Combined effects of phosphate, curdlan, and transglutaminase on the texture and microstructure of plant-based egg omelets

Abstract

This study investigates the formulation optimization of soy protein isolate (SPI)-based plant-based egg omelets using phosphate, curdlan, and transglutaminase. Phosphate salts were incorporated to improve protein solubility, and 0.6% (w/w) achieved the highest dispersion stability. Curdlan was evaluated as the primary thermal gelling agent, and 4.5% curdlan provided a balanced texture, uniform appearance, and minimized syneresis to levels comparable to egg controls. Transglutaminase (TG) was introduced to enhance the protein network cohesion, and 160 mg/g SPI produced hardness, cohesiveness, and microstructural organization similar to those of conventional egg-based omelets. Texture profile analyses, field emission scanning electron microscopy, and confocal laser scanning microscopy demonstrated that the combined application of phosphate, curdlan, and TG improved the gel network density, reduced water loss, and stabilized the protein–lipid distribution. These results suggest a formulation approach for the production of plant-based egg analogs with improved water-holding capacity, structural stability, and textural quality.