# Non-Thermal and Thermal Physical Procedures--Optimistic Solutions in the Winemaking Industry
## 3 The Influence of Thermal Technologies in Wine Quality
### Pre-Fermentative Low Temperature Treatments  
Authors have also shown that low temperature treatments (cryomaceration and cold soak maceration) influence the concentration of different volatile compounds (geraniol, linalool, nerol, \(\alpha\)-terpinene) and manifest a significant impact on wine sensory profile [23]. [PERSON] et al. [66] postulated that lower levels of some volatile compounds (lactones, benzaldehyde) are obtained when cryomaceration is involved, compared with classical methods.  
[PERSON] et al. [67] obtained higher concentrations of terpen when cryomaceration was used. Also, [PERSON] et al. [60] promoted this technique for elevating the concentrations of esters in Tamaioasa romaneasca wines.  
[PERSON] et al. [59] demonstrated a significant reduction in delphinidin 3-glucose, cyanidin-3-glucose, petunidin-3-glucose, peonidin-3-glucose, peonidin  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Intensity (W)** & **Time** & **Sample** & **Results** & **References** \\ \hline \multirow{4}{*}{1150} & \multirow{4}{*}{1, 2} & red wine (Pinot noir) & - & an increase in anthocyanins, tannins, and phenolic compounds during an 18-month age period in the bottle; & \multirow{4}{*}{[62]} \\  & & red wine (Pinot noir) & - & a shorter maceration period; & \\  & & & - & reducing the dose of SO\({}_{2}\) when processing grapes; & \\  & & & - & significant impact on chromatic characteristics. & \\ \hline \multirow{4}{*}{1200} & \multirow{4}{*}{10} & red wine (Merlot) & - & no impact on overall acidity and pH value; & \multirow{4}{*}{[63]} \\  & & red wine (Merlot) & - & greater ratios of tannins and anthocyanins; & \\  & & & - & notable color modification. & \\ \hline \multirow{4}{*}{700} & \multirow{4}{*}{12} & red wine (Cabernet Sauvignon) & - & increasing the concentration of anthocyanins, tannins, and & \multirow{4}{*}{[64]} \\  & & (Cabernet Sauvignon) & - & color intensity; & \\ \cline{1-1} \cline{3-4}  & & & Sauvignon) & - & higher value of the total phenolic index. & \\ \hline \multirow{4}{*}{500} & \multirow{4}{*}{5, 10, 15, 20} & \multirow{4}{*}{red wine} & - & reduced total phenolic content, anthocyanins levels, and & \multirow{4}{*}{[65]} \\  & & & & antioxidant activity; & \\ \cline{1-1} \cline{3-4}  & & red wine & - & major impact in reducing the total acidity; & \\ \cline{1-1} \cline{3-4}  & & & - & no effect on the electrical conductivity and pH value; & \\ \cline{1-1} \cline{3-4}  & & & - & important color modifications (higher value for L’, a*, b*). & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Correlations of microwave treatment on physicochemical parameters of wine.  
3-glucoside acetate, peonidin-3-glucoside coumarin, and malvidin-3-glucose coumarin, but a twofold increase in malvidin-3-glucose levels in Merlot wines obtained with this technique. On the other hand, the authors observed elevated concentrations of malvidin-3-glucose, peonidin-3-glucose acetate, and malvidin-3-glucose in Feteasca neagra wines. Moreover, [PERSON] et al. [23] highlighted a significant improvement of chromatic properties (increased clarity--a positive factor in the case of rose wine) of Busuioaca de Bohotin wines when cryomaceration is used in comparison with classical maceration. Cryomaceration presents minor influences (a small increase in acidity and dry extract, reduced total sugars, density) regarding the physicochemical parameters of Cabernet Sauvignon wines obtained by [PERSON] et al. [59]. It was found that prolonged contact with grape skins (12, 18, and 24 h) at low temperatures (5 and 10 \({}^{\circ}\)C) significantly increased the levels of phenolics in wines, such as caffe acid. It was also found that the wines visually had an unaltered commercial appearance [5; 68; 69].