Fermentation as a Lever to Enhance Legume Proteins: From Antinutritional Factors to Improved Quality

Owing to their high nutritional value, functional proteins, and low environmental impact, legume proteins have emerged as sustainable alternatives to animal proteins. However, their broader utilization is constrained by antinutritional factors (ANFs), which can adversely affect protein digestibility, mineral bioavailability, and techno-functional features. Fermentation has appeared as a promising approach to overcoming these limitations. Through microbial and enzymatic activities, fermentation can reduce ANFs, modify protein structures, and promote proteolysis, generating peptides and free amino acids that may improve digestibility, bioavailability, and functional properties. This review critically explores the effects of fermentation on legume proteins, concentrating on ANF reduction, protein degradation and structural modification, proteolysis, and their consequences for nutritional and techno-functional properties. Particular attention is given to protein hydrolysis and peptide generation, as well as the limitations and potential trade-offs of fermentation, including extreme proteolysis, loss of desirable functional properties, unwanted sensory changes, variability among strains and substrates, and prolonged processing. The review also discusses the incorporation of fermented legume proteins into relevant food systems, with emphasis on their functional performance and application potential. Finally, current knowledge gaps and future research priorities are highlighted to support the development of controlled fermentation strategies for nutritionally improved, functionally tailored, and industrially feasible legume protein ingredients.