title: X-ray photoelectron spectroscopic analysis of rice kernels and flours: Measurement of surface chemical composition.
abstract: The objectives of this study were to evaluate the ability of X-ray photoelectron spectroscopy (XPS) to differentiate rice macromolecules and to calculate the surface composition of rice kernels and flours. The uncooked kernels and flours surface composition of the two selected rice varieties, Thadokkham-11 (TDK11) and Doongara (DG) demonstrated an over-expression of lipids and proteins and an under-expression of starch compared to the bulk composition. The results of the study showed that XPS was able to differentiate rice polysaccharides (mainly starch), proteins and lipids in uncooked rice kernels and flours. Nevertheless, it was unable to distinguish components in cooked rice samples possibly due to complex interactions between gelatinized starch, denatured proteins and lipids. High resolution imaging methods (Scanning Electron Microscopy and Confocal Laser Scanning Microscopy) were employed to obtain complementary information about the properties and location of starch, proteins and lipids in rice kernels and flours.
authors.affiliation: The University of Queensland, School of Agriculture and Food Sciences, Qld 4072, Australia.
authors.forename: Malik A
authors.initials: MA
authors.lastname: Nawaz
authors.affiliation: The University of Queensland, School of Agriculture and Food Sciences, Qld 4072, Australia; Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 av de la Foret de Haye, TSA 40602, 54518 Vandœuvre lès Nancy, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Gaiani
authors.affiliation: The University of Queensland, School of Agriculture and Food Sciences, Qld 4072, Australia.
authors.forename: Shu
authors.initials: S
authors.lastname: Fukai
authors.affiliation: The University of Queensland, School of Agriculture and Food Sciences, Qld 4072, Australia. Electronic address: b.bhandari@uq.edu.au.
authors.forename: Bhesh
authors.initials: B
authors.lastname: Bhandari
mesh_terms: D003296:Cooking; D005433:Flour / Q000032:analysis*; D008055:Lipids / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D012275:Oryza / Q000737:chemistry*; D056951:Photoelectron Spectroscopy / Q000379:methods*; D010940:Plant Proteins / Q000378:metabolism*; D013213:Starch / Q000032:analysis*
chemical_list: D008055:Lipids; D010940:Plant Proteins; D013213:Starch
keywords: CLSM; Doongara; Surface analysis; TDK11; X-ray photoelectron spectroscopy