Comparative Physicochemical and Techno‐Functional Characterisation of Legume Protein Concentrates for Gluten‐Free Bread Applications

The increasing demand for plant‐based gluten‐free foods has driven exploration of alternative protein ingredients capable of delivering enhanced structural functionality. This study comparatively evaluated five protein concentrates from red kidney bean (RKB), peanut (PF), soybean (SF), black‐eyed bean (BEB) and melon seed (MSF) to elucidate their yield, physicochemical and structural properties, with particular emphasis on gluten‐free bread applications. SF exhibited the highest protein yield (88.79%), followed by MSF (73.65%) and BEB (72.78%), whereas RKB (67.64%) and PF (60.90%) showed lower recovery. Thermal functionality differed markedly among proteins. SF and MSF exhibited high heat‐induced coagulation (> 76%) and low water release after coagulation (< 6%), indicating strong gel network formation and moisture retention, whereas RKB and BEB showed weaker thermal aggregation and higher syneresis. Similarly, SF exhibited the smallest particle size ( Z ‐average 435 nm) and lowest polydispersity index (0.21), corresponding to high solubility and dispersion stability, whereas BEB and PF showed larger particles and greater heterogeneity. MSF demonstrated intermediate particle size (574 nm) and controlled aggregation (PDI 0.30), balancing dispersion stability and network‐forming potential. FTIR spectroscopy confirmed heat‐induced protein unfolding and enhanced intermolecular interactions consistent with network development. The incorporation of MSF or SF (5%–10%, w/w) into gluten‐free bread formulations improved loaf specific volume, reduced crumb hardness and enhanced loaf sourness and aftertaste, although accompanied by a slight increase in bitterness and astringency. These findings highlight the potential of underutilised oilseed‐derived proteins, particularly melon seed protein, as sustainable and effective structure‐forming ingredients for improving the technological and nutritional quality of gluten‐free baked products.