Structural and physicochemical properties of composites between starch nanoparticles and ?-carotene prepared via nanoprecipitation

To apply starch nanoparticles (SNP) as host materials for 13-carotene encapsulation, aqueous SNP dispersions (10, 25, 50, and 100 mg/10 mL) and 13-carotene in acetone (10, 50, 100, 150, and 200 mu g/mL) were mixed. The acetone in the mixture was evaporated to prepare SNP and 13-carotene composites, which were homogeneously dispersed in aqueous media with over 90 % solubility. When SNP content was higher than 50 mg, over 80 % of 13-carotene was encapsulated in the composite matrix. X-ray diffraction, nuclear magnetic resonance spectroscopy, and transmission electron microscopic analyses confirmed the micellar-shaped composite particles with diameters <120 nm and an amorphous structure. High SNP content in the composites enhanced 13-carotene stability under extremely hot and acidic conditions as well as against ultraviolet rays and oxidation reactions. The encapsulated 13-carotene was not readily released in simulated gastric fluid, but was gradually released in simulated intestinal fluid via SNP digestion in the composites.