Refined oils are produced through a process called refining, which involves several steps such as degumming, neutralization, bleaching, deodorization and winterization. The purpose of refining is to remove impurities, improve the oil’s color, odor, and taste, and extend its shelf life.
- Degumming: Removes gums and phospholipids from the oil using water or acid.
- Neutralization: Neutralizes free fatty acids in the oil by treating it with an alkali such as sodium hydroxide.
- Bleaching: Removes color pigments and residual impurities using clay or other absorbent materials.
- Deodorization: Removes unwanted odors and flavors using steam distillation at high temperatures and pressures.
- Winterization: Removes waxes and other high-melting point components by cooling the oil and filtering out the solid components.
After these steps, the oil is filtered and packaged for distribution. The specific steps and conditions used can vary depending on the type of oil being refined.