yasibad water: the impact on human health in the chesapeake bay region

8/22/2019 YasiBad Water: The Impact on Human Health in the Chesapeake Bay Region

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Ohmic heating: A novel technology for

food preservation

Muhammad Yasin

2003-ag-1660

PhD scholar

Supervisor

Dr. Masood Sadiq Butt

www.uaf.edu.pk


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Contents

Introduction1

Ohmic Vs conventional heating2

Ohmic heating system3

Application and conclusions4

References5

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Ohmic Heating

Ohmic heating is an advanced thermalprocessing method wherein the food

material, which serves as an electrical

resistor, is heated by passing electricitythrough it.

Electrical energy

Dissipated into heat

Rapid and uniform heating

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Cont

Ohmic heating is also called Electrical resistance heating

Joule heating

Electro-heating

Varieties of applications in the food industry

Meat industry

Milk industry

Beverage industry

Food dehydrated industry

Extraction of phyto-chemicals

(Zell et al., 2009)

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Food preservation techniques

Thermal preservation techniques

Pasteurization

Sterilization

Drying Evaporation

Distillation

Modern techniques Ohmic heating

Electric pulse

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How is ohmic heating different from conventional

thermal processing?

During conventional thermal processing Quality damage

Aseptic processing systems

Cans

Long time for complete heating

Higher energy dissipation

More damage of equipments

High risk of personal safety

Non-uniform heating

(Allali et al., 2010)

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Cont...

Ohmic heating Volumetrically heat

Greater quality product

Processing large particulate food (up to 1 inch)

Cleaning requirements are less

Reduces cooking times

Minimal mechanical damage

Better nutrients and vitamin retention

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Cont

High energy efficiency

Electrical energy (90%) converted into heat

Optimization of capital investment

Product safety

(Shim, et al., 2010)

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What type of products are

suitable for ohmic heating?

Ohmic heating can be used for heating

Liquid foods containing large particulates

Soups

Stews

Fruit slices in syrups and sauces

Heat sensitive liquids (Milk)

(Shim et al., 2010)

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Technology is useful for Proteinaceous foods

(Denature and coagulate when thermally processed)

Liquid egg(Heated in a fraction of a second without coagulating it)

(Chen et al., 2010)

Juices

(Inactivate enzymes without affecting the flavor)(Bozkurt and Icier 2009)

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Ohmic Heating System Design

key elements Power supply (generator)- produce the electricity

Electrodes

Electrode gap- distance

Thermocouple- measure temperature

Data logger

pH probe

Spectrophotometer- optical density Refractometer-Brix

(Lebovka, et al., 2005)

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Ohmic heating device

(Sastry and Palaniapan,1992)

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Commercial scale equipment

13Anderson, 2008


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Shelf-life of an ohmically processed product?

The shelf-life of ohmically

processed foods comparable with

Canned

Sterile

Aseptically processed

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Is ohmic heating environmentally

friendly?

Yes ordinary electricity

No emissions

Emerging application of ohmic heatingi.e.

Fruit peeling- less NaOH used

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Working principle

During ohmic heating AC voltage

Rate of heating directly propositional square of the

electric field strength

Electrical conductivity

Type of food

The electric field strength can be

controlled by Electrode gap

Applied voltage

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(Anderson, 2008)


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Electrolysis and contamination

Electrolysis

Dissolution of metallic (stainless steel) electrodes at 5060 Hz

Contaminate the finished products

Contribute to undesirable chemical reactions

Control measures

Using frequencies above 100 kHz prevent metal hydrolysis

Low frequencies 10 or50 or 60 Hz power can be used with

inert carbon or coated electrodes without causing noticeable

dissolution(Bansal and Chen, 2006)

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Conti

Plastic materials with suitable electrical and

mechanical properties can be used for

Housing the electrodes

For lining the stainless steel pipes through which

food products flow

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Ohmic heating: Meat Quality

80% solids food product Raise temperature (25 C to 129C in 90 seconds)

(Zuber et al.,1997)

Multi-point injection followed by optimizedtumbling

Ohmic heating cook whole muscle beef

Produce quality cooked meat

Reducing cook losses

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Cook losses with the mild Low time and long time (LTLT)ohmic method were lower than conventional heating

Flavor development was slightly reduced

Ohmic heating was optimization

End-point temperature intermediate between

High temperature and short time (HTST)

LTLT protocols

Maintain the speed

Cook loss advantages

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( Zell et al., 2009)


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Cont

Centre injection 3% saline

Soaking 5% saline for 48 h

3% saline, 16 h in bag

tumbling

( Zell et al., 2009)

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Ohmic cooking of whole beef muscle Optimization ofmeat preparation


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Omhic heating and meat Quality

Quality parameter LTLT HTST Conventional

Cooking loss Least Highest Less

Water holding capacity Least less Highest

Proximate analysis NS Moisture

reductionNS

Surface color Lighter Light dark

Chroma and hue value NS NS NS

texture profile NS Firmer NS

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TBARS of meat

23( Zell et al., 2009)


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How does ohmic heating

inactivate microorganisms?

