RHEOLOGICAL AND CALORIMETRIC PROPERTIES OF HEATED CORN STARCH SOYBEANPROTEIN ISOLATE DISPERSIONS

Differential scanning calorimetric (DSC) data on 10% (w/w) corn starch dispersion showed one endothermic peak and on soybean protein (SP) is olate dispersions two peaks attributed to 7S and 11S globulins. In cor n starch-SP isolate mixtures, thermal transitions appear to occur inde pendently of one another. Dynamic rheological data over 0.63-62.9 rad s(-1) revealed weak gel-like behavior of both 10% corn starch and SP i solate dispersions with magnitudes of storage modulus (G') being signi ficantly higher than those of loss modulus (G '') and both exhibiting slight frequency-dependence; G' of corn starch dispersion was higher t han that of SP isolate and in mixed dispersions its magnitude decrease d with increase in proportion of protein. The Maxwell model described creep-compliance data on dispersions high in corn starch, while the Bu rgers model described dispersions high in SP isolate. Plots of protein /starch ratio versus G' and instantaneous elastic modulus showed simil ar trends in phase separation and inversion.