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•Broadband optical properties of graphene and HOPG are comparatively studied by MME.•Optical and dielectric models are constructed for the ellipsometric analysis.•Some intrinsic ...features of graphene and HOPG are observed and discussed.•Physical mechanisms of these intrinsic features are revealed and compared.
Optical properties of mono-graphene fabricated by chemical vapor deposition (CVD) and highly oriented pyrolytic graphite (HOPG) are comparatively studied by Mueller matrix ellipsometry (MME) over an ultra-wide energy range of 0.73–6.42 eV. A multilayer stacking model is constructed to describe the CVD mono-graphene, in which the roughness of the glass substrate and the water adsorption on the graphene are considered. We introduce a uniaxial anisotropic dielectric model to parameterize the optical constants of both the graphene and the HOPG. With the established models, broadband optical constants of the graphene and the HOPG are determined from the Mueller matrix spectra based on a point-by-point method and a non-linear regression method, respectively. Two significant absorption peaks at 4.75 eV and 6.31 eV are observed in the extinction coefficient spectra of the mono-graphene, which can be attributed to the von-Hove singularity (i.e., the π-to-π∗ exciton transition) near the M point and the σ-to-σ∗ exciton transition near the Γ point of the Brillouin zone, respectively. Comparatively, only a major absorption peak at 4.96 eV appears in the ordinary extinction coefficient spectra of the HOPG, which is mainly formed by the π-to-π∗ interband transition.
The conformation and physicochemical attributes of proteins play important roles in determining their flexibility. This study investigates the structural flexibility of twelve different soybean ...proteins. Results suggest that amino acids not only affects protein flexibility but its spatial structure as well. In addition, β-conglycinin protein contained more flexible subunits than glycinin. The HN-87, HN-48, HH-44 and HH-53 proteins were more flexible with lower α-helix content. Other key factors that influence higher structural flexibility include higher surface hydrophobicity and fewer disulfide bonds. Furthermore, more flexible proteins ensured the unfolding of the polypeptide chain backbone and endowed them with excellent emulsifying characteristics. In all, flexible proteins showed stronger surface activity than rigid ones. These findings thus provide clear evidence on the structural flexibility-functional properties interactions of different soybean proteins.
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•The protein with more β-conglycinin and fewer basic subunits had a higher structural flexibility.•Flexible protein with lower content of α-helix would unfold the polypeptide chain backbone easily.•Flexible proteins exhibited better emulsifying and foaming properties due to their higher surface hydrophobicity.
•Quercetin/rutin quenched 7S/11S statically and 11S showed higher affinity.•Rutin showed higher binding affinity to 7S/11S via hydrophobic interactions.•Quercetin bonded to 7S/11S via van der Waals ...and hydrogen bonding interactions.•Quercetin/rutin altered secondary structures and surface hydrophobicity of 7S/11S.•The flavonoids affected the thermal stability and antioxidant capacity of 7S/11S.
The purpose of this research was to comparatively investigate the interactions between bioactive flavonoids (quercetin and rutin) and two predominant soy proteins (β-conglycinin and glycinin), and the structural and functional properties of their complexes. The binding affinities of quercetin/rutin toward 7S/11S were structure-dependent, in that rutin had a higher binding affinity than that of quercetin, and 11S exhibited higher affinity toward quercetin/rutin than that of 7S. The interactions in the 7S/11S–quercetin complexes were driven by van der Waals forces and hydrogen-bonding interactions, whereas the 7S/11S–rutin complexes exhibited hydrophobic interactions. Binding to quercetin or rutin altered the secondary structures (decrease in the α-helix and random coil contents and increase in the β-sheet content), decreased the surface hydrophobicity and thermal stability, and enhanced the antioxidant capacity of 7S and 11S. These findings provide valuable information that can facilitate the design of custom-tailored protein–flavonoid macromolecules.
