How can plant-based protein–polysaccharide interactions affect the properties of binary hydrogels? (A review)

The last two decades have seen a growing trend toward gels thanks to their attractive sensory properties, low calories, and modification ability. Plant-derived proteins have outstanding potential to replace animal proteins as they are more affordable and eco-friendly. Polysaccharide addition can improve the gelation properties of plant proteins. This paper aimed at critically analyzing the effect of the plant protein-polysaccharide compatibility on the characterization of composite hydrogels. H-bonds and β structures, increased by polysaccharides, greatly correlated with the gelation rate, superior structural integrity, and textural/rheological properties. Indeed, polysaccharides favored the transition of α-helices to β-sheets followed by the shift of amide I which made the microstructure dense, regular, and homogeneous. Subsequently, the water-holding capacity, hardness, and elastic modulus increased but the porosity, swelling ratio, and digestibility decreased. High protein concentrations increased the water-holding capacity while the swelling ratio was mostly dependent on polysaccharides. Polysaccharides had a protective role against protease penetration and gel digestibility.