**5. eBeam or β-irradiation**

Electron-beam irradiation or beta-irradiation is a technology that uses low-dose ionizing radiation to eliminate microorganisms in food and also to delay ripening by extending shelf-life. eBeam irradiation and X-rays use ionizing radiation but they are not produced by radioactive materials. The radiation is generated by an electron accelerator that is a switch-on/off electronic technology that can be disconnected when is not in use. The electrons are generated in a heavy metal-doped cathode and then increase their speed by being accelerated by radio frequency fields in a high vacuum cavity (**Figure 10**). The maximum energy allowed is 10 MeV to avoid

#### **Figure 10.**

*Radiofrequency cavity in a rodothron™-type ebeam accelerator. GUN: low energy electron producing cathode, EL: electromagnetic lens, DM: deflector magnets.*

**37**

**Figure 11.**

*Emerging Technologies to Increase Extraction, Control Microorganisms, and Reduce SO2*

tion, water is mainly affected by the formation of hydroxyl (•

the production of unstable nuclei in food. This maximum value is less than the 14 MeV necessary to generate radioactive isotopes. The energy of the radiation is related to its penetration power and it can be estimated as 3 mm depth in water per MeV. Therefore, 3 cm of water-like density products can be treated at 10 MeV.

The energy of 10 MeV makes the electrons capable of breaking the atomic and molecular bonds, thus generating ions and free radicals that can react with other molecules and produce secondary ions and radicals [47, 48]. During food irradia-

with several molecules or biopolymers in the cells, including DNA, making them unviable. The irradiation dose is measured in kiloGray (1 kGy = 1000 J/kg). Food irradiation applications can be classified according to dose: low dose (<1 kGy) with disinfection applications, medium dose (1–10 kGy) with antimicrobial effect to extend shelf-life, and high dose (10–60 kGy) for sterilization purposes [48].

(**Figure 11**) on the treated foods in order to verify if the scheduled and applied doses correspond to actual values in the food. It is essential to check at all depths to ensure that the eBeam radiation is suitable for the entire material. Radiochromic dosimeters are formed by a transparent film, inside an aluminum envelope, containing a radiochromic pigment that is colored when is irradiated, and color intensity depends on received dose. After treatment, the irradiation dose can be measured spectrophotometrically. Additionally, a radiochromic sticker is added (**Figure 11**) to each food package to verify that it has been properly treated. It is often difficult or impossible to visually detect if foods have been treated, and this

sticker is necessary to distinguish treated from untreated samples.

The dose must be checked after irradiation by locating radio-chromic dosimeters

Irradiation can be considered a non-thermal technology with slight temperature increments of a few degrees in conventional treatments. Moreover, it can be applied in refrigerated foods. The effect on sensory quality is gentle, thus many molecules with sensory repercussion as pigments or flavor compounds remain unaffected. The oxidative effect of free radicals generated during the irradiation can produce some

When the electron beam is produced, it must scan from left to right to generate a treatment surface. Electron beam must move at high frequency, usually 100 Hz, to

) radicals or peroxide (H2O2) [48]. These free radicals may react

OH), hydrogen (H•

),

*DOI: http://dx.doi.org/10.5772/intechopen.92035*

•

oxidative processes in some molecules.

*Grape sample with both, radiochromic dosimeter and sticker.*

superoxide (HO2

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

the production of unstable nuclei in food. This maximum value is less than the 14 MeV necessary to generate radioactive isotopes. The energy of the radiation is related to its penetration power and it can be estimated as 3 mm depth in water per MeV. Therefore, 3 cm of water-like density products can be treated at 10 MeV.

The energy of 10 MeV makes the electrons capable of breaking the atomic and molecular bonds, thus generating ions and free radicals that can react with other molecules and produce secondary ions and radicals [47, 48]. During food irradiation, water is mainly affected by the formation of hydroxyl (• OH), hydrogen (H• ), superoxide (HO2 • ) radicals or peroxide (H2O2) [48]. These free radicals may react with several molecules or biopolymers in the cells, including DNA, making them unviable. The irradiation dose is measured in kiloGray (1 kGy = 1000 J/kg). Food irradiation applications can be classified according to dose: low dose (<1 kGy) with disinfection applications, medium dose (1–10 kGy) with antimicrobial effect to extend shelf-life, and high dose (10–60 kGy) for sterilization purposes [48].

The dose must be checked after irradiation by locating radio-chromic dosimeters (**Figure 11**) on the treated foods in order to verify if the scheduled and applied doses correspond to actual values in the food. It is essential to check at all depths to ensure that the eBeam radiation is suitable for the entire material. Radiochromic dosimeters are formed by a transparent film, inside an aluminum envelope, containing a radiochromic pigment that is colored when is irradiated, and color intensity depends on received dose. After treatment, the irradiation dose can be measured spectrophotometrically. Additionally, a radiochromic sticker is added (**Figure 11**) to each food package to verify that it has been properly treated. It is often difficult or impossible to visually detect if foods have been treated, and this sticker is necessary to distinguish treated from untreated samples.

