Efficient stabilizing effect of low-dose zein/xanthan gum nanoparticles at the oil-water interface

The inherent propensity for aggregation necessitates the use of high concentrations of protein-polysaccharide nanoparticles to achieve stable Pickering emulsions. This study employed xanthan gum (XG) to mitigate the pronounced aggregation of zein nanoparticles by structure construction, thereby enhancing the emulsifying efficiency of zein/XG (Z/XG) nanoparticles. The Z/XG nanoparticles displayed significantly enhanced dispersity, with the absolute ζ-potential increasing from 6.25 mV to approximately 55 mV as the zein/XG ratio was optimized from 1:0 to 1:0.2. The Z/XG nanoparticles exhibited core-shell structure with zein as the core and XG as the shell, facilitated by electrostatic interactions. This structural transformation enables Z/XG nanoparticles to more readily adsorb at the oil-water interface. The addition of excess XG can further augment the stability of Z/XG emulsions due to the formation of XG networks in the continuous phase preventing the coalescence of oil droplets. It was demonstrated that a low concentration of 0.4 % Z/XG nanoparticles is sufficient to maintain emulsion stability under typical conditions of heating, pH, and ionic treatments. Overall, this study has developed a highly effective strategy to overcome the application challenges associated with protein-polysaccharide Pickering emulsions, broadening their potential applications in the food, cosmetic, and pharmaceutical industries.