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Title: Characterisation of large scale structures in starch granules via small-angle neutron and X-ray scattering
Authors: Doutch, J
Gilbert, EP
Keywords: Starch
Tree rings
Unified model
X-ray lasers
Issue Date: 2-Jan-2013
Publisher: Elsevier Science Ltd
Citation: Doutch, J., & Gilbert, E. P. (2013). Characterisation of large scale structures in starch granules via small-angle neutron and x-ray scattering. Carbohydrate Polymers, 91, 444-451. doi:10.1016/j.carbpol.2012.08.002
Abstract: Small angle scattering (SAS) techniques have a distinguished track record in illuminating the semi-crystalline lamellar structure of the starch granule. To date, there have been few attempts to use SAS techniques to characterise larger-scale structures reported from imaging techniques such as growth rings, blocklets or pores, nor how these structures would modulate the well-known scattering arising from the semi-crystalline lamellar structure. In this study, SAS data collected over an extended q range were gathered from dry and hydrated starch powders from varied botanical sources. The use of neutrons and X-rays, as well as comparing dry and hydrated granules, allowed different levels of contrast in scattering length density to be probed and therefore selected structural regions to be highlighted. The lowest q range, 0.002-0.04 (A) over circle (-1), was found to be dominated by scattering from the starch granules themselves, especially in the dry powders; however an inflection point from a low contrast structure was observed at 0.035 (A) over circle (-1). The associated scattering was interpreted within a unified scattering framework with the inflexion point correlating with a structure with radius of gyration similar to 90A (A) over circle - a size comparable to small blocklets or superhelices. In hydrated starches, it is observed that there is an inflection point between lamellar and q(-4) power-law scattering regions at approximately 0.004 (A) over circle (-1) which may correlate with growth rings and large blocklets. The implications of these findings on existing models of starch lamellar scattering are discussed. © 2013, Elsevier Ltd.
Gov't Doc #: 4594
ISSN: 0144-8617
Appears in Collections:Journal Articles

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