Characterization of whey protein concentrate-maltodextrin-pomegranate peel phenolic compounds ternary conjugate as a novel food-grade stabilizer for nano-pickering emulsion.

Developing effective food-grade stabilizers for nano-Pickering emulsions (NPEs) presents a considerable challenge, as conventional binary systems often exhibit limited functionality. The potential of ternary conjugates incorporating bioactive phenolic compounds remains underexplored. This study aimed to synthesize a novel stabilizer through covalent bonding of whey protein concentrate (WPC), maltodextrin (MD), and pomegranate peel extract (PPex) under alkaline conditions. Ultrasonication-assisted extraction (UAE), microwave-assisted extraction (MAE), and their combination (UM) were employed to extract phenolic compounds from pomegranate peel. By optimizing MAE power (300-600 W), UAE power (200 W), and extraction times (5, 10, 20 min), the highest levels of phenolic compounds (421 ± 0.13 mg Gallic acid/100 g dry peel) and antioxidant activity (90.54 ± 0.481 %) were achieved using UAE at 200 W for 30 min combined with MAE at 300 W for 5 min. Ternary conjugates were formulated with varying concentrations of PPex (0.04 %, 0.08 %, and 0.12 %). Fourier-transform infrared spectroscopy (FTIR) confirmed the interactions between WPC, MD, and PPex. NPEs prepared with ternary conjugates containing 0.12 % PPex exhibited superior stability, enhanced antioxidant activity, and reduced release of free fatty acids during in vitro digestion. Furthermore, the emulsion demonstrated a progressively organized network microstructure, contributing to improved dispersion stability. This study underscores the potential of a ternary conjugate with 0.12 % PPex to enhance NPE stability, presenting a novel approach to developing stable food-grade NPE for functional foods. Additionally, it adds value to pomegranate peel by forming natural protein-polysaccharide- phenolic compounds complex particles.