## 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
[61], where UHPH treatment (300 MPa, inlet and outlet temperatures of 23-25 \({}^{\circ}\)C and 13-15 \({}^{\circ}\)C, in-valve temperature 65-78 \({}^{\circ}\)C for 0.02 s) of white must resulted in total inactivation of wild microorganisms, and higher antioxidant activity due to inactivation of oxidative enzymes. UHPH musts showed no fermentative activity for longer than 60 days, no thermal damage and no significant changes in terpen and other aroma compounds. Similar conclusions were also drawn by [PERSON] et al. [64], who processed Cabernet Sauvignon red must with UHPH (300 MPa, inlet and outlet temperatures of 4 and 15 \({}^{\circ}\)C, in-valve temperature 78 \({}^{\circ}\)C for <0.2 s). Among others, authors highlighted the better colloidal stability of UHPH must and the protective effect of UHPH regarding polyphenols and color. Namely, UHPH must showed higher content of anthocyanins, particularly those in acylated forms (+9.3%), resulting in more red-blue color. In order to investigate the influence of UHPH (300 MPa, inlet and outlet temperatures of 4 and 14 \({}^{\circ}\)C, in-valve temperature 95 \({}^{\circ}\)C for <0.2 s) on wine characteristics, [PERSON] et al. [63] carried out alcoholic fermentation with UHPH white musts and compared it to the non-sulfited and sulfited fermentations (60 mg/L total SO2). This research also confirmed the antimicrobial and antioxidative effect of UHPH with no detrimental changes in quality characteristics, as already mentioned in the above studies. Furthermore, the same authors also used UHPH (300 MPa, inlet and outlet temperatures of 17 and 19 \({}^{\circ}\)C, in-valve temperature 94 \({}^{\circ}\)C for <0.2 s) to treat aged red wine contaminated by _Brettanomyces_, and found 6.6 log reduction and no increase in volatile phenols after 2 months of storage. Recently, [PERSON] et al. [65] studied the effect of processing Verdejo grape must by UHPH (300 MPa, inlet and outlet temperatures of 8 and 15 \({}^{\circ}\)C, in-valve  
Figure 7: Ultra–high-pressure homogenization (UHPH) working mechanism. © 2024 [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON]. Originally published in Use of UHPH to Sterilize Grape Juices and to Facilitate the Implantation of Saccharomyces and Other Emerging Fermentation Biotechnologies in Wines under CC BY 4.0 license. Available from: 10.5772/intechopen.1003954 [[https://www.intechopen.com/chapters/1156686](https://www.intechopen.com/chapters/1156686)]([https://www.intechopen.com/chapters/1156686](https://www.intechopen.com/chapters/1156686)) (accessed on 28 March 2024) [86]. temperature 92 \({}^{\circ}\)C) using non-_Saccharomyces_ yeasts with no addition of SO\({}_{2}\). The authors reported that UHPH is able to control microbial activity and oxidation in grape must, along with a favoring effect on implantation of yeast starters and a positive impact on wine quality in terms of color and aroma composition. In general, it can be concluded that UHPH is a useful tool for wine production. Analysis of recent reports in the literature has shown that UHPH technology has a clear potential for the elimination of microorganisms (especially yeast and bacteria) in grape must, the inactivation of oxidative enzymes, the reduction in SO\({}_{2}\), the easier implantation of selected yeast starters, and the improvement of colloidal and color stability, as well as the overall quality of the wine. In addition, UHPH has been approved in 2020 by the OIV (OENO 594B-2020) [77] for the treatment of musts in a continuous operating mode at a pressure of 300-400 MPa, with the aim of reducing/eliminating wild microorganisms while preserving sensory quality, limiting the use of SO\({}_{2}\), reducing/inactivating the activity of oxidative enzymes, improving the stability of the grape must, and obtaining partially fermented musts.