Soy Protein Dispersions Research Articles

FUNCTIONAL PROPERTIES OF PROTEINS FOR FOODS‐FLOW PROPERTIES

AbstractThe flow properties of dispersions of soy protein isolate (Promine‐D), casemate (Sodinol) and WPC were studied as a function of protein concentration, pH and salt concentration. Additional tests were also made on some other differently processed soy protein isolates and caseinates. The results showed that flow properties of protein dispersions could differ greatly due to differences in origin and processing conditions. The flow properties of Promine‐D dispersions were characterized by low n‐values according to the power equation, and the existence of yield values at concentrations above 8 % and pH 7. The addition of salt to soy protein dispersions reduced both yield values and the viscosity parameters. The flow properties of casemate dispersions were characterized by high n‐values and the absence of yield values with respect to changes in protein concentration, pH and salt concentration. The viscosity parameters increased enormously with concentration. Contrary to the effect on soy protein dispersions, the addition of salt caused an increase in the viscosity parameters of caseinate dispersions. The dispersions of whey protein were of low viscosity over a broad concentration range with high n‐values and no yield values. At high concentration (16‐20 %) the flow properties of WPC were more similar to those of Promine‐D than to those of caseinate. The viscosity parameters for all protein dispersions increased with pH to pH 10, whereupon the viscosity parameters of caseinate decreased markedly.