The effect of whey/soy protein fibril systems on the properties of fish gelatin stabilized emulsion gels

Abstract

In this study, we investigated the effects of whey protein isolate fibril systems (WPF) and soy protein isolate fibril systems (SPF) combined with fish gelatin (FG) on the formation of emulsion gels. The aim was to evaluate how the origin and concentration of these fibril systems influence the structural, interfacial, and rheological properties of FG-stabilized emulsion gels, as well as their impact on creaming stability. FG was mixed with varying concentrations (0–2%) of WPF and SPF at pH 7, forming electrostatic complexes due to the opposite charge interactions between FG and the protein fibril dispersions. The results revealed that adding WPF and SPF increased surface hydrophobicity and enhanced interfacial activity. Increasing WPF concentrations led to a gradual decrease in emulsion droplet size owing to the increased absorbed protein content at the interface. Additionally, there was a significant improvement in the storage modulus of the emulsion gels. Conversely, introducing a small amount (0.1%) of SPF to FG increased the particle size, suggesting potential coalescence, but further increases in SPF concentration considerably reduced the particle size. Furthermore, SPF enhanced the viscoelasticity at lower concentrations, possibly due to a more uniform distribution within the continuous phase. However, excess SPF reduced the storage modulus of the emulsion gels. Our study provides valuable theoretical insights for the application of protein fibril systems in emulsion gel systems.