Extrusion-Cooking of TPS

The stability over the course of the process was evaluated by Mitrus [1] on the basis of temperature changes recorded in each extruder section in the processing of all the applied materials with difierent process parameters. The stability of temperature behavior of a final product immediately after it had left the extruder die was also studied. Temperatures in the cylinder were measured by means of thermocouples fixed in each section and connected to meters installed in the extruder control board. The product temperature was recorded with a digital thermometer (CIE 370 type) equipped with an appropriate measuring lance. All the data were registered by PC. 

Thermoplastic Starch. Edited by Leon P.B.M. Janssen and Leszek Moscicki (g) 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-3252S-3 

During inveshgations in cases of material mixtures, material clogging in the extruder charging hopper and some difficulties with material deUvery by the screw were noted. For these reasons it was necessary to feed in material manually. The disturbances with uniform material feeding induced uncontrolled changes in the extrusion-cooking temperature, even by as much as 20 C. In cases of failure of 

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Despite the fact that TPS is considered a new material in technological terms, its basic features and processes are in fact the same as those relative to extrusion-cooking starch used in the food industry since the 1960s. This kind of processing is therefore briefly described briefly in the heading, given its importance in the development of TPS. 

Moscicki L, Mitrus M, Wojtowicz A, Oniszczuk T, Rejak A, Janssen L. Appbcation of extrusion-cooking for processing of thermoplastic starch (TPS). Food Res Int 2012 47 291-299. 

Mitrus y Moscicki (2014) showed, for example, that the appUcalion of extrusion-cooking technique to process starch-plasticizer mixtures can be one of the most economical and efficient ways to produce TPS loose-fill foams. Then extrusioncooking technique can be successfully employed for starch-based foams production. 

Thermoplastic starch extrusion-cooking is associated with a rather low energy input 0.07 kWh kg on average. The extruder power required for extrusioncooking of TPS depends on material composition an increase in the glycerol content in a mixture causes the process energy consumption to decrease. 

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