Effects of Rehydration Time, Temperature and Ultrasound Treatment on Rehydration, Quality and Structure Properties of Low Moisture Texturized Soybean Protein

This study investigated effects of rehydration time, temperature, and ultrasound treatment on rehydration rate (RR), water holding capacity (WHC), color, composition (protein content and soluble sugar content), molecular weight distribution (MWD), thermal properties and microstructure of TSP (texturized soybean protein made under low moisture condition). The increase in rehydration time and temperature increased RR, WHC, leading to loss of color, protein and soluble sugars of rehydrated TSP. The enhancement of temperature augmented the porosity of the microstructure, decreased the thermal stability, but did not change the molecular weight distribution of proteins of rehydrated TSP. After TSP was rehydrated for 20 min without ultrasound treatment, The RR and WHC curves were basically stable, and the loss of protein content reached a constant. And the rehydrated TSP at 40celcius for 20 min had a higher sensory score than other groups without ultrasound. Ultrasound further enhanced RR and WHC and shortened the time for TSP to reach water absorption saturation (15 min). Ultrasound had no significant effect on the protein content of rehydrated TSP, but reduced the soluble sugar content. There was the maximum sensory score of rehydrated TSP with ultrasound treatment at 40celcius for 15 min. These results provide theoretical support for the rehydration of TSP in food industry processes.