at 35 wt% water (cfb), reaching 30.6% relative to conventional extraction. In contrast, the suspension mode produced the greatest total polyphenol yield at 40 °C and 30 MPa with 35% water, yielding the most concentrated extract (18 mg kg¿1 GAE per dry substrate). Anthocyanin recovery peaked under suspension conditions with 85 wt% water (cfb), a condition that favors the solubilization of these highly polar compounds. These findings highlight the decisive roles of feeding mode and water content in steering selectivity during two-phase, modifier-assisted SC-CO¿ extraction of bioactives.