Efficient recovery of procyanidins from grape residue by UAE-NADES and macroporous resin

This study developed a green, efficient method for extracting and purifying procyanidins (PC) from grape pomace (GP) using ultrasound-assisted extraction (UAE) with natural deep eutectic solvents (NADES). The process was optimized through single-factor experiments and Box-Behnken Design (BBD) response surface methodology (RSM). Bioactive substances and antioxidant activities in the extracts were compared, and scanning electron microscope (SEM) analysis revealed the synergistic effects of UAE and NADES. A second-order kinetic model described the extraction process, and scale-up experiments confirmed feasibility. Macroporous resin adsorption and elution conditions were optimized for improved PC purification. The final product's purity, ingredient, and NADES solvent recovery were evaluated. This study offers a green, efficient alternative for extracting high-value bioactive compounds from food by-products, with broad application potential.