## 3 Results and Discussion
### Effect of Steeping the Barley Grains on DON Degradation by ACP  
One of the major applications of barley is in the brewing industry. Steeping is one of the crucial steps to produce malt for the beer preparation. If barley is contaminated with DON, it can be present in the final product [43]. On the other hand, the presence of moisture is a determining factor for the ACP treatment efficacy. Increasing the moisture content of the substrate was anticipated to increase the generation of ROS (e.g., hydroxyl radicals) [17; 18; 19], which could then increase the DON degradation rate. An increase in hydroxyl radicals could further increase the generation of ozone, as ozonation is catalyzed by free radicals such as hydroxyl ion [43]. The uptake of ozone by the product would then increase at higher moisture contents, since ozone is water-soluble [44]. This could increase the contact between ozone and DON and consequently improve its degradation rate. However, the degradation of DON by 6 min ACP treatment on steeped and dried barley grains was 36.3% \begin{table}
\begin{tabular}{c c} \hline \hline
**Treatment** & **DON Degradation Rate (\%)** \\ \hline No treatment, no storage & 0 [FOOTNOTE:]Footnote : Data are shown as least square means \(\pm\) standard deviations. Values with different letters are significantly different (\(p<0.05\), \(n=3\)).[ENDFOOTNOTE] \\
0 min ACP, 24 h storage & \(8.1\pm 2.7\) [FOOTNOTE:]Footnote : Data are shown as least square means \(\pm\) standard deviations. Values with different letters are significantly different (\(p<0.05\), \(n=3\)).[ENDFOOTNOTE] \\
6 min ACP, no storage & \(45.0\pm 0.9\) [FOOTNOTE:]Footnote : Data are shown as least square means \(\pm\) standard deviations. Values with different letters are significantly different (\(p<0.05\), \(n=3\)).[ENDFOOTNOTE] \\
6 min ACP, 24 h storage & \(53.6\pm 1.8\) [FOOTNOTE:]Footnote : Data are shown as least square means \(\pm\) standard deviations. Values with different letters are significantly different (\(p<0.05\), \(n=3\)).[ENDFOOTNOTE] \\
6 min ACP, 10 min storage inside treatment chamber & \(52.0\pm 1.6\) [FOOTNOTE:]Footnote : Data are shown as least square means \(\pm\) standard deviations. Values with different letters are significantly different (\(p<0.05\), \(n=3\)).[ENDFOOTNOTE] \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Effect of post-treatment storage on DON degradation on barley by ACP. (Sample B) (Table 5). This DON degradation in steeped barley grains was lower compared to that in barley grains without steeping (48.9%), as reported in Section 3.1 (Figure 2). During the steeping process, water will be absorbed and the grains will swell, which can influence the surface properties and topoplogy of the grain surfaces. The topology of the substrate surface can influence the efficiency of DON degradation by ACP treatment. The fissures and grooves on the rough surfaces of the grains could protect DON from plasma generated species [19]. The effect of the surface characteristics of the substrate was determined in previous studies for the inactivation of bacteria by ACP [45; 46; 47]. The greater inactivation of bacteria via ACP treatment was observed on smooth surfaces. Moreover, ACP treatment could modify surface topology and change surface properties. [PERSON] et al. [12] observed changes on the surface of plasma-treated barley grains compared to the untreated samples. The changes on the surface of the grains after ACP treatment could be due to the chemical reactions of the reactive species on surfaces or energy exposure by ACP. The drying step after mycotoxin inoculation on barley grains before ACP treatment had a significant impact (\(p<0.05\)) on the degradation of DON. Since the drying step was used before ACP treatment, the effect of greater moisture on the surface of barley grains due to steeping, on DON degradation during ACP treatment, was negligible.