Modelling the effect of temperature on the hydration kinetic of adzuki beans (Vigna angularis)

The Aw reduction is a widely used technique to preserve grains, which hydration kinetics needs to be studied in order to obtain optimized processes. This work evaluated the hydration kinetic of Adzuki beans, a widely consumed grain by the oriental culture, modelling its behaviour as function of temperature. The grains were soaked in water and the moisture over the time was evaluated at temperatures of 25-70 °C. The grain behaviour during water uptake showed an initial lag phase, with a low water absorption rate. Therefore, the hydration kinetic was evaluated using a sigmoidal model (R2 > 0.99). When soaking temperature was increased the hydration rate increased and both the lag phase and the moisture at the equilibrium decreased. These behaviour were, then, modelled as function of the soaking temperature (R2 > 0.99). The obtained results are potentially useful for future studies on product development, food properties and process design.