Fish oil, a valuable product rich in omega-3 polyunsaturated fatty acids (EPA and DHA), vitamins A and D, is obtained from the tissues of fatty fish species. The process of obtaining it has undergone a long evolutionary path — from primitive melting on ships to high-tech methods ensuring purity and preservation of useful substances. Modern production is a complex multistage process, strictly controlled at each stage.

Historical method: melting from cod liver

Traditionally, for centuries, fish oil was primarily obtained from cod liver. This method, known as "liver," involved the natural separation of fat. Freshly caught cod was left in large barrels, where, under the influence of solar heat, fat gradually rose to the surface. It was simply collected and filtered. A more technologically advanced approach involved melting: the liver was ground and steamed in special boilers. Under the influence of temperature, fat melted and separated from the protein mass. The obtained raw material was rich in vitamins but could have a specific smell and taste, as well as contain impurities. It was this "liver" fat that was known to Soviet children as an obligatory food supplement.

Modern industrial method: using fish bodies

Today, the main volume of fish oil is produced not from the liver, but from the bodies of fatty fish species such as anchovies, sardines, mackerel, and herring. This is so-called "fish" oil. This approach is more sustainable and allows for the production of more product. The process begins with the preparation of fish meal. Fresh raw material is delivered to processing plants, where it is first boiled in large boilers for protein coagulation and separation of the liquid fraction. The obtained mass is pressed to remove most of the water and fat. The solid residue goes into the production of fish meal, while the liquid fraction, containing water, proteins, and fat, undergoes the next key stage.

Centrifugation and purification: separation of fractions

The liquid mixture obtained after boiling and pressing is directed to high-speed industrial centrifuges. Under the action of centrifugal force, it is separated into three main fractions: light fish oil, which is collected in the center, water fraction (so-called "stickwater"), and heavy sludge containing protein residues. The separated crude oil still contains some amount of moisture, impurities, and free fatty acids. To remove them, it is washed with hot water and subjected to refining. The refining process may include neutralization, bleaching, and deodorization, resulting in a clean, transparent, and odorless product.

Technologies for preserving quality: molecular distillation

The most advanced method used for the production of high-quality food supplements and pharmaceutical preparations is molecular distillation. This is a process that takes place under deep vacuum, which allows for the separation of substances with different molecular masses at significantly lower temperatures than in normal distillation. This is critically important for preserving thermosensitive omega-3 acids, which are destroyed by strong heating. Molecular distillation effectively removes potential contaminants such as heavy metals (mercury, lead), dioxins, and polychlorinated biphenyls, which can accumulate in fish tissues. As a result, a highly purified omega-3 concentrate is obtained, which is used in capsules and pharmaceutical forms.

Thus, the modern extraction of fish oil is not just simple melting, but a sophisticated technological chain aimed at the maximum extraction of useful components, their purification from harmful substances, and the preservation of the biological value of the final product. From the raw, vitamin-rich liver fat of the past, humanity has moved on to the production of safe and standardized concentrates that meet the strict requirements of modern medicine and dietetics.
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