Inclusion complex with amylose

This is a phosphorylase-catalyzed enzymatic pol5rmerization of an a-D-glucose-l-phosphate from a maltoheptose in the presence of polycarbonates. Polycarbonates with a shorter methylene chain length such as poly(tetramethylene carbonate) is more favorable as the guest polymer to form the inclusion complex with amylose. 

Molecular Interactions. Various polysaccharides readily associate with other substances, including bile acids and cholesterol, proteins, small organic molecules, inorganic salts, and ions. Anionic polysaccharides form salts and chelate complexes with cations some neutral polysaccharides form complexes with inorganic salts and some interactions are stmcture specific. Starch amylose and the linear branches of amylopectin form inclusion complexes with several classes of polar molecules, including fatty acids, glycerides, alcohols, esters, ketones, and iodine/iodide. The absorbed molecule occupies the cavity of the amylose helix, which has the capacity to expand somewhat to accommodate larger molecules. The starch—Hpid complex is important in food systems. Whether similar inclusion complexes can form with any of the dietary fiber components is not known. 

To determine the amylose content of starch, the iodine reaction has been most commonly used because amylose and amylopectin have different abilities to bind iodine. The methods such as blue value (absorbance at 680 nm for starch-iodine complex using amylose and amylopectin standards), and potentiometric and amperometric titration have been used for more than 50 years. These procedures are based on the capacity of amylose to form helical inclusion complexes with iodine, which display a blue color characterized by a maximum absorption wavelength (kmax) above 620 nm. During the titration of starch with iodine solution, the amount (mg) of iodine bound to 100 mg of starch is determined. The value is defined as iodine-binding capacity or iodine affinity (lA). The amylose content is based on the iodine affinity of starch vs. purified linear fraction from the standard 100 mg pure linear amylose fraction has an iodine affinity of 19.5-21.0mg depending on amylose source. Amylopectin binds 0-1.2mg iodine per 100mg (Banks and Greenwood, 1975). The amylose content determined by potentiometric titration is considered an absolute amylose content if the sample is defatted before analysis. 

Inclusion complexes of amylose are rather well defined, and a consistent theory of such complexes is available that explains amylose complexes with iodine, fatty acids, alcohols, and other guest molecules.4,5 This subject is surveyed in this article because of the growing interest and importance of such complexes in pharmacology and in the food industry. It is probable that starch in its biological sources (tubers, granules) exists in the form of native complexes with proteins, lipids, mineral salts, and water. 

As with iodine, starch forms an inclusion complex with bromine vapor.205 Depending on the starch variety, different colors are developed by the complex. Maize and wheat produce an ochre color, rice produces a light-buff color, potato and sago develop a pale-yellow color, and cassava forms a cream color.69 Iodine cyanide (and bromine)-amylose complexes are brown-black and dark brown, respectively.206 The adsorption of chlorine and iodine proceeds according to the Freundlich isotherm. A discontinuity on the Freundlich isotherm plot is reported, which possibly results from the swelling of starch granules454... 

Starch in plants is accompanied by water, metal ions, lipids, proteins, sterols (such as saponins), and alkaloids (as in such exotic plants as Diascoracea).649 Several of these components can be washed out by the isolation of starch, some of them are extractable with organic solvents, and some are volatized by steam treatment. With the exception of metal ions (preceding article, p. 263), the foregoing components form physical mixtures with starch and do not chemically bond with either amylose or amylopectin. Therefore, one may assume that amylose and amylopectin form inclusion complexes with organic components that are similar to those mentioned in the preceding article. 

In subsequent years, Wulff and Kubik carried out a more elaborate study in this direction. They prepared inclusion complexes of amylose with different substrates [33]. Intra- and intermolecular cross-linking of these complexes was carried out using both cyanuric chloride and epichlorohydrin as the cross-linking agents. These... 

P-Cyclodextrin Based on 7 glucopyranose units the a-form has only 6 units Amylose derived, cyclic heptasaccharide, capable of forming inclusion complexes of drugs Inclusion complexes with drugs to mask odor to taste... 

