Fabricating oleic acid-ovalbumin complexes using an ultrasonic-coupled weakly alkaline pH technique: Improving the dispersibility, stability, and bioaccessibility of lutein in water.

• The ultrasonic coupled weakly alkaline pH technique enables the self-assembly of oleic acid (OA) and ovalbumin (OVA) molecules. • OA promotes the encapsulation efficiency of lutein (LUT) by OVA through noncovalent interactions. • The prepared LUT-OA-OVA ternary complexes exhibit spherical particles with good aqueous dispersibility. • OA-OVA complexes as encapsulated carriers can effectively improve the thermal and storage stability of LUT. • OA-OVA-based encapsulation can effectively improve the digestive stability and bioaccessibility of LUT. This study constructed a self-assembly non-covalent oleic acid (OA) and ovalbumin (OVA) complex via an ultrasonic coupled pH-driven approach to simultaneously improve the water dispersibility, stability, and bioaccessibility of lutein (LUT). The results showed that homogeneous, stable hydrophilic OA-OVA particles were obtained in optimized conditions (an OVA concentration of 4.0 mg/mL, pH 9.0, ultrasonic conditions of 200 W for 2 min, and OA-OVA molar ratios of 2:1–20:1), with the LUT encapsulation efficiency (EE) exceeding 88.9%. Furthermore, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) confirmed complete LUT encapsulation in the OA-OVA particles, displaying spherical particle formation with smooth surfaces. The OA-OVA complexes effectively improved the thermal and storage stability of LUT and significantly enhanced its bioaccessibility. These findings suggest that fatty acid-protein complexes may have potential application value as carotenoid delivery vectors. [ABSTRACT FROM AUTHOR]