Co-encapsulation of curcumin and fucoxanthin in solid-in-oil-in-water multilayer emulsions: Characterization, stability and programmed sequential release

To enhance the bioavailability of bioactives with varying efficacy in the gastrointestinal tract (GIT), a co-delivery system of solid-in-oil-in-water (S/O/W) emulsion was designed for the co-encapsulation of two bioactives in this paper. S/O/W emulsions were fabricated utilizing fucoxanthin (FUC)-loaded nanoparticles (NPs) as the solid phase, coconut oil containing curcumin (Cur) as the oil phase, and carboxymethyl starch (CMS)/propylene glycol alginate (PGA) complex as the aqueous phase. The high entrapment efficiency of Cur (82.3–91.3%) and FUC (96.0–96.1%) was found in the CMS/PGA complex-stabilized S/O/W emulsions. Encapsulation of Cur and FUC within S/O/W emulsions enhanced their UV and thermal stabilities. In addition, S/O/W emulsions prepared with CMS/PGA complexes displayed good stability. More importantly, the formed S/O/W emulsion possessed programmed sequential release characteristics, delivering Cur and FUC to the small intestine and colon, respectively. These results contributed to designing co-delivery systems for the programmed sequential release of two hydrophobic nutrients in the GIT. [Display omitted] •S/O/W emulsions were prepared by embedding NPs as solid phase into O/W emulsions.•S/O/W emulsions were constructed to co-deliver fucoxanthin (FUC) and curcumin (Cur).•Adding PGA improved the encapsulation ability of CMS-stabilized S/O/W emulsions.•The stability of S/O/W emulsions was enhanced by using CMS/PGA complexes.•CMS/PGA complex-stabilized S/O/W emulsions enabled programmed sequential release of actives.