*Emerging Technologies to Increase Extraction, Control Microorganisms, and Reduce SO2 DOI: http://dx.doi.org/10.5772/intechopen.92035*

Technologies (Barcelona, Spain) (www.ypsicon.com). It consists of a continuous device capable of working from 200 to 400 MPa and applying shear, impact, cavitation, and turbulence forces in a special valve at high speed (Mach 2). As a consequence, the particles size is reduced from 100 to 300 nm, microorganisms are destroyed, enzymes inactivated and stable emulsions are produced without additives, and consuming less energy than thermal treatments.

UHPH is highly efficient in controlling microorganisms. The antimicrobial effect is produced by the strong impact forces together with the shear stresses and the complementary effect of local cavitation and friction [7–9]. This process produces intense heating in the in-valve time but during a really short period of time of 0.02 and 0.2 s for the global residence time. The temperature in the valve can reach 100°C when the inlet temperature is 20°C, being reduced to 25°C after the valve [8] by adiabatic-expansion chilling. Even when high temperatures are reached instantaneously in the valve, as a whole it can be considered a gentle technology with no thermal effect on sensory degradation. After the UHPH process, no formation of thermal markers such as furfural or 5-hydroxymethylfurfural is observed, probably because of the very low residence time. UHPH processing using suitable in-valve temperatures can produce sterilization capable of destroying even sporulated bacteria. Because of this feature, it can be considered a gentle alternative to UHT, since in this thermal technique a temperature of 140°C for 3–4 s is necessary. In contrast, UHPH only requires a total processing time of less than 0.2 s.

UHPH can be applied to liquids containing particles, but the particle size must be lower than 500 μm. The average particle size range at the valve outlet is 100–300 nm. The valve design is a critical point, as well as the performance of the UHPH process, but especially the antimicrobial effect depends on the geometry and materials of the valve piston and seal. Especially, efficient designs are manufactured by Ypsicon [44] (**Figure 6**). UHPH systems are currently available with flow rates of up to 10,000 L/h [28]. The processing rate can be increased in a modular way by using several systems working in parallel. Some UHPH pumps can work up to 400 MPa continuously with a pressure oscillation of 1 MPa.

Concerning the elimination of microorganisms, UHPH has proven to be highly effective with 6-log reductions for *Saccharomyces* and non-*Saccharomyces* yeasts

**Figure 6.** *UHPH industrial machine (Ypsicon [28]).*

*Chemistry and Biochemistry of Winemaking, Wine Stabilization and Aging*

**3. Ultra high pressure homogenization (UHPH)**

the pressure range is higher than 200 MPa (**Figure 5B**) [7, 9].

High pressure homogenization (HPH) is a continuous treatment in which a food

liquid is pumped at high pressure and later depressurized when the fluid passes through a special valve. It is normally called HPH when pressurization occurs at 100–200 MPa (**Figure 5A**) and ultra high pressure homogenization (UHPH) when

*Color of the grape juice extracted without maceration: unprocessed (control) or pressurized at 550 MPa for* 

The "UHPH sterilization system" is a novel process, patented in Europe (EP2409583B1) by UAB (Autonomous University of Barcelona), extended to a lot of countries and exclusively exploited and manufactured by Ypsicon Advanced

*Valve components in HPH (A) and UHPH (B) systems (Ypsicon [28]). HP: high pressure, UHP: ultra high* 

**32**

**Figure 5.**

*pressure, AP: atmospheric pressure.*

**Figure 4.**

*10 min.*

**Figure 7.**

*Color evolution in the control and UHPH musts after 2 days at room temperature in the absence of SO2. White must of* Vitis vinifera *L. cv. Muscat.*

and 4-log for aerobic and lactic acid bacteria in the must [8]. All these wild microorganisms remained undetected in the must after UHPH processing at 300 MPa (inlet temperature 20°C, in-valve 98°C, outlet 26°C, and in-valve time 0.02 s) [8]. Therefore, UHPH is a powerful technology for eliminating indigenous microorganisms and facilitating the use of modern biotechnologies, such as the use of non-*Saccharomyces* or yeast-bacteria co-inoculations [2]. Simultaneously, microbial control facilitates the reduction of SO2 content.

UHPH technology has also shown high efficiency in enzyme destruction. The intense impact and shear forces that the fluid undergoes when pumped through the valve produce a molecular depolymerization that reduces colloidal particles, microorganisms, and enzymes to small fragments. In the case of cells and spores, it causes microbial death, and in the case of enzymes, it causes denaturalization and inactivation. In musts processed by UHPH, a reduction in oxidase activity higher than 90% has been observed for polyphenol oxidase (PPO) enzymes [8]. In addition, the fragmentation effect of colloidal particles can increase the nutrient availability for alcoholic fermentation, which can have positive impact on the production of fermentative aroma [8].

When measuring the color intensity in white grape musts, the value was lower in UHPH than in the unprocessed controls. This is an indication of a paler color that can be correlated with low oxidation by PPO enzymes [8]. The same results have been observed when white musts were kept at room temperature under oxidation conditions and without SO2: the UHPH musts remained pale and the controls quickly browned (**Figure 7**). UHPH is a key technology for reducing sulfites in must by controlling oxidative enzymatic activities which lead to browning and aroma degradation.
