## 3 Non-Thermal Technologies in Winemaking Process
### Other Non-Thermal Technologies in Winemaking Process
#### 3.4.1 Ultra-High Pressure Homogenization (UHPH) Effects on Microbial Populations and Wine Quality
\begin{table}
\begin{tabular}{l l l l} \hline \hline \multicolumn{1}{c}{**Sample**} & \multicolumn{1}{c}{**Processing Conditions**} & \multicolumn{1}{c}{**Key Outcomes**} & \multicolumn{1}{c}{**References**} \\ \hline \multirow{8}{*}{Red wine} & \multirow{8}{*}{15, 20 and 25 kV/cm; 8–80 Hz frequencies; 20–175 \(\upmu\)s treatment time; 35–120 kJ/kg; 4 continuous flow; T < 50 \({}^{\circ}\)C} & \multirow{8}{*}{Significant effect on _S. cerevisiae_ and _O.oeni_ inactivation: up to 4 log cycles.} \\  & & & \(\bullet\) Successful wine microbial stabilization for \\  & & & at least 4 months of storage. \\ \cline{3-3}  & & & \(\bullet\) No significant effect on wine \\ \cline{3-3}  & & & \(\bullet\) Physicochemical and sensory \\ \cline{3-3}  & & & \(\bullet\) Reduction of SO\({}_{2}\). \\ \hline \multirow{8}{*}{Red wine} & \multirow{8}{*}{10 μs; 1500 V; square bipolar pulses; continuous flow; T = 25.5 \({}^{\circ}\)C} & \multirow{8}{*}{\(\bullet\) Significant increase in color, turbidity and pH by PEF extraction treatment in both wine varieties.} \\  & & & \(\bullet\) None increase in total phenols in Arinto variety. \\ \cline{3-3}  & & & \(\bullet\) No impact of PEF stabilization treatment on wine quality. \\ \cline{3-3}  & & & \(\bullet\) None increase in total phenols in Moscatel wine. \\ \cline{3-3}  & & & \(\bullet\) None increase in total phenols in Arinto variety. \\ \cline{3-3}  & & & \(\bullet\) No impact of PEF stabilization treatment on wine quality parameters. \\ \cline{3-3}  & & & \(\bullet\) None decrease in total phenols in Moscatel wine. \\ \cline{3-3}  & & & \(\bullet\) None decrease in total phenols in Moscatel wine. \\ \cline{3-3}  & & & \(\bullet\) None effect on sensory quality of wines. \\ \cline{3-3}  & & & \(\bullet\) None reduction in pre-bottling SO\({}_{2}\) addition. \\ \hline \multirow{8}{*}{Xinomavro red wine} & \multirow{8}{*}{Stationary bench scale PEF system; 1.1 kV/cm; pulse width 10 μs; pulse period 100 μs; rectangular monopole pulses; total treatment duration 20 min} & \multirow{8}{*}{\(\bullet\) No visually detectable color alterations.} \\ \cline{3-3}  & & & \(\bullet\) Enhancement of wine sensory \\ \cline{3-3}  & & & \(\bullet\) None characteristics. \\ \cline{3-3}  & & & \(\bullet\) None accelerated wine aging. \\ \hline \multirow{8}{*}{Merlot red grapes} & \multirow{8}{*}{Continuous PEF system; 25 and 33 kV; 2–25 Hz pulse frequency; 33.1 and 41.5 kV/cm, 4.7–49.4 kJ/L} & \multirow{8}{*}{\(\bullet\) Increased extraction of a wide variety of phenolic compounds.} \\ \cline{3-3}  & & & \(\bullet\) None increase in total phenols. \\ \cline{3-3}  & & & \(\bullet\) None increase in total phenols. \\ \cline{3-3}  & & & \(\bullet\) None visually detectable color alterations. \\ \cline{3-3}  & & & \(\bullet\) Enhancement of wine sensory \\ \cline{3-3}  & & & \(\bullet\) None characteristics. \\ \cline{3-3}  & & & \(\bullet\) None accelerated wine aging. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._of oxidative enzymes, and enhancement of extraction process with low impact on sensory and nutritional quality, UPHH is considered to be a valuable tool for the wine industry [14]. In a research study by [PERSON] et al. [62], authors used UPHH (300 MPa, inlet and outlet temperatures of 20 and 25 \({}^{\circ}\)C, in-valve temperature 98 \({}^{\circ}\)C for 0.02 s) to treat white must. It was found that UHPH was able to completely eliminate non-_Saccharomyces_ wild yeasts and vegetative bacteria populations. Moreover, a high inactivation for polyphenol oxidase activity was also observed. Additionally, wines produced from UHPH treated must were better in global quality, showing more fruity notes and increased aroma complexity. Similar results were obtained in another study by [PERSON] et al.