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Browsing by Author "Gilbert, EP"

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Advances in sample environments for neutron scattering for colloid and interface science
(Elsevier, 2024-05) Le Brun, AP; Gilbert, EP
This review describes recent advances in sample environments across the full complement of applicable neutron scattering techniques to colloid and interface science. Temperature, pressure, flow, tensile testing, ultrasound, chemical reactions, IR/visible/UV light, confinement, humidity and electric and magnetic field application, as well as tandem X-ray methods, are all addressed. Consideration for material choices in sample environments and data acquisition methods are also covered as well as discussion of current and potential future use of machine learning and artificial intelligence. Crown Copyright © 2024 Published by Elsevier B.V
Application of small-angle scattering to study the effects of moisture content on a native soy protein
(Wiley-Blackwell, 2008-06) Kealley, CS; Elcombe, MM; Wuhrer, R; Gilbert, EP
The nano-and microstructure of glycinin, a soybean protein, has been investigated as a function of moisture for moisture contents between 4 and 21 wt%. Glycinin exhibits peaks in the small-angle region whose positions show minimal change with X-rays for samples up to 13% moisture. However, the use of neutron scattering, and the associated enhancement in contrast, results in the Bragg peaks being well resolved up to higher moisture contents; the associated shift in peak positions between 4 and 21% moisture are consistent with the expansion of a hexagonal unit cell as a function of moisture content. A Porod slope of similar to-4 indicates that the interface between the 'dry' protein powder and the surrounding medium at a length-scale of at least 3 mm down to similar to 20 nm is smooth and sharp. Scanning electron microscopy indicates that the powders, with low moisture content, have a porous appearance, with the porosity decreasing and microstructure expanding as the moisture content increases. © 2008, Wiley-Blackwell.
Application of small-angle X-ray and neutron scattering techniques to the characterisation of starch structure: A review
(Elsevier, 2011-05-06) Blazek, J; Gilbert, EP
Scattering methods offer the unique potential to indirectly probe materials on length scales between the capabilities of modern crystallography and microscopy, thus bridging the gap in spatial resolution between the two groups of techniques. The most significant achievement of small-angle scattering techniques in starch science has been the quantification of the lamellar architecture of semicrystalline growth rings in native starch granules. The lamellae are structurally formed by side chains of amylopectin interspersed with amylose and their behaviour upon contact with water and varying temperature has been explained using a widely accepted 'liquid crystalline' model for starch. Scattering techniques have also been recently used to explore the structural factors in native and processed starches that determine resistance to acid and enzymatic hydrolysis. Attempts have been made to apply scattering methods in understanding more complex structures in starch-based food products. Application of these techniques that are traditionally not widely used in food materials science provides fascinating challenges and opportunities. With more basic scientific methods entering food technology, it is apparent that small-angle scattering techniques deserve their place in the multi-technique approach, which aims to understand the structural mechanisms governing starch processing and digestion, and makes it possible to design and select those processes which render desirable structural morphologies. This paper summarises previous investigations and the current status of research into the structure of native starch and starch-based systems using small-angle scattering techniques. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
Application of small-angle x-ray scattering and small-angle neutron scattering to fat mimetics
(John Wiley & Sons, Ltd., 2023-05-06) Gilbert, EP
Small-angle and ultra-small angle scattering are powerful techniques that are able to reveal structure on the nanometre to micron length scales. These methods are naturally complementary to other materials characterisation approaches including various microscopies but with the advantage that minimal sample preparation is required enabling measurement of materials to be conducted in their native state. Due to the length scales probed, these methods have considerable application in the study of oleogels where the nano- and micro-structures formed directly impact macroscopic gel properties. This chapter describes small-angle and ultra-small angle scattering techniques and the detailed information that can be obtained from their application with a particular focus on oleogels. The chapter describes the fundamentals of the method, instrumentation, experimental design and data collection, as well as the rich information that can be extracted from a well-designed experiment. Differences between X-ray and neutron probes for small-angle scattering are also discussed and, relevant to the latter, the benefits of selective deuteration and contrast variation are highlighted. This is followed by a lengthy discussion of specific recent examples covering the wide range of oleogel systems. The chapter concludes with some suggestions for future opportunities in the application of these methods. © 2023 John Wiley & Sons, Inc.
