Novel food-grade water-in-water Pickering emulsions for encapsulation and delivery of hydrophilic bioactives.

Curcumin exhibits excellent bioactive potential, but its practical applications in functional foods are limited. In this study, novel food-grade water-in-water (W/W) Pickering emulsions constructed by maltodextrin/pullulan (MD/PUL) were developed to encapsulate and deliver of aqueously dispersible curcumin nanocomplex. Cellulose nanocrystals (CNCs) prepared by TEMPO oxidation method were used as Pickering stabilizers, and the 0.06 wt% CNCs-stabilized emulsions showed excellent storage stability and environmental stability. Soy protein isolate-curcumin complex (SPI-Cur) was prepared by the pH-driven method through hydrophobic interactions and hydrogen bonds, thus enhancing the water solubility of curcumin. SPI-Cur exhibited stronger binding affinity to MD than to PUL, enabling efficient encapsulation in the dispersed phase of MD/PUL Pickering emulsions. Furthermore, the emulsion system significantly enhanced the storage, photostability and thermal stability of SPI-Cur. The bioaccessibility of encapsulated SPI-Cur reached 51.98% after in vitro simulated digestion, which was significantly higher than that of free SPI-Cur (37.62%). This study provides an environment friendly strategy to address the poor water solubility and stability bottlenecks of curcumin in functional foods, and expands the application of W/W Pickering emulsions for encapsulating and delivering of hydrophilic bioactives.