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

Abstract

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.

Keywords: Bioaccessibility; Lutein; Oleic acid; Ovalbumin; Stability; Ultrasonic processing.