Retrogradation of amylose

The formation of amylopectin occurs through the action of starch branching enzyme on mal-todextrins and/or amylose to form the a-(1 6) branch linkage. Amylose or maltodextrins can be used as the substrates, but the amylose must be at a concentration of 1 mg/mL or less, as higher concentrations leads to the precipitation (retrogradation) of amylose from solution. 

Stepwise retrogradation of amylose mixtures and GPC separation of the fractions should reveal whether a preferential precipitation exists, possibly as a result of preformed double helices in solution. 

Figure 11. Stepwise retrogradation of amyloses DP 100 and 2270 (1 1). HPLC-GPC of tricarbanilates in THF. (Amylose solution 200 mg DP 100 and 200 mg DP 2270 in 4 mL DMSO and diluted with water to 100 mL.)...

Initial Rapid Processes in Retrogradation of Amylose Observed by the Light-Scattering, Stopped-Flow Method... 

He appears to be the first to study retrogradation by investigating the effeet of acid-catalyzed hydrolysis on the retrogradation of amylose (1948) and applied the method thus developed to examine the rates of retrogradation of a variety of native starehes... 

The retrogradation of amylose in solutions of enzymatically liquified starch depended on the degree of starch hydrolysis and on the manner of preparing the solution.Even at DE values of 20-30%, retrogradation occurred in solutions of <5% and >50% concentration. 

Gelatinization of sweet potato, tania, and yam tuber starches. Starch/Starke. 47, 298-306. Varavinit, S., Shobsngob, S., Varanyanond, W., Chinachoti, P., and Naivikul, O. (2003). Effect of amylose content on gelatinization, retrogradation and pasting properties of flours from different cultivars of Thai rice. Starch/Starke 55,410-415. 

The retardation of the retrogradation rate of amylose is induced by anions in the order of the Hofmeister ion series228,239)... 

Although all amylose molecules were once considered to be linear, many amylose molecules cannot be completely hydrolyzed by (3-amylase. With a concurrent or mixed action of pullulanase and beta-amylase, however, amylose can be completely hydrolyzed to maltose.150,151 These results rule out the theory that the incomplete hydrolysis of amylose by (3-amylase is a result of retrogradation, i.e. junction zone formation. It is now clear that the incomplete hydrolysis of an amylose preparation by (3-amylase is due to branching of some molecules. The (3-amylolysis limit of amylose varies from 72% to 95%152,153 compared with 55-61% for amylopectin. Amylose of most cereal starches, such as maize,154 rice,155,156 wheat157 and barley,158 give >80% (3-amylolysis... 

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