Effects of dietary n-3 polyunsaturated fatty acids and ... - FINS

1 st WorkshopXIII International Feed Technology SymposiumMATERIAL AND METHODSExtrusion of soy – dry processExtrusion of soya was carried out using extruder type M2, model 1000 “Opremazootehnička oprema” Ludbreg, Croatia. Soya was firstly dried in a dryer to a moisturelevel of 10% and then cleaned from impurities in silos. Extruder had a nominal capacityof 1000 kg/h, with installed 77 kW electromotor and a screw feeder which had a 1.5 kWelectromotor. Extruder structure is made up of four barrel segments and four screwsegments with different pitch length. Extruder screw segments are hauled onto extruderaxle and the steam lockers are placed in between segments in order to regulate thepressure in extruder. Used steam lockers were 5 3/2”, 5 3/2”, 5 ½” and 5 ½”. Theextruder head with a nozzle is placed at the very end of the screw. The first segment ofthe extruder contains a connector for water and technological steam.The process of extrusion begins by transporting soya using a screw carrier which bringsit from floor storage room into the extruder basket. The basket contains an indicator ofthe upper level, which deactivates the screw carrier when the basket becomes full. Whenthe bean becomes empty, it it activated again and it automatically doses the soy into thebasket above the extruder. Permanent magnet is located in the basket in order to preventiron that has “strayed” from reaching the extruder. From the bean, by use of the screwfeeder, soya gets into the first segment of extruder head and the extrusion process begins.Soya passes between the barrel and the screw and, by action of flight, steam lockers andrings, gets through a 1-1.5 mm gap, which results in high pressure and temperature,which at the exit from the extruder (extruder head where the nozzle is located) rangesbetween 120-130 o C . Extruded soya enters a vibration cooler where vibrations enable itsmovement on coller trays towards the top, and intense airflow produced by a ventilatorallows for the extruded mass to cool off. Exdrudate goes into the basket, located abovethe transport screw, which carries cooled extruded soya into bulk cells. From the silo, theextruded full fat soya is transported by screw conveyers to a scale where the bagging isdone.Hydro-thermal treatment of soyabeanHydro-thermal treatment of soyabean is performed in a special reactor (device) wheresoya is exposed to water steam under specific pressure (6-8 bars), within a particulartime period (7-15 min), after which the material expands rapidly.Soybean is transported to the surge bean with a volume of 5 t. It is transported from thebean by screw conveyer to a bulk elevator and further to the receiving bean, where theraw material is stored temporarily. Soya is then evenly fed into the feeding bean usingthe slide gate and from the bean gets into a reactor, in which the hydro-thermal treatmentis taking place by steam action during a specific time period. Upon the completion of thecycle, the slide gate opens and the finished product is transferred from the reactor into adryer – cooler.The start of the next cycle can take place after the slide gate has been closed. Intensivedrying-cooling of processed soybeans is performed using airflow supplied through achannel and a collector by using ventilators. Processed material is placed into a transportvehicle by screw carrier. Water steam which is vital for thermal treatment of rawsoybeans is transported from the boiler to the reactor. Operational mode is maintained237