## 4 Conclusions  
Today, plasma technology is established as a key and cross-sectional technology in many industries as a modern technological standard. It has a wide range of applications, from industry to mechanical engineering and medicine to research, and plays an important role in various areas of human life and activity.  
Plasma can be generated at different pressures and temperatures. Changing the pressure and temperature values leads to a change in the chemical species in the generated plasma, which can significantly affect the behaviour of the plasma system but also enables the generation of plasmas suitable for a very wide range of applications. In our case, we confirmed that precise control and adjustment of these parameters is key to maintaining stable, reliable and reproducible processes.  
Furthermore, our results confirm that monitoring the plasma with optical emission spectroscopy in near-real time is important to determine whether it is a plasma system at all. The high spectral resolution, a key feature of an optical emission spectrometer, allows for a more accurate identification of the excited species generated in the plasma and facilitates plasma diagnostics, i.e., the determination of the most important parameters describing the  
\begin{table}
\begin{tabular}{l l l l l} \hline
**Plasma Source** & **Gas** & **Electron Temperature** & **Electron Density** & **Reference** \\ \hline Gas discharge & Ar & Up to 2.2 eV & & \\  & Air/He & Up to 3.5 eV & 10\({}^{22}\) m\({}^{-3}\) & [58] \\ \hline Dielectric barrier discharge & Ar & 1–5 eV & 10\({}^{19}\)–10\({}^{24}\) m\({}^{-3}\) & [59] \\ \hline Plasma jet system & Ar & Up to 1.3 eV & 10\({}^{23}\) m\({}^{-3}\) & [60] \\ \hline Plasma jet system & Ar & 1 eV & 10\({}^{22}\) m\({}^{-3}\) & [61] \\ \hline Plasma jet system & Ar & 1 eV & 10\({}^{21}\) m\({}^{-3}\) & [52] \\ \hline \end{tabular}
\end{table}
Table 2: Comparison of experimentally determined plasma parameters from different studies.  
plasma, electron density, and electron temperature. For a better interpretation of the results and a better adaptation of the working conditions, it is suggested to perform measurements with different parameters of the high-voltage pulse generator (operating time, high voltage, pulse frequency, pulse duration and HV current) and different parameters for the optical emission spectrometer (integration time, scans to average). It is also possible to use other working gases instead of argon. Non-thermal plasma diagnostics in the food sector can also be improved in the future through the use of Industry 4.0 technologies: Big Data analysis for a more accurate assessment of physical quantities based on spectroscopic measurements and machine learning for predictions and finding patterns in the dynamics of complex non-thermal plasma systems.  
Conceptualization, S.P. and F.K.; methodology, S.P.; software, S.P. and F.K.; validation, S.P.; formal analysis, S.P. and F.K.; investigation, S.P. and F.K.; resources, S.P.; data curation, S.P. and F.K.; writing--original draft preparation, S.P. and F.K.; writing--review and editing, S.P.; visualisation, S.P. and F.K.; supervision, S.P.; project administration, S.P.; funding acquisition, S.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the European Union's Horizon 2020 PRIMA (The Partnership for Research and Innovation in the Mediterranean Area) programme under grant agreement No: 2032--Functionalized Tomato Products (FunTomP).  
Data Availability Statement: Data are contained within the article.  
The authors declare no conflict of interest.