Preparation of shellac nanoparticles-chitosan complexes stabilized Pickering emulsion gels and its application in β-carotene delivery

Shellac nanoparticles (SNPs)-based Pickering emulsion gels show promise as delivery carriers but face challenges due to poor emulsifying properties. This study aimed to fabricate stable emulsion gels using SNPs and chitosan (CS) complexes, creating a β-carotene delivery system. The effects of oil phase fractions, emulsifier concentrations and SNPs/CS ratios on rheological properties and the structural properties of emulsion were investigated. The formation of SNPs/CS complexes was through hydrogen bonding and electrostatic interactions. By adjusting the SNPs/CS ratio to 1/0.33, the contact angle of the complexes was optimized to approximately 90°. SNPs/CS complexes served dual roles as emulsifiers and gelling agents in the emulsion gels. Notably, the gel strength (storage modulus) of the emulsion gels remained unchanged after the encapsulation of β-carotene. Emulsion gels with SNPs/CS (1/0.25) complexes showed the highest β-carotene bioaccessibility at 80.4 %. Furthermore, this system could expand the use of shellac-based emulsion gels in food applications.