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Main Title: Elucidation of density profile of self-assembled sitosterol plus oryzanol tubules with small-angle neutron scattering
Author(s): Bot, Arjen
Gilbert, Elliot P.
Bouwman, Wim G.
Sawalha, Hassan
Adel, Ruud den
Garamus, Vasil M.
Venema, Paul
Linden, Erik van der
Flöter, Eckhard
Type: Article
Language Code: en
Abstract: Small-angle neutron scattering (SANS) experiments have been performed on self-assembled tubules of sitosterol and oryzanol in triglyceride oils to investigate details of their structure. Alternative organic phases (deuterated and non-deuterated decane, limonene, castor oil and eugenol) were used to both vary the contrast with respect to the tubules and investigate the influence of solvent chemistry. The tubules were found to be composed of an inner and an outer shell containing the androsterol group of sitosterol or oryzanol and the ferulic acid moieties in the oryzanol molecule, respectively. While the inner shell has previously been detected in SAXS experiments, the outer shell was not discernible due to similar scattering length density with respect to the surrounding solvent for X-rays. By performing contrast variation SANS experiments, both for the solvent and structurant, a far more detailed description of the self-assembled system is obtainable. A model is introduced to fit the SANS data; we find that the dimensions of the inner shell agree quantitatively with the analysis performed in earlier SAXS data (radius of 39.4 ± 5.6 Å for core and inner shell together, wall thickness of 15.1 ± 5.5 Å). However, the newly revealed outer shell was found to be thinner than the inner shell (wall thickness 8.0 ± 6.5 Å). The changes in the scattering patterns may be explained in terms of the contrast between the structurant and the organic phase and does not require any subtle indirect effects caused by the presence of water, other than water promoting the formation of sitosterol monohydrate in emulsions with aqueous phases with high water activity.
Issue Date: 2012
Date Available: 28-Jun-2016
DDC Class: 540 Chemie und zugeordnete Wissenschaften
Journal Title: Faraday discussions
Publisher: Royal Society of Chemistry
Publisher Place: Cambridge
Volume: 158
Publisher DOI: 10.1039/c2fd20020a
Page Start: 223
Page End: 238
EISSN: 1359-6640
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Appears in Collections:Inst. Lebensmitteltechnologie und Lebensmittelchemie » Publications

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