Pulsed electric field-driven electrokinetic removal of starch granule-channel proteins for enhanced starch modification

Efficient, eco-friendly removal of starch granule-channel proteins (SGCP) to enhance modifier penetration has been challenging. Current methods using chemical/biological reagents (denaturants, alkalis, proteases) suffer from toxicity, long processing times, and non-reusability. Inspired by capillary electrophoresis for protein separation, this study successfully removed SGCP from maize starch within 30 min using an 8 kV/cm pulsed electric field (PEF). This method only requires direct treatment of starch aqueous suspension to remove SGCP, and it achieved 29.9 % protein removal efficiency (primarily SGCP, along with minor amounts of intrinsic and storage proteins), comparable to the protease method but significantly faster. The mechanism of PEF-induced SGCP migration was explained using an electrokinetic migration velocity model based on Debye-Hückel-Henry theory. Using oxidized starch as a case study, we demonstrated that SGCP removal improved modification by increasing starch channel pore volume and accessibility. This work introduces an efficient, green SGCP removal technique and provides new insights into how PEF enhances starch modification, offering significant implications for improving modified starch quality and meeting sustainability criteria.