Effects of High Pressure Processing Treatment on Properties of Drawing Soy Protein

In this study, the effects of high pressure processing treatment on the properties of drawing soy protein were evaluated in order to improve its reprocessing characteristics. Drawing soy protein was treated under different high pressure conditions (200~600 MPa for 10~30 min). After that, Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV) absorption spectroscopy and endogenous fluorescence spectroscopy were employed to characterize the effect of high pressure processing on the structure of drawing soy protein. The trends of water holding capacity, surface hydrophobicity and free sulfhydryl content were used as indices to evaluate the effect of high pressure processing on the functional properties of drawing soy protein. The results showed that the relative contents of β-sheets and random coil increased with the increase of pressure and dwell time, showing the transition of secondary structure from an ordered to a disordered state. Meanwhile, the tertiary structure of the protein was highly stretched, facilitating the exposure of hydrophobic groups initially buried inside, but the the exposed hydrophobic groups were re-buried with increasing pressure or time. At 400 MPa for 10 min, the water holding capacity, free sulfhydryl content and surface hydrophobicity of drawing soy protein reached the maximum, which were 32.87%, 41.57% and 15.66% higher than those of the control group, respectively. In conclusion, high pressure processing treatment under appropriate conditions could be beneficial to improve the reprocessing characteristics of drawing soy protein, providing a reference for the application of high pressure processing technology in the production of drawing soy protein.