Casein-grape seed proanthocyanidins complexes stabilized Pickering emulsion gels based on Lycium Barbarum seed oil with excellent mechanical properties and oxidation resistance

Pickering emulsion gels received extensive attention in encapsulating fat-soluble substances such as Lycium barbarum seed oil (LBSO). However, the gels presented poor mechanical properties, otherwise, their physical encapsulation cannot inhibit lipid peroxidation. Herein, grape seed proanthocyanidins (OPCs) and casein (CAS) complexes interacted through hydrogen and covalent bonds were proposed to build Pickering emulsion gels and encapsulate LBSO, which changed the secondary structures of CAS and further enhanced emulsifying ability, oxidation resistance, and gelling performance. The CAS-OPCs gels had better microstructures and mechanical properties due to the enhancement of hydrogen and covalent interactions. Furthermore, gels with OPC contents of 8.00 mg/mL had performance in 3D printing. And gels reduced the peroxide value of LBSO (9.33 ± 0.20 to 1.39 ± 0.22 mmol/kg) after heating. This study helps reveal the possible mechanisms of OPCs on gels and provides a reference for the application and research of OPCs and CAS composites in Pickering emulsion gels.