Publications Repository - Gdańsk University of Technology

Native potato starch was sulfated, selenated, borated, silicated and zincatated by means of microwave-assisted reactions with varying doses of relevant reagents. Resulting products were characterized involving rheological behavior of pastes, their weight-average molecular weight (Mw), and radius of gyration (Rg). Most of the pastes showed shear-thinning behavior, with the flow behavior index (n) below unity. The pastes of starch sulfated and borated with boric acid exhibited n higher than native potato starch paste. They had significantly lower consistency index (K) and plastic viscosity and no yield stress. Mw values of these starches were considerably reduced. The pastes of starch selenate, borate after borax, and silicate after silicic acid, with n lower than native potato starch, had similarly lower K and plastic viscosity but, simultaneously, they showed non-zero yield stress values, and yield stress, Mw and Rg of starch selenate were reagent concentration dependent. Also magnitudes of n, K, plastic viscosity, yield stress, Mw and Rg of pastes of starch silicate after sodium metasilicate and zincatate were reagent concentration dependent. While their n rose with concentration, K and plastic viscosity significantly decreased, and yield stress ceased. The effect of temperature on the apparent viscosity of modified starch pastes followed Arrhenius equation.

Authors

• dr hab. inż. Hanna Staroszczyk link open in new tab ,
• Maciej Fiedorowicz,
• Joanna Opalińska-Piskorz,
• dr hab. inż. Robert Tylingo link open in new tab