Low-fat protein hydrolyzate from fish is one of the most promising products for the future. Markets include aquacultures and businesses which fatten veal or rear pigs and poultry; the latter use it as a high-quality feed. In these sectors, the product can replace other feeds because it is easier to digest, making the animals gain weight faster.
Having a high water solubility, it can also be used as a liquid fertilizer in agriculture. Protein hydrolyzate is also a very promising food additive for human nutrition. The product obtained is characterized by its extremely low fat content of less than one percent.
The process begins with enzyme treatment of the minced material in a reaction tank at a temperature of about 50 °C with a dwell time of one hour. The enzyme process modifies the proteins by separating the protein molecules, which consist of long chains, into smaller components. This also changes the properties of the proteins, insoluble proteins become water-soluble, and it also increases biological usability. Moreover, targeted selection of enzymes and process conditions allows properties such as taste and consistency to be precisely defined.
The fish waste treated by enzymes is subsequently moved to the 3-phase decanter which separates the suspension into an oil phase, insoluble solids and the main phase with the water-soluble proteins. The oil phase and the protein-containing phase are subsequently polished in separators. A high-speed separator with a very large clarifying surface area is used to polish the protein-containing phase. On the one hand, this allows the solubility of the proteins to be increased by removing dispersed proteins, whilst on the other, it also separates even the finest fat droplets and thus obtains a protein hydrolyzate with less than one percent fat in dry mass.