Page 43 - FoodFocusThailand No.213 DECEMBER 2023

SMART PRODUCTION

Freeze-drying assisted with microwave heating has drying time and energy usage by 91% and 90%, respectively.
intrinsic advantages over traditional freeze-drying. The products displayed considerably decreased chewiness
Products using microwave-freeze drying exhibit higher and hardness, whereas proline and glutamic acid were both
volatile retention levels than conventional freeze-dried better conserved using infrared-assisted freeze-drying by
products. However, there are still a lot of practical issues 3.84–5.54 g/100 g and 6.30–7.29 g/100 g, respectively.
that need to be overcome. Vacuum pressure and Furthermore, hybrid freeze-drying can also be used for other
microwave power in hybrid microwave freeze-drying purposes, for example, the applicability and feasibility of
systems are critical factors in determining product quality. microwave-assisted freeze-drying for various monoclonal
High microwave power causes freeze-drying to fail if the antibody formulations, as well as its impact on the attributes of
sample temperature exceeds the triple point on a phase the final product. It was confirmed that microwave-assisted
diagram (solid, liquid, and gas). On the other hand, drying freeze-drying remarkably reduces drying times while retaining
at insufficient microwave power may also result in more product quality, which is also a prerequisite for continuous
significant losses of substances due to the extended processing.
drying period. Therefore, regulating the process These hybrid freeze-drying techniques may not be widely
parameters in microwave freeze-drying is highly required known and are not yet used in large-scale industry. Therefore, it
to produce superior nutritive and sensory quality food is an essential opportunity for entrepreneurs to begin learning
products. the possibilities of these technologies and how they can be
2. Infrared-assisted Freeze-drying applied in the production process to achieve maximum benefits.
Infrared freeze-drying is one of the most promising If the entrepreneur has implemented these processes
drying methods among the combined freeze-drying- appropriately and is worthy of investing, it will help increase
based approaches, which yields better product quality product value and create a competitive advantage.
while providing a faster drying process. Infrared freeze-
drying is an innovative drying process that uses infrared
rather than electric heating plates to generate energy for
ice sublimation, which increases heat transfer rates.
Uniform heating and high energy transfer efficiency are More Information Service Info C006
two advantages of infrared heating, mainly because
infrared radiation enters a product to a specific depth
and raises its temperature without heating the air around
it, as a medium is not necessary for the infrared-based
heating process.
Although it has been indicated that IR-assisted
freeze-drying yields products with nutritional and sensory
qualities comparable to conventional freeze-dried
products, a thick structure on the product surface layer
and large pores in the material center are usually seen
during various infrared freeze-drying trails. Collapse
happens as a result of an excessive rise in product
temperature when exposed to IR, which adversely
impacts the product’s physicochemical properties. Under
optimal conditions, infrared microwave vacuum freeze-
drying has the potential for large-scale industrial
production due to the faster drying time and capacity to
create high-quality dried food products.

Applications of Hybrid Freeze-Drying
Technologies in Food Dehydration
Hybrid freeze-drying is a promising technology frequently
used to dry food, especially fruits and vegetables.
However, there are few reports on its application in drying
meat and poultry, seafood, and beverages. Recently,
hybrid freeze-drying was applied in numerous applications
to process fresh products. The research investigated the
potential of freeze-drying alone and infrared-assisted
freeze-drying to dehydrate edible insects (Proteotia
brevitarsis larva). This suggested that an infrared
provided the sublimation energy required for fast freeze-
drying. Compared with freeze-drying, continuous
infrared-assisted freeze-drying considerably reduced
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