electroporation in food processing - tu berlin...principle of pef effect on cellular tissue...

Electroporation in Food Processing

Claudia Siemer Stefan Toepfl

Number of publication peer review

publications (1995-2012)

Web of science, "pulsed electric field", "PEF" or "electroporation" in title and limited to web of science category "food science and technology"

19.11.2012 Electroporation in Food Processing

Claudia Siemer 2

Electroporation in Food Processing

2. Historical background

1920 Pasteurization of milk „Electropure Process“ Ohmic Heating and free radical formation

1949 Electroplasmolysis of plant material B.L. Flaumenbaum, Odessa

1960 Patent, H. Doevenspeck Phase separation, non-thermal effects on microorganisms

1967 Sale & Hamilton First systematic studies, Identification of main processing parameters.

Historical Background

Electric Treatment of Food


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ELCRACK – Development at Krupp Maschinentechnik

Heinz Doevenspeck

Volker Stempel

Werner Sitzmann

2. Historical background

3. Principle of PEF

Aganovic et al., 2012

Yeast cells

before and after PEF

treatment


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3. Principle of PEF

E


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3. Principle of PEF

Effect on cellular tissue

untreated PEF


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4. Application in Food

Inactivation of microorganisms (5 to 30 kV/cm, 75 to 300 kJ/kg)

Cell disintegration of biological tissue (0,1 to 5 kV/cm,

5 to 50 kJ/kg)


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4. Application in Food Inactivation of microorganisms

0 40 80 120

-7

-6

-5

-4

-3

-2

-1

0

0 40 80 120

-7

-6

-5

-4

-3

-2

-1

0

0 40 80 120

-7

-6

-5

-4

-3

-2

-1

0

0 40 80 120

-7

-6

-5

-4

-3

-2

-1

0

B. megateriumS. cerevisaeL. innocua

lg (

N/N

0)[

-]

Specific Energy [kJ kg-1]

E. coli

35°C

45°C

55°C

Inactivation of E. coli, L.innocua, S. cerevisae and B. megaterium in ringer solution with an electrical conductivity of 1.25 mS cm-1 after PEF treatment with graphite anode and a field strength of 16 kV cm-1

Toepfl et al., 2007 19.11.2012

Electroporation in Food Processing Claudia Siemer

9

untreated PEF treated

mic

rob

ial cou

nt

[cfu

/ml]

1e+0

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

1e+7

Total plate count

yeast

4. Application in Food Example: Carrot Juice

4,07 log

3,05 log


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time [days]

0 2 4 6 8 10 12 14

tota

l p

late

co

un

t [c

fu/m

l]

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

1e+7

1e+8

1e+9

untreaed

PEF treated

time [days]

0 2 4 6 8 10 12 14

ye

ast

[cfu

/ml]

1e+0

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

untreaed

PEF treated

Total plate count

Yeast

4. Application in Food Example: Carrot Juice

Detection limit

Shelf life of untreated carrot juice: 3 days Shelf life of PEF treated carrot juice: 9 days


Claudia Siemer 11

4. Application in Food Example: Grape Juice

1,0E+00

1,0E+01

1,0E+02

1,0E+03

1,0E+04

1,0E+05

1,0E+06

1,0E+07

Untreated PEF

mic

rob

ial c

ou

nt

[cfu

/ml]

E. coli

S. cerevisiae

pH value: 3,13 Conductivity: 1,3 Electric field strength: 12,2 kV/cm Specific energy: 137,4 kJ/kg

Detection limit

5,42 log reduction

4,43 log reduction


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1,0E+00

1,0E+01

1,0E+02

1,0E+03

1,0E+04

1,0E+05

1,0E+06

0 5 9 15 20 26 30 35 40 44 50 55 61

mic

rob

ial c

ou

nt

[cfu

/ml]

time [days]

Total Plate count

Untreated

PEF high

PEF middle

PEF low

1,0E+00

1,0E+01

1,0E+02

1,0E+03

1,0E+04

1,0E+05

1,0E+06

1,0E+07

1,0E+08

0 5 9 15 20 26 30 35 40 44 50 55 61

mic

rob

ial c

ou

nt

[cfu

/ml]

time [days]

Yeast

Untreated

PEF High

PEF middle

PEF low

4. Application in Food Example: Grape Juice

Shelf life extension: From less than 15 days to

more than 61 days.


