Enhancing the stability of ovalbumin-based Pickering emulsions using hydroxypropyl methylcellulose at varying ratios

Thermally denatured ovalbumin (OVA) was used to prepare particles for stabilizing Pickering emulsions. OVA could be partially unfolded through controlled thermal denaturation, exposing hydrophobic groups and enhancing its interfacial adsorption and emulsification ability compared to other proteins and polysaccharides. Partial replacement of OVA with hydroxypropyl methylcellulose (HPMC) modulated the formation of a three-dimensional network in the continuous phase, thereby influencing the emulsion's macrostructure. Cryo-scanning electron microscopy (cryo-SEM) revealed that the oil-water interface was primarily stabilized by OVA-based Pickering particles, while the addition of HPMC transformed the bulk-phase OVA particles from a simple stacked arrangement into a more stable three-dimensional network. This transformation significantly reduced droplet size and improved the macroscopic stability of the emulsion when observed on day 29 of storage. Further analysis using FTIR and TGA revealed that interactions had occurred between OVA and HPMC, as indicated by an increased peak height and width in the 3,200–3,600 cm⁻¹ region, as well as a DTG peak shift from 328 to 347 °C. In addition, molecular dynamics simulations and molecular docking further confirmed that hydrogen bonding had occurred between OVA and an HPMC molecule, elucidating the mechanism by which mixing OVA-HPMC ratios affected the microstructure at the molecular level. This study provides theoretical insights into the stabilization mechanism of Pickering emulsions based on protein-polysaccharide complexes.