As for the life level has been increased rapidly, nowadays people prefer to
choose healthier diet method and snacks with lower salt and oil content. About the
fried fruit and vegetable chips, there must be some oil content inside the
chips, whichever frying technology you adopt. This is we can’t deny. But we have
solution in the production process to reduce the oil content and make the chips
healthier.
The solution is a system method. To get the best de-oiling
effect, we should combine the production technology and production machine. Only
choose right production technology and machines, we can realize the aim finally.
There are two ways should be both done for one same
production program. One is freezing rapidly in the preprocess program, the
other is de-oiling in the same chamber of vacuum frying under reduced pressure.
Freezing
rapidly
The moisture of raw material will change into ice crystal
in the freezing process. Ice crystal inside the frozen cells will be sublimed
under vacuum condition leaving pores in the food matrix and accelerate the
moisture loss and sequentially decrease the final moisture content. Slow freezing produces
big size crystal, which damages the cell. Then it could increase oil
penetration, since oil could penetrate into damaged cell during the frying,
Thus, fast freezing is preferred to minimize oil uptake.
Vacuum de-oiling
Centrifugation for removing the chips surface oil
is an important part of the post-frying process and should be part of the
frying equipment. Centrifugation done while the pressure is still low will significantly
decrease the amount of surface oil that can penetrate the porous products when
breaking the vacuum. This is the vacuum de-oiling I said. Centrifuged under
vacuum, has a significantly lower oil content than atmospheric centrifuged chips.
Atmospheric centrifuging is done in a separated machine after breaking the
vacuum. The surface oil will go into vacuum fried chips when we break the
vacuum of the vacuum frying chamber. Even you increase rotary speed of centrifuging,
the effect is not good as vacuum de-oiling. If you increase too much speed, the
chips will be broken and reduce final vacuum fried chips quality. Meanwhile,
the rotary speed of atmospheric de-oiling is almost 10 times as vacuum
de-oiling, the rotary time is of atmospheric de-oiling is almost 20-30 times as
vacuum oiling. The production cost is much higher.
Our vacuum fryer has been equipped with automatic
de-oiling function. It will be done in the vacuum frying chamber under stable reduced
pressure and temperature condition. Rotary speed is below 300 rpm, and rotary
time is about 1~3 minutes. Oil removed from chips will returned into oil tank automatically
and could be recycled for next vacuum frying.
