Bond Content Research Articles

Effect of long‐chain inulin on the rheological properties, water state, gluten structure, and microstructure of frozen dough

SummaryThis study aimed to investigate the effects of long‐chain inulin (FXL) on the water state, rheological properties, gluten depolymerisation, and microstructure of frozen dough. The results suggested that FXL improved the water state and rheological properties of the frozen dough. It also significantly enhanced the proportion of bound water, G′, G″ value, and the pasting properties of the frozen dough. FXL effectively increased the content of disulfide bonds, α‐helix, and β‐sheet structures in gluten, thereby enhancing its thermal stability and inhibiting depolymerisation. Microstructure results demonstrated that FXL improved the continuity and uniformity of the gluten‐starch network structure in frozen dough, effectively reducing the mechanical damage caused by ice crystals. The addition of 1 g/100 g FXL better alleviate the deterioration of frozen dough quality during frozen storage and improved its overall quality. These results indicated that FXL can be used as a promising cryoprotectant in frozen dough.

Molecular Structure and Properties of Resistant Dextrins from Potato Starch Prepared by Microwave Heating.

The dextrinization of potato starch was performed using a sophisticated single-mode microwave reactor with temperature and pressure control using 10 cycles of heating with stirring between cycles. Microwave power from 150 to 250 W, a cycle time from 15 to 25 s, and two types of vessels with different internal diameters (12 and 24 mm) and therefore different thicknesses of the heated starch layer were used in order to estimate the impact of vessel size used for microwave dextrinization. The characteristics of resistant dextrins (RD) including solubility in water, total dietary fiber (TDF) content, color parameters, the share of various glycosidic bonds, and pasting and rheological properties were carried out. The applied conditions allowed us to obtain RDs with water solubility up to 74% at 20 °C, as well as TDF content up to 47%, with a predominance of low-molecular-weight soluble fiber fraction, with increased content of non-starch glycosidic bonds, negligible viscosity, and a slightly beige color. The geometry of the reaction vessel influenced the properties of dextrins obtained under the same heating power, time, and repetition amounts. Among the conditions used, the most favorable conditions were heating 10 times for 20 s at 200 W in a 10 mL vessel and the least favorable were 15 s cycles.

Formation of coatings from accelerated ions of fluorinated fullerene C<sub>60</sub>(CF<sub>3</sub>)<sub>12</sub>

The first results of the deposition of coatings from accelerated ions of fluorinated fullerene C60(CF3)12 are presented. The coatings were formed at room temperature on Si substrates from a beam of singly charged C60(CF3)+12 ions with an energy of 5 keV, as well as from an ion beam, which also contained doubly charged C60(CF3)122+ ions and a certain amount of ionized fragments of molecules. The properties and structure of coatings obtained from accelerated ions of fluorinated fullerene are compared with the properties and structure of coatings obtained from accelerated C60 fullerene ions under the same conditions. According to X-ray photoelectron spectroscopy, fluorinated fullerene coatings contain about 4% fluorine. Investigations of the coatings structure and chemical bonds by X-ray photoelectron spectroscopy and Raman scattering showed that the presence of fluorine leads to decrease in the content of sp3 bonds and the formation of graphite-like sp2 structures. Coating hardness (H) and Young's modulus (E) compared to C60 ion coatings decrease from 36 to 18 GPa and from 245 to 133 GPa, respectively. The H/E ratio remained the same (~0.14). Tribological tests have shown for all coatings a friction coefficient close to 0.1. Also, all coatings are characterized by very low wear, less than 10–7 mm3/N∙m for coatings obtained from C60(CF3)12 ions, the contact angle is ~76°–78°. In the absence of fluorine, for the coating obtained from C60 ions, it is ~90°.

Effect of β-sitosterol+γ-oryzanol-based oleogels on protein conformation and gel properties of Nemiperus virgatus surimi.

The impact of β-sitosterol+γ-oryzanol-based oleogels or peanut oil on the protein conformation and gel quality of Nemiperus virgatus surimi was evaluated. A significant reduction in gel strength, texture parameters and water holding capacity (WHC) of surimi was found as oil concentration increased (P < 0.05). However, compared with peanut oil, the gel strength, hydrophobic interaction and disulfide bond content of surimi gel containing oleogels increased by 6.919%, 32.635% and 12.409%, respectively, when the oil concentration was 10 g kg-1. Both oleogels and peanut oil could enhance the whiteness of surimi gel. Oleogels induced the unfolding of surimi proteins, and promoted the conformational shift from α-helix to β-sheet structure. Furthermore, oleogels filled the gaps of protein networks to make the microstructure of surimi gel more compact and uniform, improving the WHC and reducing the cooking loss. γ-Oryzanol+β-sitosterol-based oleogel alleviated the adverse influences of direct addition of peanut oil on the gel and textural properties of surimi products. © 2024 Society of Chemical Industry.

