Encapsulation of β-carotene in chitosan pickering nanoemulsion: Effect of process parameters and their stability

β-carotene, a vital carotenoid, is limited by poor solubility and stability. Though Pickering nanoemulsions offer superior protection for β-carotene than conventional nanoemulsions, developing food-grade Pickering nanoemulsions remains challenging due to particle size and amphiphilicity issues. This study developed a food-grade Pickering nanoemulsion stabilized by chitosan nanoparticles via high-power ultrasonication. Under optimized conditions (pH 6.5, 2 % oil phase, 1.0 wt% chitosan, 455 W ultrasonication for 180 min), a stable nanoemulsion of 388 nm was obtained with minimized β-carotene loss. These nanoemulsions exhibited exceptional environmental stability, maintaining robust stability under varying pH (3.0–7.0), ionic strength (100–500 mM NaCl), and thermal stress. Thermal stability and extended storage tests demonstrated superior β-carotene protection compared to conventional Tween 20-stabilized emulsions. This work provides a novel strategy for food-grade Pickering nanoemulsions, enabling β-carotene application in functional foods and pharmaceuticals.