Application of time-resolved small angle neutron scattering to non-equilibrium kinetic studies
(Springer Nature, 2011-11-15) Mata, JP; Hamilton, WA; Gilbert, EP
Small-angle neutron scattering (SANS) provides structural information on the length scale from one to several hundred nanometres. Time-resolved SANS measurements (TR-SANS) therefore yield kinetic information on the evolution from one quasi-static structure to another. The technique offers complementary information to neutron spectroscopic methods where the focus is dynamics. Approaches for maximising time resolution in SANS are described, along with the particular advantages of neutrons, and some recent examples are discussed. © 2023 Springer Nature
Characterisation of large scale structures in starch granules via small-angle neutron and X-ray scattering
(Elsevier Science Ltd, 2013-01-02) Doutch, J; Gilbert, EP
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.
Characterising food materials and the case for extended q scattering
(International Union of Crystallography, 2021-08-14) Gilbert, EP
When designing food products, it is important to understand and predict structure-function-property relationships within food constituents. This includes knowledge of not only the structure of native materials but also their structural changes across a wide range of length scales brought about by food processing. The inherent complexity of food systems therefore calls for an arsenal of techniques and instrumentation that can access a broad range of dimensions. The Australian Nuclear Science and Technology Organisation (ANSTO) commenced the ‘Food Materials Science Programme’ to explore opportunities for the utilisation of the nuclear based methods, including small and ultra-small angle neutron scattering ((U)SANS), in a quest to extend the understanding of complex food systems. This presentation will highlight the role of (U)SANS in the context of broader materials characterisation methods, using several examples1-8. © The Author
Correlation of thermostability and conformational changes of catechol 2, 3-dioxygenases from two disparate micro-organisms
(Elsevier Science BV, 2013-10-01) Sokolova, AV; Huang, SL; Duff, AP; Gilbert, EP; Li, WH
We have investigated the structure of recombinant catechol 2, 3-dioxygenase (C23O) purified from two species in which the enzyme has evolved to function at different temperature. The two species are mesophilic bacterium Pseudomonas putida strain mt-2 and thermophilic archaea Sulfolobus acidocaldarius DSM639. Using the primary sequence analysis, we show that both C23Os have only 30% identity and 48% similarity but contain conserved amino acid residues forming an active site area around the iron ion. The corresponding differences in homology, but structural similarity in active area residues, appear to provide completely different responses to heating the two enzymes. We confirm this by small angle X-ray scattering and demonstrate that the overall structure of C23O from P. putida is slightly different from its crystalline form whereas the solution scattering of C230 from S. acidocaldarius at temperatures between 4 and 85 degrees C ideally fits the calculated scattering from the single crystal structure. The thermostability of C230 from S. acidocaldarius correlates well with conformation in solution during thermal treatment. The similarity of the two enzymes in primary and tertiary structure may be taken as a confirmation that two enzymes have evolved from a common ancestor. © 2013, Elsevier Ltd.
Design and implementation of a differential scanning calorimeter for the simultaneous measurement of small angle neutron scattering
(IOP Science, 2014-04-08) Pullen, SA; Booth, N; Olsen, SR; Day, B; Franceschini, F; Mannicke, F; Gilbert, EP
For almost 30 years, at synchrotron facilities, it has been possible to perform small-angle x-ray scattering experiments whilst simultaneously measuring differential scanning calorimetry (DSC). However, a range of challenges exist to enable the collection of simultaneous small-angle neutron scattering (SANS) and DSC data associated not only with intrinsic flux limitations but also scattering geometry and thermal control. The development of a DSC (temperature range ca. −150 ◦C to 500 ◦C) suitable for SANS is detailed here and its successful use is illustrated with combined measurements on a binary blend of normal alkanes in which one component has been deuterium labelled. © 2014, IOP Publishing Ltd
Deuteration of non-labile protium in starch: biosynthesis and characterisation from yeast-derived starch granules
(Elsevier, 2024-11-01) Russell, RA; Caruana, L; Yepuri, NR; Oldfield, DT; Nguyen, TH; Rawal, A; Gilbert, EP
Deuterium labelling of the non-labile protium atoms in starch granules has been achieved for the first time, by growing genetically modified yeast on deuterated media. Mass spectrometry of the glucose monomers from digested starch showed 44 % average deuteration of the non-labile protium when grown on partially deuterated raffinose (with average deuteration 48 %); yielding starch with 26 % average overall deuteration. Non-labile deuteration was also demonstrated using D2O solvent in the culture medium. Solid-state NMR revealed that deuteration was not evenly distributed across the monomer, being highest at the C6 carbon and lowest at the C1 carbon. SANS revealed two structural features at q = 0.05 Å−1 and 0.4 Å−1, the first corresponding to a lamellar repeat of approximately 12–13 nm while the latter is consistent with B-type crystalline polymer packing. Furthermore, solvent contrast variation SANS analysis yielded a contrast match point of 66 mol% D2O indicative of approximately 30–35 % average deuteration of the bulk granules, consistent with mass spectroscopy. When coupled with the more traditional process of exchange of labile protium in the hydroxyl groups by D2O solvent exchange, the biosynthesis of highly deuterated starch opens new opportunities for neutron scattering experiments involving multicomponent starch-based systems. © 2024 Published by Elsevier Ltd.
