Effect of sodium caseinate on the quality of gluten-free rice bread

To address challenges associated with rice bread, including excessive hardness, rapid staling, pale color, and lack of aroma, this study added sodium caseinate (NaCas) at different concentrations (0, 2.5%, 5.0%, 7.5%, 10.0%) to rice flour, and determined its pasting properties, the fermentation characteristics and microstructure of rice dough, as well as the baking quality and storage-related hardness of the rice bread. Results indicate that NaCas significantly reduces the gelatinization viscosity of rice flour. At an addition level of 10%, the peak gelatinization viscosity decreases by 42.1%, while the retrogradation value is significantly reduced at addition levels of 7.5% and 10.0%. Scanning electron microscopy (SEM) reveals that NaCas forms a membrane-like structure in the batter, enhancing gas retention capacity. When the addition level reaches 10.0%, the gas retention coefficient achieves a maximum value of 91.45%. Regarding bread quality, NaCas addition significantly increases the proportion and density of the bread core, improves specific volume, deepens crust color, reduces hardness, chewiness, and adhesiveness, and enhances elasticity. At an addition level of 7.5%, overall acceptability reaches its highest score of 6.72. NaCas also markedly slows down the aging rate of bread during short-term storage, limiting hardness increase to 41.2% over a 72-hour storage period, which is significantly better than the 76.8% hardness change observed in the control group. In conclusion, NaCas proves to be an effective improver for enhancing the quality characteristics of gluten-free rice bread.