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Detection limit

Detection limit

1,0E+00

1,0E+01

1,0E+02

1,0E+03

1,0E+04

0 290 265 226 189 309 351

Tota

l Pla

te c

ou

nt

[cfu

/ml]

Specific energy [kJ/kg]

Total viable count1,0E+00

1,0E+01

1,0E+02

1,0E+03

1,0E+04

1,0E+05

1,0E+06

0 14 30

Tota

l pla

te c

ou

nt

[cfu

/ml]

Time [d]

untreated

PEF low

PEF high

Charateristics: Conductivity: 6,51 mS/cm pH value: 5,6 Health benefit because of high mineral concentration

4. Application in Food Example: Coconut water

Electric field strength: 14 kV/cm


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290,0 265,1 226,1 188,9 351,3

290,0 265,1 226,1 188,9 351,3

Specific energy

inputs [kJ/kg];

E= 14 kV/cm


Enzyme activity in coconut water

Coconut water starts getting pink after 24 h storage No enzyme inactivation by PEF Due to temperature impact, coloration is accelerated


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13,2 kV/cm;

351,3 kJ/kg;

Tout= 85,7 °C


untreated

80 °C; 5 min Polyphenoloxidase

- Still active after PEF (same slope as untreated)

- Thermal inactivation at 80 °C for 5 min


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untreated PEF treated thermal

35 kV/cm, 59 µs (Schuten et al., 2004)

4. Application in Food Example: Orange Juice

Orange Juice contaminated with yeasts and other microorganisms after storage of

7 days. After storage of 3 weeks the PEF treated juice is enzymatic and microbial stable.

The shelf life of the thermal treated juice was 5 weeks, but with changes in flavor.


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0

5

10

15

20

25

30

35

40

45

Eth

yl

bu

tyra

te

α-pinene

Octa

na

l

Lim

on

en

e

De

ca

na

l

% lo

ss o

f co

mp

ou

nd

PEF 240 µs

PEF 480 µs

Heat

4. Application in Food Example: Orange Juice

Jia et al., 1999

- Aromaprofile - Less loss of volatile compounds after PEF treatment compared to heat treatment Loss of volatile compounds due to degassing Shelf life of 35 days


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time [d]

0 2 4 6 8 10 12 14

tota

l via

ble

co

un

t [lo

g c

fu/g

]

1e+2

1e+3

1e+4

1e+5

1e+6

1e+7

1e+8

1e+9

rawmilk

314 kJ/kg

244 kJ/kg

210 kJ/kg

65 kJ/kg

4. Application in Food Example: Milk

without cooling

specific energy [kJ/kg]

0 50 100 150 200 250 300

ina

ctiva

tio

n [

log

N/N

0]

-6

-5

-4

-3

-2

-1

0

E.coli

L.innocua

Inactivation of E.coli (5,8 log at 200 kJ/kg) and

L. innocua (5,9 log at 237 kJ/kg) Detection limit

Product: Raw milk pH value: 6,9 Fat content: 3,7 to 5,1 % Conductivity: 4mS/cm Applied electric field strength: 12 kV/cm Shelf life limit


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4. Application in Food Example: Milk

Lactoferrrin

Highest inactivation of analyzed microorganism

(12 kV/cm, 237 kJ/kg)

Loss of Lactoferrin is about 15 %.


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0 100 200 300 400

lacto

ferr

in c

on

ce

ntr

atio

n [

mg/L

]

0

20

40

60

80

100

lactoferrin

0 2 4 6 8 10 12 14 16 18 20 2210

0

101

102

103

104

105

106

Mic

rob

ial co

un

t (c

fu/m

l)

Storage time (days)

untreated: total aerobic count

untreated: yeats and molds

untreated: Lactic acid bacterie

treated: total aerobic count

treated: yeasts and molds

treated: Lactic acid bacteria

detection limit

4. Application in Food Industrial example


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Hoogesteger, NL

4. Application in Food Industrial example


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0 50 100 150 200

ina

ctiva

tio

n [

log N

/N0]

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

neutral pH, 8 kV/cm

neutral pH, 6 kV/cm

acid pH, 8 kV/cm

acid pH, 6 kV/cm

detection limit

Siemer et al., 2011

4. Application in Food Inactivation of bacterial endospores

80 °C

For inactivation of bacterial endospores PEF is used in

combination with thermal energy

Detection limit

Inactivation of B. subtilis spores in Ringer solution with a conductivity of 4 mS/cm Less energy at acid pH value for maximum inactivation required


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4. Application in Food Cell disintegration By applying PEF to cellular tissue the following

mass transport processes can be improved:

