Hydrolysis dextrins

Figure 9 shows Lineweaver-Burk plots of dextrin hydrolysis rates in the presence of the block copolymer. Again, fairly good straight lines are obtained. Some other kinetical investigations also were made for the catalytic activity of the block copolymer, and similar tendencies of catalytic behavior were found compared with that of the random copolymer. 

Figure 8. Dependence of dextrin hydrolysis rates (v) on the substrate concentration in the presence of the block copolymer at 70°C. [Catalyst] = 1.00 X 10 2N. Catalyst (mole ratio of vinyl alcohol to styrenesulfonic acid units in the copolymer) (O) sulfuric acid (%) block copolymer No. 1 (1-4) (A) block copolymer No. 2 (9.8) (A) block copolymer No. 3 (22.1).

Converted starches, also called thin-boiling starches, are produced by degradation of the starch chains into small segments. They can be cooked in water at higher concentrations than native starches. Low-viscosity starches are needed in applications where a high solid starch paste with a pumpable and workable viscosity is required. There are four classes of commercial converted starches dextrins (hydrolysis in solid-state) acid-modified starches (hydrolysis in a slurry) oxidized starches and enzymically depolymerized starches. 

Preparation and comparison of catalytic activity of immobilized Amyloglucosidase with native enzyme on dextrin - hydrolysis... 

Figure 1 Comparison of actitivites of chitin-immobilized and native Amyloglucusidases on dextrin-hydrolysis...

Fig. 12. Lineweaver-Burk plot of the kinetic data of the dextrin hydrolysis in the presence of a copolymer of vinyl alcohol and ethylene sulfonic acid (80 °C). Copolymer contained 1.0 mole % sulfonic groups and 99 mole % vinyl alcohol groups. [Copolymer] = 5.0 x 10" mole 1 Copolymer A No. 3, O No, 5,...

Carbohydrates may be divided into monosaccharides, disaccharides and polysaccharides. The monosaccharides under certain conditions react as polyhydroxy-aldehydes or polyhydroxy-ketones two important representatives are glucose CjHjjO (an aldose) and fructose (laevulose) CgHuO, (a ketose). Upon hydrolysis di- and polysaccharides 3deld ultimately monosaccharides. Common disaccharides are sucrose, lactose and maltose (all of molecular formula C,2H2. 0,), whilst starch, dextrin and cellulose, (CjHjoOj), in which n > 4, are typical polysaccharides. 

Amylase occurs in many plants, such as barley, wheat, rye, soy beans, and potatoes, where it is generally accompanied by some a-amylase. [ -Amylase initiates hydrolysis at the nonreducing end of an amylose or amylopectin chain, and removes maltose units successively until the reducing end of the molecule is encountered in amylose or a branch is met in amylopectin. ( -Amylase is used commercially in the preparation of maltose symps. After P-amylase hydrolysis of amylopectin there remains a P-amylase limit dextrin. ( -Amylase has been used as a probe of the fine stmcture of amylopectin (43-46). 

Fig. 10. Plots of the relative rate constants of the hydrolysis of dextrin vs. the mole ratio of vinylalcohol unit to vinylsulfonic acid unit, o PVS VA, Polyvinylalcohol + HPVS (Ref.

The hydrolysis of starch by salivary and pancreatic amylases catalyze random hydrolysis of a(l—>4) glycoside bonds, yielding dextrins, then a mixmre of glucose, maltose, and isomaltose (from the branch points in amylopectin). 

Pacsu4 5 has suggested a structure for starch involving a small number of non-cyclic hemiacetal linkages, the number being presumably sufficient to account for the number of endgroups determined by the methylation method. Halsall, Hirst and Jones6 have commented on this structure, however, and have shown it to be incompatible with the results of periodate-oxidation studies. In addition, these authors pointed out that it would be difficult to explain enzymic hydrolysis and dextrin formation on the basis of such a structure. 

A second method that is frequently used to measure the dextrinogenic activity of alpha amylases is based upon the hydrolysis of starch to dextrins of low molecular weight which give a red or a colorless solution with iodine. 

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