EFFECT OF MACHINE AND PROCESS PARAMETERS ON THE PERFORMANCE OF A SINGLE SCREW FLOATING FISH FEED EXTRUDER

Abstract Development of fish feed technology in aquaculture sector is very low in Nigeria due to poor techniques involved in formulation and processing. This study examined the influence of machine and process parameters on the performance of a floating fish feed single screw extruder and a blend of feed mixture was used for the experiment. The influence of the experiment on the extrudate responses were studied using response surface methodology. Moisture contents wet basis of (20 %, 30 % and 40 %) and screw speed of (158.5 rpm, 245 rpm and 334 rpm) were used. Analysis of variance showed the effect of screw speed on expansion ratio, specific mechanical energy and machine efficiency to be significant and effect of moisture content on floatability, sinking velocity and expansion ratio to be significant. While floatability increased with increased screw speed and increased moisture content and sinking velocity decreased with increased screw speed and increased with increased moisture content. Expansion ratio increased with increased screw speed and moisture content. Specific mechanical energy increased with increased screw speed and decreased with increased moisture content. The extruder efficiency decreased with increased speed and moisture content.