Improvement in Freeze-Thaw Stability of Rice Starch by Soybean Protein Hydrolysates-Xanthan Gum Blends and its Mechanism

To improve the freeze-thaw stability of rice starch (RS), the soybean protein hydrolysates (SPHs), xanthan gum (XG), and the blends of SPHs with XG (SPHs-XG) are added. The syneresis, thermal, texture, rheological properties, and morphological features of samples during seven freeze-thaw cycles (FTCs) are investigated by syneresis measurement, differential scanning calorimetry (DSC), textural properties analysis (TPA), dynamic rheological, NMR, and SEM. As a result, SPHs-XG is more effective for improving the freeze-thaw stability and showed improved structure manifestations with the lower retrogradation rate (22.78%), hardness (153.29 g), gumminess (54.57), and solid-like structure (p < 0.05). Moreover, the water-holding capacity is increased and the microstructure is effectively stabilized. All these results suggested that SPHs-XG could be a potential ingredient to improve the quality of rice starch-based frozen foods.