How vegetable oil is refined
- The main stages of the vegetable oil refining process
- Water degumming and neutralization
- Equipment for refining vegetable oil
- Benefits and importance of vegetable oil refining
- Improving oil quality and stability
- Ensuring a long shelf life
- Compliance with food safety standards
Vegetable oil is one of the key ingredients in the food industry. It is widely used for cooking and food production. However, crude vegetable oil usually contains undesirable impurities such as free fatty acids, waxes, pigments, seed residues, and other substances that can affect quality and stability of oil. To remove these impurities, a refining process consisting of several stages is carried out.
The main stages of the vegetable oil refining process
Refining process includes several stages, each of which removes different impurities from the oil.
Water degumming and neutralization
The first step in the refining process is water degumming and neutralization. The crude vegetable oil is treated with steam or hot water, which moisturizes it and removes phosphorus and other hydrophilic substances. A neutralizing agent, usually an alkali, is then added to the oil to bind free fatty acids and other acidic impurities to form a soapstock.
The oil may have a yellow or brown color due to the presence of pigments and organic substances. To improve the appearance and remove the pigments, the oil is bleached. Absorbents, such as activated carbon or clay, are usually used to adsorb pigments and peroxide compounds. Vacuum bleaching device is the only way to remove chlorophyll pigments. The oil then passes through filters that remove the bleaching agents.
The third stage is winterization. The oil contains waxy substances that can create sediment. To avoid this, the oil is subjected to the winterization process that involves cooling, which causes the waxy substances to precipitate. Subsequent filtration removes it from the oil, leaving the pure oil.
The last stage is deodorization. Unrefined oil has an odor and taste caused by odorants – aromatic substances. Additionally, during the refining process, vegetable oil can acquire unpleasant odors and tastes caused by the presence of volatile organic compounds. To remove these odors, the oil is deodorized using sharp steam and the principle of distillation. This allows getting a tasteless and odorless oil.
Equipment for refining vegetable oil
A complete refining and deodorizing line consists of various equipment:
- Tank equipment, in which the oil is heated, cooled and settled. Tanks can be made of different steels, contain coils, gear motors.
- Pressure filters are used to purify oil during the bleaching and winterization process. The filter plates are arranged vertically.
- Police filter removes small impurities from the oil. It is a cylindrical container with a removable bag.
- Deodorizer – a bubbling tank with coils, in which aromatic substances are removed from oil. This vertical tank can be additionally equipped with a thin-film column.
Completeness and capacity of the line depends on the needs each individual enterprise.
Benefits and importance of vegetable oil refining
Refining is an important process that significantly affects the chemical composition of oil and its consumer qualities.
Improving oil quality and stability
Refining improves oil quality by removing undesired impurities. This includes free fatty acids, pigments, waxes, and other substances that can negatively affect the flavor, color, and odor of the oil. Refined oil becomes more stable and has better resistance to oxidation, which ensures its long shelf life.
Ensuring a long shelf life
Removing impurities and volatile compounds prevents the oil from oxidation and aging. Refined oil has a more stable chemical structure and can retain its properties for a long time.
Compliance with food safety standards
Oil refining is an important step in ensuring the oil safety for human consumption. Removing undesirable substances such as free fatty acids and pigments helps to comply with food quality and safety standards. Refined oil produced on the lines of TAN LLC meets the hygiene requirements and can be used in various products.