Starch waxy-type, formation

To explain the variation in the phosphate content of starches, it is postulated that some plants contain a specific phosphatase such an enzyme would have to possess unusual powers of penetration, since R-en-zyme, for example, cannot attack the interior of an amylopectin molecule. Moreover, a considerable proportion of the phosphorus would be situated in outer chains there is no evidence for this. (5) The formation of waxy-type starches is attributed to a low activity of the debranching enzyme caused by the presence of an inhibitor(s) to the debranching mechanism or by a deficiency of the debranching enzyme. Waxy-type starches should, therefore, contain a higher degree of branching than that actually observed (about 5%). 

The acid hydrolysis of starch granules from potato, waxy maize, and amylo-maize-7 was studied in different ratios of mixtures of two of the four alcohols, from 100/0 to 0/100% in 10% (v/v) intervals [53]. Again, a series of soluble limit dextrins was obtained in 48-72 hr of reaction. The average d.p. of the limit dextrins decreased as the content of the higher alcohol was increased. Plots of the d.p. of the limit dextrins vs. the ratio of each alcohol mixture produced curves that resembled titration curves, with different plateau regions in which the d.p. of the limit dextrins changed very slowly or not at all. These plateau regions were characteristic and dependent on the types of alcohols, the volume ratios of the two alcohols in the mixture, and the type of starch. It was proposed that the formation of... 

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