Effects of pulsed electric field (PEF) pretreatment on the extraction yield and characteristics of rapeseed cake protein

Rapeseed cake (RC), a protein rich by-product of oil extraction, is an underutilized resource with potential for plant-based food applications. This study investigated the effects of pulsed electric field (PEF) pretreatment on the extraction, functional, and structural properties of rapeseed protein concentrate (RPC). RC was treated under four PEF conditions, combining two pH values (7.0 and 11.5) and two specific energy levels (24 and 71 kJ/kg). PEF treatments caused notable changes in the secondary structure of rapeseed protein, particularly a reduction in α-helix content, which was associated with enhanced protein solubility and increased viscosity under higher specific energy, neutral pH conditions (PEF 4). Oil-holding capacity and emulsifying properties remained largely unchanged. These findings demonstrate that PEF can selectively modulate protein structure to improve specific functional properties, revealing a condition-dependent effect that can be exploited in protein extraction and formulation. By linking structural alterations to functional outcomes, this work provides novel insights into the use of non-thermal PEF technology for valorizing RC and tailoring plant protein functionality. Overall, the study demonstrates how PEF influences protein properties, offering a foundation for future research on improving plant protein functionality and exploring potential applications in plant-based and hybrid food products.