Facile controlling internal structure of β-carotene-loaded protein nanoparticles by Flash Nanoprecipitation

As one of the most significant carotenoids, β-carotene is applied widely in human nutrition and reducing incidence of chronic diseases, due to its highest provitamin A activity. The nano-carrier technology has been used to prepare β-carotene-loaded nanoparticle to improve bioavailability in functional food and beverage, as β-carotene is high hydrophobic. However, the control of the internal structure of β-carotene-loaded nanoparticle is not investigated and the relationship between internal structure and release have not been well understood. Here, we report a kinetic-controlled method, Flash Nanoprecipitation, which allows to control the internal structure of β-carotene-loaded nanoparticle, from compact core-shell structure with high packing density to loose structure with low packing density. The different structures show obviously different release behavior: loose structure associates with high release of β-carotene, while compact structure associates with slight release. TEM and dynamic-static light scattering are employed to characterize the morphology and internal structure, respectively. The developed strategy could be helpful for practical application of β-carotene nanoparticles with tunable properties.