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•Oxidized dextrans (ODex) with different aldehyde group contents are prepared.•ODex is used as a green cross-linking agent for gelatin to obtain hydrogels.•A high content of aldehyde ...groups leads to an enhanced degree of cross-linking.•The composite hydrogels are thermally stable with excellent mechanical properties.•Adjustment of the hydrogel characteristics allows the controlled release of curcumin.
Controlled drug delivery could minimize side effects while maintaining a high local dose. Herein, a hydrogel carrier was prepared by forming dynamic imine bonds between gelatin and oxidized dextran (ODex) of different molecular weights (Mw = 10, 70, and 150 kDa). The morphology, thermal stability, rheology, mechanical properties, and swelling properties of the hydrogels and the controlled release of curcumin were characterized. When dextran with a higher Mw was used, the ODex contained more aldehyde groups, which led to a higher degree of cross-linking, considerably shorter gel time, decreased hydrogel porosity, and well-controlled release of curcumin. In addition, the cross-linked hydrogels exhibited not only high thermal stability but also excellent mechanical properties. However, because the matrix was hydrophilic, the swelling properties of the hydrogels were not significantly affected by the Mw of ODex. These observations suggest an approach for designing nutrient delivery carriers with improved controlled release.
Comparison between oxidized hydrogen-substituted graphyne (O-HsGY) and graphene oxide (GO) on adsorption and electrochemical properties were studied as well as the possible mechanisms were discussed ...on the effects of modification by deep eutectic solvents (DESs)/ionic liquids (ILs) and composition with multi-walled carbon nanotubes oxide (O-MWCNT). And the effects of DESs and ILs for GO and O-HsGY were compared. The electrical conductivity of the modification materials by DESs/ILs were improved and the aggregation of GO was prevented to some extent. The specific surface area and pore size of composite materials were larger, which could provide more active sites for the electrolyte ions and genotoxic impurities for adsorption/desorption and diffusion. Due to the different extent of expanded interlayer space after modification and better dispersity in solution, the GO-related materials have better adsorption and electrochemical capacitance properties compared with O-HsGY-related materials. There was much inductive affection of groups in DES3 which can effectively inhibit the stacking of GO sheets. And DES3-GO showed good adsorption performance for three types of aniline genotoxic impurities with the adsorption performance of 12.21 mg g
−1
, 8.11 mg g
−1
and 15.98 mg g
−1
by static adsorption experiment, respectively. The larger surface area and pore size were obtained for the composites modified by IL and the oxidation of GO was reduced to a greater extent which improved the conductivity of GO. And the specific capacitance of 130.57 F g
−1
was obtained for IL2-GO/O-MWCNT at the current density of 1.5 A g
−1
.
Graphical Abstract
This study aimed to identify the most suitable delivery system for quercetin. To achieve this objective, four delivery systems, i.e., coarse emulsions, nano-emulsions, high internal phase emulsions ...(HIPEs), and emulsion gels, were prepared and characterized by structure, rheology, stability, and bioaccessibility. The nano-emulsion exhibited the smallest particle size, highest absolute ζ-potential, and best thermal stability and storage stability. The HIPEs showed the best freeze-thaw and oxidative stability. Regarding rheology, all delivery systems exhibited elastic gel-like behavior, which consistent to the characteristics of non-Newtonian fluids. The encapsulation efficiencies of quercetin in these delivery systems were greater than 81.56%. The lowest rate of free fatty acid release was observed in the HIPEs, and the highest bioaccessibilities of quercetin were observed in the nano-emulsion and emulsion gel. Thus, the nano-emulsion is the most suitable for the delivery of quercetin among the four delivery systems.
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•Coarse emulsion, nano-emulsion, HIPEs, and emulsion gel were fabricated.•The encapsulation efficiency of quercetin in these delivery systems was >81.56%.•HIPEs decreased the release rate of FFA during in vitro simulated digestion.•The nano-emulsion and emulsion gel exhibited the highest bioaccessibilities.•The nano-emulsion was the most suitable for the delivery of quercetin.
