Addition of cationic guar-gum and oleic acid improved the stability of plasma emulsions prepared with enzymatically hydrolyzed egg yolk

Abstract The plasma, which is an effective contributor to the emulsifying properties of egg yolk, could offer new pathways in emulsification technology. This study investigated the influence of cationic guar gum (CGG) and oleic acid (OA) on the emulsion stability of the subtilisin-hydrolyzed natural plasma (NP). The results showed that the enzyme-hydrolyzed plasma (EP) contributed to the higher ζ-potential, smaller D[4,3] and lower initial interface tension of the droplets than the NP, which improved emulsion stability. The enzymatic hydrolysis of plasma enhanced the electrostatic repulsions of the droplets and accelerated the adsorption of proteins at the interface. As the addition of CGG increased from 0.020% to 0.040% (w/v), the EP droplets with higher ζ-potential and smaller D[4,3] were formed because of the interactions between the interface membrane. The addition of CGG at 0.030% (w/v) significantly increased the emulsifying stability index of the EP (from 22.9 to 55.4). After 375 min of holding, the cream layer decreased from 68% to 58% when 0.040% (w/v) CGG and 1% (v/v) OA were added to the emulsion. These results confirmed that the EP with CGG and OA enhanced the viscosity and the weak-gel structure, which improved the stability of the emulsion.