engleski

Properties of extrudates produced from semolina

The aim of this research was to determine properties of extrudates produced from semolina with moisture set to 15% and 20%. Semolina was extruded in extruder Do-Coder, Brabender 19/20 DN ; GmbH, Duisburg, Germany at temperature profile 135/170 °C, with screw 4:1 and 4 mm die, and extrudate diameter, expansion ratio, texture and viscosity were determined. The obtained results showed that extrudate diameter and expansion increased proportionally to semolina moisture, as well as hardness of extrudates, whereas fracturability wasn’t influenced by moisture content. Water absorption index of semolina increased after extrusion proportionally to moisture content of raw semolina. In addition, extrusion resulted in increase of peak viscosity and breakdown, with more pronounced effect on semolina with 20% moisture. Raw semolina was most stable during shearing at high temperatures expressed as breakdown value, whereas samples extruded at 20% moisture were least prone to retrogradation, which was expressed as “setback”.

wheat ; semolina ; extrusion ; viscosity ; texture

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