How critical is the deacidification step in preserving oil stability throughout the refining process?

Dearth of fatty acids is a crucial step in the edible oil refining process. The purpose of deacidification is to remove free fatty acids (FFA) from crude oil, which are key factors affecting the quality, taste, and shelf life of oil. The presence of free fatty acids in oil not only leads to undesirable flavors but also accelerates oil rancidity, lowers the smoke point, and may cause irritation to the digestive system.

National standards specify corresponding acid value requirements for various types of edible oils, typically requiring it to be below 0.3 mg/g. Since crude oil cannot meet this standard, it needs to be deacidified through refining equipment.

The refining deacidification process mainly includes chemical deacidification and physical deacidification. Chemical deacidification operates on the principle of acid-base neutralization, where alkali is added to the crude oil to neutralize the free fatty acids, generating fatty acid salts (soapstock) for subsequent removal. Physical deacidification involves the removal of free fatty acids through distillation under high-temperature and high-vacuum conditions. Both processes have their advantages: chemical deacidification has relatively lower equipment requirements and can further remove some pigments and gums, while physical refining has lower losses, produces no wastewater, but demands higher equipment performance and pretreatment. Oil mills can flexibly choose or combine these two methods based on the characteristics of the oil type.

The deacidification process enhances oil quality in multiple aspects. It removes free fatty acids, thereby extending the shelf life of the oil, as FFA is the primary substrate for oil oxidation. Additionally, the deacidification process further reduces phosphorus content and trace metal ion concentrations, improving the oxidative stability of the oil.

Parameter control during the deacidification process is critical. Minor changes in factors such as temperature, alkali concentration, mixing intensity, and time can affect the deacidification efficiency and refining losses. Huatai Oil Machinery customizes production line equipment based on user needs, providing process design, free installation, and debugging services to ensure the equipment achieves optimal production efficiency and oil quality.