Modulating the microstructure and rheological properties of low-fat cheese: Combined effects of emulsion gel formulation, phase state, and coagulation mechanism

This study presents an innovative fat-replacement strategy by systematically elucidating the application mechanisms of structured emulsion gels loaded with DHA/ARA microcapsules in low-fat cheese, focusing on the combined contributions of emulsion formulation, phase state, and distinct coagulation kinetics. The results revealed that as the oil phase mass fraction reached 40 wt%, the system underwent a catastrophic phase inversion from oil-in-water (O/W) to water-in-oil (W/O) driven by lipophilic emulsifiers, with the W/O emulsion gels exhibiting pronounced strain-hardening behavior and superior tribological lubrication under large deformations. Upon incorporating emulsion gels into the cheese matrix, O/W emulsion gels demonstrated excellent compatibility with the casein network due to their hydrophilic continuous phase. In contrast, W/O emulsion gels reconstituted into complex W/O/W double emulsions within the cheese milk, forming a multi-compartmentalized physical barrier that achieved the protection of the active ingredients. Low-field nuclear magnetic resonance and proton density magnetic resonance imaging further demonstrated that fermentation/rennet-induced coagulation formed a continuous, highly ordered protein matrix promoting a higher proportion of bound water (T 21 ). Crucially, LAOS analysis revealed that the lipid domains acted as active fillers within the casein lattice, dissipating mechanical energy via intra-cycle strain-stiffening to enhance toughness and elasticity while eliminating texture defects. These findings provided a crucial theoretical basis for tailoring and optimizing the microstructure and textural properties of functional cheese by regulating emulsion gel types and coagulation processes.