scholarly journals Characterization of gliadin, secalin and hordein fractions using analytical techniques

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Rani ◽  
Dalbir Singh Sogi ◽  
Balmeet Singh Gill

AbstractProlamins, alcohol soluble storage proteins of the Triticeae tribe of Gramineae family, are known as gliadin, secalin and hordein in wheat, rye and barley respectively. Prolamins were extracted from fifteen cultivars using DuPont protocol to study their physiochemical, morphological and structural characteristics. SDS-PAGE of prolamins showed well resolved low molecular weight proteins with significant amount of albumin and globulin as cross-contaminant. The β-sheet (32.72–37.41%) and β-turn (30.36–37.91%) were found higher in gliadins, while α-helix (20.32–28.95%) and random coil (9.05–10.28%) in hordeins. The high colloidal stability as depicted by zeta-potential was observed in gliadins (23.5–27.0 mV) followed secalins (11.2–16.6 mV) and hordeins (4.1–7.8 mV). Surface morphology by SEM illustrated the globular particle arrangement in gliadins, sheet like arrangement in secalins and stacked flaky particle arrangement in hordeins fraction. TEM studies showed that secalin and hordein fractions were globular in shape while gliadins in addition to globular structure also possessed rod-shaped particle arrangement. XRD pattern of prolamin fractions showed the ordered crystalline domain at 2θ values of 44.1°, 37.8° and 10.4°. The extracted prolamins fractions showed amorphous as well as crystalline structures as revealed by XRD and TEM analysis. Space saving hexagonal molecular symmetry was also observed in TEM molecular arrangement of prolamins which has profound application in development of plant-based polymers and fibres.

2021 ◽  
Author(s):  
MONIKA Rani ◽  
Dalbir Singh Sogi ◽  
Balmeet Singh Gill

Abstract Prolamins extracted from wheat, rye and barley cultivars were analysed for colour characteristics, SDS-PAGE, Amino Acid, Dynamic Light Scattering (DLS), Zeta Potential, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) to elucidate the structure. Amino acid analysis showed significant variation among the prolamins and the predominant essential amino acids were found to be leucine, phenylalanine and valine whereas predominant non-essential amino acids were glutamic acid, arginine and aspartic acid. All the prolamins exhibited positive zeta-potential, however gliadin had a significantly higher zeta potential value. TEM studies of prolamins revealed the compact globular structure but gliadin also had rod-shaped structure. Morphology by SEM illustrated the globular particle arrangement in gliadin and sheet like arrangement in secalin and hordein. XRD pattern of prolamin showed the ordered crystalline domain of prolamin at 44.1°, 37.8° and 10.4°. The d-spacing obtained from XRD and TEM analysis also supports the crystalline domain of prolamin apart from amorphous domain.


2014 ◽  
Vol 6 (10) ◽  
pp. 3490-3499 ◽  
Author(s):  
L. C. Giannossa ◽  
M. Acquaviva ◽  
G. E. De Benedetto ◽  
P. Acquafredda ◽  
R. Laviano ◽  
...  

This study focuses on defining compositional and structural characteristics of ceramic bodies and surfaces of thin-walled pottery (2nd cent. BC–3rd cent. AD) in the Vesuvian area.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ziwen Wang ◽  
Jifang Du ◽  
Shuaifeng Wu ◽  
Yingqi Wei ◽  
Jianzhang Xiao ◽  
...  

