Modification of Starches

Of particular importance for modifications of starch are the enzyme degradation products such as glucose symps, cyclodextrins, maltodextrins, and high fmctose com symps (HFCS). Production of such hydrolysis products requites use of selected starch-degrading enzymes such as a-amylase,... 

There are five prime factors that determine the properties of starches 1. starch is a polymer of glucose (dextrose) 2. the starch polymer is of two types linear and branched 3 the linear polymeric molecules can associate with each other giving insolubility in water 4. the polymeric molecules are organized and packed into granules which are insoluble in water and 5 disruption of the granule structure is required to render the starch polymer dispersible in water. The modification of starch takes into account these factors. 

It appears that estimates of the dimensions of the unit cell for the B -modification of starch (or amylose) are reasonably in agreement, but that structural interpretations of these observations are at variance. 

Zweifel, C., Conde-Petit, B., and Escher, F. 2000. Thermal modifications of starch during high-temperature drying of pasta. Cereal Chem. 77, 645-651. 

Modification of Starch and Other Saccharides by Crafting Hydrophobic Chains... 

Fig. 3.4 Modification of starch by butadiene telomerization. Influence of the catalyst mass and temperature on the degree of substitution (DS).

Variations of this method are possible in several ways. First of all, cyclodextrin which is available on a large scale by enzymatically catalyzed modification of starch can be tailored by chemical reactions. Furthermore, copolymerizations between different host-guest complexes are possible whereby in some cases the reactivity ratios differ from those reported in literature. 

Fortuna, L, Juszczak, L., Palasinski, M. (1999). Changes in granule porosity on modification of starch. Zywnosc Technol. Jakosc, 5, 124-130. 

Kudla, E., Tomasik, P. (1992). The modification of starch by high pressure. Part II. Compression of starch with additives. Starch, 44,253-259. 

Pukkahuta, C., Shobsngob, S., Varavinit, S. (2007). Effect of osmotic pressure on starch New method of physical modification of starch. Starch, 58, 78-90. 

Chakraborty, S., Sahoo, B., Teraka, I., Miller, L. M., Gross, R. A. (2005). Enzyme-Catalyzed regioselective modification of starch nanoparticles. Macromoleculess 38,61-68. 

Depolymerizing modification of starch usually involves the use of enzymes, acid- (and less frequently base-) catalyzed hydrolysis, and thermolysis alone and thermolysis combined with acid-catalyzed hydrolysis (see a recent survey in this Series2). Despite several studies, the physical treatment of starch has not yet resulted in major practical applications. The aim of this Chapter is to review physical methods as tools for the treatment of starch which deliver amounts of energy suitable for depolymerizing starch to target products. It should be noted that the duration of such processes does not need to exceed that for conventional, namely enzymic, chemical, and thermal modifications. Moreover, a potential advantage of nonconventional physical treatments is the fact that they generate no waste products. 

Solvent used in modification of starch Temperature of observation (°C) ... 

It should be mentioned that a solventless method of hydrolytic modification of starch has recently been developed. The method employs solid superacids, per-fluorinated resin-sulfonic acids, which successfully catalyze hydrolysis of starch (and other polysaccharides) and offer the possibility of continuous-process applications in plug-flow reactors.34... 

Very few reports have been published on the use of X-rays for modification of starch, although the formation of deoxy compounds on irradiation of solid potato starch with 5 X 106 rads under nitrogen has been described. The amount of deoxy compounds formed is related almost linearly to the irradiation dose, and formation of 2-deoxy-D-arabi no-hexose is the major process there are almost no side-pro-cesses. Similar qualitative, but not quantitative, behavior is shown by 1% aqueous solutions of D-glucose, D-xylose, L-arabinose, D-ribose, sucrose, and cellulose powder (Fig. 14). Starch is the most resistant to irradiation among carbohydrates tested.74... 

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