**8. Conclusions**

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

aroma, and precursors [55, 56].

intensity of light can reach values 105

approved by FDA for food processing [59].

produces ca. 1 kW/cm<sup>2</sup>

**7. Pulsed light**

**Figure 15.**

(Udine University, Italy) is also working in the use of US to improve the maceration process and has developed a prototype to favor a faster extraction of polyphenols,

*Cavitation cells disposed in a tubular structure with the sonoplates to apply the US waves.*

Pulsed light (PL) is the use of wide spectrum (170–2600 nm) high intensity light

folds higher than the sun radiation at sea level

on the irradiation surface. PL was initially used in Japan

[57] applied in short flashes during a few microseconds. The spectrum includes ultraviolet, visible, and near infrared radiation. PL spectrum is quite similar to the solar radiation, but having lower wavelengths from the UV (<320 nm), which, in the case of sun light, these are filtered by the ozone layer in the atmosphere. The

[58]. PL technology uses very short energization times, for example, a flash lamp applying energy of 300 J during 300 μs produces a peak intensity of 1 MW which

in the 1970s; later, in 1988, it was developed by a Californian company PurePulse Technologies Inc., but the applications in the food industry increased after it was

The antimicrobial effect of PL is due to dimerization of DNA pyrimidines promoted by the 254 nm UV radiation but also due to the localized instantaneous heating producing membrane and cell wall breakage [57]. The effect on membrane

**40**

**Figure 16.**

*Pulsed light system to treat grape surface for the elimination of microorganisms in a continuous flow.*

Emerging non-thermal technologies open new possibilities in winemaking technology, generally facilitating at the same time the control of indigenous microorganisms and the use of new biotechnologies such as the fermentation with non-*Saccharomyces* yeasts or the use of yeast-bacteria co-inoculations. Most of them (HHP, UHPH, PEF, eBeam, and US) also facilitates a faster extraction of phenolic compounds from the grape skins, including not only pigments and tannins, but also aromatic and flavor compounds, thus reducing the maceration times. Several of them (UHPH, PEF, US, and PL) can be applied in a continuous mode when the crushed grape or must is pumped to the fermentation tank, increasing the processing yield and reducing the dead times. Some of these technologies, such as UHPH, produce an intense inactivation of oxidative enzymes, preserving better the sensory quality and strongly reducing the SO2 needs. Finally, most of these technologies have low energetic requirements, so the running costs are moderated.