Inactivates microorganisms

Low-frequency (50-60 Hz)

Build up electrical charges

Heat across microbial cells

It is not necessary to claim such effects since

heating is the main mechanism(Ayse et al., 2010)

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Ohmic heating Decrease

Decimal reduction time (D value)

Temperature requirements (z value)

For

Escherichia coliin goat milk

Bacillus licheniformisin in cloudberry jam

(Pereira et al., 2007)

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Fermentation

Reduced lag period of the bacteria

Lactobacillus acidophilus

Dairy manufacturer utilizing the ohmic heating process

Shorten the total processing time Speedier process

Save overhead and labor costs

(Cho et al., 1996; Anderson, 2008)

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Fermentation at 30C Lag period decreased by 94%

Ohmic heating

Did not change the generation time

Significant decrease in maximum growth

Enhances the early stages

Inhibits the late stages of growth

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(Cho et al., 1996)


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Conti...

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Fermentation at 35C

Minimal effect on

Glucose utilization

Lactic acid production

(Cho et al., 1996)


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juices

Rheological Characteristics of Quince Nectar DuringOhmic Heating

Ohmic heating as an electrical heating having

Same heating curve of conventional method

Changing voltage gradient (10-40 V/cm) at 50 Hz

The change of rheological constants at different holding

Times

(0, 10, 15, 20 and 30 minutes)

Temperature range(65-75 C)

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(Bozkurt and Icier, 2009)


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The activation energy

9.88 3.24 kJ/mol ohmic heating

10.08 2.53 kJ/mol conventional heating

Results Thermal effects

(Bozkurt and Icier 2009)

Grape juice

Deactivation polyphenoloxidase(Icier et al., 2008)

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Electrical conductivity of fruits

(Sarang et al., 2008; Tulsiyan et al., 2008) 31


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Rice bran oil extraction using ohmic heating

Ohmic heating increased 92% lipids extracted

Lowering the frequency of alternating current (AC)

Increased oil extraction

By electroporation

Enhance extraction of non-polar constituents

(Lakkakula, et al., 2004)

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Conclusions

Non-thermal food preservation techniqueeffective for

Meat processing

Juices processing

Fruit and vegetable processing

Milk processing

Ohmic heating little effect on

Flavor

Taste

Overall acceptance

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Future trends

Quantification of effect of ohmic heating on major

nutrients

Reliable modeling and prediction of ohmic heating

patterns

Well-defined product specifications and processparameters

Ascorbic acid, vitamins, phytochemicals

Heat channeling Hot spots and cold spots,

complex coupling Electrical field distributions

Particle size, shape, Liquid viscosity,

pH Specific heat

Thermal conductivity, Solid liquid ratio

Electrical conductivity

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Potential application of ohmic

heating in food processing

Potential

Application

BalancingExtraction

Peeling

Starch

gelatinizationFermentation

Dehydration

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Refernces

Anderson, D.R. 2008. Ohmic heating as an alternative food

processing technology. MSc Thesis, Kansas State University,

Manhattan, Kansas.

Ayse, B., Handan, A., and Filiz, I. 2010. Inactivation Kinetics

ofAlicyclobacillus acidoterrestris spores in orange juice by ohmic

heating: effects of voltage gradient and temperature on inactivation.

Journal of Food Protection, 73(2): 299-304.

Bozkurt, H., Icier, F. 2009. Rheological characteristics of quince

nectar during ohmic heating. International Journal of Food

Properties, 12(4): 844 859.

Chen, C., Abdelrahim, K., Beckerich, I. 2010. Sensitivity analysis of

continuous ohmic heating process for multiphase foods. Journal of

Food Engineering Journal of Food Engineering, 98(2): 257-265

Cho, H.Y., Yousef, A.E., and Sastry, S.K. 1996. Growth Kinetics of

Lactobacillus acidophilus Under Ohmic Heating. Biotechnology and

Bioengineering, 49: 334-340.36


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Conti

Icier, F., Yildiz, H., Baysal, T. 2008. Polyphenoloxidase deactivation

kinetics during ohmic heating of grape juice. Journal of Food

Engineering, 85: 410417

Khoyi, M.R., and Hesari, J. 2007. Osmotic dehydration kinetics of

apricot using sucrose solution. Journal of Food Engineering, 78(4):

13551360.

Lakkakula, N.R., Lima, M., and Walker, T. 2004. Rice bran

stabilization and rice bran oil extraction using ohmic heating.

Bioresource Technology 92: 157161

Lebovka, N.I., Praporsic, I., Ghnimi, S., and Vorobiev, E. 2005. Does

electroporation occur during the ohmic heating of food? Journal of

Food Science 70(5): 308-311.

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Conti

Pereira, R., Martins, J., Mateus, C., Teixeira, J.A., and Vicente, A.A.

2007. Death kinetics ofEscherichia coliin goat milk and bacillus

licheniformisin cloudberry jam treated by ohmic heating. Chemical

Papers, 61 (2):121-126.

Sastry, S. K., and Palaniapan, S. 1992. Mathematical modeling and

experimental studies on ohmic heating of liquid-particle mixtures in a

static heater. Journal of food process engineering, 15(4): 241-261.

Shim, J.Y., Lee, S.H., and Jun, S. 2010. Modeling of ohmic heating

patterns of multiphase food products using computational fluid

dynamics codes. Journal of Food Engineering, 99(2): 136-141.

Zell, M., Lyng, J.G., Cronin. D.A., and Morgan, D.J. 2009. Ohmic

heating of meats: Electrical conductivities of whole meats and

processed meat ingredients. Meat Science, 83(3): 563-571.

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Questions

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