By thermal processing, the fish based raw material is separated into a water-phase (stickwater). and solid phase (press cake), illustrated in Figure 1.4.1. Briefly, the raw material is heated to T > 80 ℃ to coagulate proteins, inactivate microorganisms, disrupt fat deposits and release oil and water. After the heat treatment, the material is mechanically pressed to squeeze out oil and water from the coagulated material, the press cake. The press cake is rich in non-water-soluble proteins, bones and minerals. The press cake is dried and ground to desired particle size to produce a protein rich powder. The liquid phase is separated into water and oil phases, where the water phase, the stickwater, contains proteins, amino acids other water-soluble compounds present in the raw material. To read more about the fish meal process, see more.