Deuterium effects in human serum albumin with nanoparticle silica kinetics
(Australian Institute of Nuclear Science and Engineering, 2016-11-29) White, JW; Raynes, JK; Mata, JP; Gilbert, EP; Knott, RB; de Campo, L
Light scattering shows three stages of the interaction of 80Å radius silica nanoparticles with human serum albumin in buffered solutions. The structures formed in the fast stage, twenty minutes after mixing, have been identified in a “stopped flow” neutron small angle scattering experiment. Good scattering functions were obtained at two-minute time resolution for this phase of the interaction in D2O and H2O. pH dependent changes in structure are analysed using standard fitting programs with a minimum number of parameters. This experiment was aimed to find the structural signature of nanoparticle-protein interaction, possibly the “protein corona” supposed to be formed as a means to promote entry of nanoparticles into cells. Here we use small “engineered” nanoparticles where the indications of toxicity are strong. We show with nanometric resolution that for our system, the association is largely a form of protein-induced aggregation distinct from the protein corona hypothesis. The corona might well be the mode of interaction for small proteins and nanoparticles 10-100 times larger than we have studied, but measurements on widely used commercial products may be more relevant.
Differential effects of genetically distinct mechanisms of elevating amylose on barley starch characteristics
(Elsevier Science Ltd, 2012-07-01) Regina, A; Blazek, J; Gilbert, EP; Flanagan, BM; Gidley, MJ; Cavanagh, C; Ral, JP; Larroque, O; Bird, AR; Li, ZY; Morell, MK
The relationships between starch structure and functionality are important in underpinning the industrial and nutritional utilisation of starches. In this work, the relationships between the biosynthesis, structure, molecular organisation and functionality have been examined using a series of defined genotypes in barley with low (<20%), standard (20–30%), elevated (30–50%) and high (>50%) amylose starches. A range of techniques have been employed to determine starch physical features, higher order structure and functionality. The two genetic mechanisms for generating high amylose contents (down-regulation of branching enzymes and starch synthases, respectively) yielded starches with very different amylopectin structures but similar gelatinisation and viscosity properties driven by reduced granular order and increased amylose content. Principal components analysis (PCA) was used to elucidate the relationships between genotypes and starch molecular structure and functionality. Parameters associated with granule order (PC1) accounted for a large percentage of the variance (57%) and were closely related to amylose content. Parameters associated with amylopectin fine structure accounted for 18% of the variance but were less closely aligned to functionality parameters. © 2012, Elsevier Ltd.
Digestion of food proteins: the role of pepsin
(Taylor & Francis, 2025-01-21) Yang, MX; Yang, Z; Everett, DW; Gilbert, EP; Singh, H; Ye, AQ
The nutritive value of a protein is determined not only by its amino acid composition, but also by its digestibility in the gastrointestinal tract. The interaction between proteins and pepsin in the gastric stage is the first step and plays an important role in protein hydrolysis. Moreover, it affects the amino acid release rates and the allergenicity of the proteins. The interaction between pepsin and proteins from different food sources is highly dependent on the protein species, composition, processing treatment, and the presence of other food components. Coagulation of milk proteins under gastric conditions to form a coagulum is a unique behavior that affects gastric emptying and further hydrolysis of proteins. The processing treatment of proteins, either from milk or other sources, may change their structure, interactions with pepsin, and allergenicity. For example, the heat treatment of milk proteins results in the formation of a looser curd in the gastric phase and facilitates protein digestion by pepsin. Heated meat proteins undergo denaturation and conformational changes that enhance the rate of pepsin digestion. This review provides new ideas for the design of food products containing high protein concentrations that optimize nutrition while facilitating low allergenicity for consumers. © 2025 The Author(s). Published with license by Taylor & Francis Group, LLC. This is an open access article distributed under the terms of the Creative Commons attribution-nonCommercial-noderivatives license.
