Ohmic heating technology
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Transcript of Ohmic heating technology
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Non thermal food preservation methods with special reference
to ohmic heating
H.M.D.N. HerathAG/2011/3113
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Content
• Food preservation classification • What is ohmic heating? • Important benefits • Ohmic heating processing step• Applications• Advantages to ohmic systems• Disadvantages to Ohmic Systems• Summary
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Food preservation methods
Thermal preservation
Heating processing
Cold processing
Non thermal preservation
Irradiation
Ohmic heating
Ozonation
High pressure processing
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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
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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
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Important benefits
1. Fast Processing
2. Homogeneous Treatment
3. Compactness of an Ohmic Installation
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Ohmic heating processing step
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Applications• Sensitive Products egg products,
processed fruits,
• Fouling Products sauces, creams, cream cheese, viscous materials
• Value-Added Products
Ohmic processed commercial available products
• .
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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
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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
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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.
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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.
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Disadvantages to Ohmic Systems
• High installation cost
• Can not apply for all the food
• Increased electrical conductivity of food materials
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Summary
• Ohmic heating system can be consider has a better in all over the world .
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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.
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THANK YOU