Understanding starch gelatinization and rheology modeling of tapioca starch- NaCl/CaCl blends: Thermodynamic properties and gelatinization reaction kinetics during pre- and post-ultrasonication.

The presence of salt can impact the fluid phase and gelatinization process of starch granules. The variation in viscosity and rheology models including the Herschel-Bulkley, the Casson model, and the power law, were determined by adding salts before and after starch ultrasonication. Non-isothermal kinetics can be utilized for the mathematical modeling of the gelatinization process and the evolution of the reaction. Unlike Na ions, Ca ions notably elevate viscosity. The Casson model accurately predicts viscosity data. Results indicate that the addition of Na ions decreases yield stress by up to 60.4 %, while Ca ions increase by up to 100.8 %. Adding Na ions decreases the required thermal energy by as much as 49.6 %, while the presence of Ca ions can lead to a substantial increase of up to 337.1 % compared to control samples. The positive ∆G indicates a non-spontaneous gelatinization process. The addition of NaCl promotes a spontaneous reaction, while the addition of CaCl increases the Gibbs energy. The changes in entropy are minimal, implying minimal changes in starches' disorder structure.