Steps for preparation
- Corn oil is expeller-pressed, then solvent-extracted using hexane or 2-methylpentane (isohexane)
- The solvent is evaporated from the corn oil, recovered, and
re-used. After extraction, the corn oil is then refined by degumming and/
or alkali treatment, both of which remove phosphatides.
- Alkali treatment also neutralizes free fatty acids and
removes colour (bleaching).
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Final steps in refining include winterization (the removal of waxes), and deodorization by steam distillation of
the oil at 232–260 °C (450–500 °F) under a high vacuum