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vacuum frying
time：2017-05-18 source：LianHuibrowse：133
Vacuum frying is a method when a food product is deep-fried under vacuum (no
pressure) or near vacuum conditions. The general method is as follows. The
foodstuff is enclosed into a specialised pressure vessel containing a deep fryer.
The vessel is connected to a vacuum pump. After this the vessel depressurizes.
The foodstuff is immersed into frying oil within the vessel, fried for the required
time, and then lifted up from the oil. Finally the vessel is re-pressurized again (1,3).
The re-pressurization should be done quickly (5). A centrifugation step can also be
inserted for removal of excess frying oil after the frying step before the
pressurization (1).
This technique has shown to reduce the amount of fat in the fried product (1,3).
This might be because of the lower temperature that is needed to boil water and
oil under vacuum conditions. The removal of excess fat has shown to be important.
A report shows that the optimal time for removal is just after the frying but before
the re-pressurization step (centrifuged within the pressure vessel) (1). Also the fast
re-pressurization has been shown to be a key factor in reducing the fat content (5).
Although the fat content is reduced, the quality is still maintained and even
superior to normal deep-frying in some cases. It should be stated that some
reports show an increase in fat content, although these are fewer than those who
show the opposite effect.
Images
Additional effects
Apart from the fat reducing ability, the lowered temperature in vacuum frying may
also
reduce the formation of acrylamide
: Acrylamide is a possible carcinogenic
compound that is produced when protein and reducing sugars are heated above
150°C (7).
Preservation of natural colour and favours (2,3).
The colour of the finished product is lighter than if the product is fried at
atmospheric pressure (6).
As the vessel in which the product is vacuum fried needs time for pressurising and
depressurising, the process will take longer time.
The pressurisation step is also energy consuming and an increase in energy
consumption is therefore expected.
Important process
parameters
Time, temperature, pressure, type of frying oil, time of breakage of vacuum (faster
is better), de-oiling before pressurisation.
Oil absorption rate is related to the moisture loss rate during the vacuum frying
process. The oil absorption rate can be increased by higher oil temperatures and
lower vacuum pressures (6).
Vacuum frying is a method when a food product is deep-fried under vacuum (no
pressure) or near vacuum conditions. The general method is as follows. The
foodstuff is enclosed into a specialised pressure vessel containing a deep fryer.
The vessel is connected to a vacuum pump. After this the vessel depressurizes.
The foodstuff is immersed into frying oil within the vessel, fried for the required
time, and then lifted up from the oil. Finally the vessel is re-pressurized again (1,3).
The re-pressurization should be done quickly (5). A centrifugation step can also be
inserted for removal of excess frying oil after the frying step before the
pressurization (1).
This technique has shown to reduce the amount of fat in the fried product (1,3).
This might be because of the lower temperature that is needed to boil water and
oil under vacuum conditions. The removal of excess fat has shown to be important.
A report shows that the optimal time for removal is just after the frying but before
the re-pressurization step (centrifuged within the pressure vessel) (1). Also the fast
re-pressurization has been shown to be a key factor in reducing the fat content (5).
Although the fat content is reduced, the quality is still maintained and even
superior to normal deep-frying in some cases. It should be stated that some
reports show an increase in fat content, although these are fewer than those who
show the opposite effect.
Images
Additional effects
Apart from the fat reducing ability, the lowered temperature in vacuum frying may
also
reduce the formation of acrylamide
: Acrylamide is a possible carcinogenic
compound that is produced when protein and reducing sugars are heated above
150°C (7).
Preservation of natural colour and favours (2,3).
The colour of the finished product is lighter than if the product is fried at
atmospheric pressure (6).
As the vessel in which the product is vacuum fried needs time for pressurising and
depressurising, the process will take longer time.
The pressurisation step is also energy consuming and an increase in energy
consumption is therefore expected.
Important process
parameters
Time, temperature, pressure, type of frying oil, time of breakage of vacuum (faster
is better), de-oiling before pressurisation.
Oil absorption rate is related to the moisture loss rate during the vacuum frying
process. The oil absorption rate can be increased by higher oil temperatures and
lower vacuum pressures (6).
Important product
parameters
What can it be used for?
Products
Potato chips, apple slices, vegetable based snacks.
Also, this technology is probably suited for products that are already suitable for
normal (at atmospheric pressure) deep-frying; however this needs to be evaluated.
Operations
Deep-frying at vacuum pressure.
Solutions for short
comings
Deep-fried food is a large part of the food industry. The big problem with it is the
high fat content that deep fried products have. A technology that reduces the fat
content without compromising the edible quality (and according to reports
increases the quality) has therefore a large industrial potential today. The only
obstacle is the economy, both for the industry (purchase and increased operating
costs) and for the consumer (increased price due to the increased industrial costs
pressure) or near vacuum conditions. The general method is as follows. The
foodstuff is enclosed into a specialised pressure vessel containing a deep fryer.
The vessel is connected to a vacuum pump. After this the vessel depressurizes.
The foodstuff is immersed into frying oil within the vessel, fried for the required
time, and then lifted up from the oil. Finally the vessel is re-pressurized again (1,3).
The re-pressurization should be done quickly (5). A centrifugation step can also be
inserted for removal of excess frying oil after the frying step before the
pressurization (1).
This technique has shown to reduce the amount of fat in the fried product (1,3).
