Department of Food Science, University of Copenhagen, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.
Carbohydr Polym. 2013 Sep 12;97(2):502-11. doi: 10.1016/j.carbpol.2013.05.014. Epub 2013 May 15.
Hydration of granular, gelatinized and molecularly modified states of potato starch in terms of molecular mobility were analyzed by (13)C and (31)P solid-state MAS NMR. Gelatinization (GEL) tremendously reduced the immobile fraction compared to native (NA) starch granules. This effect was enhanced by enzyme-assisted catalytic branching with branching enzyme (BE) or combined BE and β-amylase (BB) catalyzed exo-hydrolysis. Carbons of the glycosidic α-1,6 linkages required high hydration rates before adopting uniform chemical shifts indicating solid-state disorder and poor water accessibility. Comparative analysis of wheat and waxy maize starches demonstrated that starches were similar upon gelatinization independent of botanical origin and that the torsion angles of the glycosidic linkages were averages of the crystalline A and B type structures. In starch suspension phosphorous in immobile regions was only observed in NA starch. Moreover phosphorous was observed in a minor pH-insensitive form and as major phosphate in hydrated GEL and BE starches.
采用（13）C 和（31）P 固态 MAS NMR 分析了颗粒状、胶凝和分子改性状态的马铃薯淀粉的水合作用，从分子迁移率方面进行了分析。与天然淀粉颗粒相比，胶凝化（GEL）极大地降低了不可移动部分。通过使用分支酶（BE）或结合 BE 和β-淀粉酶（BB）催化的外切水解进行酶辅助催化支化，增强了这种效果。糖苷α-1,6 键的碳需要高的水合速率才能采用均匀的化学位移，这表明固态无序和水不可及性差。对小麦和蜡质玉米淀粉的比较分析表明，胶凝化后淀粉相似，与植物来源无关，并且糖苷键的扭转角是结晶 A 和 B 型结构的平均值。在淀粉悬浮液中，仅在天然淀粉中观察到不可移动区域的磷。此外，在水合 GEL 和 BE 淀粉中，磷以 minor pH-insensitive 形式和 major phosphate 形式存在。
