Ultrasound-Assisted Extraction of Bioactive Compounds from Pomegranate Peel Using Vinegar with α-Cyclodextrin as a Green Solvent

The recovery of polyphenols from pomegranate peel is limited by conventional extraction methods that rely on organic solvents. This study evaluated the ultrasound-assisted extraction (UAE) of dehydrated pomegranate peel using greener solvent systems based on distilled vinegar combined with α-cyclodextrin (αCD) to enhance the solubilization and recovery of phenolic compounds. The resulting extracts were characterized by total antioxidant capacity (DPPH free radical scavenging assay), total phenolic content (TPC, Folin–Ciocalteu assay), targeted phenolic analysis (HPLC-QTOF-MS analysis) and antimicrobial activity (Kirby–Bauer well-diffusion assay) against Listeria monocytogenes and Salmonella enterica. The unbuffered vinegar system (V2) exhibited the highest antioxidant capacity (2372.1 ± 109.7 µmol TE/g DW), significantly exceeding the methanolic control (1147.5 ± 477.6 µmol TE/g DW; p < 0.05). The vinegar-αCD system (V2-10) showed the highest TPC (196.2 ± 15.6 mg GAE/g DW), while HPLC-QTOF-MS identified punicalagin as the predominant phenolic compound (26.1–64.5 mg/g DW), with the highest total quantified phenolic content (76.2 mg/g DW). Vinegar-based extracts also inhibited L. monocytogenes (33.1–46.7 mm) and S. enterica (19.9–24.3 mm). Overall, UAE combined with vinegar-αCD solvents represents a promising green extraction strategy for obtaining polyphenol-rich extracts from pomegranate byproducts, providing comparative insights into solvent-dependent differences in phenolic profiles and bioactivity.