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Non thermal food
preservation methods
with special reference
to ohmic heating
H.M.D.N. Herath
AG/2011/3113
1
Content
• Food preservation classification
• What is ohmic heating?
• Important benefits
• Ohmic heating processing step
•...
3
Food
preservation
methods
Thermal
preservation
Heating
processing
Cold
processing
Non thermal
preservation
Irradiation
O...
What is ohmic heating?
• Ohmic heating is an advanced terminal
processing method where in the food material
which serves a...
History
• The concept of ohmic heating of foods is not new
• In the nineteenth century, several processes were
patented th...
Important benefits
1. Fast Processing
2. Homogeneous Treatment
3. Compactness of an Ohmic Installation
6
7
Electrodes
Feed pump hopper
Viscous food
Ohmic heating processing step
8
Storage tanks
Tubular coolers
Holding tubes
9
10
Applications
• Sensitive Products egg products,
processed fruits,
• Fouling Products sauces, creams,
cream cheese, viscous...
Ohmic processed commercial
available products
• .
Advantages
• Heating food materials by internal heat
generation
– Conventional heat transfer has limited dielectric
penetr...
Advantages cont..
– Reducing risks of fouling on heat transfer
surface and burning of the food products
– It results in mi...
Advantages cont.
• Optimization of capital investment and
product safety as a result of high solids
loading capacity.
• Ea...
Advantages cont.
• Reducing maintenance cost (no moving
parts).
• Ambient-temperature storage and
distribution when combin...
Disadvantages to Ohmic Systems
• High installation cost
• Can not apply for all the food
• Increased electrical conductivi...
Summary
• Ohmic heating system can be consider
has a better in all over the world .
18
Reference
• (De Alwis and Fryer 1990)
De Alwis, A. and P. Fryer (1990). "The use of direct resistance heating in the
food ...
THANK YOU
20
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Ohmic heating technology

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Ohmic heating technology

  1. 1. Non thermal food preservation methods with special reference to ohmic heating H.M.D.N. Herath AG/2011/3113 1
  2. 2. Content • Food preservation classification • What is ohmic heating? • Important benefits • Ohmic heating processing step • Applications • Advantages to ohmic systems • Disadvantages to Ohmic Systems • Summary 2
  3. 3. 3 Food preservation methods Thermal preservation Heating processing Cold processing Non thermal preservation Irradiation Ohmic heating Ozonation High pressure processing
  4. 4. What is ohmic heating? • Ohmic heating is an advanced terminal processing method where in the food material which serves as an electrical resistor, is heated by passing electricity through Which result in rapid & uniform heating • Electrical resistance heating or joule heating or electro-heating 4
  5. 5. History • The concept of ohmic heating of foods is not new • In the nineteenth century, several processes were patented that used electrical current for heating flowable materials • Within the past two decades, new and improved materials and designs for ohmic heating have become available. The Electricity Council of Great Britain has patented a continuous-flow ohmic heater and licensed the technology to APV Baker 5
  6. 6. Important benefits 1. Fast Processing 2. Homogeneous Treatment 3. Compactness of an Ohmic Installation 6
  7. 7. 7 Electrodes Feed pump hopper Viscous food Ohmic heating processing step
  8. 8. 8 Storage tanks Tubular coolers Holding tubes
  9. 9. 9
  10. 10. 10
  11. 11. Applications • Sensitive Products egg products, processed fruits, • Fouling Products sauces, creams, cream cheese, viscous materials • Value-Added Products 11
  12. 12. Ohmic processed commercial available products • .
  13. 13. Advantages • Heating food materials by internal heat generation – Conventional heat transfer has limited dielectric penetration – Heating takes place volumetrically and the product does not experience a large temperature gradient within itself as it heats 13
  14. 14. Advantages cont.. – Reducing risks of fouling on heat transfer surface and burning of the food products – It results in minimal mechanical damage and better nutrients and vitamin retention. – High energy efficiency because 90% of the electrical energy is converted into heat 14
  15. 15. Advantages cont. • Optimization of capital investment and product safety as a result of high solids loading capacity. • Ease of process control with instant switch- on and shut-down. 15
  16. 16. Advantages cont. • Reducing maintenance cost (no moving parts). • Ambient-temperature storage and distribution when combined with an aseptic filling system. • A quiet environmentally friendly system. 16
  17. 17. Disadvantages to Ohmic Systems • High installation cost • Can not apply for all the food • Increased electrical conductivity of food materials 17
  18. 18. Summary • Ohmic heating system can be consider has a better in all over the world . 18
  19. 19. Reference • (De Alwis and Fryer 1990) De Alwis, A. and P. Fryer (1990). "The use of direct resistance heating in the food industry." Journal of Food Engineering 11(1): 3-27. • (Halden, De Alwis et al. 1990, Icier and Ilicali 2005) Halden, K., et al. (1990). "Changes in the electrical conductivity of foods during ohmic heating." International Journal of Food Science & Technology 25(1): 9-25. • (Icier and Ilicali 2005) Icier, F. and C. Ilicali (2005). "Temperature dependent electrical conductivities of fruit purees during ohmic heating." Food Research International 38(10): 1135-1142. 19
  20. 20. THANK YOU 20

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