To identify the water softening mechanisms that caused landslides in Panzhihua Airport, China, property and saturation tests of the mudstones extracted from a representative landslide were proposed. In this paper, water saturation tests were carried out on samples of carbonaceous mudstone collected from the east side of the No. 12 landslide at the airport. A number of different analytical techniques and mechanical tests were used to determine changes in chemical composition, mineral assemblages, and mudstone structural characteristics, including shear strength, after the mudstone had been softened. Three kinds of changes caused by water and three mudstone softening stages are proposed. The results show that the water has a significant influence on the properties of the mudstone, so the stability of the mudstone in the watery period is a big threat to the upper structure. A model for water immersion mudstone strength softening is developed. The model incorporates a permeability coefficient, the hydraulic gradient, and time; the model can be used to determine the mudstone’s shear strength and internal friction angle. This study provides a reference for the study of rock softened by water immersion.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Aisha Malik ◽  
S. Hameed ◽  
M. J. Siddiqui ◽  
M. M. Haque ◽  
M. Muneer

Nanocrystalline TiO2particles doped with different concentrations of Cerium (Ce, 1–10%) have been synthesized using sol-gel method. The prepared particles were characterized by standard analytical techniques such as X-ray diffraction (XRD), FTIR and Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The XRD analysis shows no change in crystal structure of TiO2after doping with different concentrations of Ce, which indicates the single-phase polycrystalline material. The SEM analysis shows the partial crystalline nature of undoped, and doped TiO2and TEM analysis shows the particle sizes were in the range of 9–14 nm in size. The a.c. analysis shows that the dielectric constantεand dielectric loss tanδdecrease with the increase in frequency. The dielectric property decreases with the increase in dopant concentration. It is also observed that the impedance increases with an increase in dopant concentration. The photocatalytic activity of the synthesized particles (Ce-doped TiO2) with dopant concentration of 9% (Ce) showed the highest photocatalytic activity for the degradation of the dye derivative Remazol Brilliant Blue R in an immersion well photochemical reactor with 500 W halogen linear lamp in the presence of atmospheric oxygen.


2020 ◽  
Vol 21 (3) ◽  
pp. 1012
Author(s):  
Fusheng Sun ◽  
Xiaoxue Xie ◽  
Yufan Zhang ◽  
Jiangwei Duan ◽  
Mingyu Ma ◽  
...  

The present research reported the effects of structural properties and immunoreactivity of celiac-toxic peptides and wheat storage proteins modified by cold jet atmospheric pressure (CJAP) plasma. It could generate numerous high-energy excited atoms, photons, electrons, and reactive oxygen and nitrogen species, including O3, H2O2, •OH, NO2− and NO3− etc., to modify two model peptides and wheat storage proteins. The Orbitrap HR-LC-MS/MS was utilized to identify and quantify CJAP plasma-modified model peptide products. Backbone cleavage of QQPFP and PQPQLPY at specific proline and glutamine residues, accompanied by hydroxylation at the aromatic ring of phenylalanine and tyrosine residues, contributed to the reduction and modification of celiac-toxic peptides. Apart from fragmentation, oxidation, and agglomeration states were evaluated, including carbonyl formation and the decline of γ-gliadin. The immunoreactivity of gliadin extract declined over time, demonstrating a significant decrease by 51.95% after 60 min of CJAP plasma treatment in vitro. The CJAP plasma could initiate depolymerization of gluten polymer, thereby reducing the amounts of large-sized polymers. In conclusion, CJAP plasma could be employed as a potential technique in the modification and reduction of celiac-toxic peptides and wheat storage proteins.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Kamonpan Wongyai ◽  
Phitchayapak Wintachai ◽  
Rasimate Maungchang ◽  
Parawee Rattanakit

A green, simple, and rapid synthesis of gold nanoparticles using plant extract, Cryptolepis buchanani Roem. and Schult, and their applications are first described in this paper. The formation of gold nanoparticles was visually observed by the appearance of a ruby red color, which was further indicated by an absorption peak at 530 nm in UV-Vis spectroscopy. Optimization of reaction parameters for the gold nanoparticles was also investigated. Various analytical techniques were employed as part of the process of characterizing the resulting gold nanoparticles. Fourier transform infrared (FTIR) analysis revealed that the phenol compounds present in the extract were responsible for gold(III) reduction and stabilization of gold nanoparticles. Transmission electron microscopy (TEM) analysis showed that the gold nanoparticles were spherical in shape with an average diameter of 11 nm. Powder X-ray diffraction (XRD) pattern indicated that the green synthesis approach produced highly crystalline, face-centered cubic gold nanoparticles. Energy-dispersive X-ray spectroscopy (EDS) measurements confirmed the presence of elemental gold in the prepared nanoparticles. The negative zeta potential value of gold nanoparticles was found to be -30.28 mV. The green synthesized gold nanoparticles expressed effective antibacterial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Acinetobacter baumannii and exhibited an excellent catalytic property in terms of its reduction ability of methylene blue.


Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1877
Author(s):  
Yue Xu ◽  
Zhongjiang Wang ◽  
Baokun Qi ◽  
Anqi Ran ◽  
Zengwang Guo ◽  
...  

Chiba tofu is a new type of vegetarian food prepared with soy protein isolate (SPI). According to factory feedback, the SPI stored in the factory storeroom in summer undergoes reactive oxidation, which changes the structure of SPI and further affects the quality of Chiba tofu. Consequently, the main objective of this study was to prepare Chiba tofu with SPI with different storage periods and evaluate the effect of different degrees of oxidation on structural characteristics of SPI and rheology, texture, microstructure and sensory properties of Chiba tofu. The carbonyl content and turbidity of SPI significantly increased, and the contents of free sulfhydryl (SH) and disulfide bond (S-S) simultaneously decreased with storage time. The oxidation changes the SPI conformation, leading to a transition of α-helix and β-turn to β-sheet and random coil during the storage periods. In the SDS–PAGE analysis, oxidation promoted the SPI molecules crosslinked and aggregated, which affected the quality of Chiba tofu. In short storage periods (0–12 days), SPI was relatively moderately oxidized when the carbonyl content was between 4.14 and 6.87 mmol/g. The storage and loss modulus of Chiba tofu both increased, the network was compact, and the hardness and springiness of Chiba tofu showed an increasing trend. Moreover, in longer storage periods (12–30 days), the SPI was relatively severely oxidized when the carbonyl content was between 7.24 and 9.14 mmol/g, which had an adverse effect on Chiba tofu rheological and texture properties, microstructure, and sensory properties. In sensory evaluation, Chiba tofu stored 12 days had the highest overall quality score than that stored on other days. This study is expected to provide an argument for the better industrial production of Chiba tofu.


2002 ◽  
Vol 712 ◽  
Author(s):  
Andrew Lins ◽  
Lucille A. Giannuzzi ◽  
Frederick A. Stevie ◽  
Beth Price ◽  
Mark Tucker ◽  
...  

ABSTRACTMany issues in the examination, treatment, and authentication of works of art depend on the accurate characterization of thin layers, which may challenge the resolution and detection limits of instrumentation routinely used for analyses, particularly SEM-EDS and EPMA. Such thin layers are the focus of recent conservation analysis in preparation for a major retrospective of Thomas Eakins' works. Interpretation of Eakins' paintings has often been complicated by mechanical and chemical cleaning procedures performed after the artist's death in 1916.Recent advances in Focused Ion Beam (FIB) technology provide means for preparing specimens of thin layers that can be analyzed directly by transmission electron microscopy (TEM) yielding resolution in the nanometer range or better. This paper describes initial work undertaken to elucidate the inorganic components in the uppermost paint layers from Eakins' The Crucifixion, completed in 1880. Using TEM, we have observed a 250-500 nm Pb-rich nanocrystalline region, a pigment free zone less than 2 μm thick, and a lead white paint layer. An analysis of samples from two paintings that were subjected to mild cleaning operations did not show comparable Pb-rich nanocrystals. These results suggest that The Crucifixion may have been subjected to a more aggressive cleaning treatment which caused the entrainment of the Pbrich material–not resolvable by traditional analytical techniques – at the painting's surface. The use of FIB/TEM has enabled clear identification of the thin paint surface layers and offers enormous promise for understanding the processing and alteration of artists' materials, including issues of authentication.


