Exploring the role of protein fibrillation in modulating water-in-oil-in-water emulsion properties: a study on rice bran protein

Abstract Protein-based nanoparticles have gained attention in stabilising emulsions since it has a wide range of application. This study utilised rice bran protein (RBP) as a raw material to form RBP fibrils via acid heat treatment. Transmission electron microscopy revealed after 6 hr of heating, RBP adopted an elongated fibrillar structure. During fibril formation, an increase in thioflavin T fluorescence intensity was observed, along with the emergence of numerous well-organised β-sheet configurations. The water-in-oil-in-water (W/O/W) double emulsions prepared during the fibrils formation were analysed by particle size, viscosity, and laser coaggregation microscopy. The results indicate that, compared to unheated RBP, emulsions prepared with RBP fibers exhibited reduced aggregation, a significantly smaller particle size, significantly increased viscosity, a greater thickness of RBP fibers at the oil–water interface, and significantly enhanced stability (p < .05). The improved emulsion characteristics were directly linked to the interfacial features of the RBP fibrils. This study provides a method for constructing stable W/O/W ratios.