A comprehensive review of kidney bean proteins: extraction, composition, techno-functional properties, and emerging food applications

Kidney beans (Phaseolus vulgaris L.), a nutritionally rich and globally available legume, represent a promising yet underutilized plant protein source. These phaseolin-rich globulins exhibit a balanced amino acid profile and <i>β</i>-sheet-dominant secondary structures supporting thermal and structural stability. However, due to their naturally limited solubility, emulsifying capacity, and gelling properties, kidney bean proteins often require post-extraction modifications to enhance their functionality. These modifications include physical (heat, ultrasound, high-pressure), chemical (acylation), and biological (fermentation or enzymatic) modifications. They induce conformational rearrangements, modulate surface charge, and enhance interfacial behavior that expand its applicability across a range of food systems, including plant-based analogues, packaging, and encapsulation but also reduce anti-nutritional components and improve digestibility. This review critically evaluates the current state of knowledge on kidney bean proteins, focusing on extraction, structural and compositional characteristics, techno-functional modifications, and potential food applications. Alongside conventional extraction methods, novel approaches such as deep eutectic solvents are being evaluated for their potential to enhance protein yield while preserving native structural integrity. Additionally, emerging modification technologies, including cold plasma, microfluidization, and pulsed electric field, are highlighted as promising tools for precise structural tailoring and enhancement of functional properties such as solubility, emulsification, and gelation in plant-based proteins.