Starch amylose from

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 ). 

Not only does glucose appear somewhat earlier but also it is liberated in higher concentrations in the hydrolyzates from potato starch than in those from amylose. In addition, Table VI presents evidence for the more rapid liberation of glucose from waxy maize starch than from... 

Products Formed from Potato Starch, from Waxy Maize Starch and from Corn Amylose by Purified Maltose-free Pancreatic Amylase... 

FIGURE 5.8 Unit cells (outlined in each diagram) and helix packing in A and B polymorphs of starch. Reprinted from Carbohydrate Research, Vol. 61, Wu and Sarko (1978b), The double helical molecular structure of crystalline A-amylose, Pages 27-40, with permission from Elsevier. 

The hypochlorite/water solutions were pretitrated to pH 8.5 with 1.0 N HCl in order to neutralize the presence of inherent sodium hydroxide. Leaching out of non-crystalline amylose from the native starch granules has been previously described in systems with pH values greater than 9.0 (24). 

Starch, another of the most abundant polymers of glucose, is stored by most green plants in a semicrystalline form in numerous small granules. These granules, which are usually formed within colorless membrane-bounded plastids, have characteristic shapes and appearances (Fig. 4-6) that vary from plant to plant. One component of starch, amylose, is a linear polymer of many a-D-glucopyranose units in 1,4 linkage (Fig. 4-7) as in maltose. Starch granules always contain a second kind of molecule known as amylopectin.58... 

Probably the most important carbohydrate polymer in food, certainly from a nutritional standpoint, is starch, and Chapter E2 presents three units that can be used for starch isolation and characterization. UNITE2.1 condenses many different starch isolation methods into one scheme for starch isolation from virtually any plant source. In this protocol, the author notes the care that must be taken to prevent starch degradation during isolation. unite2.2 presents a simple enzymatic analysis method that can be used for estimation of starch in food. Finally, unit E2.3 describes a colorimetric method to determine starch amylose content. Again, different combinations of the units in this chapter can be used to characterize starch from any source. 

The "selective absorption method employed by Ashford et al(Refs 5 6) in the study of starch avoids the use of harsh swelling agents but employs adsorbing agents (such as cotton activated charcoal or Fuller s earth) to remove amylose from amylopectin when in aq soln. The cotton-amylose adsorbate is formed instantly when a cold corn starch paste(2%) is brought into contact with cotton and can be washed free of amylopectin with w. The cotton-adsorbate is then readily decomp by boiling w to give a clear soln of amylose and the solid is obtained by con eg the soln to... 

Starch was determined colorimetrically by Whistler s iodine method using amylose from corn starch (G.R. TCI Chemical Co.) as a standard (10). 

Free radicals originating from starch, amylose, and amylopectin form well-distinguished 1 3 1 or 1 4 1 triplets showing hyperfine splitting of 30 gauss. These triplets are attributed to the derivatives of alkyl radicals produced by abstraction of hydrogen atoms from the 2-, 3-, and/or 4-positions of glucose residues.269... 

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