Models for starch

Ziegler, G. R., Creek, J. A., and Runt, J. (2005). Spherulitic crystallization in starch as a model for starch granule initiation. Biomacromolecules 6,1547-1554. 

Kokini, J.L., Baumann, G.C., Bresslauer, K., Chedid, L.L., Herh, P., Lai, L.S. A kinetic model for starch gelatinization and effect of starch/protein interactions on rheological properties of 98 % amylopectin and amylose rich starches. In Spiess, W.E.L., Schubert, H. (eds.) Engineering and Foods, Advanced Process, pp. 109-121. Elsevier/Applied Science Publishers, New York (1990)... 

Kinetic Model for Starch Digestion and Product Release. Before the comprehensive mathematical model could be constructed, some assumptions were made from prior research on polymer degradation (10) (a) the diffusion of both the enzyme and the products in the plastic matrix obeyed Pick s first law, (b) the... 

In this paper the behavior of oligosaccharides corresponding to models for starch hydrolysis or amylolysis products was discussed. The role of the chemical structure on the elution volume was pointed out in relation to the nature of the glycosidic linkage. Combination with optical rotation improves the quality of analysis. The behavior of cyclic and branched oligomers was also discussed. 

Waigh TA, Kato KL, Donald AM, Gidley MJ, Clarke CJ, Riekel C, (2000) Side-chain liquid-crystalline model for starch , Stareh/Starke, v52 nl2 450-460. 

Morris, V. J., Gunning, A. P., Faulds, C. B., Williamson, G., and Svensson, B. (2005). AFM images of complexes between amylose and Aspergillus niger glucoamylase mutants, native, and mutant starch binding domains A model for the action of glucoamylase. Starch-Starke 57,1-7. 

Erlander, S. R. (1998b). Starch biosynthesis. II. The statistical model for amylopectin and its precursor plant glycogen. Starch/Stdrke. 50, 275-285. 

In this plant, where would you expect to find (a) PEP carboxylase, (b) rubisco, and (c) starch granules Explain your answers with a model for C02 fixation in these C4 cells. 

The investigations carried out by Professor French and his students were based on sound experimental approaches and on intuitive theoretical considerations. The latter often resulted in new experiments for testing a hypothesis. On the basis of theoretical considerations, Professor French proposed a model for the structure of the amylopectin molecule, and the distribution of the linear chains in this molecule. This model was tested by utilizing enzymes that selectively cleave the linear chains, and the results substantiated the theoretical deductions. He proposed a theory on the nature and types of reactions occurring in the formation of the enzyme - starch complex during the hydrolysis of starch by amylases. In this theory, the idea of multiple attack per single encounter of enzyme with substrate was advanced. The theory has been supported by results from several types of experiments on the hydrolysis of starch with human salivary and porcine pancreatic amylases. The rates of formation of products, and the nature of the products of the action of amylase on starch, were determined at reaction conditions of unfavorable pH, elevated temperatures, and increased viscosity. The nature of the products was found to be dramatically affected by the conditions utilized for the enzymic hydrolysis, and could be accounted for by the theory of the multiple attack per single encounter of substrate and enzyme. 

Studies by French and associates on the structure of starch by X-ray crystallography, and, more recently, on the structure of the starch granule by electron microscopy, have resulted in the proposal of new models for the structure of starch and of starch granules. The X-ray studies... 

A typical profile for starch hydrolysis using soluble amylase is shown in Fig. 1. The profile predicted by the kinetics model is also shown. Clearly, the model describes the experimental concentration profiles very well. The model curves also show the insensitivity of the model fit to Km there is very little difference in the quality of the model predictions with Km = 5 g/L and Km = 50 g/L. Similarly, a typical profile for starch hydrolysis using immobilized amylase is shown in Fig. 2. The model also predicts these data very well, with little sensitivity to the Km value. 

Figure 5.16 Schematic model for the arrangement of amylopectin in potato starch. Crystalline layers containing double helical linear segments in amylopectin molecules form a continuous network consisting of left-handed helices packed in tetragonal arrays. Neighboring molecules are shifted relative to each other by half the helical pitch. (Adapted with permission from reference 3)...

The weaving of the yarn was conducted on a Draper model X P loom operating at 160 picks per minute. A 115 g/ni (3.4 oz/ydZ) printdoth fabric was produced with approximately 68 ends by 70 picks. The statistical data accumulated during the weaving opera-ation of the three types of yarn treatments are presented In Table VI. The average number of breaks per hour In warp yarn for starch, fermented starch, and enzyme-degraded starch was 1.62, 1.37, and 1.45, respectively. 

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