Degumming eliminates phospholipids so as to enhance its physical stability. The process is necessary also to facilitate further steps in refining.
Phospholipids can treat dark coloured oil and they can also serve as precursors of oil off -flavor. Free fatty acids, pigments and other impurities are also partially removed by degumming.
The impurities have to be removed in the early refining stage for two main reasons
As these cause high refining losses because of their emulsifying properties
They decompose, and darken the oil because of their thermal instability.
Dewaxing of oil is a process of eliminating higher melting point constituents like waxes or triglycerides from oil by gradually cooling vegetable oils and separating saturated glycerides from the oil.
Normally Dewaxing process carried out at higher temperature (18-20 °C) to avoid the crystallization of saturated triglycerides & amalgamation of waxes & saturated triglycerides.
