INFLUENCE OF SOME FACTORS ON THE PROCESS OF EXTRUSION DURING THE PRODUCTION OF FISH FEED

Abstract

Studies were conducted in the production of food for demersal fish /carp/ by extrusion. Featured are three different regimes for moisture content of the feeding mixture - 25%, 28% and 30%, which is extruded with a twin-screw extruder. The influence of temperature was examined in the range 80 : 100 0C at constant load on the main engine of the extruder of 190 to 200 A. The capacity of the facility, working within the selected parameters, is determined.
Defined are the density of the produced extrudates and the index of expansion. Experiment results show that at a certain temperature range increasing the moisture content of the mixture leads to increased density of extrudates and reduced index of expansion. Generally the heating temperature of the feed affects the quality characteristics - increasing the index of expansion and reducing extrudates' density at same moisture rate. Observations were conducted on the water resistance of the food. The produced extrudates retain their shape within four hours, then after a stay in aquatic environment for more than eight hours they are destroyed to smaller pieces. Given the selected formulation and conditions of the experiment it can be said that the achieved water resistance of the feed for carp is good.