The production of fish meal is generally completed through several key processes, including cooking, pressing, drying, grinding, and storage. While the basic processing principle is relatively straightforward, variations in raw material freshness, processing technology, equipment, and operational experience can result in significant differences in the final product quality.
1. After cooking, the fish protein coagulates, allowing a large amount of water and oil to be released.
2. The cooked fish is then conveyed into a perforated pressing chamber, where it is mechanically compressed. The liquid mixture of oil and water (fish liquor) is extracted, while the solid press cake is discharged from the outlet. The extracted fish liquor is further separated into fish oil and stickwater through an oil-water separation process.
3. The stickwater is recycled back into the system and mixed with the press cake before entering the drying stage to produce whole fish meal. There are two main drying methods: direct drying and indirect drying. Direct drying can significantly affect product quality, so modern systems increasingly adopt steam-based indirect drying or low-temperature vacuum drying to ensure better quality.
4. Finally, larger fish bones are finely ground into powder and blended with the fish meal before packaging and storage.
