Publication: A study of ordered structure in acid-modified tapioca starch by<sup>13</sup>C CP/MAS solid-state NMR
Issued Date
2004-12-07
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01448617
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2-s2.0-9644281089
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Mahidol University
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SCOPUS
Bibliographic Citation
Carbohydrate Polymers. Vol.58, No.4 (2004), 383-389
Suggested Citation
Napaporn Atichokudomchai, Saiyavit Varavinit, Pavinee Chinachoti A study of ordered structure in acid-modified tapioca starch by<sup>13</sup>C CP/MAS solid-state NMR. Carbohydrate Polymers. Vol.58, No.4 (2004), 383-389. doi:10.1016/j.carbpol.2004.07.017 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/21262
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Title
A study of ordered structure in acid-modified tapioca starch by<sup>13</sup>C CP/MAS solid-state NMR
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Abstract
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 0.90aw(25°C) using13C 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 from13C 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 (α = 0.05) indicating that the double helices that were not arranged into crystalline regions either had been hydrolyzed or rystallized. © 2004 Elsevier Ltd. All rights reserved.