The dynamics of a twin screw food extrusion process, including product quality attributes (PQA), to change in feed rate, water rate, screw speed, and barrel temperature at zone 5 were defined. Two PQA variables clearly dominated, colour-b and collet moisture content, which were highly correlated to bulk density. Product temperature at the die also showed high steady-state correla tion with bulk density. Moisture in the barrel was the primary driver for the colour-b and collet moisture content responses. Barrel temperature-5 was important in the response of product temper ature, but excessive delay times made it less important as a control variable. The gains indicated a non-linear system over the response range explored.
Chang Z. and Tan J. (1993a). Determination of model structure for twin-screw food extrusion. part I: multi-loop. Transactions of the Institute of Chemical Engineers71(C): 11-19.
2.
Chang Z. and Tan J. (1993b). Determination of model structure for twin-screw food extrusion. part II: multi-variable. Transactions of the Institute of Chemical Engineers71(C): 20-26.
3.
Costin M.H., Taylor P.A. and Wright J.D. (1982). A critical review of dynamic modeling and control of plasticating extruders. Polymers Engineering and Science22(7): 393-401
4.
Fletcher S.I., Prescott E.H., Richmond P. and Smith A.C. (1984). A study of the extrusion cooking of maize grits . In: Profitability of Food Processing, Institute of Chemical Engineers Symposium Series No. 84. New York, NY: Permagon Press. pp. 67-77.
5.
Fletcher S.I., Richmond P. and Smith A.C. (1985). An experimental study of twin-screw extrusion - cooking of maize grits. Journal of Food Engineering4: 291-312.
6.
Harper J.M. (1981). Extrusion of Foods, vols I and II. Boca Raton, FL: CRC Press.
7.
Kochhar A.K. and Parnaby J. (1977). Dynamical modeling and control of plastics extrusion processes. Automatica13: 177-183.
8.
Kochhar, A.K. and Parnaby J. (1978). Comparison of stochastic identification techniques for dynamic modeling of plastics extrusion processes. Proceedings of the Institute of Mechanical Engineers192: 299-309.
9.
Lu Q. (1992). Dynamic Modeling and Analysis of a Twin Screw Extruder. PhD Dissertation. University of Missouri, Columbia, MO.
10.
Moreira R., Srivastava A. and Gerrish J. (1990). Feedforward control model for a twin-screw food extruder. Food Control1(3): 179-184.
11.
Mulvaney S.J. and Hsieh F.H. (1988). Process control for extrusion processing. Cereal Foods World33(12): 971-976.
12.
Mulvaney S.J., Hsieh F.H., Onwulata C., Brent Jr. J. and Huff H.E. (1988). Computer control and modeling of an extruder: dynamics. ASAE Paper No. 88-6517. St. Joseph, MI: ASAE.
13.
Nejman N., Shakourzadeh K. and Bouvier J. (1992). State reproducibility and relative gain analysis in twin-screw extrusion cooking. In: Kokini J.L., Ho C. and Karwe M. (eds), Food Extrusion Science and Technology. New York: Marcel Dekker, Inc. pp. 519-526.
14.
Olkku J., Hassinen H., Antila, J. and Pohjanpalo H. (1980). Automation of HTST-extrusion cooker. In: Linko P., Malkki Y., Olkku J. and Larinkari J. (eds), Food Process Engineering. London : Applied Science Publishers, Ltd. pp. 777-790.
15.
Owusu-Ansah J., van de Voort F.R. and Stanley D.W. (1984). Textural and micro-structural changes in corn starch as a function of extrusion variables. Canadian Institute of Food Science and Technology Journal17(2): 65-70.
16.
Richburg, L. (1989). Modeling and control of a twin-screw extruder . Masters Thesis. Texas A & M University, College Station, TX, USA.
17.
Richburg L. and Whittaker A.D. (1988). Modeling and control of a twin screw extruder . ASAE Paper No. 88-6515. St. Joseph, MI: ASAE.
18.
Schonauer S.L. (1995). Product quality adaptive control system for a food extruder. PhD Dissertation. Agricultural Engineering. Texas A & M University. College Station, TX, USA.
19.
Seborg D.E., Edgar T.F. and Mellichamp D.A. (1989). Process Dynamics and Control. New York: John Wiley & Sons.
