Optimization of Lentils, Peas, and Beans-based Vegetable Burger Formulation Using D-optimal Mixture Design

The growing request for plant-based meat substitutes reflects a global shift toward more sustainable, ethical, and health-promoting dietary practices. Legumes, due to their high protein and fiber content, are ideal for the formulation of such products. This study focused on the development of a plant-based burger made from lentils, peas, and black beans, with particular attention paid to optimizing ingredient proportions to achieve balanced nutritional, technological, and sensory properties. With this in mind, a three-component D-optimal mixture design was implemented. The assessment of the nutritional properties of the legume-based plant burger, both before and after cooking, revealed high protein (8.15%) and crude fiber (6.33%) contents. After cooking, the protein amount remained relatively stable, indicating good thermal stability of the protein matrix, but a marked decrease in fiber content was noticed. The cooking properties of the legume-based plant burger demonstrated a technologically stable formulation, suitable for ready-to-eat consumption. The product exhibited moderate cooking loss (13.10 ± 0.69%), along with minimal reductions in diameter (1.94 ± 0.22%) and thickness (7.75 ± 0.80%), indicating good structural integrity during cooking and effective shape retention. Lipid absorption remained controlled (19.62 ± 0.42%), while moisture retention (58.79 ± 1.08%) indicated a moderate water-holding capacity. These findings confirm the product's favorable thermal behavior. Rheological analysis showed that after cooking, the network of the burger became more elastic, which was confirmed by Scanning Electron Microscopy analysis (SEM), revealing a compact and homogeneous structure. To sum up, given its qualities and richness, especially in proteins, the elaborated vegetarian burger could constitute a substitute for the meat-based one.