Encapsulation of β-carotene-loaded oil droplets in caseinate/alginate microparticles: Enhancement of carotenoid stability and bioaccessibility

β-carotene was encapsulated in biopolymer microparticles formed by electrostatic complexation to improve its water-solubility, chemical stability, and bioavailability characteristics. The β-carotene-loaded microparticles had a particle size (1.87 ± 0.03 μm) larger than that of caseinate emulsions (0.48 ± 0.01 μm) ( P  < .05). Microparticles were stable to aggregation over a wide pH range (3–7) and at high salt levels (0–1000 mM NaCl), and protected β-carotene from degradation during storage. For instance, around 32% carotenoid was retained after 42 days storage at 25 °C in the microparticles, whereas <10% was retained in the emulsions. An in vitro digestion experiment showed that the β-carotene in microparticles had a higher bioaccessibility and chemical stability (67.57 ± 2.72% and 80.03 ± 1.95%, respectively) than in emulsions (30.03 ± 1.87% and 70.87 ± 1.52%, respectively) ( P  < .05). These results may facilitate the design of nutraceutical delivery systems for application in food, supplement, and pharmaceutical products.