Pulsed Electric Field-Modified Hot-Pressed Peanut Meal Protein for Gel-like High Internal Phase Emulsions

Hot-pressed peanut protein isolate (HPPI), severely denatured during oil extraction, exhibits limited interfacial functionality, restricting its application in structured emulsions. In this study, high-voltage pulsed electric field (PEF) was employed to modulate the structural and interfacial properties of HPPI, a sustainable food biopolymer. PEF treatment induced conformational rearrangement, including a shift in secondary structure from α-helix to β-sheet and increased exposure of hydrophobic residues. These structural changes reduced particle size and increased surface charge, with optimal modification at 2.5 kV/cm. Consequently, interfacial activity was significantly improved, as evidenced by decreased interfacial tension and increased dilatational modulus, indicating a more elastic interfacial film was formed. The modified protein (2.5 kV/cm) effectively stabilized high internal phase emulsions (HIPEs) with typical gel-like viscoelastic features, achieving optimal stability at 2.0 wt% protein concentration, 75% oil phase fraction, and NaCl concentrations below 100 mM. Overall, PEF treatment enhances the interfacial functionality of HPPI by modulating its structure and interfacial film properties, thereby facilitating the fabrication of biopolymer-based food-grade HIPEs for practical food applications.