alkali refining

Alkali refining is a process used to remove undesirable components from fats and oils, primarily for edible purposes. These components include free fatty acids, waxes, and pigments that contribute to color and flavor.1

The process involves treating the fats or oils with an aqueous solution of a mild alkali, such as sodium hydroxide or sodium carbonate, at temperatures between 40 to 85 °C (104 to 185 °F). This treatment forms soaps from the free fatty acids, along with other impurities, which are then separated from the oil. This separation can be done by settling in a tank (batch refining) or by using centrifuges in a continuous system.1

After refining, the oil is typically washed with water to remove any remaining alkali and soapstock. The resulting refined oil is neutral, lighter in color, and more stable against rancidity, making it suitable for industrial use or further processing into edible oils.1