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

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.