Effect of Ultrasonication on the Hydration Behaviour of Paddy

This study examined the impact of ultrasonication at 20 kHz, and 90% of rated power on the hydration behaviour of paddy (var. BPT 5204) at a soaking temperature of 60°C, and compared it with the conventional soaking methods at 30 °C and 60°C using various kinetic models. Ultrasonication significantly accelerated hydration by inducing mechanical and cavitational effects, such as the sponge effect and inertial flow, resulting in enhanced water absorption and faster grain hydration. While conventional soaking required 33 hours at 30°C and 9 hours at 60°C to reach saturation moisture content (35±1% w.b.), ultrasonication achieved the same in just 3 hours. Kinetic modelling revealed Page model provided the most accurate representation of the hydration process under ultrasonication. Application of ultrasonication at a hydration temperature of 60°C, yielded approximately a two-fold increase in effective diffusion rates (1.18 x 10^-10 m² s^-1) when compared to effective moisture diffusivity at 60°C hydration temperature alone. The kinetic modelling of paddy hydration under the optimized ultrasonication conditions identified in this study can serve as a basis for improving the soaking process in industrial parboiling through suitable integration into large-scale grain processing. This approach has the potential to reduce energy consumption and processing time; however, further research is required to evaluate its scalability, applicability to other grains, and economic feasibility while ensuring the preservation of grain quality parameters.