Irradiation can be considered a non-thermal technology with slight temperature increments of a few degrees in conventional treatments. Moreover, it can be applied in refrigerated foods. The effect on sensory quality is gentle, thus many molecules with sensory repercussion as pigments or flavor compounds remain unaffected. The oxidative effect of free radicals generated during the irradiation can produce some oxidative processes in some molecules.

When the electron beam is produced, it must scan from left to right to generate a treatment surface. Electron beam must move at high frequency, usually 100 Hz, to

**Figure 11.** *Grape sample with both, radiochromic dosimeter and sticker.*

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

Electron-beam irradiation or beta-irradiation is a technology that uses low-dose ionizing radiation to eliminate microorganisms in food and also to delay ripening by extending shelf-life. eBeam irradiation and X-rays use ionizing radiation but they are not produced by radioactive materials. The radiation is generated by an electron accelerator that is a switch-on/off electronic technology that can be disconnected when is not in use. The electrons are generated in a heavy metal-doped cathode and then increase their speed by being accelerated by radio frequency fields in a high vacuum cavity (**Figure 10**). The maximum energy allowed is 10 MeV to avoid

*Radiofrequency cavity in a rodothron™-type ebeam accelerator. GUN: low energy electron producing cathode,* 

*PEF experimental unit to process the crushed grapes at a flow of 3 t/h to improve the polyphenols extraction in* 

**36**

**Figure 10.**

*EL: electromagnetic lens, DM: deflector magnets.*

**5. eBeam or β-irradiation**

*the maceration-fermentation stage of red winemaking.*

**Figure 9.**

treat each irradiated section several times in a second. The electron beam is moved by using intense electromagnetic fields. When the food is moved below the treatment plane, all food volume is irradiated. The received dose depends on the speed at which the food moves below the irradiation section that is controlled by using a belt conveyor (**Figure 12**).

The external appearance of foods after irradiation frequently remains unaffected; sometimes, a brighter outer aspect can be observed (**Figure 13A**) [16]. Irradiation doses of 0.5–1 kGy produce 1 log reductions in yeast and lactic acid bacteria in grapes [16] without modifications in the external appearance and firmness [16]; similar effects have been observed in other fruits [49, 50]. Irradiation dose of 10 kGy produces 6-log reductions in yeasts and 3-log in bacteria [16]; this dose decreases firmness and softens the texture of grapes, thus enhancing the extraction of pigments in juice (**Figure 13B**) [16].

Irradiation can also be considered non-thermal technology with high efficiency to eliminate indigenous microorganisms from grapes. This reduction in the population of microorganisms allows a better implantation of selected yeasts and the reduction in SO2 doses. Depending on the irradiation dose (10 kGy), better

**Figure 12.** *Electron beam accelerator and detail of the irradiation process.*

**Figure 13.**

*(A) External appearance of grapes irradiated at 0.5, 1, and 10 kGy. (B) Color of juice from the irradiated grapes.*

**39**

**Figure 14.**

*waves.*

*Emerging Technologies to Increase Extraction, Control Microorganisms, and Reduce SO2*

extraction of pigments and polyphenols can be observed with subsequent improve-

Ultrasound (US) is sonic waves with a frequency range of 20–100 kHz producing cavitation phenomena with locally extreme temperature and pressure. Cavitation is generated by compression-decompression cycles producing the formation and implosion of gas bubbles [51] (**Figure 14**). This phenomenon produces intense agitation and dispersive effects that help to disrupt vegetal tissues, depolymerizing cell walls and favoring a better extraction. US efficiency in extraction processes

US technology can be used in winemaking for continuous processing of crushed grapes. As a consequence, there is a weakening of the cell wall and an increase in the extraction of tannins, pigments, and aromatic compounds [15, 19, 20, 52]. This effect can also be enhanced with the use of pectolytic enzymes [53]. When enzymes are used as the sole extraction technique, tannin concentration is 13% higher while, after US treatment, there is an increase of 16%. The initial use of enzymes followed by the subsequent application of US is especially synergistic increasing color

Antimicrobial effect of US is quite reduced, and the intensity and time needed normally produce significant increments of temperature. Therefore, it is difficult to consider US as a non-thermal technology. However, US produces synergistic antimicrobial effects when applied together with conventional thermal technologies

Industrial devices are currently available to process crushed grapes increasing extraction and reducing maceration times. The sonication device has a tubular structure to increase sonication surface, normally with a polygonal section to better dispose of the sonoplates (**Figure 15**). Currently, this technology is developed by several companies; among them, Agrovin inside a H2020 European project, has developed the Perseo™ system [54] with 50 kW of power and 8 cavitation cells to process up to 10 t/h [52, 54]. With this technology, it is possible to reduce maceration times from 7 to 2–3 days with similar contents of anthocyanins and tannins; moreover, the aromatic fraction is in the same time enhanced. Prof. Emilio Celotti

*Implosion of bubbles and cavitation produced by alternative compression-rarefaction effects generated by US* 

*DOI: http://dx.doi.org/10.5772/intechopen.92035*

improves when the frequency is closed to 30 kHz [52].

intensity (18%) and tannin content (30%) [53].

or emerging non-thermal processes.

ments on the maceration processes.

**6. Ultrasound**

extraction of pigments and polyphenols can be observed with subsequent improvements on the maceration processes.
