Chemical oil refining of edible oil refers to the process of using chemical methods to remove impurities in edible oils and fats to improve the purity and quality of oils and fats. The following is a detailed introduction to the chemical refining of edible oils:
I. Process Overview of chemical oil refining
The chemical refining of edible oils mainly includes steps such as degumming, deacidification (alkali refining), decolorization, and deodorization. Each step is aimed at removing different impurities in oils and fats, thereby improving the quality of oils and fats.
II. Specific steps of chemical oil refining
1. Degumming
Principle: Using the hydrophilicity of colloid impurities such as phospholipids, they are condensed and separated under conditions such as water, acid, electrolyte or heating.
Operation: Usually carried out before water washing or alkali refining, the colloid impurities are condensed and precipitated by adding acid, electrolyte or heating, and then removed by filtering or centrifugal separation.
2. Deacidification (alkali refining)
Principle: Use alkali solution to neutralize free fatty acids in oils and fats to generate water-soluble soap stock, thereby separating it from oils and fats.
Operation: Commonly used alkali solutions include sodium hydroxide and potassium hydroxide. Add alkali solution to the oil in a certain proportion, stir and react at an appropriate temperature for a period of time, and then remove the soap stock and impurities by centrifugation or filtration. The parameters such as the amount of alkali solution, temperature, stirring intensity and time need to be adjusted according to the type of oil and the impurity content.
3. Decolorization
Principle: Use adsorbents to adsorb pigments in oils and remove them.
Operation: Commonly used adsorbents include activated clay, activated carbon, etc. Add adsorbents to the oil in a certain proportion, stir and react at an appropriate temperature for a period of time, and then separate the adsorbent and pigment by filtration or centrifugation. Parameters such as the amount of adsorbent, temperature and time also need to be adjusted according to the type of oil and the impurity content.
4. Deodorization
Principle: Use the distillation principle under high temperature and vacuum conditions to remove volatile odor molecules in oils and fats.
Operation: Under vacuum and high temperature conditions, use the distillation principle to separate volatile odor molecules in oils and fats together with steam under the action of deodorization equipment. By controlling parameters such as deodorization temperature, time and vacuum degree, odor substances in oils and fats can be effectively removed.
Ⅲ. Advantages and Disadvantages of chemical oil refining
Advantages
Chemical refining can effectively remove impurities such as free fatty acids, colloids, pigments and odor substances in oils and fats, and improve the purity and quality of oils and fats.
The soap stock generated during the alkali refining process has an adsorption effect, which can remove other impurities at the same time and improve the refining efficiency.
Disadvantages
Chemical refining requires the use of chemical reagents such as alkali solution, which increases production costs and processing difficulties.
Pollutants such as wastewater may be generated during the alkali refining process, which need to be properly handled to avoid pollution to the environment.
Ⅳ. Precautions of chemical oil refining
During chemical refining, the operating conditions and parameters of each step should be strictly controlled to ensure the refining effect and product quality.
Wastewater, waste residue and other pollutants generated during the refining process should be properly handled in accordance with environmental protection requirements.
Refined edible oil should undergo strict quality inspection to ensure that it meets relevant standards and regulations.
In summary, the chemical refining edible oil process is a complex and delicate process. Through the synergistic effect of each step, it can effectively improve the purity and quality of oils and fats. At the same time, it is also necessary to pay attention to issues such as environmental protection and quality control.