SOY AND MEAT PROTEINS AS FOOD EMULSION STABILIZERS 1. VISCOELASTIC PROPERTIES OF CORN OIL-IN-WATER EMULSIONS INCORPORATING SOY OR MEAT PROTEINS

The creep compliance-time response of 50% (wt/wt) corn oil-in-water emulsions has been studied at a constant stress of 47.8 dyne cm⁻² over the pH range 2.5–7.5. The emulsions were stabilised by acid precipitated (APSP), 7S(7SPRF) or 11S(11SPRF) soy protein fractions, water soluble (WSMP) or salt soluble (SSMP) meat protein fractions. All the emulsions exhibited viscoelasticity. WSMP emulsions exhibited the highest initial viscoelasticity parameter values and this was attributed to the strong interlinking of WSMP loops adsorbed on the surfaces of adjacent oil drops. The parameter values of all the emulsions increased during the first 5–7 days storage and then they decreased. At any selected pH the 7SPRF emulsions exhibited the largest relative increase in parameter values. The changes in viscoelasticity during storage were explained on the basis of the relative effects of further protein loop interlinkage and drop coalescence.