Remodeling of β-Carotene-Encapsulated Protein-Stabilized Nanoparticles during Gastrointestinal Digestion In Vitro and in Mice.

The remodeling of β-carotene-encapsulated protein nanoparticles (NPs) during digestion in vitro and in vivo was investigated. The NPs were formed using three different proteins. Hydrolysis of the surface protein during digestion resulted in structure remodeling of NPs and the formation of small-sized micellar-like aggregates below 100 nm, accelerating the release of β-carotene into the aqueous phase. However, the reduced surface ζ-potential in the intestinal fluid suggested the adsorption of bile salts, favoring the formation of small-sized micellar-like aggregates. A shifted peak of β-carotene in the micellar phase from 965 cm-1 to about 855 cm-1 in Fourier transform infrared spectroscopy analysis indicated that β-carotene existed in the amorphous state. Microstructure observation in vivo further confirmed that β-carotene was loaded in micellar-like aggregates and dispersed uniformly in water. The cellular uptake study showed that the absorption rate of digested NPs was significantly increased by 1.34- to 4.16-fold when compared with undigested NPs.