Effect of ultrasonication and temperature on hydration process and hardness of two cowpea types

Ultrasonication deployment provides a green and non-thermal option to traditional hydrothermal treatment. This study presents the impact of ultrasonication and soaking temperatures (30 and 50°C) on the water uptake and hardness of two cowpea types under increasing soaking times (15–240 min). Moisture content and hardness of the studied samples were measured using standard test methods and instruments. An increase in soaking temperature and the use of ultrasonication enhanced water uptake and reduced hardness. Ultrasonication improved mass transfer, which enhanced the diffusion of water uptake. The samples' water uptake and softening characteristics were significantly modeled with high accuracy (R² = 0.99) using sigmoidal and first-order kinetics equations, respectively. The impact of sonication was found to be more significant at 30°C soaking of the studied cowpeas as the soaking time increased. This work justified using ultrasonication as a green technique to enhance the softening of cowpeas.