Gastrointestinal fate and antioxidation of β-carotene emulsion prepared by oat protein isolate-Pleurotus ostreatus β-glucan conjugate

beta-carotene has been often used as a hydrophobic nutrient in many functional foods owning to its excellent antioxidant activity. However, the poor orally bioavailability of beta-carotene limits its utilization. To overcome such limitation, a delivery system was designed for the encapsulation of beta-carotene based on oil-in-water emulsion stabilized by oat protein isolate - Pleurotus ostreatus beta-glucan Maillard conjugate. The results showed that such conjugate protected emulsion against environmental stresses by increasing steric and electrostatic repulsion between droplets, mainly manifesting as their smaller particle size and higher surface charge. Additionally, conjugate promoted lipid digestion and formation of mixed micelles, leading to an improved gastrointestinal fate of encapsulated beta-carotene, especially for its in vitro bioavailability. Such effects could enhance the cellular antioxidant activity of encapsulated beta-carotene in Caco-2 cells. Our findings confirmed that Maillard conjugate can structure an emulsion-based delivery system for the encapsulation of hydrophobic ingredients to improve their utilization.