Direct in situ determination of the surface area and structure of deposited metallic lithium within lithium metal batteries using ultra small and small angle neutron scattering
(Wiley, 2023-10-10) Didier, C; Gilbert, EP; Mata, JP; Peterson, VK
Despite being the major cause of safety and performance issues in lithium metal batteries, experimental difficulties in quantifying directly the morphology of lithium deposited at electrode surfaces have meant that the mechanism of metallic lithium growth within batteries remains elusive. This study demonstrates that quantitative detail about the morphology of metallic lithium within batteries can be derived non-destructively and directly using in situ ultra-small and small-angle neutron scattering. This information is obtained over a large electrode area in cells where lithium deposition processes are typical of real-world applications. Complex variations of surface area and interfacial distances 1–10 µm and 100–300 nm are revealed in size that are influenced by current density and cell cycling history, providing valuable insight into the growth of metallic lithium features detrimental to battery performance. Such quantitative insight into the process of lithium growth is required for the development of safer high-performance lithium metal batteries. © 2023 Commonwealth of Australia. Advanced Energy Materials published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License.
Dynamical transition in a large globular protein: macroscopic properties and glass transition
(Elsevier, 2010-01) Kealley, CS; Sokolova, AV; Kearley, GJ; Kemner, E; Russina, M; Faraone, A; Hamilton, WA; Gilbert, EP
Hydrated soy-proteins display different macroscopic properties below and above approximately 25% moisture. This is relevant to the food industry in terms of processing and handling. Quasi-elastic neutron spectroscopy of a large globular soy-protein, glycinin, reveals that a similar moisture-content dependence exists for the microscopic dynamics as well. We find evidence of a transition analogous to those found in smaller proteins, when investigated as a function of temperature, at the so-called dynamical transition. In contrast, the glass transition seems to be unrelated. Small proteins are good model systems for the much larger proteins because the relaxation characteristics are rather similar despite the change in scale. For dry samples, which do not show the dynamical transition, the dynamics of the methyl group is probably the most important contribution to the QENS spectra, however a simple rotational model is not able to explain the data. Our results indicate that the dynamics that occurs above the transition temperature is unrelated to that at lower temperatures and that the transition is not simply related to the relaxation rate falling within the spectral window of the spectrometer. © 2010, Elsevier Ltd.
Effect of acid dextrinisation on enzyme-resistant starch content in extruded maize starch
(Elsevier, 2010-05) Htoon, AK; Uthayakumaran, S; Piyasiri, U; Appelqvist, IAM; Lopez-Rubio, A; Gilbert, EP; Mulder, RJ
The enzyme-resistant starch (ERS) content in processed high amylose and regular maize starches has been studied, with and without acid dextrinisation. The physicochemical and structural characteristics of the starches were analysed using a variety of techniques. The increase in ERS in high amylose maize starch with dextrinisation was related to the formation of a critical molecular weight fraction (MW ~ 20,000) that could rearrange structurally. Further dextrinisation reduced the processed starch MW to below where it could still form ERS. Regular maize starch containing less than 30% amylose did not increase its resistance to amylase digestibility with acid dextrinisation, probably due to impairment of amylose rearrangement by the numerous branched amylopectin chains. The ERS, which is likely to form during the enzyme-digestion process, is a linear molecule with a maximum degree of polymerisation (DP) of 30, irrespective of the starch source, processing conditions applied or type and amount of acid used. © 2010, Elsevier Ltd.
Effect of enzymatic hydrolysis on native starch granule structure
(American Chemical Society, 2010-12-13) Gilbert, EP; Blazek, J
Enzymatic digestion of six starches of different botanical origin was studied in real time by in situ time-resolved small-angle neutron scattering (SANS) and complemented by the analysis of native and digested material by X-ray diffraction, differential scanning calorimetry, small-angle X-ray scattering, and scanning electron microscopy with the aim of following changes in starch granule nanostructure during enzymatic digestion. This range of techniques enables coverage over five orders of length-scale, as is necessary for this hierarchically structured material. Starches studied varied in their digestibility and displayed structural differences in the course of enzymatic digestion. The use of time-resolved SANS showed that solvent-drying of digested residues does not induce any structural artifacts on the length scale followed by small-angle scattering. In the course of digestion, the lamellar peak intensity gradually decreased and low-q scattering increased. These trends were more substantial for A-type than for B-type starches. These observations were explained by preferential digestion of the amorphous growth rings. Hydrolysis of the semicrystalline growth rings was explained on the basis of a liquid-crystalline model for starch considering differences between A-type and B-type starches in the length and rigidity of amylopectin spacers and branches. As evidenced by differing morphologies of enzymatic attack among varieties, the existence of granular pores and channels and physical penetrability of the amorphous growth ring affect the accessibility of the enzyme to the substrate. The combined effects of the granule microstructure and the nanostructure of the growth rings influence the opportunity of the enzyme to access its substrate; as a consequence, these structures determine the enzymatic digestibility of granular starches more than the absolute physical densities of the amorphous growth rings and amorphous and crystalline regions of the semicrystalline growth rings. © 2011, American Chemical Society.
