International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 1 Issue7 pp 009-011 October 2012
www.ijsret.org
ISSN 2278 - 0882
Microcontroller Based High Voltage Pulse Electric Field Generator for
Pasteurization
1
Sudhir Kumar Singh, 2Vinayak Yadav
kavsud220607@gmail.com, Vinayaky126@gmail.com
1,2
Electronics & Communication Engineering
Babu Banarasi Das Institute of Engineering Technology & Research Centre,
Jahangirabad Bulandshahr, U.P
ABSTRACT
In This paper describes the design and implementation of
Microcontroller based High Voltage pulse electric field
generator for Liquid food pasteurization. It generates a
high voltage (15 kV) approximately in the frequency range
from 250 Hz to 30 kHz. This high voltage applied for food
pasteurization, which is placed between two electrodes.
Keywords: Fly back transformer, Microcontroller, Pulsed
electric field, Treatment Chamber, milk, Juice, water.
I.
INTRODUCTION
Pulsed Electric Field (PEF) is a technology used for nonthermal pasteurization of foods. PEF involves the
application of pulses of high voltage to foods placed
between 2 electrodes. For food quality attributes, PEF
technology is considered superior to traditional heat
treatment of foods because it avoids or greatly reduces the
detrimental changes of the sensory and physical properties
of foods, like color, flavor, texture and nutrients [1, 2, 3, 4,
5]. Using PEF, bacteria and other harmful microorganisms
are inactivated. Pulse waveforms commonly used in PEF
technology.
Square waveform is the most efficient and effective
waveform in the PEF application [6], and frequency can be
varied from 250 Hz to 30 k Hz.
II.
PROPOSED
PULSE
GENERATOR
SYSTEM REQUIREMENTS
The elements of the PEF system1. Battery /AC power supply
2. Microcontroller Atmel AT89S52
3. Push Button Switch
4. Displays
5. Regulated Voltage Circuit
6. Switching Circuitry
7. High Voltage Fly back Transformer
8. Treatment Chamber
Fig 2. Functional block diagram of proposed high voltage
pulse generator
III.
Fig 1. (a) Oscillatory Decay Pulse (ODP)(b) Exponential
Decay Pulse (c) Square Pulse
FLY BACK TRANSFORMER
The transformer consists of two windings and couple of U
type ferrite cores with air gaps, as shown in Fig. The two
windings were wound to the one side of the core. The
secondary circuit was fitted on the lower part and right
side of the step-up transformer.
IJSRET @ 2012
International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 1 Issue7 pp 009-011 October 2012
www.ijsret.org
Fly back transformers, however, not only transfer energy
to their secondary, but they also store energy for a
Considerable amount of time. In fact, fly back
transformers act as pure inductors during one first half
cycle, and Then acts as a pure transformer in the other half
cycle. This behavior is made possible by an air gap in the
ferrite Core. This air gap increases the reluctance of the
core, which thereby increases its ability to store magnetic
Energy.
ISSN 2278 - 0882
permeability and results in either reversible or irreversible
breakdown of the cell [7].
Fig 5. Electroporation of a cell membrane
IV.
EXPERIMENTAL RESULTS
Fig 4 and Fig 5 shows 250 Hz and 30 kHz voltage wave on
a 10 k Ω final load, respectively. It can be seen, the pulse
generated is a square wave in both cases. These signals
were used in the treatment chamber to inactivate microbes
in juice.
Fig 3. Cross section of Fly Back Transformer
Treatment Chamber
The Treatment chamber is used determined electric field
strength generated by high voltage generator, in which
liquid food flow. The raw material for treatment chamber
is stainless steel plate; it was safe for all food products.
The treatment chamber shapes is in the form of cylindrical
and cover on the top.
Fig 6.1. High voltage pulse at 250 Hz
Fig 4. Types of treatment chambers for inactivation of
microorganisms by pulsed power: (a) perpendicular flow,
(b) parallel flow
Fig 6.2. High voltage pulse at 30 kHz
Electroporation
The application of PEF results in the accumulation of
charges on the cell membrane and eventually a change in
the voltage across the membrane. This increases the cell
V.
CONCLUSIONS
Microcontroller based high voltage pulse electric field
generator has been presented. A variable frequency from
250 Hz to 30 kHz can be generated for the high voltage
IJSRET @ 2012
International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 1 Issue7 pp 009-011 October 2012
www.ijsret.org
(15 kV) approximately. Solid state semiconductor
technology has been used to generate pulses of high
voltage with a variable frequency. It can be used to
pasteurize fluids such as juices, milk and soups without
using Additives. This technology can substitute for
conventional heat Pasteurization.
•
It is restricted to food products with no air bubbles
and with low electrical Conductivity.
•
It has no detrimental effects on product quality
found.
•
The PEF method is not suitable for most of the
solid food products containing Air bubbles when placed in
the treatment chamber.
•
It is not suitable for solid food products which are
not Pump able.
ISSN 2278 - 0882
[7] K. H. Schoenbach, R. P. Joshi, R. H. Stark, F. C.
Dobbs, and F. J. Beebe, “Bacterial decontamination of
liquids with pulsed electric fields,” IEEE Trans. Dielectr.
Electr. Insul., vol. 7, no. 5, pp. 637–645, Oct. 2000.
This process has a number of advantages over
conventional techniques: Simple and practical to construct,
continuous flow of water, no expensive.
High voltage pulsed electric field (PEF) has been
recognized as the world's most popular and most advanced
techniques sterilization.
REFERENCES
[1] Quass, D. W. “Pulse Electric Field processing in the
food industry. A status report on PEF”. Palo Alto CA.
Electric Power Research Institute. CR- 109742. 1997.
[2] LEWIS, M. y Heppell, N. (2000). Continuous Thermal
Processing of Foods: Pasteurization and UHT
Sterilization. Gaithersburg, Maryland: An Aspen
Publication.
[3] BARBOSA-CÁNOVAS, G.V. (1998). Nonthermal
Preservation of Foods. New York:
Marcel Dekker.
[4]
http://www.fao.org/ag/ags/agsi/Nonthermal/
nonthermal_1.htm (Seen 10/03/2009).
[5] http://www.cfsan.fda.gov/~comm/iftpef. html (Seen
15/04/2008).
[6] B. Qin, Q. Zhang, G. V. Barbosa-Canovas, B. G.
Swanson and P. D. Pedrow, "Inactivation of
microorganisms by pulsed electric fields of different
voltage waveforms, " Dielectrics and Electrical Insulation,
IEEE Transactions, vol. 1, pp. 1047- 1057, 1994.
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