Insights into the interaction of DHA/EPA-containing phospholipids with modified whey protein isolate (mWPI) and...

This study developed a composite microgel system utilizing modified whey protein isolate (mWPI) and chitosan quaternary ammonium salt (CQAS) for encapsulating docosahexaenoic acid and eicosapentaenoic acid-containing phospholipids (PL-DHA/EPA). Single-component systems exhibited limited encapsulation efficiencies of 15.50% (mWPI-PL) and 30.92% (CQAS-PL), attributed to high-pressure homogenization-induced protein denaturation and insufficient electrostatic interactions, respectively. The composite mWPI-CQAS-PL system achieved 88.75% encapsulation efficiency through synergistic electrostatic charge neutralization and interpenetrating polymer network formation, with positive zeta potential (+41.5 mV) ensuring colloidal stability and complete absence of phase separation over thirty days. Microstructural characterization revealed bi-layered particle architecture (approximately 10 μm) featuring CQAS-rich outer shells and mWPI cores with uniform phospholipid distribution. Fluorescence spectroscopy evidenced protein-phospholipid interactions through excimer formation (480 nm) and microenvironmental polarity changes (430 nm), while molecular docking validated hydrogen bonding interactions. This mechanistic framework establishes design principles for advanced phospholipid delivery systems, significantly advancing marine lipid processing through innovative encapsulation strategies that preserve bioactivity while enhancing delivery performance.