Extraction of Antioxidants from Grape and Apple Pomace: Solvent Selection and Process Kinetics

Polyphenols have become a research target due to their antioxidant, anti-inflammatory and antimicrobial activity. Obtention via extraction from natural sources includes the revalorization of food wastes such as grape pomace (GP) or apple (AP). In this work, GP AP were submitted liquid–solid using different solvents industrial interest. Process kinetics studied measuring total phenolic content (TPC) antioxidant capacity (AC), while liquor composition was analyzed employing chromatographic methods. Extraction processes water-solvent mixtures stood out better options, with particular preference for water 30%–ethanol 70% (v/v) at 90 °C, mixture that quickly extracts up 68.46 mg GAE/gds (Gallic Acid Equivalent per gram dry solid) 122.67 TEAC/gds (TROLOX equivalent in case GP, ethylene 10%–ethylene glycol 90% 70 °C allows reach 27.19 27.45 TEAC/gds, AP. These can be well-described by second-order kinetic model solubility-related parameter first fast-washing two parameters slow mass transfer controlled second phase. liquors found rich quercetin sugar moieties highlighted flavonols, cinnamic acids, anthocyanins. Therefore, identical conditions comparative analysis TPC AC results time, we concluded ethanol/water are adequate polyphenols high efficiency environmentally benign nature.