Drying Reducing drying time, energy saving

Freezing Reducing freezing time, energy saving

Extraction Increase of juice yield, extraction of valuable

compounds

Distillation Reduction of distillation time, increase of

product yield


Claudia Siemer 24

Siemer et al., 2012

0

20

40

60

80

Mo

istu

re c

on

ten

t [%

]

0 40 80 120 160Drying time [min]

0

20

40

60

80

100

Mo

istu

re c

on

ten

t [%

]

0 1 2 3 4 5 6Drying time [h]

20

40

60

80

Mo

istu

re c

on

ten

t [%

]

0 10 20 30Drying time [h]

0

10

20

30

40

50

Mo

istu

re c

on

ten

t [%

]

0 1 2 3 4 5Drying time [h]

t untreated

PEF

untreated

untreated

untreated

PEF

PEF

PEF

Coconut T= 60°C

Grape T= 60°C

Potato T= 50°C

Paprika T= 60°C

4. Application in Food Drying


Claudia Siemer 25

Jalté et al., 2009

The potato cells are destroyed due to the PEF treatment. Ice crystals are formed outside the cell and the structure of the potato slice can

be maintained.

4. Application in Food Freezing


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PEF untreated

E= 1,8 kV/cm 40 Impulse

0

200

400

600

800

1000

1200

1400

0

0,8

7

1,7

4

2,6

3,4

7

4,3

4

5,2

1

6,0

8

6,9

5

7,8

2

8,6

8

9,5

5

Weg [mm]

Kra

ft [g]

unbehandelt HSI behandeltPEF-treated control

1.8 kV/cm, 40 Pulses

[mm]

Fo

rce [

g]

PEF treatment influences the structure of potatoes

4. Application in Food Structure improvement


Claudia Siemer 27

Pulsed Electric Fields Potato processing

Alternative treatment to thermal preheating to - obtain the same

cut quality - less water and

energy consumption

- avoid odour issues.

Energy too high, liquid and

solid loss

Optimum softening

Pulsed Electric Field Processing Optimum Settings

López et al., 2009

70 °C

20 °C

Low PEF treatment (1 kV/cm), untreated

4. Application in Food Sugar extraction Sugar extraction yield with and without PEF treatment at different extraction temperatures

Increase of extraction efficiency with regard to:

- Reduce extraction temperature - Reduce extracting time - Reduce energy costs


Claudia Siemer 30

JonaG

old

contr

ol

2 k

J/k

g

10 k

J/k

g

20 k

J/k

g

enzym

e

JG

+ G

D

contr

ol

5 k

J/k

g

10 k

J/k

g

15 k

J/k

g

enzym

e0

10

20

30

40

50

60

70

80

juic

e y

ield

[%

]

Size

Reduction

Enzymatic

Treatment

Mixing

Holding

Separation

(Pressing)

Pasteurization

(thermal)

PEF

Treatment

Separation

(Decanter)

Pasteurization

(thermal/PEF)

Juice

Pomace

Extraction

Pectin

Size

Reduction

Juice

Impact of PEF-treatment (2 kV/cm) on Jona Gold (JG) and

Golden Delicious (GD) juice yield using a decanter centrifuge.

Juice yield including an eventual transition of solids to juice

4. Application in Food Extraction of apple juice

Toepfl 2006 19.11.2012


31

0 10 20 30 40 50 60 70 80 90

20

30

40

50

60

70

80

90

MA-Xpress

PEF 2 kJ/kg

control

juic

e y

ield

(%

)

pressing time (min)

Juice yield from industrial apple mixture using a horizontal filter press HPL 200, dependent on press time and pre-treatment.

2 4 6 8 10 12

20

25

30

35

40

45

50

55

60

65

70

75

80

pressing time (min)

control

3 kJ/kg

6 kJ/kg

enzyme

juic

e y

ield

[%

]

Press curve of Jona Gold mash after different pretreatments using a wrapped cloth press. Pressure was increased from 0 to 20 bar in increments of 4 bar.

Clogging of filter elements Larger surface area

4. Application in Food Extraction of apple juice

Toepfl 2006 19.11.2012


32

4. Application in Food Distillation of rose oil


Claudia Siemer 33

Dobreva et al., 2010

5. Equipment design Scalability

5 and 30 kW system Capacity: 1.500 kg/h and 10.000 kg/h for cell disintegration 200 l/h and 1.200 l/h for microbial inactivation

80 kW system Capacity: 50.000 kg/h for cell disintegration 5.000 l/h for microbial inactivation


