Colloidally stable rice protein-carboxymethyl cellulose complexes tailoring high-protein liquids

Stable rice protein liquids with a high protein concentration of 6.0 wt% were prepared. • A salt-free strategy was developed using cation-exchange resins to replace HCl. • The aggregation of RPs is significantly inhibited in an environment without NaCl. • The thermal stability of the RCs was improved through the interaction between RPs and CMC. • The stability and rheological properties of rice protein liquids were regulated by adjusting the mass ratio of RPs/CMC. Protein-polysaccharide complexation represents a unique paradigm for spatially arranging protein particles to formulate concentrated dispersions. However, this strategy is not applicable to hydrophobic rice proteins (RPs) with low solubility. The objective of this study is to develop a salt-free strategy for preparing high-concentration and stable RP liquids, suitable for high-protein foods. We first prepared uniform RP nanoparticles (29 nm) by cation-exchange resins (CERs) that released H + and replaced Na + while neutralizing OH − in an alkaline solution. Thus, the generation of NaCl was circumvented eliminating the self-aggregation of RPs. Then, the electrostatic interactions between RPs and an anionic polysaccharide, carboxymethyl cellulose (CMC), were enabled by CER-induced refolding of unfolded RPs. This strategy allowed us to create stable protein-polysaccharide complexes with a protein content up to 6.0 wt%, which were resistant to self-aggregation and had controllable rheological properties that are pivotal for designing high-protein foods. Download: Download high-res image (163KB) Download: Download full-size image