Pulsed Electric Field processing on food.

1. PULSED ELECTRIC
FIELD

2. PULSED ELECTRIC FIELD
What is Pulse?
• A pulse is a single disturbance that moves
through a medium from one point to the
next point.
• A disturbance is in some identifiable
medium.
• Energy is transmitted from place to place,
but the medium does not travel between
two places.

3. What is pulsed electric field?
• Pulsed electric field (PEF) used short electric pulses for the
short time peroid to preserve the food.
• Pulsed electric field (PEF) treatment is an promising method for
non-thermal processing of foodstuff.
• It is one of the most appealing technology because-
-short treatment time(typically below 1 second).
-reduced heating effect.
-energy lost during heating food is minimized.
-for fresh-like characteristics of food, along with high sensorial
quality and nutrient content.
• It is suitable for preserving liquid and semi-liquid foods
removing micro-organisms and producing functional
constituents.
Examples:- milk, fruit juices, soup, egg etc.

4. Principle
• PEF technology is the application of short pulses of high
electric fields with duration of microseconds micro- to
milliseconds and intensity in the order of 10-80 kV/cm on
the food.
• The processing time for food can be calculated by
multiplying the number of pulses times with effective pulse
duration.
• The process is based on pulsed electrical currents delivered to
a product placed between a two electrodes.
• The applied high voltage results in formation of an electric
field that causes microbial inactivation by cell membrane
breakdown (irreversible).

5. Working
• PEF technology is based on a pulsing power delivered to the
product placed between a set of electrodes confining the
treatment gap of the PEF chamber.
• The equipment consists of a high voltage pulse generator and a
treatment chamber with a suitable fluid handling system and
necessary monitoring and controlling devices.
• Food product is placed in the treatment chamber, either in a static
or continuous design, where two electrodes are connected
together with a nonconductive material to avoid electrical flow
from one to the other.
• Generated high voltage electrical pulses are applied to the
electrodes, which then conduct the high intensity electrical
pulse to the product placed between the two electrodes.
• The food product experiences a force per unit charge, the so-
called electric field, which is responsible for the irreversible cell
membrane breakdown in microorganisms.

6. • This leads to dielectric breakdown of the microbial cell
membranes and to interaction with the charged
molecules of food.
• Hence, PEF technology has been suggested for the
pasteurization of foods such as juices, milk, yogurt, soups,
and liquid eggs.

9. Input
requirements
of PEF
Microbial
inactivation
15-40kV/cm
Improvement
of mass
transfer in
plant/animal
cell
0.7-3.0kV/cm
In applejuice
22-34kV/cm
Sludge
disintegration
10-20kv/cm

10. Advantages
• LESS TREATMENT TIME.
• LOW TREATMENT TEMPRATURE.
• Substitute for conventional heat pasteurization or it can
operate at room temperature to retain quality and heat-
sensitive vitamins.
• Increase shelf life and maintain food safety with low processing
costs.
• Minimally processed foods of fresh quality, which have higher
nutritional value because of color and flavor retention
• PEF inactivates vegetative micro-organisms including
yeasts, spoilage micro-organisms and pathogens.
• Reduction in microorganisms: 4-6 log
• It can be used to pasteurize fluids such as juices, milk and soups
without using additives.

11. • PEF causes the formation of large, permanent pores in
cellular tissues, which can be used to improve juice yield,
increase concentrations of functional components and
enhance the characteristics of dried produce.
• It can support or replace conventional processing
techniques such as enzymatic maceration and mechanical
disintegration.
• Low electric field strength and/ or pulse number causes
reversible cell rupture stimulating a stress reaction in plants
or cell cultures and allowing enzymes or proteins with
potential health benefits to be harvested.
• PEF can be used as batch and continuous process.
• Used for pretreatment applications for improvement of
metabolite extraction.

12. Disadvantages
• High capital cost.
• PEF treatment is effective for the inactivation of
vegetative bacteria only.
• Micro-organisms are destroyed by PEF but spores, with
their tough protective coats, and dehydrated cells are able to
survive.
• Refrigeration is required to extend shelf-life.
• Treatment does not inactivate enzymes
• PEF treatment has considerable added value for specific product
ranges.
• PEF is a continuous processing method, which is not suitable for
solid food products that are not pump able.
• PEF processing is restricted to food products with no air
bubbles and with low electrical conductivity.

13. Applications
Microbial Inactivation by PEF
• The applicability of PEF for microbial
inactivation of liquid food has been proven by a
high number of studies investigating the impact of
PEF on vegetative organisms in model as well as
real food material.

15. Juice processing
• When PEF treatment is introduced, juice of
exceptional sensorial quality is obtained that closely
resembles the juice of freshly squeezed fruits but
which is safe from a microbial point of view.
• An additional advantage for producers is the
extension of the shelf life that is obtained.
• The shelf life of fresh orange juices is extended by PEF
treatment from a few days to a few weeks.
• This extension considerably simplifies the
distribution of this kind of juice and results in less
waste of juice that otherwise would have expired

17. Milk Processing

18. Pef Treatment Of Microalgae,
Seaweed, And Other Aquatic
Species
• Different varieties of macro- and microalgae are
sources of vitamins, pigments, proteins as well
as antixodative and bioactive substances.
• Algae extracts applying PEF treatment could provide
a potential toward a gentler downstream
processing.
• There is an increasing in the yield after PEF
treatment, mainly in the case of extractablity of
growth hormones.

19. Plant Oil Extraction
• Sitzmann and Munch (1988) reported an enhanced
separation of tankage emulsions when extracting
protein and fat from animal tissue.
• A similar effect can be expected after PEF treatment of
oil seeds prior to recovery.
• Yield and quality of oils has been studied and high oil
yield was developed.
• Oil recovery from olives was improved by 7.4% after a
PEF treatment at 1.3 kV/cm in comparison to the
control sample.

20. Meat & Fish Treatment
• Disintegration of animal cellular tissue is used to enhance
the curing of fish or meat products.
• In case of raw ham a long-term curing and air drying is
applied. During such procedures a PEF treatment can be
applied to improve mass transfer processes and to
accelerate curing, reducing the time requirements.
• An increase in mass transfer rates, resulting in faster water
transport to the product surface and therefore drying time
can be reduced.
• This will lead to drastic saving of energy and better
utilization of production capacities during convective air
drying.

21. Sugar Processing
• In Conventional procedures for production of sugar from
beets, disintegration and destruction of cell
membranes a thermal treatment at temperatures in the
range from 70 to 78°C is applied.
• The membrane de-naturation results in an acceleration of
sugar release into the extraction media, but also cell wall
components such as pectin
may become soluble and can diminish juice purity and
quality.
• A PEF treatment of sugar beets could increase mass
transfer rates and could allow to reduce extraction
temperatures and better quality of sugar can be obtained.

22. References
http://www.slideshare.net/steffin101/applications-of-pulse-electric-field
http://www.sciencedirect.com/science/article/pii/S1466856411000701
http://www.smartmilk.eu/
http://link.springer.com/article/10.1007%2Fs12393-009-9011-7
http://www.docstoc.com/docs/76279678/Pulsed-Electric-Field-Processing-(PDF)
https://epgp.inflibnet.ac.in/Home/ViewSubject?catid=15