The Application of Cold Atmospheric Plasma (CAP) in Barley Processing as an Environmentally Friendly Alternative

Abstract

Cold atmospheric plasma (CAP) is a novel and versatile technology, which is not yet used in the food and agricultural sector for barley processing. In lab-scale applications, the technology shows potential in extending shelf life and ensuring food safety and quality, e.g., during storage. CAP reactive nature counteracts insect pests, fungi, and bacteria, but also improves seed germination and facilitates plant growth not only under stress conditions. Its generation does not require water, chemicals, or solvents and consumes little energy due to low operating temperatures (<60 °C) with a short time span that makes additional production steps (e.g., cooling) obsolete. Therefore, CAP is a sustainable technology capable of further optimising the use of limited resources with the potential of offering solutions for upcoming environmental challenges and political requirements for replacing existing practices and technologies due to the growing impact of climate change. This review summarises recent developments and findings concerning CAP application in barley production and processing with air as the process gas. Furthermore, this comprehensive overview could help identify further research needs to overcome its current technical limitations, e.g., efficiency, capacity, etc., that hamper the upscale and market introduction of this environmentally friendly technology.

Keywords: barley grains; cold atmospheric plasma; detoxification; disinfestation; food processing; germination; microbial inactivation; mycotoxins; plant growth; reactive species.

Figure 1

The four states of matter (adapted from [22]).

Figure 2

Different CAP systems: (a) dielectric barrier discharge, (b) corona discharge, (c) plasma jets (Adapted from [12,26]).

Figure 3

Possible pathways of ROS and RNS formation while using ambient air as process gas [28,36,42,44].

Figure 4

Potential CAP use in different production stages.

Figure 5

Vision of the Project “Physics for Food” (pictures 3 and 4 reproduced with permission from Paulina Druse, INP Greifswald, 2022).

Figure 6

Mechanisms of antimicrobial CAP effects.