A separate problem is presented by starch that contains fatty acids (lipids) for instance, maize, rice, and wheat starch. The naturally occurring lipids form inclusion complexes vnth amylose that exhibit texture and morphology different from those of native starch granules. These differences are reflected by the behavior of starch at a relatively low temperature for instance, gelatinization at — 120 °. The process involved is a high-temperature retrogradation, with participation of the proton dissociated from the com-plexed fatty acid residue. A Cjj acid complexed in the helical structure of... 

The iodine-binding capacity of starch is dependent on the degree of polymerization (DP). Amylose forms with iodine a helical inclusion complex with an intense blue colour, which possesses an absorption maximum at wavelengths between 620 and 680 nm. Amylopectin has much less iodine-binding capacity because of its branched character, leading to a red-violet colour with absorption maximum of 540 nm 31. 

Formation of insoluble inclusion compounds with amylose-the water soluble part of starches-is another important application area for monoglycerides, especially saturated distilled monoglycerides (Krog, 1981). By complexing the amylose, monoglycerides improve texture of starch-based foods such as processed potato products, macaroni, noodles and other pasta foods. 

Karkalas J., Ma S., Morrison W.R., Pethrick R.A., Some factors determining the thermal properties of amylose inclusion complexes with fatty acids, Carbohydr. Res., 268, 1995, 233-247. 

Closely related to the helical amyloses are the cycloamyloses which are produced by enzymatic degradation of amylose by glucosyl transferase enzymes. Cycloamyloses, better known as cyclodex-trins (Table 10.5), have been characterised with 6,7,8 and 9 glucose units (a,p,Y,8, varieties). The p form (10.28a) is the most studied and most used to date. Like the helical amyloses, the toroidalshaped cyclodextrins can form inclusion complexes with various molecules. These are usually formed by adding guest molecules to saturated solutions of the latter. 

It has been shown that amylose forms inclusion complexes with iodine and many kinds of organic compounds in aqueous solution. Thus, the most probable model for the interaction of aunylose with TNS is an inclusion complex. Since cyclodextrins form inclusion complexes with TNS and enhance TNS fluorescence in aqueous solution ( ), it is interesting to compare fluorescence decay parameters for TNS-atmylose system with those for TNS-cyclodextrin systems. The values of lifetimes for amylose are the same as those for Y-cyclodextrin. However, the relative content of the long lifetime for amylose is much smaller than that for Y-cyclodextrin.Y -Cyclodextrin is expected to form both 1 1... 

Measurement of inclusion complex with P-cy-clodextrin and amylose... 

In this chapter, an overview of hierarchically fabrication of eco-friendly supramolecular nanocomposites by means of inclusion complexation by amylose in the vine-twining polymerization was presented. The method was achieved by the phosphorylase-catalyzed enzymatic polymerization in the presence of the designed graft copolymers with guest polymeric chains. Inclusion complexation of amylose chains with guest chains in the intermolecular graft copolymers took place with the progress of the polymerization to construct the supramolecular nanocomposite... 

The interactions of cyclohexa- and cyclohepta-amyloses with non-steroidal anti-inflammatory drugs, particularly the effects of inclusion on the solubility and stability of the drugs in water, have been studied. The formation of inclusion complexes with cyclohepta-amylose increased the solubility of a number of the drugs in water and also accelerated the degradation of agar-propazone in water. These inclusion complexes can also be obtained in powdered form by freeze-drying and coprecipitation methods. ... 

The chromatogram zones colored by iodine can be fixed later by treatment with a 0.5-1 Vo aqueous starch (amylose) solution. This yields the well known, deep blue iodine-starch inclusion complex which is stable over a prolonged period. This reaction... 

An aqueous 1 % starch (amylose) spray can be sprayed on later to intensify the color contrast between the chromatogram zones and the layer background the well known blue-colored iodine starch inclusion complexes are formed. This later treatment with starch solution should only be carried out when the iodine excess has evaporated from the layer background so that only traces of iodine remain in the chromatogram zones. Otherwise the whole chromatogram will be colored dark blue (test at a corner of the chromatogram ). 

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