Improved recovery of antioxidants from aronia juice processing residue via optimization of extraction variables based on multi-prediction models

Aronia melanocarpa, which has attracted attention for its outstanding antioxidant activity, is usually consumed as a juice, leaving considerable residue after processing into beverages. Recycling these by-products as feedstock for biorefineries is an important strategy for achieving a sustainable circular economy through biowaste management. In this study, the optimal extraction conditions for efficient antioxidant recovery from A. melanocarpa juice-processing residue (AJPR) were determined using statistical methods. Based on the Plackett-Burman design (PBD), four variables (shaking speed, solid loading, ethanol concentration, and total volume) were found to have significant effects on antioxidant extraction. The optimum points of the selected four variables were calculated by multi-regression models from response surface methodology (RSM), and the determined conditions were as follows:196.2 rpm, 71.3 g/L, 54.3% ethanol, and 137.8 mL of total volume. The DPPH• IC50 and ABTS•+ TEAC value of AJPR extracts were determined to be 2.02 mg/mL and 11.49 mg/mL, respectively, exhibiting promising potential as an antioxidant. The recovered polyphenol, flavonoid, and anthocyanin contents were 80.4, 42.5, and 14.1 mg/g-biomass, respectively. We show that bioengineering technologies can be used to achieve a circular economy by recycling discarded biowaste into value-added substances.