Maltodextrins molecules

Figure 7.13 Hydrophobic van der Waals interaction ofthe CH-ir bonds of a maltodextrin molecule sandwiched between two tryptophan indole rings. (Adapted from Otsuki etal.175)...

In contrast, amylopectin contains 1—>6 glycosidic branch points at regular intervals. These result in an open, treelike stracture. Amylopectin is more readily hydrolyzed by amylase, and this results in a mixture of small, branched maltodextrin molecules that are often referred to as limit dextrins. Limit dextrins are further hydrolyzed by maltase. 

Acids can also break the long chains into shorter molecules, much as heat does, to form polydextrins, maltodextrin, or dextrin. Enzymes are used to do the same thing. 

Cyclodextrins are formed in the degradation of starch and dextran by the action of cyclodextrin/glucanosyltran-sferases [EC 2.4.1.19]. These enzymes also catalyze so-called acceptor reactions in which the cyclodextrin ring is opened and an acceptor molecule (e.g., glucose) is added to the reducing end of the maltodextrin chain. 

An increasing concentration of anionic surfactant can strengthen the electrostatic repulsive forces between the maltodextrin associates, as modified by the addition of the negatively charged head-groups of the surfactant to the neutral molecules of polysaccharide. The consequence of this effect is a reduction in the extent of maltodextrin association. In combination with the other effects, this leads to parameter dependency with a local maximum and minimum below the cmc of the surfactant (see Figures 6.10a and 6.10b). 

Anokhina, M.S., Semenova, M.G., Belyakova, L.E., Polikarpov, Yu.N. (2007). The modification of the molecular and thermodynamic parameters of the low-DE potato maltodextrin in an aqueous medium through the interactions with anionic small-molecule surfactants. Food Hydrocolloids, 21, 693-703. 

Maltodextrins and corn syrup solids are most often defined by their dextrose equivalence (DE). DE is a measure of the degree of hydrolysis of the starch molecule which compares the reducing power of the sugar groups as compared to the reducing power of an equal weight of glucose present. 

This principle is applied for the potential development in the EPMEs and for obtaining the intensity of the current in amperometric immuno-sensors. For the enantioselective, potentiometric electrodes, it is necessary to find a molecule with a special architecture that can accommodate the enantiomer. In this regard, cyclodextrins and their derivatives, maltodextrins, antibiotics and fullerenes and their derivatives were proposed [17-52]. 

The maltose molecule is too small to be fitted conveniently into the molecular barrier hypothesis, but the receptor for this substance functions well with maltodextrins which do have higher molecular weights. The receptor is induced with maltose, a substrate which is doubtless commonly encountered in the diet of enteric bacteria. Biologically the receptor serves for transport of maltose and for chemotaxis to this substrate (72). The data presented in Table IV, especially that pertaining to the ferrichrome receptor, demonstrate convincingly that phage receptors were designed for nutritious substances. 

It is the amylose component of starch that gives the blue color when KI/I2 solution is added. To study the iodine-iodide color of amyloses of different d.p. values, maltodextrin-amylose molecules, with various avg. d.p. values from 6 to 568 were prepared by Bailey and Whelan [62], using phosphorylase, a-D-glucopyranosyl-1-phosphate, and maltohexaose. The colors of the various sized maltodextrins (1 mg) were observed when 10 1 (w/w) KI/I2 solution was added. The first color to be observed was faint red for avg. d.p. 12 a red-purple color was observed for avg. d.p. 31 a purple color was observed for avg. d.p. 40 and a blue color was observed for avg. d.p. 45. The increase in the blue value was linear as a function of avg. d.p. up to avg. d.p. 60 the absorbance at 645 nm then slowly increased and reached a maximum at avg. d.p. of 400. The intensity of the iodine/iodide color in the low molecular weight range was dependent on the concentration of the iodine. When the concentration of the iodine was increased 10-fold, the intensity was increased 50% [62]. 

A rather widespread family of proteins, found in the periplasmic space of gramnegative bacteria, complexes certain small molecules and allows them to be transported through the cell wall or activate chemotaxis. Each of these functions involves a consecutive interaction with specific membrane proteins. The molecules transported are amino acids, sulfate, mono- and oligosaccchrides. In this way ABP complexes L-arabinose (K 0.98 x 10 M), and MBP (maltodextrin-binding protein) complexes maltose (ATj 35 x 10 M) and maltodextrins. It is in this series that are found the strongest possible bonds between sugars and proteins. The dissociation rate ( i 1.5 s ) is indicative of the upper limit of the ionic transport rate. Hydrogen bonds... 

Specificity is a property of monocomponent systems and it occurs when the method is free of interference. Selectivity is related to the complexity of the matrix and it occurs when not more than one ion (molecule) interferes in determination. Enantioselectivity is a relatively new term introduced for the assay of enantiomers.257258 An analytical method is enantioselective when it can discriminate between enantiomers. Enantiospecificity is an extreme case of enantioselectivity. It is possible to create the conditions for a highly enantioselective analysis, and in this case enantiospecificity can also occur. For example, a maltodextrin with dextrose equivalence (DE) of 4.0 to 7.0 was used in capillary zone electrophoresis as a stationary phase for the separation of the enantiomers,259 and also in the design of a potentiometric, enantioselective membrane electrode.260 The method for capillary zone electrophoresis is enantioselective, as it is for the potentiometric method. 

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