58-7 |
Transport characteristics of single - screw extrusion cooking process |
L. WANG1, G. M. Ganjyal, C. L. Weller, D. D. Jones4, and M. A. Hanna5. (1) Department of Biological Systems Engineering, University of Nebraska, Lincoln, L. W. Chase Hall, Lincoln, NE 68583, (2) Dept. of Biological Systems Engineering, Univ. of Nebraska, Lincoln, L.W. Chase Hall, PO Box 830726, Lincoln, NE 68583-0726, (3) Industrial Agricultural Products Center, Univ. of Nebraska, Lincoln, 211 L.W. Chase Hall, Lincoln, NE 68583-0730 The food extrusion has been tailored as one of emerging technologies for improved quality and nutritional value of food supply. The single screw extruder, which has a simple geometry, is one of popular extruders used in the food industry. The interaction of raw ingredients, product and equipment is very important to design an extruder and apply the extrusion technology for producing value-added products. However, the process of extrusion cooking is not well understood due to the complex transport characteristics, chemical and physical changes in the materials. A mathematical model is thus developed to analyze the transport characteristics during the single-screw extrusion cooking process. The transport phenomena through the channel of the screw and the die are modeled, respectively. Two flows are coupled with the same pressure and mass flow rate at the entrance of the die. The variations in thermal properties of raw ingredients such as density, thermal conductivity, and specific heat are included in the model. The model is solved by a finite element scheme and validated with experimental data. The validated model is further used to carry out a sensitivity analysis for evaluating the effects of variations in operating parameters, design parameters and properties of raw materials on the throughout and quality of final products.
Session 58, Food Engineering: Transport processes and kinetics
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