Fabrication and Characterization of High Internal Phase Pickering Emulsions Stabilized with Quaternary Complexes of Lactoferrin, Epigallocatechin-3-Gallate, High Methoxylated Pectin and β-Cyclodextrin

In this study, self-assembled quaternary complexes of lactoferrin (LF), epigallocatechin-3-gallate (EGCG), high methoxylated pectin (HMP) and β-cyclodextrin (β-CD) were constructed and characterized, and successfully utilized for stabilizing high internal phase Pickering emulsions (HIPPEs). In comparison with ternary complexes, the quaternary complexes had lower interfacial tension (reduced by about 3 mN/m) and more appropriate wettability (contact angle close to 90°), and were more effective in stabilizing HIPPEs (smaller droplet size and enhanced homogeneity). The dense cross-linking network of the quaternary complexes endowed HIPPEs with higher viscoelasticity (increasing elasticity and viscosity by up to 1.9 and 5.3 times, respectively), textural properties, 3D printing characteristics, and refrigeration stability. β-CD significantly improved the antioxidant activity of HIPPEs (up to 2.1 times) by interfering with the combination of EGCG with LF or HMP. In addition, the self-assembly sequence could flexibly regulate the structures and emulsifying properties of the quaternary complexes, with the LF-β-CD-EGCG-HMP complex having the most pronounced effect. In conclusion, this study provides a theoretical basis for the construction of protein-polyphenol-polysaccharide-polysaccharide complexes and their applications in HIPPEs.