The influence of incorporating rice bran oil body on the protein-based emulsion-filled gels and delivery properties: A study from gel behavior to functional applications.

Abstract

The protein-based emulsion-filled gel serves as a delivery carrier for hydrophobic active ingredients, and its performance is significantly influenced by the type of filler. Rice bran oil body (RBOB), as a plant-based natural filler, the regulation of its role in the protein-filled gel system remains unclear. In this study, different concentrations of RBOB were incorporated into the soybean protein isolate (SPI) gel matrix to construct a composite emulsion-filled gel system. The effects of RBOB filling amount on the gel structure characteristics were systematically evaluated. Subsequently, the optimal concentration of RBOB was used to encapsulate lycopene, and its in vitro digestion release behavior and bioaccessibility were assessed. The results showed that RBOB (6.25%) formed an active filler effect through its surface proteins' hydrophobic interaction with the SPI matrix and interface bridging. This enhanced the compactness and continuity of the gel network, improved the structural properties and water holding capacity of the gel, and achieved effective regulation of the gel's microstructure. In terms of delivery performance, RBOB efficiently loaded lycopene in a lipid-soluble core. The physical barrier formed by the interface protein layer of RBOB and the SPI network effectively delayed the chemical degradation of the active components. Meanwhile, the unique structure of RBOB promoted the formation of mixed micelles, significantly enhancing the micelization rate and bioaccessibility of lycopene. In conclusion, RBOB can exert dual regulatory effects at both the structural reinforcement and functional delivery levels, providing theoretical guidance for the efficient utilization of hydrophobic active factors.