Hydration properties and phosphorous speciation in native, gelatinized and enzymatically modified potato starch analyzed by solid-state MAS NMR

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• 作者：Flemming H. Larsen ; Miros?aw M. Kasprzak ; Helle N. L?rke ; Knud Erik B. Knudsen ; Sven Pedersen ; Anne S. J?rgensen ; Andreas Blennow
• 关键词：Starch ; Branching enzyme ; ¦Â-Amylase ; Hydration ; Solid-state NMR ; HPSEC
• 刊名：Carbohydrate Polymers
• 出版年：2013
• 出版时间：12 September, 2013
• 年：2013
• 卷：97
• 期：2
• 页码：502-511
• 全文大小：1205 K

文摘

Hydration of granular, gelatinized and molecularly modified states of potato starch in terms of molecular mobility were analyzed by ¹³C and ³¹P 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 ¦Â-amylase (BB) catalyzed exo-hydrolysis. Carbons of the glycosidic ¦Á-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.