Effect of ingestion temperature on the pepsin-induced coagulation and the in vitro gastric digestion behavior of milk
(Elsevier B. V., 2023-05) Yang, MX; Ye, AQ; Yang, Z; Everett, DW; Gilbert, EP; Singh, H
Pepsin-induced protein coagulation occurs in the gastric environment when the milk pH is above the isoelectric point of casein proteins. In this study, the effect of milk temperature (4–48 °C) on the hydrolysis of κ-casein by pepsin and the consequent protein coagulation was studied at pH 6.0 for 120 min. Quantitative determination of the released para-κ-casein showed that both the κ-casein hydrolysis reaction rate constant and the pepsin denaturation rate constant increased with an increase in temperature. The temperature coefficient (Q10) of the specific hydrolysis of κ-casein was calculated to be ∼1.95. The coagulation process was investigated by the evolution of the storage modulus (Gʹ). At higher temperature, the milk coagulated faster but had a lower firming rate and Gʹmax with larger aggregates and voids were observed. The digestion behavior of the milk ingested at 4 °C, 37 °C, or 50 °C was investigated for 240 min in a human gastric simulator, in which the milk temperature increased or decreased to 37 °C (body temperature) over ∼ 60 min. The coagulation of the 4 °C milk was slower than for the 37 °C and 50 °C milk. The curd obtained from the 4 °C milk had a looser and softer structure with a significantly higher moisture content at the initial stage of digestion (20 min) which, in turn, facilitated the breakdown and hydrolysis of the caseins by pepsin. During the digestion, the curd structure became more cohesive, along with a decrease in moisture content. The knowledge gained from this study provides insight into the effect of temperature on the kinetics of pepsin-induced milk coagulation and the consequent digestion behavior. © The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync- nd/4.0/).
Effect of β‐glucan on technological, sensory, and structural properties of durum wheat pasta
(American Association of Cereal Chemists, 2012-03-01) Aravind, N; Sissons, M; Egan, N; Fellows, CM; Blazek, J; Gilbert, EP
beta-Glucan is known to have valuable properties for preventative health and is finding widespread use in foods. This study investigated the benefit of adding a commercial source of beta-glucan, Barley Balance (BB) flour, as a functional ingredient in spaghetti. Durum wheat semolina was substituted with BB at levels of 7.5, 15, and 20%, from which spaghetti was prepared on a laboratory scale. The substitution of BB increased the beta-glucan content of semolina from 0.3 to 6% in uncooked and 8% in cooked pasta. Antioxidant activity (measured by 2,2-diphenyl-1-picrylhydrazyl) increased with BB and did not decline significantly on process-ing and cooking. Compared with the control, 7.5% BB had no or minimal effect on pasta cooking loss, stickiness, water absorption, aroma, and sensory texture. However, at higher doses, pasta became less yellow and more brown, firmer, of inferior aroma, more rubbery, and chewy, but less floury to the mouth. The extent of starch digestion decreased with increasing quantities of BB, suggesting that BB may lower glycemic index, with microscopy data suggesting that this decrease was mediated through the development of a more intensive fiber or fiber/ protein matrix retarding enzymatic access to starch granules. © Copyright 2012 AACC International.
Effects of monoglycerides on pasting properties of wheat starch after repeated heating and cooling
(Elsevier, 2011-07-01) Blazek, J; Gilbert, EP; Copeland, L
The effects of repeated heating and cooling on the properties of pastes prepared from a commercial wheat starch (Triticum aestivum L.) with added monoglycerides were studied using a Rapid Visco Analyser (RVA). The nanostructure of the freeze-dried pastes was determined by X-ray diffraction and small-angle X-ray scattering. Pastes prepared from the wheat starch alone, or from the starch mixed with tripalmitin, which does not form complexes with starch, produced regular viscosity profiles in the RVA when subjected to multiple heat-cool cycles. In comparison, the effects of adding monoglycerides (or monoacylglycerols) depended on the chain length and saturation of the fatty acid of the monoglyceride. Repeated heat-cool cycles in the RVA of the starch with different monoglycerides induced the formation of complexes of varying stability that influenced the viscosity trace of the paste during multiple heating and cooling cycles. Small-angle X-ray scattering in combination with X-ray diffraction proved useful in describing the nanostructural changes in the RVA pastes induced by monoglycerides and temperature cycling. The results indicate that the functional properties of starch pastes may be manipulated through the strategic selection of an added monoglyceride. (C) 2011 Elsevier Ltd. All rights reserved.

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