Synergistic effects of phosphorylation modification and protocatechuic acid copolymerization improve the physical and oxidation stability of high internal phase emulsion stabilized by perilla protein isolate

A compact antioxidant interfacial layer was fabricated by combining phosphorylation treatment with protocatechuic acid (PA) copolymerization to enhance the physical and oxidative stability of high internal phase emulsions (HIPEs) prepared using perilla protein isolate (PPI). The covalent binding between PPI and phosphate groups induced conformational changes, facilitating the interaction between PPI and PA. The formed phosphorylated PPI-PA conjugates (LPPI-PA) exhibited a reduced particle size of 196.75 nm, promoting their adsorption at the interface. HIPEs prepared by LPPI-PA conjugates showed higher storage stability due to decreased droplet size, increased interfacial protein adsorption content (90.48%), and the formation of an interconnected network within the system. Additionally, the combination of LPPI and PA anchored PA to the interface, significantly inhibiting lipid oxidation in HIPEs as evidenced by low levels of lipid hydroperoxide (30.33 μmol/g oil) and malondialdehyde (379.34 nmol/g oil). This study holds significant implications for improving the stability of HIPEs.