This might be because of the lower temperature that is needed to boil water and
oil under vacuum conditions. The removal of excess fat has shown to be important.
A report shows that the optimal time for removal is just after the frying but before
the re-pressurization step (centrifuged within the pressure vessel) (1). Also the fast
re-pressurization has been shown to be a key factor in reducing the fat content (5).
Although the fat content is reduced, the quality is still maintained and even
superior to normal deep-frying in some cases. It should be stated that some
reports show an increase in fat content, although these are fewer than those who
show the opposite effect.
Images
Additional effects
Apart from the fat reducing ability, the lowered temperature in vacuum frying may
also
reduce the formation of acrylamide
: Acrylamide is a possible carcinogenic
compound that is produced when protein and reducing sugars are heated above
150°C (7).
Preservation of natural colour and favours (2,3).
The colour of the finished product is lighter than if the product is fried at
atmospheric pressure (6).
As the vessel in which the product is vacuum fried needs time for pressurising and
depressurising, the process will take longer time.
The pressurisation step is also energy consuming and an increase in energy
consumption is therefore expected.
Important process
parameters
Time, temperature, pressure, type of frying oil, time of breakage of vacuum (faster
is better), de-oiling before pressurisation.
Oil absorption rate is related to the moisture loss rate during the vacuum frying
process. The oil absorption rate can be increased by higher oil temperatures and
lower vacuum pressures (6).
Important product
parameters
What can it be used for?
Products
Potato chips, apple slices, vegetable based snacks.
Also, this technology is probably suited for products that are already suitable for
normal (at atmospheric pressure) deep-frying; however this needs to be evaluated.
Operations
Deep-frying at vacuum pressure.
Solutions for short
comings
Deep-fried food is a large part of the food industry. The big problem with it is the
high fat content that deep fried products have. A technology that reduces the fat
content without compromising the edible quality (and according to reports
increases the quality) has therefore a large industrial potential today. The only
obstacle is the economy, both for the industry (purchase and increased operating
costs) and for the consumer (increased price due to the increased industrial costs
Important product
parameters
What can it be used for?
Products
Potato chips, apple slices, vegetable based snacks.
Also, this technology is probably suited for products that are already suitable for
normal (at atmospheric pressure) deep-frying; however this needs to be evaluated.
Operations
Deep-frying at vacuum pressure.
Solutions for short
comings
Deep-fried food is a large part of the food industry. The big problem with it is the
high fat content that deep fried products have. A technology that reduces the fat
content without compromising the edible quality (and according to reports
increases the quality) has therefore a large industrial potentiVacuum frying is a method when a food product is deep-fried under vacuum (no
pressure) or near vacuum conditions. The general method is as follows. The
foodstuff is enclosed into a specialised pressure vessel containing a deep fryer.
The vessel is connected to a vacuum pump. After this the vessel depressurizes.
The foodstuff is immersed into frying oil within the vessel, fried for the required
time, and then lifted up from the oil. Finally the vessel is re-pressurized again (1,3).
The re-pressurization should be done quickly (5). A centrifugation step can also be
inserted for removal of excess frying oil after the frying step before the
pressurization (1).
This technique has shown to reduce the amount of fat in the fried product (1,3).
This might be because of the lower temperature that is needed to boil water and
oil under vacuum conditions. The removal of excess fat has shown to be important.
A report shows that the optimal time for removal is just after the frying but before
the re-pressurization step (centrifuged within the pressure vessel) (1). Also the fast
re-pressurization has been shown to be a key factor in reducing the fat content (5).
Although the fat content is reduced, the quality is still maintained and even
superior to normal deep-frying in some cases. It should be stated that some
reports show an increase in fat content, although these are fewer than those who
show the opposite effect.
Images
Additional effects
Apart from the fat reducing ability, the lowered temperature in vacuum frying may
also
reduce the formation of acrylamide
: Acrylamide is a possible carcinogenic
compound that is produced when protein and reducing sugars are heated above
150°C (7).
Preservation of natural colour and favours (2,3).
The colour of the finished product is lighter than if the product is fried at
atmospheric pressure (6).
As the vessel in which the product is vacuum fried needs time for pressurising and
depressurising, the process will take longer time.
The pressurisation step is also energy consuming and an increase in energy
consumption is therefore expected.
Important process
parameters
Time, temperature, pressure, type of frying oil, time of breakage of vacuum (faster
is better), de-oiling before pressurisation.
Oil absorption rate is related to the moisture loss rate during the vacuum frying
process. The oil absorption rate can be increased by higher oil temperatures and
lower vacuum pressures (6).
Important product
parameters
What can it be used for?
Products
Potato chips, apple slices, vegetable based snacks.
Also, this technology is probably suited for products that are already suitable for
normal (at atmospheric pressure) deep-frying; however this needs to be evaluated.
Operations
Deep-frying at vacuum pressure.
Solutions for short
comings
Deep-fried food is a large part of the food industry. The big problem with it is the
high fat content that deep fried products have. A technology that reduces the fat
content without compromising the edible quality (and according to reports
increases the quality) has therefore a large industrial potential today. The only
obstacle is the economy, both for the industry (purchase and increased operating
costs) and for the consumer (increased price due to the increased industrial costsal today. The only
obstacle is the economy, both for the industry (purchase and increased operating
costs) and for the consumer (increased price due to the increased industrial costs
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