ŻYWNOŚĆ. Nauka. Technologia. Jakość, 2006, 1 (46) Supl.,  143 - 151

IWONA SITKIEWICZ, SYLWIA DENOCH

RHEOLOGICAL PROPERTIES AND RETROGADATION OF SOME SELECTED MODIFIED WAXY MAIZE STARCHES

S u m m a r y

The rheological properties of pastes made of modified waxy maize were investigated and compared with the properties of native starch. Apparent viscosity curves were plotted using a rotational viscosimeter type Brookfield DV-III V 3.3 RV. Changes in rheological parameters occurring whilst storing the pastes investigated were analysed as was the resistance of the pastes to the freezing-thawing cycles. Furthermore, during the storage of pastes, the light transmission intensity was assessed using a Turbiscan Lab apparatus. Within the investigated range of shear rates, the starch pastes appeared to be non-Newtonian and shear-thinned fluids showing a thixotrophy phenomenon. The modified starch pastes were characterized by a higher stability of their rheological parameters during their storage, as well as by a certain resistance to the freezing-thawing cycles compared to the native starch paste of waxy maize. The modified starch pastes were less transparent than the native starch paste; however, their transparency did not change during the storage.

Key words: waxy maize starch, chemically modified starch, stability during storage, freezing-thawing stability, retrogradation