Intensity-dependent modulation of duck myofibrillar protein unfolding-aggregation kinetics by pulsed electric fields

Pulsed electric field (PEF), an emerging non-thermal processing method, has been extensively used to modulate the physicochemical and structural properties of proteins. This study systematically investigates the effects of PEF at varying electric field intensities (EFIs) on the physicochemical characteristics and conformation of duck myofibrillar proteins (DMPs). Under low-EFI conditions (1 and 2 kV/cm), a significant increase in protein solubility was found, accompanied by a reduction in average particle size. These results suggest that applying an electric field disrupts the non-covalent interactions that maintain protein aggregates, thereby facilitating the dissociation of macromolecular complexes. Meanwhile, a decrease in α-helix content indicated a more disordered overall protein structure. In contrast, high-EFI groups (3 and 4 kV/cm) exhibited intense electric fields, prompting burial of exposed hydrophobic regions. This structural alteration facilitated aggregation among DMPs and led to the sequestration of certain fluorescent groups. In addition, surface topography analysis using atomic force microscopy (AFM) revealed morphological changes consistent with aggregation. Furthermore, molecular dynamics simulations validated these conclusions by demonstrating a structural evolution pattern in which DMPs gradually unfolded and subsequently aggregated as EFI increased. Thus, this study provided comprehensive insights into the mechanisms of PEF regulation in protein molecules and established a theoretical foundation as well as technical support for expanding its applications in protein-containing food processing.