**3.2. High pressure processing (HPP)**

High pressure processing (HPP), also known as high-hydrostatic pressure (HHP) or ultrahigh pressure (UHP), is capable of inactivating both pathogenic and vegetative spoilage microorganisms by using pressure rather than heat [38]. HPP mainly uses water as a medium to transmit pressure ranging from 100 to 800 MPa to foods [29]. The basic components of an HPP system include a pressurization vessel, a pressure transmitting fluid, a material handling unit, and supporting heating and cooling system components (see **Figure 2**) [39]. During HPP, food in flexible packages/containers is placed in a holding basket and lowered into the reaction chamber. High hydrostatic pressure is generated through the action of a piston or pump, which compresses the pressure-transmitting fluid allowing for uniform distribution throughout the product matrix [29]. Vitamins, flavor compounds and pigments survive the process while denaturation of proteins, gelation, hydrophobic reactions, lipid phase changes and ionization of molecules is able to modify the integrity of cell walls and membranes [38]. By optimizing HPP parameters of pressure (P), temperature (T) and duration time (t); important foodborne pathogens can be inactivated whilst preserving and/or enhancing the nutritional and organoleptic properties of food and vegetables [29].

walls and membranes, proteins and enzymes also facilitate the release and extraction of bound carotenoid from the cellular matrix, increasing its bioaccessibility [29]. Aadil et al. studied the effects of thermal-assisted HPP versus thermal processing of grapefruit juice and observed that processed juice at 250 MPa/60°C/3 min had an improvement in total carotenoid and anthocyanin content compared to control and thermally treated samples [43]. In the same study, ascorbic acid contents were reduced from 25.58 to 19.32 (mg/100 ml) in HPP and 17.28 (mg/100 ml) in thermal processed samples. While retention of vitamin C was higher under HPP compared to thermal processing, the elevated temperatures are most likely responsible for its depletion in both cases.

An Evaluation of the Impact of Novel Processing Technologies on the Phytochemical…

http://dx.doi.org/10.5772/intechopen.77730

197

**Figure 2.** Schematic of a batch high pressure processing setup. Adapted from Chakraborty et al. [39].

Ultrasound (US) employs mechanical sound waves at frequencies between 20 kHz and 500MHz, and has emerged as an alternative technique, capable of inactivating microorganisms for food preservation [29, 44]. US systems are either batch or continuous type, that include sonication baths, ultrasonic probes and vibrating systems, and can be applied to liquid foods or solid type matrices embedded in a transmitting liquid medium (typically water) (see **Figure 3**) [45]. US mode of action is attributed to the *"cavitation"* phenomenon in which micro-bubbles generated in the transmitting medium by the sonication device, oscillate, grow in size and eventually collapse producing shock waves that induce a number of thermal, mechanical and chemical effects. As stated by Majid et al. the high temperatures, pressures, shear forces and free radicals generated in the cavitation zone affects cell walls and membranes for microbial inactivation,

Jabbar et al. in evaluating the combined effects of blanching and sonication (frequency 20 kHz, amplitude level 70%) on carrot juice, reported improvements in the retention of chlorogenic acid, total carotenoids, lycopene and lutein content [45]. The increase in the bioavailability of these

whilst retaining sensory, nutritional and functional characteristics of the food [44].

**3.3. Ultrasound (US)**

On investigating the effects of mild temperature (50°C) and HPP (300 and 600 MPa) on the shelf life of strawberry purée, Marszałek et al. showed that higher pressure values resulted in prolonging shelf life from 4 to 28 weeks [40]. However, HPP was unable to preserve vitamin C and anthocyanin content in the treated purée, resulting in significant degradation of 20 and 5% higher at 600 than at 300 MPa respectively. The inactivation of endogenous enzymes such as β-glucosidase, polyphenol oxidase (PPO) and peroxidase (POD) are mainly responsible for anthocyanin degradation during storage. However, other factors such as temperature, light, pH, sugars, presence of oxygen, sulfites, ascorbic acid, metal ions and co-pigments may also destabilize anthocyanin compounds and accelerate its decomposition [41].

