Evaluating the viscoelastic properties of soy protein isolate by creep–recovery behavior

Abstract

The viscoelastic properties of soy protein isolate (SPI) were investigated by creep–recovery under creep time (75 s, 150 s, 300 s, and 600 s), shear stress (1 Pa, 6 Pa, 10 Pa, and 20 Pa), and creep temperature (25°C, 50°C, and 80°C). Creep compliance (JC) increased proportionally with creep time from 75 to 600 s and with stress from 1 to 20 Pa, it decreased proportionally with temperature from 25 to 80°C. Results showed that the flow behavior of SPI varied along with creep time, stress, and temperature. Creep compliance data were best-fitted to 4-element Burgers model (R2 > .94), the instantaneous compliance (J0), retardation compliance (J1), retardation time (r1), steady-state viscosity (η0), and recovery (%) have significant changes with creep time, stress, and temperature (p < .05). Adding maltodextrin (MD) accelerated the deformation of SPI. The flexibility and rigidity of SPI molecular chains was dependent on creep time, stress, and temperature. Practical applications In this research paper, we studied the viscoelasticity of SPI using the creep–recovery analysis. The chain flexibility, rigidity, and viscidity of SPI molecules were discussed at creep time, shear stress, and creep temperature. At the same time, the viscoelasticity of SPI adding of MD is also discussed. According to the experiment, this study provides new insights into the viscoelastic properties of SPI and builds a fundamental foundation for the comprehensive utilization of SPI in the food industry.