The Properties and Emulsion Stabilization of Fish Gelatin Regulated by Introducing Pectin

In this study, the complexes (FG-P) based on fish gelatin (FG) and pectin (P) were prepared by a simple physical blending within a range of pectin concentrations (0-2%, w/v). The structure, interface, and emulsification properties of the obtained FG-P were analyzed. The binding between FG and pectin was dominated by electrostatic interaction and hydrogen bonding. Introducing pectin substantially increased the viscosity of FG-P. The water contact angle of FG-P gradually decreased with increasing pectin concentration. The highly interfacial viscosity and hydrophilicity of FG-P hindered the interfacial adsorption at the oil/water phase, thereby increasing the interfacial tension and phase angle. This was further manifested as an increase in the viscous modulus and a decrease in both the total modulus and elastic modulus. Despite the inhibition of interfacial adsorption, the unabsorbed FG-P was uniformly dispersed in the continuous phase to form a compact network structure, accompanied with improved rheological properties. Correspondingly, the emulsion precipitation phenomenon was effectively inhibited, and the stability of FG-P stabilized emulsions was improved with decreased droplet size.