Garcia-Parra et al. investigated the effect of thermal assisted HPP to preserve pumpkin puree under varying combinations of pressure and temperature (300, 600, 900MPa/60, 70, 80°C< 71min) and found that treatments at higher pressures were effective in maintaining and/or increasing the individual carotenoids (lutein, α-carotene and β-carotene) [42]. Similar studies on orange, carrot and tomato juices/purees also showed significant increases in carotenoid content and antioxidant activity [28]. It is believed that the mechanism of pressure-induced disruption of cell An Evaluation of the Impact of Novel Processing Technologies on the Phytochemical… http://dx.doi.org/10.5772/intechopen.77730 197

**Figure 2.** Schematic of a batch high pressure processing setup. Adapted from Chakraborty et al. [39].

walls and membranes, proteins and enzymes also facilitate the release and extraction of bound carotenoid from the cellular matrix, increasing its bioaccessibility [29]. Aadil et al. studied the effects of thermal-assisted HPP versus thermal processing of grapefruit juice and observed that processed juice at 250 MPa/60°C/3 min had an improvement in total carotenoid and anthocyanin content compared to control and thermally treated samples [43]. In the same study, ascorbic acid contents were reduced from 25.58 to 19.32 (mg/100 ml) in HPP and 17.28 (mg/100 ml) in thermal processed samples. While retention of vitamin C was higher under HPP compared to thermal processing, the elevated temperatures are most likely responsible for its depletion in both cases.

#### **3.3. Ultrasound (US)**

bioaccessibility of phytochemicals [29, 31]. As cited in Ricci et al. investigations using PEF assisted maceration on Tempranillo grape skin with treatments of 5 and 10 kV/cm increased the polyphenol and anthocyanin extraction in wine processing [31]. Results showed total polyphenols index in PEF treated wines was 13.7% higher (5 kV/cm treatment) and 29.0% higher (10 kV/cm treatment) with respect to the control after 96 h maceration; and at the end of fermentation color intensity also improved of 23.93 (control), 27.04 (5 kV/cm treatment), and 29.33 (10 kV/cm treatment). Increased juice recovery (9–25%) and higher amounts of total phenolics (up to 22%) and total anthocyanins (up to 26%) in PEF treated raspberries and press cakes extracts were reported [36]. With sweet cherries, PEF applied at low field strengths, increased production of volatiles, (aldehydes and alcohols) known to have desirable odors was reported by Sotelo et al. [37].

High pressure processing (HPP), also known as high-hydrostatic pressure (HHP) or ultrahigh pressure (UHP), is capable of inactivating both pathogenic and vegetative spoilage microorganisms by using pressure rather than heat [38]. HPP mainly uses water as a medium to transmit pressure ranging from 100 to 800 MPa to foods [29]. The basic components of an HPP system include a pressurization vessel, a pressure transmitting fluid, a material handling unit, and supporting heating and cooling system components (see **Figure 2**) [39]. During HPP, food in flexible packages/containers is placed in a holding basket and lowered into the reaction chamber. High hydrostatic pressure is generated through the action of a piston or pump, which compresses the pressure-transmitting fluid allowing for uniform distribution throughout the product matrix [29]. Vitamins, flavor compounds and pigments survive the process while denaturation of proteins, gelation, hydrophobic reactions, lipid phase changes and ionization of molecules is able to modify the integrity of cell walls and membranes [38]. By optimizing HPP parameters of pressure (P), temperature (T) and duration time (t); important foodborne pathogens can be inactivated whilst preserving and/or enhancing the nutritional

On investigating the effects of mild temperature (50°C) and HPP (300 and 600 MPa) on the shelf life of strawberry purée, Marszałek et al. showed that higher pressure values resulted in prolonging shelf life from 4 to 28 weeks [40]. However, HPP was unable to preserve vitamin C and anthocyanin content in the treated purée, resulting in significant degradation of 20 and 5% higher at 600 than at 300 MPa respectively. The inactivation of endogenous enzymes such as β-glucosidase, polyphenol oxidase (PPO) and peroxidase (POD) are mainly responsible for anthocyanin degradation during storage. However, other factors such as temperature, light, pH, sugars, presence of oxygen, sulfites, ascorbic acid, metal ions and co-pigments may also

Garcia-Parra et al. investigated the effect of thermal assisted HPP to preserve pumpkin puree under varying combinations of pressure and temperature (300, 600, 900MPa/60, 70, 80°C< 71min) and found that treatments at higher pressures were effective in maintaining and/or increasing the individual carotenoids (lutein, α-carotene and β-carotene) [42]. Similar studies on orange, carrot and tomato juices/purees also showed significant increases in carotenoid content and antioxidant activity [28]. It is believed that the mechanism of pressure-induced disruption of cell

destabilize anthocyanin compounds and accelerate its decomposition [41].

**3.2. High pressure processing (HPP)**

196 Phytochemicals - Source of Antioxidants and Role in Disease Prevention

and organoleptic properties of food and vegetables [29].

