Starch gelatinization behavior

Last years the polymeric surface - active substances began to use as modifiers of organic reagent properties. In our work the behavior of synthetic polymers (polysulphonilpiperidinilmethylenhydroxide (PSPMH), polyvinylpyrrolidone (PVP), polyamines - polyguanidine and metacide) and natural polymers (starch, gelatin) for various molecular masses are investigated. 

Hart, P.E. and Blanshard, J.M.V. 1982. The effect of extraction method upon gelatinization behavior of wheat starch granules. Starch/Stdrke 34 293-296. 

Yang, W. H., Datta, A. K., and Rao, M. A. 1997. Rheological and calorimetric behavior of starch gelatinization in simulation of heat transfer, in Engineering and Food at ICEF 7/Part 2, ed., pp. K1-K5. Sheffield Academic Press, London. 

Surfactants modify the gelatinization behavior of starch. Figure 22 shows the changes in amylograph gelatinization curves for wheat starch caused by the inclusion of 0.5% of various emulsifiers (35). Of the three emulsifiers shown, DATEM is... 

Thixotropy and Other Time Effects. In addition to the nonideal behavior described, many fluids exhibit time-dependent effects. Some fluids increase in viscosity (rheopexy) or decrease in viscosity (thixotropy) with time when sheared at a constant shear rate. These effects can occur in fluids with or without yield values. Rheopexy is a rare phenomenon, but thixotropic fluids are common. Examples of thixotropic materials are starch pastes, gelatin, mayoimaise, drilling muds, and latex paints. The thixotropic effect is shown in Figure 5, where the curves are for a specimen exposed first to increasing and then to decreasing shear rates. Because of the decrease in viscosity with time as weU as shear rate, the up-and-down flow curves do not superimpose. Instead, they form a hysteresis loop, often called a thixotropic loop. Because flow curves for thixotropic or rheopectic Hquids depend on the shear history of the sample, different curves for the same material can be obtained, depending on the experimental procedure. 

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