Causal Relations between Structural Features of Amylopectin, a Semicrystalline Hyperbranched Polymer

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• 作者：Torsten Witt ; Robert G. Gilbert
• 刊名：Biomacromolecules
• 出版年：2014
• 出版时间：July 14, 2014
• 年：2014
• 卷：15
• 期：7
• 页码：2501-2511
• 全文大小：451K
• ISSN：1526-4602

文摘

The relationships were determined between molecular properties of amylopectin, a hyperbranched glucose polymer and the major component of starch, and higher-level structures in native starch (double helices, crystallinity and crystalline鈥揳morphous lamellae). Parameters from NMR, differential scanning calorimetry, and size exclusion chromatography of 尾-limit dextrins of a series of waxy starches, together with literature data, gave information on relationships between the structure of the interior of the amylopectin molecule and crystallinity. The structure of internal B chains (those with one or more branches) of amylopectin influences both crystalline properties and crystallinity. More B chains produce larger crystalline鈥揳morphous lamellae, probably by expanding the amorphous lamellae, while larger B chains increase the ability of annealing to increase order through greater mobility for the chains to rearrange at higher temperatures. This study brings into question the common assumption that A chains (unbranched chains) are necessarily smaller than B chains.