Analysis of the native structure of starch granules with small angle x-ray microfocus scattering

Waigh, Thomas A., Donald, Athene M., Heidelbach, Florian, Riekel, Christian and Gidley, Michael J. (1999) Analysis of the native structure of starch granules with small angle x-ray microfocus scattering. Biopolymers, 49 1: 91-105. doi:10.1002/(SICI)1097-0282(199901)49:1<91::AID-BIP9>3.0.CO;2-9


Author Waigh, Thomas A.
Donald, Athene M.
Heidelbach, Florian
Riekel, Christian
Gidley, Michael J.
Title Analysis of the native structure of starch granules with small angle x-ray microfocus scattering
Journal name Biopolymers   Check publisher's open access policy
ISSN 0006-3525
1097-0282
Publication date 1999-01
Sub-type Article (original research)
DOI 10.1002/(SICI)1097-0282(199901)49:1<91::AID-BIP9>3.0.CO;2-9
Volume 49
Issue 1
Start page 91
End page 105
Total pages 15
Place of publication Hoboken, NJ, United States
Publisher John Wiley & Sons
Language eng
Abstract Small angle x-ray microfocus scattering patterns were obtained from 4 μm regions of hydrated potato starch granules. The 9 nm lamellar reflection was found to be modulated along two fiat streaked layer lines symmetrically related, and arranged in a weak four point pattern. This provides evidence for two populations of tilted lamellae in the granule present in equal quantities, but opposite angles of tilt. The paucity of reflections in the scattering patterns implies the existence of correlated disorder between the lamellae, and is a product of either their liquid crystallinity or a well- developed defect structure between the constituent amylopectin helices. The angular position of the four point modulation (17.25°) on the scattering patterns is compared with the values predicted from a superhelical lamellar model containing cumulative disorder along its axis, and good agreement is found with the data. The physical basis for the occurrence of these helical lamellae is examined on the basis of the model of amylopectin as a chiral side chain liquid-crystalline polymer (T. A. Waigh et al., Macromolecules, 1997, Vol. 30, pp. 3813-3820; Faraday Discussions, 1996, Vol. 103, pp. 325- 337). Small angle x-ray microfocus scattering patterns were obtained from 4 μm regions of hydrated potato starch granules. The 9 nm lamellar reflection was found to be modulated along two flat streaked layer lines symmetrically related, and arranged in a weak four point pattern. This provides evidence for two populations of tilted lamellae in the granule present in equal quantities, but opposite angles of tilt. The paucity of reflections in the scattering patterns implies the existence of correlated disorder between the lamellae, and is a product of either their liquid crystallinity or a well-developed defect structure between the constituent amylopectin helices. The angular position of the four point modulation (17.25°) on the scattering patterns is compared with the values predicted from a superhelical lamellar model containing cumulative disorder along its axis, and good agreement is found with the data. The physical basis for the occurrence of these helical lamellae is examined on the basis of the model of amylopectin as a chiral side chain liquid-crystalline polymer.
Keyword Starch granule
Small angle x-ray microfocus scattering
Correlated disorder
Amylopectin
Side chain liquid crystal polymer
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Article first published online: 8 February 1999.

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Nutrition and Food Sciences Publications
 
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