Microstructure, texture, rheology, flavor, and sensory attributes of spreadable processed cheese as affected by partial substitution with thermal-sonicated mung bean protein vegan cheese.

Hybrid processed cheeses combining dairy and plant proteins have gained increasing attention in response to sustainability and health concerns. In this study, Mozzarella-based processed cheeses were partially substituted (5%-15%) with mung bean protein (MBP)-based vegan cheese, and evaluated for their structural, physicochemical, and sensory characteristics. The MBP-based vegan cheese was produced via acid-induced curdling of a thermal-sonicated MBP-oil emulsion. This work investigated combined effects of thermal sonication during MBP preparation together with its substitution level on microstructural, textural, rheological, flavor volatile, and sensory properties of hybrid processed cheeses. Untreated MBP formed large, weakly interacting aggregates that disrupted casein network continuity, resulting in heterogeneous microstructures and pronounced beany off-flavors. In contrast, short- and long-time thermal sonication produced more homogeneous oil droplets or finer, partially aggregated protein-oil structures, respectively. These structural differences altered droplet packing and protein interactions, producing nonlinear, concentration-dependent increases in matrix elasticity and thermal stability from untreated to long-time sonicated systems. Mechanistically, sonication restructured the MBP-oil interface by modifying droplet size distribution, interfacial protein organization, and electrostatic interactions, thereby governing protein-fat network formation and volatile partitioning within the hybrid matrix. In parallel, volatile profiles reflected a balance between cavitation-driven oxidative pathways, promoting aldehyde conversion and acid and lactone formation, and matrix-mediated retention of aroma compounds within the evolving protein-fat network. Consequently, sensory responses followed a similar trend, and processed cheeses with untreated MBP-based vegan cheese retained pronounced beany notes, those with short-time thermal-sonicated vegan cheese showed moderate improvement, and hybrid processed cheeses formulated with long-time thermal-sonicated vegan cheese exhibited lowest off-flavor intensity and greatest similarity to the dairy control. These findings demonstrate that controlled thermal sonication enhances functional performance of plant proteins, enabling their effective incorporation into hybrid processed cheeses without compromising structural integrity, flavor balance, or sensory quality.