Effect of flaxseed gum on the formation, stability and anthocyanins loading of water in oil (W/O) emulsion

Flaxseed gum (FG) has been reported as a natural emulsifier to stabilize oil-in-water (O/W) emulsions, but the effect of FG on water-in-oil (W/O) emulsions remains underexplored. Herein, the influences of FG on the formation, stability, and anthocyanin loading of W/O emulsion were investigated. Results demonstrated that FG with moderate concentration range could decrease the droplet size and polydispersity index (PDI), while increase zeta potential, apparent viscosity, and modulus values (G’ and G’’). Emulsions containing FG exhibited more uniform droplet distribution, increased viscoelasticity, and better stability. Moreover, the addition of FG within the aqueous phase of W/O emulsions increased loading efficiency and encapsulation stability of anthocyanins derived from black rice bran. Anthocyanins exhibited no significant effect on micromorphology and particle size distribution of the emulsions. W/O emulsions significantly improved thermostability and photostability of anthocyanins in a FG concentration-depended manner. Mechanistically, interfacial synergy between FG and PGPR contributes to the stabilization of the oil-water interface, while interactions between FG and anthocyanins in the aqueous phase further enhance encapsulation efficiency and stability of BRAs. This work exemplifies the development of natural alternatives to chemically synthesized emulsifiers, and provides new insights for construction of robust W/O emulsions and their derived delivery systems.