Claudia Siemer 34

5. Equipment design Scalability

5 and 30 kW system Pulse transformer system - Capacitors charged by power

supply - Current rate controlled by

transistors - Limited peak power


Claudia Siemer 35

80 kW system Marx generator

- Contains stack of capacitors, charged in parallel

- Discharge controlled by transistors and in series

- Oprating, if one stack is destroyed

Product line

5. Equipment design Line setup


Claudia Siemer 36

Capacity:

500 – 1.000 kg/h System for tubers, fruits and vegetables, 1 – 5 t/h

5. Equipment design Treatment of solid products


Claudia Siemer 37

80 kW setup for PEF processing of tubers, consisting of processing

belt (left, bottom right), belt width 1.000 mm

Turn-key, 50 t/h system, potato industry

5. Equipment design Treatment of solid products


Claudia Siemer 38

Average and peak power

Scale Typology Specification Capacity Disintegration

Capacity Preservation

Units realized

5 kW 6 MWp

Laboratory scale

Transformer DN 10 to 30 mm 30 kV max voltage 200 A max current 1.000 Hz max rep rate 1500x1150x1600 mm 3 x 400 V, 32 A

1.500 kg/h 200 l/h 20

30 kW 20 MWp

Technical / semi-industrial scale

Transformer DN 20 to 40 mm 30 kV max voltage 700 A max current 500 Hz max rep 1500x1150x1600 mm 3 x 400 V, 80 A

10.000 kg/h 1.200 l/h 10

80 kW 300 MWp (Multiple 160 kW 240 kW)

Industrial scale

Semi-conductor-based Marx Generator

DN 40 to 100 mm 60 kV max voltage 5.000 A max current 300 Hz max rep rate 5.000x1.300x2.500 mm 3 x 400 V, 160 A

50.000 kg/h

5.000 l/h

2


Claudia Siemer 39

5. Equipment design

Due to PEF disintegration of cellular tissue can be achieved resulting in improved mass transfer processes.

Using PEF an energy efficient preservation of

heat sensitive products can be achieved.

Equipment on an industrial scale available.

http://www.elea-technology.eu 19.11.2012 Electroporation in Food Processing

Claudia Siemer 40

Thank you for your attention!

Contact: Claudia Siemer

[email protected]


Claudia Siemer 41


Claudia Siemer 42

Aganovic, K., C. Siemer, S. Toepfl and V. Heinz (2012). Microscopic analysis of Saccharomyces cerevisiae and Listeria innocua after PEF, HPP and temperature treatment in Ringer’s solution. Kongress Lebensmitteltechnologie GDL. Dresden.

Dobreva, A., F. Tintchev, V. Heinz, H. Schulz and S. Toepfl (2010). Effect of pulsed electric fields (PEF) on oil yield and quality during destillation of white oil-bearing rose (Rosa alba L.). Zeitschrift für Arznei- und Gewürzpflanzen Vol.15, No.3, pp. 127-131.

Jalté, M., J.-L. Lanoisellé, N. I. Lebovka and E. Vorobiev (2009). Freezing of potato tissue pre-treated by pulsed electric fields. LWT - Food Science and Technology Vol.42, No.2, pp. 576-580.

Jia, M., Q. Howard Zhang and D. B. Min (1999). Pulsed electric field processing effects on flavor compounds and microorganisms of orange juice. Food Chemistry Vol.65, No.4, pp. 445-451.

López, N., E. Puértolas, S. Condón, J. Raso and Á. Ignacio (2009). Enhancement of the solid-liquid extraction of sucrose from sugar beet (Beta vulgaris) by pulsed electric fields. LWT - Food Science and Technology Vol.42, No.10, pp. 1674-1680.

Siemer, C., K. Elbers, S. Toepfl and V. Heinz (2011). Influence of pH value and conductivity on the inactivation of B. subtilis spores by PEF in combination with high temperature. iFood conference. Osnabrueck.

Siemer, C., S. Toepfl and V. Heinz (2012). Mass Transport Improvement by PEF - Applications in the Area of Extraction and Distillation. Distillation - Advances from Modeling to Applications. S. Zereshki, InTech: pp. 211-232.

Toepfl, S. (2006). Pulsed Electric Fields (PEF) for Permeabilization of Cell Membranes in Food- and Bioprocessing - Applications, Process and Equipment Design and Cost Analysis. Fakultät III - Prozesswissenschaften der Technischen Universität Berlin. Berlin. PhD.

Toepfl, S., V. Heinz and D. Knorr (2007). High intensity pulsed electric fields applied for food preservation. Chemical Engineering and Processing Vol.46, No.6, pp. 537-546.

References

electroporation in food processing - tu berlin...principle of pef effect on cellular tissue...

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