Non thermal food
with special reference
to ohmic heating
• Food preservation classification
• What is ohmic heating?
• Important benefits
• Ohmic heating processing step
• Advantages to ohmic systems
• Disadvantages to Ohmic Systems
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
• The concept of ohmic heating of foods is not new
• In the nineteenth century, several processes were
patented that used electrical current for heating
• 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
1. Fast Processing
2. Homogeneous Treatment
3. Compactness of an Ohmic Installation
Ohmic processed commercial
• Heating food materials by internal heat
– Conventional heat transfer has limited dielectric
– Heating takes place volumetrically and the
product does not experience a large
temperature gradient within itself as it heats
– 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
• Optimization of capital investment and
product safety as a result of high solids
• Ease of process control with instant switch-
on and shut-down.
• Reducing maintenance cost (no moving
• Ambient-temperature storage and
distribution when combined with an
aseptic filling system.
• A quiet environmentally friendly system.
Disadvantages to Ohmic Systems
• High installation cost
• Can not apply for all the food
• Increased electrical conductivity of food
• Ohmic heating system can be consider
has a better in all over the world .
• (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
• (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):