Drying Grain Pretreated by Low-Voltage Spark-Discharge Plasma Channel

Abstract

The food industry and agriculture use such electrophysical technologies as ozonation, pulsed electric field, and low-temperature plasma. They increase the shelf-life of food products, as well as help to advance food processing. This article features pretreatment with a low-voltage spark-discharge plasma channel as a means to increase the efficiency of grain drying. The grain material involved three samples of soft wheat seeds. Sample 1 was subjected to direct contact with the electrodes while sample 2 underwent treatment on a dielectric substrate. The control remained untreated. The kinetics of grain-drying in the open air was studied using a thermal agent at 110°C after pre-treatment with a low-voltage spark-discharge plasma channel. This experiment also involved scanning electron microscopy tools to detect changes in surface structure. The electron microscopy showed that the dielectric substrate accelerated moisture removal, probably as a result of the emerging surface effects that developed a new continuum in the grain structure. This treatment made it possible to reduce the drying time by 15–25%, compared to the control sample. The drying rate curves demonstrated acceleration in the initial period, associated with additional electroosmotic forces and changes in the absorption properties. The samples treated with low-voltage spark-discharge plasma channel showed a 20% reduction in total energy consumption. Electrophysical technology based on a low-voltage spark-discharge plasma channel proved to be an effective pre-drying procedure. Further research is needed to scale the technology in a flow mode and to identify its effect on shelf-life.

Keywords

• food raw materials
• grain material
• drying
• electrophysical technologies
• spark discharge
• ozone-air mix
• drying efficiency
• drying kinetics
• electroosmotic force