Effects of High-Voltage Discharge Plasma on Drying Properties, Microstructure, and Nutrients of Oat Grass

In this study, the drying properties of new-mown oat grass were investigated using three methods: high-voltage discharge plasma drying (HVDP), hot-air drying (HAD), and natural air drying (AD). The HVDP process mainly generates discharge plasma between needle electrodes and a dielectric plate by changing the discharge voltage. HVDP, which is a new type of non-thermal drying technology, uses the energy exchange associated with the action of plasma and the non-uniform electric field force to accelerate the evaporation of water. The results show that HVDP has obvious advantages in terms of the drying rate and drying time, as well as reducing energy consumption while retaining nutrients. In particular, under the condition of 35 kV, HVDP not only effectively shortened the drying time and reduced the energy consumption but also selectively degraded the nutrient-reducing substances (e.g., lignin) and retained the substances positively correlated with the nutrient quality, significantly improving the nutrient content of the treated oat grass. In conclusion, as an innovative non-thermal drying technology, HVDP has great potential to improve the drying efficiency and reduce nutrient degradation in oat grass, providing an innovative solution to improve its quality and utilisation.