Carboxymethyl cellulose with different charge density regulates the thermal aggregation behavior of myofibrillar protein to tailor dysphagia diet.

Thermosensitivity of myofibrillar protein (MP) limits the development of meat protein-based dysphagia foods. This study aimed to design the texture-modified food via improving the thermal stability of MP using carboxymethyl cellulose (CMC) with different charge density. Results showed that the aggregation inhibition effect of MP/CMC complexes was significantly dependent on the increase in CMC charge density, which was maintained around 0.46 (OD600nm) during heating, while pure MP was increased to 0.60. The denaturation peak of MP/CMC complex was shifted from 57.63 °C to 59.15 °C, which was even vanished with adding higher charge density CMC. It was found that the more stable protein conformation was formed by strong electrostatic interaction of CMC in salt-free media. Meanwhile, the steric hindrance and electrostatic repulsion conferred by CMC chains reduced hydrophobic interactions and disulfide bonds between complexes, thereby decreasing the protein aggregation behavior. During the cooling process, hydrophilic CMC promoted the formation of MP molecular networks through hydrogen bonding, achieving the fluid MP of different thicknesses modulated by polysaccharide charge density coverage from level 1 to level 4 within International Dysphagia Diet Standardization Initiative (IDDSI) framework. The findings are expected to provide a theoretical basis for the development of MP-based fluid foods.