Ultrasound (US) employs mechanical sound waves at frequencies between 20 kHz and 500MHz, and has emerged as an alternative technique, capable of inactivating microorganisms for food preservation [29, 44]. US systems are either batch or continuous type, that include sonication baths, ultrasonic probes and vibrating systems, and can be applied to liquid foods or solid type matrices embedded in a transmitting liquid medium (typically water) (see **Figure 3**) [45]. US mode of action is attributed to the *"cavitation"* phenomenon in which micro-bubbles generated in the transmitting medium by the sonication device, oscillate, grow in size and eventually collapse producing shock waves that induce a number of thermal, mechanical and chemical effects. As stated by Majid et al. the high temperatures, pressures, shear forces and free radicals generated in the cavitation zone affects cell walls and membranes for microbial inactivation, whilst retaining sensory, nutritional and functional characteristics of the food [44].

Jabbar et al. in evaluating the combined effects of blanching and sonication (frequency 20 kHz, amplitude level 70%) on carrot juice, reported improvements in the retention of chlorogenic acid, total carotenoids, lycopene and lutein content [45]. The increase in the bioavailability of these

**Figure 3.** Schematic of a probe-type sonication system. Adapted from Jabbar et al. [45].

compounds might be attributed to the breakdown of cell walls and disruption of chromoplasts created by cavitation pressures allowing for release of membrane bound carotenoids. These results were similar to Abid et al. and Zou and Hou, when investigating US on different quality parameters of apple and blue berry juice respectively [46, 47]. Sonication showed increased levels of ascorbic acid, total phenolics, flavanols and flavonoids, and increased antioxidant activity due to the extraction and availability of these compounds. In a contrasting study by Dias et al. soursop juice subjected to varying levels of sonication energy, showed that increasing US intensity resulted in lower levels of phenols, ascorbic acid and higher levels of total color difference between sonicated and untreated samples [48]. The apparent decreases in overall phytonutrient content was attributed to increasing temperature and free radical formation that produced strong oxidizing effects during cavitation. Yao et al. investigating the effects of US on cyanidin-3-glucoside in blueberries, demonstrated that the pathway for degradation was the pyrolysis of water molecules creating –OH radicals involved in the opening of anthocyanin ring formation [49]. US-assisted extraction of various phytochemicals has grown in interest because of the potential industrial application to provide an efficient and energy saving extractive method.

nucleic acids and proteins disrupting DNA and RNA structures, as well as rupturing bacterial cells due to localized overheating from absorption [50–52]. Similarly, the nonionizing effects of UV-C radiation at low doses has been the subject of numerous studies and documented by Maharaj et al. as having positive impacts on phytochemicals and sensory properties, either by

Manzocco et al. on studying the effect of PL on fresh-cut apple of increasing fluence ranges of 0, 8.8

modification of metabolic respiration and controlling the formation of brown polyphenols [54]. Similar studies on the effects of PL support this theory as observed by Lopes et al. On the effects of the exposure mode of light treatment on fresh-cut mangoes. PL treatments of 1 pulse (0.7 J/

tive impacts on maintenance of yellow color and lower mass loss during storage [55]. Significant improvements in firmness were most likely associated with higher levels of UV-C, which either directly suppress cell wall hydrolase activity or indirectly via increase polyamine content that inhibit the enzyme. In the same study, there were marked increases in carotenoid and ascorbic acid content at the higher fluence intensity treatments. The authors noted the increase in the biosynthesis of these compounds with antioxidant activity could be an adapted photo-protective response to increasing oxidative stresses caused by UV-radiation. Koh et al. demonstrated that PL treatment on fresh-cut cantaloupe, a nonacidic fruit, resulted in the retention of phenolic and ascorbic acid content, albeit at much lower levels when compared to other studies on acidic types [56]. The study also highlighted that at much higher fluence treatments of 11.7 and 15.6 J/cm2 there was a significant reduction in ascorbic acid content attributed to photothermal degradation of heat labile ascorbic acid at the higher intensities. At low PL dosage rates of 2 and 4 J/

, Pataro et al. recorded significant increases in total carotenoids, lycopene and phenolics in whole, uncut tomatoes and Annurca apples [57]. Investigations on raspberries known to be high in antioxidant compounds showed that PL in combination with sanitizer washing was able to significantly increase the total phenolic and anthocyanin content both directly after treatment,

showed a significant decrease in browning of PL treated samples attributed to the

An Evaluation of the Impact of Novel Processing Technologies on the Phytochemical…

http://dx.doi.org/10.5772/intechopen.77730

199

) reduced the respiration rate with posi-

preserving its content in fruits and vegetables or increasing it following treatment [53].

**Figure 4.** Schematic diagram of a high intensity pulsed-light system. Adapted from Abida et al. [52].

) and 1 pulse for 4 days (2.8 J/cm2

and 17.5 J/cm2

), 4 pulses (2.8 J/cm2

cm<sup>2</sup>

cm<sup>2</sup>