2017 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Sébastien Maillette ◽  
Caroline Peyrot ◽  
Tapas Purkait ◽  
Muhammad Iqbal ◽  
Jonathan G. C. Veinot ◽  
...  

Environmental contextThe fate of nanomaterials in the environment is related to their colloidal stability. Although numerous studies have examined their homoagglomeration, their low concentration and the presence of high concentrations of natural particles implies that heteroagglomeration rather than homoagglomeration is likely to occur under natural conditions. In this paper, two state-of-the art analytical techniques were used to identify the conditions under which nanosilver was most likely to form heteroagglomerates in natural waters. AbstractThe environmental risk of nanomaterials will depend on their persistence, mobility, toxicity and bioaccumulation. Each of these parameters is related to their fate (especially dissolution, agglomeration). The goal of this paper was to understand the heteroagglomeration of silver nanoparticles in natural waters. Two small silver nanoparticles (nAg, ~3nm; polyacrylic acid- and citrate-stabilised) were covalently labelled with a fluorescent dye and then mixed with colloidal silicon oxides (SiO2, ~18.5nm) or clays (~550nm SWy-2 montmorillonite). Homo- and heteroagglomeration of the nAg were first studied in controlled synthetic waters that were representative of natural fresh waters (50μg Ag L–1; pH 7.0; ionic strength 10–7 to 10–1 M Ca) by following the sizes of the nAg by fluorescence correlation spectroscopy. The polyacrylic acid-coated nanosilver was extremely stable under all conditions, including in the presence of other colloids and at high ionic strengths. However, the citrate-coated nanosilver formed heteroaggregates in presence of both colloidal SiO2 and clay particles. Nanoparticle surface properties appeared to play a key role in controlling the physicochemical stability of the nAg. For example, the polyacrylic acid stabilized nAg-remained extremely stable in the water column, even under conditions for which surrounding colloidal particles were agglomerating. Finally, enhanced dark-field microscopy was then used to further characterise the heteroagglomeration of a citrate-coated nAg with suspensions of colloidal clay, colloidal SiO2 or natural (river) water.


Author(s):  
Xiao-Peng Peng ◽  
Jing Bian ◽  
Shuang-Quan Yao ◽  
Cheng-Ye Ma ◽  
Jia-Long Wen

Elucidating the chemical and structural characteristics of hemicelluloses and lignin in the p-coumarate 3-hydroxylase (C3H) down-regulated poplar wood will be beneficial to the upstream gene validation and downstream biomass conversion of this kind of transgenic poplar. Herein, the representative hemicelluloses and lignin with unaltered structures were prepared from control (CK) and C3H down-regulated 84K poplars. Modern analytical techniques, such as 13C NMR, 2D-HSQC NMR, and gel chromatography (GPC), were performed to better delineate the structural changes of hemicelluloses and lignin caused by transgenesis. Results showed that both the hemicelluloses (H-CK and H-C3H) extracted from control and C3H down-regulated poplar wood have a chain backbone of (1→4)-β-D-Xylan with 4-O-Me-α-D-GlcpA as side chain, and the branch degree of the H-C3H is higher than that of H-CK. With regarding to the lignin macromolecules, NMR results demonstrated that the syringyl/guaiacyl (S/G) ratio and dominant substructure β-O-4 linkages in C3H down-regulated poplar were lower than those of control poplar wood. By contrast, native lignin from C3H down-regulated poplar wood exhibited higher contents of p-hydroxybenzoate (PB) and p-hydroxyphenyl (H) units. In short, C3H down-regulation resulted in the chemical and structural changes of the hemicelluloses and lignin in these poplar wood. The identified structures will facilitate the downstream utilization and applications of lignocellulosic materials in the biorefinery strategy. Furthermore, this study could provide some illuminating results for genetic breeding on the improvement of wood properties and efficient utilization of poplar wood.


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