Understanding the interactions that determine temperature-dependent behavior and structure formation in multicomponent hydrocolloid systems is essential for designing plant-based foods. This study investigated the structural, rheological, and thermophysical characteristics of starch-based emulsion-filled gels, focusing on how lipids and plant proteins influence starch network formation, viscoelasticity, and thermal behaviour.

Model systems consisted of potato, pea, and tapioca starches in native, waxy, oxidized, pregelatinized, cross-linked, or OSA-modified form. Gels were prepared either as starch hydrogels or as emulsion-filled gels with rapeseed oil or coconut fat as lipid phase. To probe protein–starch–lipid interactions, selected gels were prepared using soluble (potato protein), moderately soluble (pea protein), less soluble (pea protein), or insoluble (zein) proteins (0–8 %, w/w). Rheology, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, and confocal laser scanning microscopy (CLSM) provided a multiscale description of temperature-dependent structural and mechanical changes. Complementary cheese-specific tests included a modified Schreiber melting test, water-holding capacity (WHC), fat release, and tests on color changes under different heating conditions.

Temperature sweeps revealed characteristic viscoelastic transitions, i.e., melting, in G′/G″ and energy dissipation ratio, below 95 °C in oxidized and waxy starches. Cross-linked and substituted starches exhibited higher elastic moduli and predominantly softening, if any. Protein addition delayed or inhibited melting as a function of protein solubility. ATR-FTIR spectra further suggested changes in hydrogen-bonding patterns and starch–protein interactions. WHC supported a strong influence of proteins on water holding capacity. Micrographs confirmed emulsion-filled hydrogel structures across all formulations, with variations in droplet size distribution with starch viscosity during gelatinization, and coalescence upon heating. In cheese-specific tests, gels with solid fat showed higher water retention, and generally lower fat release. The addition of proteins seemingly increased interfacial stabilization, thus reducing fat release. Overall, this study sheds light on how interactions between starch and proteins dictate the rheological, thermal, and macroscopic behavior of composite hydrogels. These insights support the rational design of plant-based foods with tunable melting and viscoelastic properties.