By using a systems analytical model (SAM) and a fuzzy logic control software (fuzzy CIM) extrusion experiments were designed, that enabled a differentiation of the influence of the thermal energy input, expressed by the product temperature (PT), and the influence of the specific mechanical energy input (SME) on the molecular structure of extruded starch. The chromatographic examination of the molecular changes in the starch clearly revealed the influence of the extrusion cooking conditions on molecular degradation.The molecular size of extruded starch, expressed as the weight average of the molecular weight (M __ w ), decreased exponentially when SME increased. In the range of 110-180 °C, PT had no significant influence on M __ w so that the observed reduction of M __ w was primarily dependent on the increase in SME. By contrast, the polydispersity depended both on PT and SME. The influence of PT on the polydispersity was of minor significance up to 160 °C, increasing more steeply at higher temperatures. PT increase above 180 °C resulted in increasing reducing power of the extruded starch, whereas SME had almost no effect on reducing power. Only at a PT of more than 180 °C small amounts of short chain molecules with a degree of polymerisation (DP) smaller than 6 could be determined.

Research Paper__ w than at lower ones. Cold water solubility (CWS) of extrudates was dependent both on M __ w and PT. This dependency was similar to that of the CPV. The sediment volume depended on M __ w , PT and water content of the material on extrusion of the starch.

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Es wurden Extrusionsversuche zur Herstellung von kationischer Kartoffelstarke unter Verwendung von Kartoffelstarke, Natronlauge und 3-Chlor-2-hydroxypropyltrimethylammoniumchlorid (Chlorhydrin) mit dem Ziel durchgefuhrt, den EinfluR der Extrusionsparameter auf die Reaktionseffizienz (R.E.) und den von ihr abhangigen Substitutionsgrad (D.S.) untersuchen zu konnen. Die Extrudate wurden dazu benutzt, um eine geeignete Analysenmethode zur genauen Bestimmung des D.S. zu entwickeln. Damit die notwendige analytische Genauigkeit erreicht werden kann, mussen alle stickstoffhaltigen Substanzen, die nicht chemisch an die Molekiile der Starke gebunden sind, vor der Bestimmung des Stickstoffgehalts der kationischen Starke quantitativ aus dieser extrahiert werden. Es konnte mit Extraktionsexperimenten gezeigt werden, daR die Extrahierbarkeit solcher Substanzen aus gemahlenen kationischen Kartoffelstarkeextrudaten von der Penetration des Losungsmittels durch die Extrudatpartikel und der Diffusion der loslichen Substanzen in den Partikeln in das Losungsmittel abhangt. Optimale Ergebnisse wurden fur die R.E. durch Suspendieren von einem Teil gemahlenem kationischem Kartoffelstarkeextrudat in zehn Teilen Losungsmittel erzielt, das aus 80% Ethanol und 20% Wasser (w/w) bestand. Die Suspension mu5te 40min bei 80°C in einem verschlossenen GlasgefaR belassen werden. In dem fur die Extrusion gewahlten experimentellen Bereich konnten konstante Reaktionsbedingungen fur die Kationisierung eingehalten werden. Neben der Variation der Formulierung der reaktiven Komponenten wurde ihr D.S. von der Variation der Extrusionsparameter beeinflufit. In dem fur den D.S. untersuchten Bereich von 0,03 bis 0,lO wurde eine R.E. von 80% erzielt. Chemical und Processing Aspects of the Production of CationicStarch Using Extrusion Cooking. Cationic potato starches were produced by carrying out the chemical reaction under varying extrusion cooking conditions in order to investigate the influence of the extrusion parameters on the reaction efficiency (R.E.) and the degree of substitution (D.S.) dependent on this. The extrudates were used to develop a suitable analytical method for an accurate determination of the D.S. To achieve the necessary analytical accuracy all nitrogen containing substances not chemically bound to the molecules of the starch must quantitatively be extracted from the cationic starch prior to the determination of its nitrogen content. It could be shown by extraction experiments that the extractability of such substances from ground cationic potato starch extrudates is dependent on the penetration of the solvent through the extrudate particles and the diffusion of the soluble substances in the particles into the solvent. Optimal results for the R.E. were achieved by suspending one part ground cationic potato starch extrudate in ten parts solvent consisting of 80% Ethanol and 20% water (wlw). The suspension had to be kept in a sealed glass vessel for 40min at a temperature of 80°C. Within the experimental range of the extrusion experiments th...