Crude
vegetable oil is inedible due to the
presence of harmful elements like free fatty acids (FFA), gums, sediments,
odoriferous and coloring materials. These need to be removed completely to make the oil edible.
Refined vegetable oil is sourced from
the seeds of various plant sources. The fats from plant seeds are
polyunsaturated and are identified by a
chemical structure enabling these to stay
in fluid state at room temperatures , but also become quickly rancidity through oxidation- that can also
release cancer-causing free radicals in
the body. The refining process that removes these impurities is a highly intensive mechanical and chemical
process.
Refining ensures the removal of gums, waxes, phosphatides and free
fatty acid (F. F.A.) from the oil and the process also impart uniform colour
and eliminates unpleasant smell by removing
of odiferous matter. Refining is carried out in two ways a) Batch operation
. It is usually carried out for
processing less than thirty tones of oil per 24 hours, or for oil with F.F .A. content of 1 % and less normally batch process is recommended.
Batch process is normally preferred as it requires low capital investment, simplicity of
operation and low maintenance thus enabling a viable proposition even at low
capacities of 10 TPD b) continuous
operation. Though chemical refining is widespread, physical refining is carried out with certain oils .
The multiple steps
involved are :
Degumming / Neutralization
A process of removing
phospholipids- that can lead to dark
colored, off -flavor oil in order to improve its physical stability and
facilitate further refining.
Continuous Bleaching
“Bleaching” is a process of selective removal of Color pigments, Dirt, Trace metals, Removal of polycyclic Aromatic compounds, Phospholipids and other impurities by the physical and chemical interaction of an adsorbent with an oil or fat to improve its quality.
Deodorization
Deodorization is a
physical vacuum stripping process wherein
a given amount of a stripping agent (usually steam) is passed for a
given period of time through hot oil at a low pressure to remove volatile components. However, since it is
usually carried out at high temperature (220 to 250°C), some chemical, thermal
effects may take place as well.
MECTECH ADVANTAGE :
DEGUMMING
Mectech chooses customized
degumming processes based on methods of processing, chemicals used and the
content of phosphatides in the crude vegetable oil.
BLEACHING
●
MECTECH's
customized design of bleacher requires
no mechanical agitation and bleaching is carried out under optimum conditions
of moisture content to achieve perfect results - thus saving on power consumption.
●
MECTECH's
customized design of bleacher
prevents leakages from gland system and
almost maintenance free. b) avoids dead area & lower consumption of bleaching earth. c)
guarantees better and consistent quality d)
ensures minimum heat energy requirement.
DEODORIZATION
●
Most
efficiently designed oil to oil heat exchanger fitted in last tray of
Deodorizer
●
Elaborate
and efficient design of fatty acid scrubbing recovery system prevents charring of oil
during the process.
