Fabrication and characterization of the W/O/W multiple emulsion through oleogelation of oil.

W/O/W emulsions were easily prepared by oleogelation of the oil phase using rice bran wax (RBX) and their microstructure, stability, rheology and protection of proanthocyanidins and β-carotene were investigated. Formation of the W/O/W emulsion was confirmed using confocal laser scanning microscopy and staining of the inner aqueous phase by tartrazine. The average particle size and viscosity of the emulsion increased as the RBX concentration increased. Moreover, RBX increased the stability of the emulsion and the emulsion was the most stable when the RBX concentration was 8.0% or 10.0%. On the other hand, the W/O/W emulsions were used to simultaneously encapsulate proanthocyanidins and β-carotene. Specifically, proanthocyanidins and β-carotene in RBX-containing emulsions were more stable and had higher bioaccessibility than in the emulsion without RBX. Besides, both their chemical stability and bioaccessibility reached the maximum value when the RBX concentration was 8.0% or 10.0%. In summary, the optimal RBX concentration was 8.0%.