Subcritical water-treated soy protein-gum Arabic core-shell nanoparticles as phytosterol carriers

Authors：Lu, Wei; Wang, Mengping; Chen, Jiafeng; Wang, Jinmei^*

Source：International Journal of Food Science and Technology, 2023, 58(12): 6496-6506.

DOI：10.1111/ijfs.16763

• Core-shell nanoparticles
• gum Arabic
• phytosterol
• soy protein
• subcritical water

Soy protein-gum Arabic (GA) core-shell nanoparticles were fabricated as carriers for hydrophobic phytosterol (PS) using an anti-solvent precipitation (pH 7.0) and then coating GA on the surface of protein-based PS nanoparticles at pH 4.5. PS nanoparticles stabilised by heat-treated soy protein isolate (SPI), especially subcritical water-treated SPI (SW, 120 degrees C), exhibited higher encapsulation efficiency (EE), loading amount (LA) and colloidal stability than native SPI-stabilised PS nanoparticles. The highly flexible conformation and more exposed hydrophobic clusters of SW-treated SPI could result in a quick encapsulation of more PS into the interior of protein molecules during anti-solvent precipitation. However, for native SPI with rigid globular structure, the loading of PS mainly occurred on the surface hydrophobic sites of protein molecules. After introducing GA (>= 5 mg mL(-1)) to PS nanoparticles fabricated by SW-treated SPI, submicron-sized (D-h 250.71 similar to 341.76 nm) core-shell nanoparticles with high acid solubility and thermal stability were formed. The coating of GA decelerated the digestion of SW-treated SPI, and improved the EE, LA and in vitro bioaccessibility of PS under acidic environment. These results reveal the protein structure dependence of PS encapsulation and provide a simple approach to fabricate biopolymer-based nanoparticle delivery system for hydrophobic bioactives in acidified functional drinks.