•Heat-induced SPH gels comprised basic B polypeptide in 11S and β subunits in 7S.•Ultrasound enhanced the hardness of SPH gels at pH 3–9.•Ultrasound increased ionic and hydrogen bonds of SPH gels at ...pH 7–9.•SPH gel treated by pH 7 + ultrasound exhibited the superior gelation characteristics.
This study aimed to evaluate the gelation characteristics of soybean protein hydrolysate (SPH) extracted by enzyme-assisted aqueous extraction. Specifically, the changes in gelation behaviors for heat-induced (95 °C, 20 min) SPH dispersions treated with pH (pH 3, 5, 9; pH 7 as control) and ultrasound (U; 240 W, 30 min) were investigated. The results showed that typical gel behavior with high elastic nature in the viscoelasticity and network structures were observed during the heating process, where the disulfide bond played a dominant role in the gel network formation of all the samples. Notably, the heat-induced aggregation in the SPH gels was mainly formed by the association of the basic B polypeptide in 11S and β subunit in 7S. The most superior SPH gel was formed at pH 7 when assisted by ultrasonication during the heating process. This as-synthesized gel showed a uniform filamentous structure and exhibited the more excellent textural, rheological and thermal properties than those of the samples formed under acidic and alkaline conditions. These results are of great value in revealing the gelation mechanism of SPH.
Spray-drying can stabilize high-moisture-content oil bodies (OBs) against adverse environmental conditions and improve the nutritional value of foods containing OBs. This study investigates the ...effect of the dextrose equivalent (DE) of maltodextrin (MD) on the physicochemical properties and oxidative stability of soybean OB microcapsules during spray-drying. Adding MD to OB microcapsules reduced the surface-oil content and improved the drying yield and encapsulation efficiency. Microcapsules produced by MD having a DE of 10 (MD 10) returned the highest microencapsulation yield (88.84 g/100 g) and efficiency (93.41 g/100 g). OBs stabilized by MD 10 (OB-MD 10) also exhibited optimal water content, water activity, reconstitutability, hygroscopicity, density, and flowability. The addition of MD 10 reduced the size and narrowed the size distribution of microcapsules, thereby reducing agglomeration. Furthermore, MD 10 produced a more effective interfacial barrier, thereby improving the thermal and oxidative stability of the microencapsulated OBs, which can be explained by the molecular structure of the carrier. MD 10 was found to be the most effective wall material for stabilizing OBs. This work establishes spray-drying as a promising method for the industrial production and application of OBs as functional oil products that can carry biologically active ingredients.
•Soybean oil bodies (OBs) were encapsulated using maltodextrin (MD) by spray-drying.•MD-encapsulated OBs were more-stable than spray-dried free OBs.•MD increased the thermal and oxidative stability of OB microcapsules.•MD with dextrose equivalent of 10 (MD 10) produced the most stable OB microcapsules.
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•Complex formation of SPI with dextran dialdehyde (ODex) via Schiff base reaction.•A novel biopolymer-based nanoparticle delivery system for curcumin was developed.•The thermal and ...storage stability of nanocomplex was improved by ODex.•The nanocomplex has excellent antioxidant properties.•Controlled release properties of curcumin improved by ODex.
Dextran dialdehyde (ODex) was added to a nanocomplex of soy protein isolate (SPI)-curcumin (Cur) to improve its stability and achieve controlled release of Cur. The SPI-to-ODex mass ratio was optimized to achieve excellent properties and stability. Interactions between various components were confirmed by spectroscopic analysis, and the effect of ODex on the stability and bioactivity of SPI-Cur colloids was discussed. ODex was found to be crosslinked with SPI via the Schiff base reaction, which increased the ζ-potential and improved the surface hydrophobicity of nanocomplexes. At a SPI-to-ODex mass ratio of 20:1, the nanocomplex had a smaller particle size (199.2 nm), higher ζ-potential (−45.48 mV), and higher encapsulation efficiency (96.25%). Furthermore, adding ODex changed the network structure and effectively improved the thermal and storage stability of Cur as well as its antioxidant properties. Moreover, controlled release of Cur was observed during simulated digestion in the gastrointestinal environment.
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