1. Normal direct heating drying
Most of the processing of fish meal is done through several processing steps of boiling, pressing, drying, grinding and packaging. The principle of fish meal processing is relatively simple, but the quality of the fish meal produced varies greatly due to the different freshness of the raw materials and the different processing techniques and processing experience. After the fish is boiled, the protein is coagulated, a large amount of water and oil are ran out, and the cooked fish is sent to a perforated pipe, and the mixed oil and water fish liquid will be squeezed out to leave agglomerates. Fish comes out from the back of the compressor. The fish liquid mixed with oil and water is separated by oil and water to produce fish oil and fish water. The fish water will be added to the agglomerated fish by pipe back to the machine and dried to make whole fish meal. Fish meal drying is divided into two modes: direct heating drying and indirect drying. Direct heating drying has a great influence on the quality of fish meal. It is now changed to steam indirect or low temperature vacuum drying. Finally, the dried fish bones are ground into powder and added to the fish meal for packaging.
2. Low temperature steam drying
Three strict requirements for high quality fish meal processing: freshness of the fish, rapid low temperature drying, and cooling before packaging.
Freshness of the fish: The fishing fleet has a modern cooling system that ensures the freshness of the fish. In a short period of time, using huge and progressive production equipment, fish can be made into fish meal quickly and in large quantities.
Rapid low-temperature drying process (two-stage drying process): The first stage is steam drying. Since the steam system operates at low pressure, its operating temperature is 30 degrees Celsius lower than the so-called dish dryer. Effectively maintain high digestibility of fish meal. The second stage uses an indirect hot air drying system to make the quality of fish meal ahead of other fish meal factories.
When the protein is at a high temperature, its amino acid structure will be changed. In practical applications, its digestibility will be reduced for fish meal. In the traditional process, the final step of drying, and there is not enough humidity to protect the protein, so heating will cause the temperature to continue to rise, and the protein will be coked and damaged. In order to avoid protein damage, a two-stage indirect hot air drying process is used in the production process instead of the conventional conventional direct fire drying system. This is the key to maintaining high digestibility of fish meal. It has been proven in the breeding of poultry, carp, carp and shrimp, using the same fresh raw materials, which can increase the digestibility by 2% in the body than the fish meal produced by the conventional steam drying system.