## 3 Results and Discussion
### Pilot Plant Tests  
Table 4 provides a summary of the operating conditions pertaining to temperature, pressure, and extraction time for the three conducted tests. Regarding the temperature, the experiments were conducted at different temperatures: 55 \({}^{\circ}\)C for the first test, 78 \({}^{\circ}\)C for the second test, and 87 \({}^{\circ}\)C for the third test. The variation in temperature indicates an exploration of different thermal conditions to optimise the extraction process. Typically, higher temperatures can enhance the extraction efficiency by accelerating the dissolution kinetics of polyphenols from organic matrices [31; 32]. However, there is a balance to strike, as excessively high temperatures might lead to the degradation of heat-sensitive compounds or alterations in the chemical composition of the extract [33].  
The pressure conditions also varied across the tests, with the first test conducted at 0.54 bar, the second at 1 bar, and the third at 1.2 bar. Pressure can influence the solubility of compounds and impact the extraction efficiency. In general, higher pressures may enhance solubility [34], particularly for non-polar solvents, potentially leading to increased extraction yields [35]. However, too high a pressure might introduce operational challenges and increase energy consumption.  
All three tests were conducted for a duration of 3 h each. Extraction time is a critical parameter that affects the quantity and quality of the extracted compounds [36]. Longer extraction times may allow for a more thorough extraction of polyphenols from the matrices, but there is a practical limit beyond which any additional extraction time may not significantly improve yields and could instead lead to increased costs and energy consumption.  
Looking at the dry residue % (Table 5), extract 1 and concentrated 1 have relatively lower values compared to extract 2 and concentrated 2, while extract 3 and concentrated 3 show the highest values. This indicates differences in the concentration of solids between the extracts and their concentrated forms.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Operatives Variables** & **1** & **2** & **3** \\ \hline
**Temperature** & 55 \({}^{\circ}\)C & 78 \({}^{\circ}\)C & 87 \({}^{\circ}\)C \\
**Pressure** & 0.54 bar & 1 bar & 1.2 bar \\
**Time of extraction** & 3 h & 3 h & 3 h \\ \hline \end{tabular}
\end{table}
Table 4: Operating conditions relating to temperatures, pressure, and time for the three tests carried out.  
Regarding total phenols (mg/L of _A. gallic_) (Table 5), there is a significant increase in total phenols when comparing the extracts to their concentrated forms. Extract 1 has the lowest phenol content, while extract 3 has the highest. The concentration process appears to enhance the total phenolic content in the solutions.  
Finally, concerning the antioxidant activity (umol TEAC/mL) (Table 5), the trend is similar to that of total phenols; in fact, the antioxidant activity increases in the concentrated solutions compared to the extracts. Extract 1 shows the lowest antioxidant activity, while extract 3 has the highest. On the basis of the results obtained, we can state that the concentration process seems to enhance the antioxidant capacity of the solutions.