Effects of high pressure on functional properties of soy protein

Torrezan, R., Tham, W.P., Bell, A., Frazier, R. ORCID: https://orcid.org/0000-0003-4313-0019 and Cristianini, M. (2007) Effects of high pressure on functional properties of soy protein. Food Chemistry, 104 (1). pp. 140-147. ISSN 0308-8146 doi: 10.1016/j.foodchem.2006.11.013

Abstract/Summary

Simultaneous measurement of the effects of low soy protein concentration, pH and high pressure treatment at room temperature on solubility, emulsifying properties and rheological properties (loss modulus, G '') of soy protein isolate (SPI) were evaluated. Central composite rotatable designs (2(3)) were employed over two pH ranges (2.66-4.34 and 5.16-6.84) with SPI concentration (0.32-3.68%) and pressure (198-702 MPa) as the other independent variables. The surface responses were obtained for protein solubility, emulsifying activity index (EAI) and G ''. The samples with the highest effect on protein solubility, EAI and G '' values were evaluated, as well, by electrophoresis and free sulphydryl determination. The pH was the main factor that affected protein solubility, with solubility at a maximum at pH < 3 or pH > 6. Increasing SPI concentration and decreasing/increasing the pH away from the isoelectric point both caused a reduction in EAI. Loss modulus (G '') was found to increase with SPI concentration in both pH ranges. (c) 2006 Elsevier Ltd. All rights reserved.