Enhancing the hydration process of common beans by ultrasound and high temperatures: Impact on cooking and thermodynamic properties

Although many technologies have been applied to enhance the hydration process of grains, some combinations and mechanisms still need better description. Consequently, this work studied how the combination of ultrasound and temperature affected the hydration process of one variety of legume grain, as well as described their thermodynamic properties of hydration and the impact on cooking kinetics. White kidney beans were hydrated using ultrasound technology (28 W/L of volumetric power and 45 kHz of frequency) at four different temperatures (25, 35, 45 and 55 °C). In addition, the softening kinetics during cooking at boiling temperature was studied by penetration analysis. Further, the thermodynamic properties, such as activation enthalpy, Gibbs free energy and entropy were determined. It was demonstrated that despite both technologies improve the hydration process individually, hot temperatures hinder the ultrasound effect. Further, the thermodynamic properties of the hydration phenomenon were affected by ultrasound, suggesting how the molecules rearrangement is affected by this technology during hydration. Finally, the use of both technologies did not affect softening kinetics of the bean during cooking process.