Influence of the Emulsifier Sodium Caseinate–Xanthan Gum Complex on Emulsions: Stability and Digestive Properties

In this study, virgin coconut oil (VCO) nanoemulsions were prepared by ultrasonication using a sodium caseinate (SC) and xanthan gum (XG) complex as an emulsifier. The stability and digestion characteristics of SC/XG–VCO emulsions formed by co-adsorption and SC–VCO–XG emulsions formed by layer adsorption were compared. The stability of the two emulsions was studied under different pH, ionic strength, heat treatment, freeze–thaw cycles, and storage conditions, and the droplet size and zeta potential were used as indicators to assess the stability. In addition, the stability of oxidation and the digestive properties of both emulsions were studied. It was found that the SC–VCO–XG emulsions had better environmental stability, oxidative stability, storage stability, and digestibility compared to SC/XG–VCO emulsions. This study has shown that the formation method of protein–polysaccharide stabilized emulsions has an impact on the stability and digestibility properties of the emulsions, and that the emulsion carriers constructed by layer adsorption are more suitable for subsequent industrial production and development.