Formation of hydrophilic co-assemblies with improved functional properties between tilapia protein isolate and sodium caseinate

Functional enhancement of aquatic proteins still faces great challenges, resulting in their highly under-utilized applications in the field of intensive food processing. In this study, the tilapia protein isolate-sodium caseinate co-assemblies were prepared using a pH cycle strategy. The aggregation properties, component interactions, and functional properties of the formed co-assemblies were investigated. Results of particle size, zeta potential, surface hydrophobicity, and SEM indicated that tilapia protein isolates and sodium caseinate generated co-assemblies with reduced aggregation properties. Component interactions revealed that sodium caseinate binds to tilapia protein isolate mainly through hydrogen bonding and hydrophobic interactions, which inhibits the refolding of tilapia protein isolate to form more structurally ordered hydrophilic co-assemblies. Functional properties studies showed that co-assemblies with improved water solubility (reached 77.08%) and emulsification properties compared to tilapia protein isolated when the mass ratio of tilapia protein isolated to sodium caseinate was T/N = 1:1. In this experiment, the functional properties of tilapia protein isolate were enhanced by a simple, green, and efficient method, which is expected to be applied in the food industry.