Development and Optimization of Cold Plasma Pretreatment for Drying on Corn Kernels

This study was conducted to optimize a process of cold plasma pretreatment for hot-air drying on corn kernels. Effects of plasma pretreatment time (30, 40, 50 s), plasma pretreatment power (300, 400, 500 W) and drying temperature (37.5, 45, 52.5 °C) on drying time and drying rate during this process were investigated. Polynomial equations were established through a three-factor and three-level Box-Behnken design and used to evaluate the optimal operational conditions for the drying process. The optimal pretreatment conditions were drying temperature at 52.5 °C, plasma pretreatment time of 50 s and plasma pretreatment power of 500 W, and the corresponding drying rate and drying time were 3.6163 (g/g h^-1 ) and 1.29 hr, respectively. The AFM images showed that cold plasma pretreatment can change the topography of the treated surface with some micro-holes, which explain how the plasma pretreatment can improve the drying process. PRACTICAL APPLICATION: Cold plasma pretreatment can improve the efficiency of corn kernels drying. Furthermore, it has potential application for reducing energy consumption in drying. Cold plasma pretreatment could be potentially applied in grain drying.