In its crude form, the oil is permeated with impurities, that must be
eliminated not only to make it edible, but also to enhance the color, texture
and taste and prevent rancidity. The multi stage process that
eliminates these impurities & attracts consumers with taste and
acceptability to earn greater returns is called refining. The crude oil must
necessarily undergo the refining process to remove the inherently harmful
elements for human consumption including free fatty acids (FFA),
gums, sediments, odoriferous and coloring materials present to make the oil
edible.
Some of
the impurities present in the Oil are:
Gums: These
phospholipids are of two types: hydratable and non-hydratable. The Hydratable
gums are eliminated during degumming process.
Hydrolysis Products of Oils: Diglycerides and monoglycerides and free fatty acids are
produced during hydrolysis and are removed during neutralization .
Proteineous Matter, Carbohydrates, Resins: Are eliminated during neutralization step.
Pigments : Coloring Matter including chlorophyll (green colour)
carotene (red colour), anthophyll (yellow colour) and gossypol (orange colour) impart
distinctive colour to the oil and need to be removed.
Odorous Chemicals: Occurring
in small quantities, their presence makes the product detestable by
imparting pungent and even unacceptable odour. These
volatile substances are removed during deodorization.
Waxes:
Waxes are characterized as high melting esters of fatty alcohol
with long chain fatty acids are eliminated through dewaxing .
MECTECH undertakes the multiple steps needed – often in combination
at all the stages. After undergoing the process of neutralization,
bleaching and deodorization, the oil is made safe and fit for human
intake. Through inimitable innovation and customization, value adds
optimization into each process to enhance the processes and returns.
The various steps undertaken for refining vegetable oils are:
Degumming / Neutralization
The process of eliminating the embedded phospholipids in order to
enhance its physical stability and facilitate further refining is called
degumming. Phospholipids turn the oil lead dark and even off -flavor. Free
fatty acids, pigments and other impurities are also partially removed by
degumming.
Mectech has revolutionized the degumming processes by
incremental enhancements. These processes are customized according to the
methods of processing, chemicals used and the content of phosphatides in the
crude vegetable oil.
Continuous Bleaching
“Bleaching” is the selective elimination of pigments and impurities
through interacting it physically and chemically with an
adsorbent in order to enhance its quality. It eliminates
various impurities like Color pigments, Dirt, Trace metals, Removal
of polycyclic Aromatic compounds, Phospholipids.
MECTECH's customized design of bleacher eliminates the need for
mechanical agitation. Hence bleaching is accomplished under optimum conditions
of moisture content to achieve perfect results ensuring power consumption
saving for the entire system.
With the absence of mechanically agitated bleacher, the quality of
oil improves due to lack leakages from gland system. It also eliminates
maintenance costs arising out of wear and tear as
the Mectech bleacher is maintenance free.
Mectech’s customized bleacher also ensures that the bleaching
earth remains under suspension thus avoiding dead areas, resulting
in lower consumption of bleaching earth. Moreover, due to the bleaching process being executed under controlled
parameters, better and consistent quality of resultant oil is guaranteed, that
is crucial to its marketability.
Deodorization
In this vacuum stripping process, a given amount of a stripping
agent (usually steam) is passed for a given period of time through hot oil at a
low pressure. The physical process removes various volatile components. The
customized Mectech designed oil-to-oil heat exchanger fitted in the
last tray of Deodorizer is optimally efficient to ensure minimum heat energy requirement. The elaborate and
efficient design of fatty acid scrubbing recovery system ensures
virtually no transfer of fatty acid into barometric condenser. The most custom
designed heating coil by Mectech prevents charring of oil during the
process.
