STRUCTURAL AND TECHNOLOGICAL EFFECTS OF MAIZE PROTEIN IN SOY-PEA PLANT-BASED BURGERS

The growing demand for healthier and more sustainable foods has accelerated innovation in plant-based products, particularly plant-based burgers. Soy protein isolate (SPI) and pea protein isolate (PPI) are the most commonly used ingredients due to their functional properties and ability to reproduce meat-like textures. However, combining different protein sources can improve both technological and sensory characteristics. In this context, maize protein concentrate (MPC), a by-product of starch and oil extraction, currently used mainly in animal feed, emerges as a promising functional and sustainable ingredient for plant-based formulations. This study aimed to evaluate the effect of combining SPI, PPI, and MPC in the production of texturized vegetable proteins (TVPs) by thermoplastic extrusion, focusing on their application in plant-based burgers. The extrusion process was carried out under fixed operational parameters, following a third-order mixture design with three independent variables: X₁ (MPC), X₂ (SPI), and X₃ (PPI), resulting in 12 experimental formulations. All TVPs were used for burger preparation, except E9 (33% SPI + 66% PPI) and E10 (100% PPI), which failed to form stable textures. Burgers were produced using hydrated TVP, a canola oil and fully hydrogenated fat blend (40%:60%), water, methylcellulose, sodium chloride, monosodium glutamate, seasonings, and sodium erythorbate. The ingredients were homogenized in a planetary mixer for 3 minutes, portioned into 100 g patties, shaped, frozen, and stored at –18 °C. The burgers were evaluated for structural stability, sliceability, weight loss after freezing and cooking, and diameter reduction. Results showed that the inclusion of MPC improved structural integrity and textural performance. Formulations containing 33–66% MPC combined with SPI or PPI exhibited better sliceability and lower cooking losses than those containing SPI or PPI alone. Weight loss after freezing remained below 2% for all samples, while cooking losses ranged from 1.5 to 15.9%, with higher reductions observed in SPI-rich formulations. PPI alone failed to generate stable structures, but when blended with MPC, it produced robust TVPs that yielded more cohesive burgers. Formulations E5 (33% PPI + 66% MPC), E8 (66% PPI + 33% MPC), and E6, E11, and E12 (balanced mixtures of SPI, PPI, and MPC) presented superior structural, thermal, and visual stability. In conclusion, MPC proved to be a functional and sustainable ingredient for plant-based burger formulations, improving texture, robustness, and stability while adding value to an underutilized industrial by-product. Its use supports circular economy practices and enhances resource efficiency in the development of high-quality plant-based foods.