14. Ohmic Heating

16. Principle of ohmic heating
electric current is passed through foods heating occurs in the form of internal energy generation within the material temperature rise throughout its volume
rapid and uniform heating
HIGH TEMPERATURE SHORT TIME (HTST) PROCESSES
Fig. 1 Principle of ohmic heating

18. THE CONCEPT OF OHMIC HEATING
Based on the passage of alternating electrical current through a food product that serves as an electrical resistance.
The electrical power introduced into the product is translated into heat.
The electrical currents passed along or across the flowing fluid.

19. Fig. 2(d) Schematic drawing of ohmic cell for liquid sample

20. Fig. 3 Picture of Ohmic heating device

26. GENERATE HEAT IN SITU PASSAGE OF ELECTRIC CURRENT:
Electric resistance of material: heat by
P= I2R
A commercial process and some proposed processes
Need to model and control the system- study stationary food mixtures

38. Microwave Heating Heating system
less time at lower cost
get more product
Heating system
Microwave penetrate a food and heating extends with in the entire food material
Rate of heating is therefore more rapid

48. Ionic Polarization
Electrical field is applied to food solution containing ions, and ion move at an accelerated pace due to their in herent charge the resulting collisions between the ions

49. Dipole Rotation Polar molecule Such as water
Molecule have a random orientation when an electric field is applied the molecules orient themselves according to the polarity of the field

52. Penetration Depth of Microwave
Distribution of energy within a material is determined by α’ follow

53. Penetration Depth of Microwave
Field penetration depth (Z)

59. Application of Microwave
Dehydration
Freeze drying
Processing of meat & meat product
Blanching
Thawing
Pasteurization and Sterilization

71. Induction Heating

72. The Concept Of Induction Heating
When an electrically conductive material is placed in a varying magnetic field

73. Basic Induction Heating
Rapid heating rate 125 C /s

74. Induction Heating Application Systems
coils within the bottom of the rice cooker create the magnetic field. When the inner nonstick aluminum cooking pan with stainless steel outer lining is placed into the rice cooker and the unit is activated, a magnetic field is generated to create instant heat.

75. Application

76. Induction Heating system Rice Cooker
Induction technology heats the entire nonstick inner pan for consistent.