A study of ordered structure in acid-modified tapioca starch by 13C CP/MAS solid-state NMR
A study of ordered structure in acid-modified tapioca starch by 13C CP/MAS solid-state NMR
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DOI：
10.1016/j.carbpol.2004.07.017
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发表时间：
2004-12-07
影响因子：
11.2
通讯作者：
Chinachoti, P
中科院分区：
文献类型：
--
作者：
Atichokudomchai, N;Varavinit, S;Chinachoti, P
早先有报道称，对木薯淀粉进行酸改性可以提高片剂的机械强度。用C-13CP/MAS核磁共振和X-射线衍射仪监测了这些淀粉在0.90a(W)(25℃)下平衡后有序结构(双螺旋)的发展。随着水解时间的延长，无定形组分的共振峰强度减小，而双螺旋组分的共振峰强度增大。用C-13CP/MAS、核磁共振和X-射线衍射法测得的相对结晶度(%)均随时间的延长而急剧增加，然后趋于平稳。最初相对双螺旋含量和结晶度的增加是由于无定形结构域的水解性破坏、部分水解性直链淀粉的回生和游离支链淀粉双螺旋的结晶。192 h后，这两个参数没有显著差异(α=0.05)，表明没有排列到结晶区的双螺旋已经被水解或结晶。(C)2004爱思唯尔有限公司。保留所有权利。
Acid modification of tapioca starch earlier reported to increase the mechanical strength of tablets. The development of ordered structure (double helices) of these starches was monitored after equilibrating at 0.90 a(w) (25 degreesC) using C-13 CP/MAS NMR and X-ray diffraction. As the hydrolysis time increased, the intensity of the resonance for C1 and C4 amorphous fractions decreased while that for C1 and C4 double helix fractions increased. Relative crystallinity (%) obtained from C-13 CP/MAS NMR and X-ray diffraction methods both increased sharply initially and then levelled off with hydrolysis time. The initial increase in relative double helix content and crystallinity was due to a hydrolytic destruction in the amorphous domain, retrogradation of the partially hydrolyzed amylose and crystallization of free amylopectin double helices. After 192 h, these two parameters were not significantly different (alpha=0.05) indicating that the double helices that were not arranged into crystalline regions either had been hydrolyzed or crystallized. (C) 2004 Elsevier Ltd. All rights reserved.