Dextrin conformation

It is noteworthy that most of the chemical shift values for all three polymers may be closely approximated ( ) by calculations based on data for monomeric reference compounds. These findings illustrate, therefore, the general validity of studies on low molecular weight model compounds for einalysis of spectra of carbohydrate polymers. Many examples of equally satisfactory comparisons of this kind are to be found in studies on other polysaccharides (11,23). These polymers include glucans (l6), mannans (2k, 2 ), limit dextrins (26), lichenin (2j), agarose (28) and various polysaccharides of fungal and microbial orgins (e.g., 7,8,29-31). Observed departures from expectation have been attributed to specific conformational influences ( 8). 

Concentration has a role in conformation dextrins are random coils in dilute dispersions and compact coils in less dilute dispersions (McCurdy et al., 1994). 

Bellanger, N., and Perly, B. (1992), NMR investigations of the conformation of new cyclo-dextrins-based amphiphilic transporters for hydrophobic drugs Molecular lollipops, /. Mol. Struct., 15, 215-226. 

Dextrin.—Dextrin is a carbohydrate made from starch (chiefly from corn or potato starch) by the application of heat (yellow dextrin) or by treatment with both heat and acids (white dextrin). It forms a paste with water, the yellow variety tending to swell up and dissolve much more readily than the white. When examined microscopically in alcohol mounts, the grains, while conforming in general outline to those of the type of starch from which the dextrin was prepared, nevertheless show more conspicuous striations and clefts.. Corn dextrin shows distinct striations, whereas striations Digitized by Microsoft ... 

Fig. 11.—Model of a-dextrin from top. The D-gliicose residues are in the Cl conformation. The background is ruled at 5 cm. intervals, corresponding to 5.5 A. in the models.

Inoue Y, Kuad P, Okumura Y, Takashima Y, Yamaguchi H, Harada A. 2007. Thermal and photochemical switching of conformation of poly(ethylene glycol) substituted cyclo dextrin with an azobenzene group at the chain end. J Am Chem Soc 129(20) 6396 6397. 

The FTIR absorbance spectra of pullulan can be seen in Figure 31.15, being similar, mostly, to dextrin. Information on the glucopyranosyl units conformation in the polysaccharide can be acquired in the fingerprint region located between 1250 and 800 cm". ... 

This article reviews physical and physico - chemical studies on linear ma1to - dextrins. The various crystalline forms of the dextrins are described and the melting and glass transition behavior discussed. Solution conformations and the viscous behavior of dilute and concentrated aqueous solutions are considered. In addition factors affecting the Interaction of small solutes with the dextrins In aqueous solution are discussed and compared with the known behavior of cyclodextrins. 

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