A state-of-the-art review in legume protein gelation: mechanisms, structure-function relationships, modification...

The rapid expansion of plant-based food systems has stimulated growing interest in legume proteins as sustainable structural ingredients. Among their functional properties, gelation plays a key role in determining the texture, structural stability, and water-holding capacity of plant-based foods such as meat analogues, dairy alternatives, and fat replacers. To overcome the inheret mechanical limitations of these plant-based matrices, this review moved beyond traditional background analyses to critically evaluate the multiscale structure-function relationships governing gel formation. Both thermal- and non-thermal-induced gelation pathways, including acid-, salt-, and enzyme-induced systems, were discussed, with emphasis on molecular interactions such as hydrophobic interactions, hydrogen bonding, electrostatic interactions, and disulfide bond formation. Importantly, a clear distinction was drawn between the effects of intrinsic and extrinsic factors (e.g., protein composition, concentration, pH, and ionic strength) and deliberate processing interventions. Furthermore, recent strategies for improving gel properties through physical technologies, chemical modifications, and biological approaches were reviewed. A comparative analysis revealed that integrated modification strategies exhibited superior efficacy over single treatments, driven by structural 'priming' effects where initial physical unfolding enhanced subsequent covalent cross-linking. These advancements were discussed together with emerging applications in texture engineering, fat replacement, encapsulation, and 3D food printing. Overall, this review provides a framework for understanding and regulating legume protein gel structure-function relationships and supports the rational design of next-generation plant-based structured foods, emphasizing the future need for predictive modeling and targeted evaluations in complex food matrices.