Kinetic modeling and thermodynamic properties of soybean cultivar (BRS257) during hydration process

The hydration kinetics of transgenic soybean cultivar BRS257 was studied at temperatures 30, 40, 50, and 60 °C for 480 min. Peleg and Omoto–Jorge models and its generalized equations were used in this work to describe the kinetics of water absorption. At all temperatures, the models represented the main trends of the hydration process with deviations of less than 3%. However, the Peleg model presents the best fit to the experimental data ( R 2 = 0.99; P < 3.0%; RMSE = 0.97; SE = 1.07). The moisture transfer is affected by temperature, with higher absorption rates at higher temperatures and the Peleg's constant K 1 decreased, while K 2 was almost constant. The activation energy ( E a ) = −34.797 kJ/mol and average enthalpy (Δ H ) = −37.442 kJ/mol, entropy (Δ S ) = −1.917E–01 kJ/mol/K, Gibbs free energy (Δ G ) = 2.347E+01 kJ/mol were estimated from the adjusted parameters and Arrhenius equation. The values obtained show that hydration is not a spontaneous phenomenon. The grain density (0.97 ± 0.08 g/cm 3 ) presented almost constant values during the experiments. Practical applications The practical application of this work aims to evaluate the hydration process of the transgenic cultivar BRS257, for different conditions of time and temperature. This cultivar presents an important characteristic compared to other cultivars, because it does not require severe thermal treatment conditions to inactivate the Lipoxygenases enzymes, responsible for an adstringent taste. This work allowed to know thermodynamic properties of the hydration process. Furthermore the appropriate model is useful for future process optimization, aiming to decrease the time and the energy required.