2. How Does Microwave Heat Foods?
Microwaves interact with polar water
molecules and charged ions.
The friction resulting from molecule
alignment and migration of charged ions in
rapidly alternating electromagnetic field
generates heat within foods.
Federal Communication Commission (FCC)
allocates 915 MHz and 2450 MHz bands for
microwave heating applications.
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3. Current Industrial Applications
Microwave ovens operating at 2450
MHz
2450 and 915 MHz systems between 10
to 200 kW heating capacities are used
in the food industry,
• Precooking bacons
• Tempering deep frozen meats
• Meat patties
• Precooking many other foods products
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4. Advantages Of Microwave
Sterilization
Reduction in the thermal processing time
Fresh-like taste and texture, and
improves visual appeal
Increases retention of nutrients
Better energy usage
Post packaging processing
Great opportunities for innovative food
companies
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5. Can Microwave Sterilization Be Used
For Processing All Foods?
Conventional thermal treatments.
The shorter time and more uniform
volumetric heating.
Salmon fillets, macaroni and cheese,
massed potato and beef in gravy cab.
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7. Can Microwave Sterilization Be Used
For Processing All Foods?
Advantages -product properties, state,
shape and thickness, processing system
design.
Compared with conventional food
processing, microwave sterilization could
potentially improve sensory, appearance and
nutritional value.
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8. Shelf Life Of Microwave Processed
Products
Microwave sterilization can achieve the
same reduction of bacterial population as
conventional retorting.
Packaging materials - Plastic trays or
pouches.
Normal shelf life is 2-3 years or longer.
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9. How Are Microwave Processed Foods
Stored?
Microwave sterilized foods can be stored at
ambient temperatures and re-heated in
the common household microwave prior to
consumption.
These products do not require
refrigeration
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10. How Economical Is Microwave
Sterilization Processing?
Ability to heat solid, semi-solid and meal
combination food products
More rapid heating and preservation of
sensory and nutritional quality
Possibility of ascetic packaging
High throughout of processed foods
Possibility of incorporation of microwave
processing equipment in the existing
processing lines.
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12. Microwave Applicators
The most common form of an applicator
(>50%)-multimode type.
In principle, it is an extension of the
domestic microwave oven but built for
large scale material processing
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18. Industrial Applications
Food tempering
Meat, fish, fruit, butter and other foodstuffs can
be tempered for cold store temperature(-3ºC)
For ease of further processing such as grinding
the meat in the production of burgers or blending
and portioning butter packs.
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19. Industrial Applications
Heating and cooking
Many foodstuffs have been cooked by
microwaves for various stages of
processing.
• Bacon cooking in a combination system,
• Meat coagulation to upgrade scrap and
doughnut
• Cooking for frying.
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20. Industrial Applications
Pasteurisation and sterilisation
Food products, such as bread, precooked foods
and animal feedstuffs have been processed
using microwaves for pasteurisation or
sterilisation or simply to improve their
digestibility.
Food pasteurisation of sealed packs under
pressure can be effected by microwave energy.
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21. Conclusions
Microwave heating has been established in a
number of industrial sectors.
• Tempering
• Blanching
• Sterilising
• Cooking
• Puffing
Vacuum drying offers the biggest
opportunity for microwave processing.
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Three major compartments 1. Power unit – Generate microwave at required frequency band.2. Applicator – Material is subjected to intense microwave fields.3. Control circuitary– Optimize and regulate overall performance of the heater.
Multimode resonant applicators consist of a metallic enclosure into which a microwave signal is coupled through a slot and suffers multiple reflections.The superposition of the incident and reflected waves gives rise to a standing wave pattern or mode.