Fishmeal and Fish Oil Production Process

The processing of raw materials for fishmeal and fish oil production basically follows a cycle of cooking, processing, extraction and drying. While producing fishmeal and fish oil, only steam is formed as a by-product. In fact, the product contains all the raw materials, but does not include most of the moisture in it. Processing follows strict quality management procedures to ensure that final product parameters meet confirmed nutrient and contaminant range requirements. This process is very technically demanding in order to preserve the nutrient content of the raw materials as much as possible and to ensure the successful transfer of these components to the final fishmeal and fish oil products.

Fresh fish is cooked at a temperature of 85°C to 90°C to coagulate the protein and release part of the oil. This process also inactivates the microorganisms. Clean transfer, storage devices, short storage times and reduced temperatures maximize the inactivation of microorganisms and avoid spoilage. At the same time, a relatively low temperature can inhibit the enzymatic action of the fish and prevent it from spoiling in another way. The cooked fish is then transferred to a screw press, where the juice is squeezed, the fish is pressed into fish cakes, and transferred to a dryer.

The squeezed juice goes through a decanter to separate out the remaining solid matter, and then goes through a centrifuge to separate the oil and produce a thick fish juice. The fish juice is then evaporated and concentrated. The concentrated viscous fish juice is then mixed with the fish cakes in the dryer. A typical dryer contains coils from which hot steam enters the dryer. These coils can control the temperature up to 90°C (the steam temperature is controlled by its flow rate), so that the moisture content of the dried fish cake is only about 10%. Low-temperature dryers, such as indirect steam dryers or vacuum dryers, operate at a lower temperature.

The fish oil will go through purification and other steps to separate out more solid impurities, and use a special filter to remove the oil-soluble impurities in the fish oil. Other, more elaborate processing procedures result in clear, odor-free fish oil for pharmaceutical or nutritional use, such as fish oil capsules.