Extraction kinetics and yield optimization of aronia pomace using supercritical CO₂

The increasing interest in Aronia melanocarpa berries for their antioxidant properties sets the necessity to define sustainable strategies to valorize the by-products. This study investigates the use of supercritical carbon dioxide (scCO2) extraction, with and without ethanol as a co-solvent, for recovering lipophilic and phenolic compounds from aronia pomace. Extractions were performed at 20, 30, and 40 MPa and temperatures of 50, 70, and 90 degrees C. A yield of about 2.7 g per 100 g of dried pomace was obtained at 40 MPa and 90 degrees C. However, the highest total phenolic content of about 165 mg of gallic acid equivalent per 100 g of dried pomace was achieved with 5 % ethanol co-solvent at 50 degrees C and 30 MPa. The lipid extracts were rich in linoleic acid and the wax portion increased under low-density scCO2 conditions. A feedforward neural network was developed to model extraction kinetics and predict yield as a function of temperature, pressure, and time, demonstrating high predictive accuracy. These findings highlight scCO2 extraction as a viable route for the efficient and selective recovery of valuable bioactives from aronia pomace, contributing to a circular bioeconomy.