563 research outputs found

    Expansion of the whole wheat flour extrusion

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    A new model framework is proposed to describe the expansion of extrudates with extruder operating conditions based on dimensional analysis principle. The Buckingham pi dimensional analysis method is applied to form the basic structure of the model from extrusion process operational parameters. Using the Central Composite Design (CCD) method, whole wheat flour was processed in a twin-screw extruder with 16 trials. The proposed model can well correlate the expansion of the 16 trials using 3 regression parameters. The average deviation of the correlation is 5.9%

    Modelling extrudate expansion in a twin-screw food extrusion cooking process through dimensional analysis methodology

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    A new phenomenological modelling framework is proposed to correlate the extrudate expansion and extrusion process parameters through dimensional analysis methodology. As dimensional analysis is independent of system or equipment structure, the proposed equation may provide a general expression for the extrudate expansion behaviours and process operation conditions. This work includes extrusion cooking trials, model development and data analysis

    A new engineering method for understanding extrusion cooking process

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    A new engineering method is proposed to understand extrudate expansion and extrusion operation parameters for starch based food extrusion cooking process through dimensional analysis principle, i.e. Buckingham pi theorem. Three dimensionless groups, i.e. pump efficiency, water content and temperature, are suggested to describe the extrudate expansion. Using the three dimensionless groups, an equation is derived to express the extrudate expansion. The model has been used to correlate the experimental data for whole wheat flour and fish feed extrusion cooking. The average deviations of the correlation are respectively 5.9% and 9% for the whole wheat flour and the fish feed extrusion. An alternative 4-coefficient equation is also suggested from the 3 dimensionless groups. The average deviations of the alternative equation are respectively 5.8% and 2.5% in correlation with the same set of experimental data

    A general extrudate bulk density model for both twin-screw and single-screw extruder extrusion cooking processes

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    Effects of extrusion parameters and raw materials on extrudate expansion are respectively investigated in a twin-screw extruder and a single-screw extruder extrusion cooking experiments for fish feed, wheat, and oat & wheat mixture processing. A new phenomenological model is proposed to correlated extrudate bulk density, extrusion parameters and raw material changes based on the experimental results. The average absolute deviation (AAD) of the correlation is 2.2% for fish feed extrusion in the twin-screw extrusion process. For the single-screw extrusion process, the correlation AAD is respectively 3.03%, 5.14% for wheat and oat & wheat mixture extrusion; and the correlation AAD is 6.6% for raw material change effects. The correlation results demonstrate that the proposed equation can be used to calculate extrudate bulk density for both the twin-screw extruder and the single-screw extruder extrusion cooking processes
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