| 摘要 |
PURPOSE: A method of preparing high protein, high fat sinking aquatic feed products useful in aquatic farming operations for efficient growth of fish is provided, which is characterized in that a proteinaceous starting mixture is preconditioned and extruded with a zone of reduced pressure along the length of the extruder barrel for densification of the final extrudate. CONSTITUTION: A method of preparing a high protein, high fat sinking aquatic feed comprising the steps of: providing a starting mixture including from about 15-55% by weight protein and at least about 1% by weight starch, said starch being present as a separated free component; preconditioning said starting mixture by adding moisture thereto and subject the starting mixture to conditions of heat and agitation; and passing the preconditioned starting mixture into and through an extruder having an elongated barrel with an elongated, axially rotatable, flighted screw therein and an endmost extrusion die to form a self-sustaining extrudate having a specific gravity of greater than 1, said passing step including the steps of creating a condition of reduced pressure at a zone along the length of and within said barrel upstream of said die for densifying the preconditioned starting mixture within said barrel, said method further including the step of adding fat to said starting mixture and/or extrudate so that the extrudate has a total fat content of from about 10-40% by weight. |
