Page 47 - FoodFocusThailand No.198 September 2022

SPECIAL FOCUS

1. Right Frequency for the Right Food and have higher carcinogenic substances. Preheating by MW & RF can reduce the cooking
Application There are many frequencies time and improve the color of the surface. Spring roll is a good example of this case.
generating heat in foods. Each frequency creates 4. Quality Improvement for Pasteurization and Sterilization Products Rapid heating
a different energy transfer rate and temperature after packing using MW & RF not only improves the quality and nutrition of products but
profile. In household MW, 2,450 MHz is the most also eliminates the risk of contamination after the pasteurization or sterilization process.
common frequency used, while the industrial level This rapid heating can create a better product appearance, extend product shelf life and
has a wide range from 2,450 MHz and 915 MHz increase customer satisfaction.
for microwave (MW), and 13.56 MHz, 27.12 MHz,
and 40.68 MHz for radio frequency (RF).
Therefore, choosing the right frequency is crucial
in food production.
2. Reflection and Direction of Wave The
advanced reflection technique and wave direction
are essential to creating a consistent temperature
for different food products. As a result, a unique
design of the reflection plate or advanced
technique for a specific application is a vital part
of MW & RF at the industrial level.
Why Microwave and Radio
Frequency?
Heating by microwave and radio frequency is
much faster than other heating methods as it is There are many applications that MF & RF can be applied and create a difference,
transferred directly to the water content area. So such as the elimination of insects contaminated with raw materials or increasing efficiency
this can be applied to improve the production in compound extraction.
process in many aspects as follow:
1. Defrosting and Tempering MF & RF is
the best defrosting method as heat can transfer More Information Service Info C005
through the packaging. This technique minimizes
the temperature gap between the surface and
core temperature to around +/- 2°C, so the surface
temperature can be controlled to not over 0°C to
protect microbial growth. In contrast, conventional
defrosting takes longer, creating a high temperature
on the surface and allowing microbial growth
quickly.
In addition to product quality, the speed and
uniformity brought by the MW & RF processes
can minimize the product drip losses and
degradation of up to 8% of total weight or eliminate
all weight losses as the best result caused by
conventional defrosting methods. In some cases,
the MW & RF investment reach a breakeven point
within 1-2 years just from drip losses saving.
2.Drying Typically, a conventional process
requires a high temperature and a long time to
remove moisture from the core products as the
heat is conducted from the surface to the core.
While MF & RF can heat directly to the water-
contain area, so removing moisture is easy even
in the product's core. Besides saving energy and
cost, this method is a better way to control quality.
The bakery processing is a good sample using
this technique.
3. Preheating The conventional frying and
baking processes usually take a long time as heat
conducts slowly from the surface to the core, so
the surface of products may be overcooked.
Moreover, the products will absorb too much oil

SEP 2022 FOOD FOCUS THAILAND 47

23/8/2565 BE 20:04
45-47_Special Focus_TSUS.indd 47 23/8/2565 BE 20:04
45-47_Special Focus_TSUS.indd 47