Food Biochemistry and Food Processing (2 edition)

BLBS102-c39 BLBS102-Simpson March 21, 2012 14:20 Trim: 276mm X 219mm Printer Name: Yet to Come

752 Part 7: Food Processing

Table 39.2.Parameters of Weibull Model for Microbial Inactivation Using Pulsed Electric Field (Ngadi and

Dehghannya 2010)

Control

Parameter Product or Medium Microorganism pH

E

(kV/cm) αβ Reference

Treatment

time

Citrate–phosphate

McIlvaine buffer Yersinia enterocolitica 7.0

15 1.67 0.33

Alvarez et al. (2003a)

25 0.02 0.22

Lactobacillus plantarum

7.0 25 234.90 0.99

Gomez et al. (2005a)

6.5 25 41.98 0.98

5.0 25 14.54 0.99

3.5 25 12.81 0.98

Listeria monocytogenes

7.0

15 2101.0 0.85

Gomez et al. (2005b)

25 111.40 0.62

6.5

15 2514.0 0.57

25 57.24 0.61

5.0

15 108.20 0.36

25 4.31 0.39

3.5

15 17.64 0.34

25 0.95 0.43

Orange juice-milk

beverage

Escherichia coliCECT

516 (ATCC 8739)

4.05

15 0.68 0.31

Rivas et al. (2006)

25 0.17 0.27

Lactobacillus plantarum 4.05

15 29.07 0.49

Sampedro et al. (2006)

25 0.03 0.16

Specific

energy

Citrate–phosphate

McIlvaine buffer

Yersinia enterocolitica

7.0

15 0.71 0.32

Alvarez et al. (2003a)

25 0.03 0.22

Listeria monocytogenes

15 1135.0 0.85

Alvarez et al. (2003b)

25 158.2 0.62

treatment of various liquid foods, including apple juice, orange

juice, and milk, has not shown any significant physicochemical

changes. PEF-processed yogurt-based drink retained its physi-

cal and chemical characteristics (Evrendilek et al. 2004). There

was a slight decrease in vitamin C content in PEF-treated or-

ange juice compared to heat-treated orange juice (Zhang et al.

1997). In a comparative study of orange juice pasteurized by

ultra-high temperature (processing at 110◦C, 120◦C, and 130◦C

for 2 and 4 s) and PEF (20 and 25 kV/cm for 2 ms), Gallardo-

Reyes et al. (2008) concluded that although there was no dif-

ference in pH and soluble solids obtained with both treatments

and freshly squeezed control samples, the color of PEF-treated

sample was closer to the control. PEF inactivates various types

of enzymes. A reduction of about 95% in the residual activ-

ity of polyphenol oxidase (PPO) in apple juice was observed

when treated with PEF. Decreased pectin methylesterase (PME)

and PPO activity and nonenzymatic browning were observed

in the carrot juice (Luo et al. 2008). When treated with PEF,

strawberry, tomato, and water melon juice noticed a decreased

level of nonenzymatic browning (Aguilo-Aguayo et al. 2009a,

2009b). The activity of lipoxygenase andβ-glucosidase in straw-

berry juice was reduced effectively (Aguilo-Aguayo et al. 2008).

There are indications that as a result of its influence on en-

zymes and bioactive compounds, PEF may affect quality of

cheese produced using PEF-processed milk. Electric field inten-

sity (E) and treatment temperature significantly affected rennet