W/O/W emulsion-filled egg white gel co-stabilized by protein and γ-cyclodextrin MOFs with multi-chamber encapsulation potential

Egg white gel (EWG) is a highly important raw and auxiliary material in food industry. With the increasing demand of consumers for nutrition, developing a modification method for regulating the texture of traditional egg white gel while enhancing its nutritional efficacy has become a challenge. Herein, a hierarchical W/O/W double emulsion filled gel was fabricated via a two-level emulsification process. The primary W/O emulsion, stabilized by synthesized γ-cyclodextrin metal-organic frameworks (CD-MOFs) Pickering emulsifiers, was incorporated into an egg white solution, where the endogenous emulsifying properties of the proteins facilitated the formation of the secondary O/W interface. The stability and morphology of the CD-MOFs-stabilized W/O emulsion (CDME) were analyzed, and the gel properties, molecular interactions, and microstructure of the W/O/W emulsion filled EWG gel (CDME-EWG) was then evaluated. The results indicated that CD-MOFs at 6 mg/mL (CDME-6) significantly enhanced the stability of the Pickering emulsion. This effect was achieved through the formation of a dense interfacial film at the oil/water boundary, which effectively promoted droplet dispersion and suppresses coalescence. Furthermore, the emulsion filled gel with 6 mg/mL CD-MOFs (CDME-EWG6) promoted the cross-linking within the gel network, leading to a more compact structure, enhanced water retention (52.84%) and hardness (887.00 g), as well as the enhancement in encapsulation capability (81.77%) and bioavailability (41.18%) of lutein. This study proposed a novel strategy for improving the performance of protein gels, which also provided the potential for co-encapsulation of multi-component bio-actives via the porous CD-MOFs and compartmentalized chamber within the W/O/W emulsion