Extraction and microencapsulation of bioactive compounds from pomegranate (Punica granatum var. Wonderful) residues

Pomegranate peels and seeds are industrial residues considered interesting sources of punicalagin (PU) and punicic acid (PA), respectively. To optimise their extraction process and protect them against environmental factors, pomegranate residues were extracted with supercritical CO2 (SC-CO2) using a Box–Behnken design and then optimal extracts encapsulated by spray-drying applying a 22 central composite design. Peel extracts showed a PU content of 0.4–9.5% with optimal extraction conditions of 400 bar, 43 °C and 20% ethanol. On the other hand, SC-CO2 seed extracts showed a PA content of 65.1–78.4% with 450 bar, 48 °C and 10% ethanol as optimal extraction parameters. Otherwise, the encapsulation efficiency of SC-CO2 extracts was significantly affected by core/wall material ratio and its quadratic effect. This parameter ranged from 35.1% to 72.4% for peel extracts and from 68.2% to 92.7% for seed extracts. Results showed that the proposed technologies are a feasible approach to the integral utilisation of residues from the pomegranate industry.