Most of the processing of fish meal is completed by boiling, pressing, drying, grinding and packaging. The principle of fish meal processing is relatively simple, but the quality of fish meal produced is very different because of the different freshness of raw materials, processing technology and equipment and processing experience. After the fish is cooked, the protein is coagulated, and a large amount of water and oil run out. The cooked fish is sent to a perforated pipe for extrusion, and the fish juice mixed with oil and water will be extruded, leaving the caked fish out of the back of the compressor. The fish juice mixed with oil and water is separated by oil and water to produce fish oil and fish water. Fish water will be returned to the machine through the pipeline and added to the caked fish, but it will be dried to make whole fish meal. Fish meal drying can be divided into two ways: direct fire drying and indirect drying. Direct fire drying has a great influence on the quality of fish meal, so steam indirect or low temperature vacuum drying is used now. Finally, the dried big fish bones are ground into powder, and fish meal is added for packaging.

2. Low temperature steam drying

Three strict requirements for high-quality fish meal processing: fish freshness, rapid low-temperature drying and cooling before packaging.

Freshness of fish: The fishing fleet has a modern cooling system to ensure the freshness of fish. Can use huge and advanced production equipment in the shortest time,

Can quickly and massively make fish into fish meal.

Rapid low-temperature drying process (two-stage drying method): The first stage is steam drying. Because the steam system operates at low pressure, its operating temperature is 30 degrees Celsius lower than that of the so-called dish dryer, which effectively maintains the high digestibility of fish meal. In the second stage, the indirect hot air drying system is used to make the quality of fish meal ahead of other fish meal factories.

Protein's amino acid structure will change at high temperature. In practical application, the digestibility of fish meal will be reduced. In the traditional process, at the last step of drying, there is not enough humidity to protect protein.

Therefore, heating will cause the temperature to continue to rise, and protein will be damaged by coking. To avoid damage to protein,

In the production process, the two-stage indirect hot air drying method is used instead of the general traditional direct fire drying system. This is the key point to maintain high digestibility of fish meal. It has been proved in the feeding of poultry, salmon, mink and shrimp that using the same fresh raw materials can increase the digestibility of fish meal in vivo by 2% compared with that produced by the general traditional steam drying system.