Enhanced DC surface discharge characteristics of epoxy composites treated by dielectric barrier discharge plasma fluorination and its mechanisms

Surface flashover is a destructive high-voltage discharge phenomenon greatly limiting the update of modern power electronic and electrical equipment. Surface plasma treatment is a high-energy, eco-friendly, and convenience method, it changes the surface properties and owns potential to improve flashover voltage. In the present work, plasma fluorination (PF) technique are used to treat EP/Al2O3 composites, surface morphology, element and bonds content, surface trap, conductivity, charging, and DC flashover voltage are tested and simulated, the effects of plasma on surface discharge are explained through the investigation from microscopic molecular reactions to macroscopic flashover characteristics. It indicates the 20 min PF modified sample exhibits the superior DC flashover performance, increasing by 17 % compare to untreated sample. During PF modification, the epoxy chains are degraded and fluorinated, the degradation rather than fluorination of molecular chains introduce large amounts of shallow traps into the composites, accelerating carriers’ migration and improving surface conductivity, causing surface charges to dissipate through surface conductance. Consequently, the surface electric field distortion degree reduces, and the subsequent gas ionization and plasma formation in the gas phase is suppressed, leading to the improvement of DC flashover voltage after PF modifications.

Effects of Moisture Migration and Changes in Gluten Network Structure during Hot Air Drying on Quality Characteristics of Instant Dough Sheets.

The impact of hot air drying temperature on instant dough sheets' qualities was investigated based on water migration and gluten network structure changes. The results revealed that the drying process redistributed the hydrogen proton, with deeply bound water accounting for more than 90%. The T2 value decreased as the drying temperature increased, effectively restricting moisture mobility. Meanwhile, microstructural analysis indicated that instant dough sheets presented porous structures, which significantly reduced the rehydration time of instant dough sheets (p < 0.05). In addition, elevated drying temperatures contributed to the cross-linking of proteins, as evidenced by increased GMP and disulfide bond content (reaching a maximum at 80 °C), which improved the texture and cooking properties. Hence, the water mobility was effectively reduced by controlling the drying temperature. The temperature had a facilitating impact on promoting the aggregation of the gluten network structure, which improved the quality of the instant dough sheets.

Alcohol pretreatment for depolymerization and fractionation of corn stalk

The development of an efficient pretreatment technology to depolymerize and fractionate lignocellulose into glucan, xylan, and lignin is crucial for lignocellulose biorefinery. In this study, alcohol pretreatments using methanol and pentanol were developed and compared. Based on the solubility of the two alcohols, the methanol and pentanol pretreatments are homogeneous and biphasic, respectively. Carbon flow analysis revealed that 1kg of corn stalk (CS) yielded 111.9g of lignin with the homogeneous pretreatment (lignin yield: 60.0 %), while 149.8g of lignin was obtained with the biphasic pretreatment (lignin yield: 80.3 %). Biphasic pretreatment yielded the lignin with higher activity (more β-O-4 bond content). Additionally, 210.4g and 267.0g of glucose were obtained from the enzymatic hydrolysis of homogeneously and biphasically pretreated CS, respectively, where glucose yields were 53.0 % and 67.2 %, respectively. Fourier Transform infrared spectroscopy and X-ray diffraction were employed to verify the component fractionation results. The Hansen solubility parameter and combined severity factor analysis were used to evaluate the effects of various factors on component fractionation. Nuclear magnetic resonance and mechanistic analyses were performed to explore the process of component fractionation. Overall, we discovered that biphasic pretreatment was significantly better than homogeneous pretreatment in component fractionation, including component recovery and lignin activity.

Unveiling the structural and physico-chemical properties of glutenin macropolymer under frozen storage: Studies on experiments and molecular dynamics simulation

Glutenin macropolymer (GMP) plays an important role in wheat gluten fractions, and extensively presents in the frozen dough. However, the effects of freezing treatment on GMP remain not abundantly understood. In this study, we investigated the structure and physico-chemical properties of GMP under frozen storage through experimental methods and bioinformatics algorithms. Results revealed that freezing treatment weakened the structure and properties of GMP to varying degrees, and GMP might have tolerance to short-term freezing storage. During frozen storage, portions of α-helix in GMP were converted into β-turn and random coil, slight changes in the tertiary structure, and its surface hydrophobicity increased by 4.8 %. SDS-PAGE profiles indicated that the depolymerization behavior mainly occurred above the Mw of 70.0 kDa. Slight changes were observed in the content of free thiol groups and disulfide bonds during frozen storage. Combination of fluorescence spectroscopy and intermolecular interactions suggested that hydrogen bonds and hydrophobic interactions were probably important indicators for evaluating the deterioration of GMP. Frozen storage resulted in an unfolded and open protein network. Moreover, freezing treatment led to a main conversion from strongly bond water to weakly bond water. However, no significant changes in water distribution were observed during the first 7 days of frozen storage. The viscoelastic loss of GMP primarily occurred in the first fourteen days, but tan δ did not significantly increased, indicating that protein has not been seriously deteriorated. Molecular dynamics simulation further supplemented and validated these experimental results from molecular level through analysis of root mean square deviation, root mean square fluctuation, solvent-accessible surface area, radius of gyration and the number of hydrogen bonds.

Investigation of wettability and icing on the steel surface using laser surface treatment

Icing impairs normal functionality for a variety of industries and applications. Research on hydrophobic surfaces is being conducted to solve the icing problem. In this study, a hydrophobic surface was fabricated on SM490A using a nanosecond laser. The change in surface microstructure was observed. Hydrophilicity was immediately observed right after laser irradiation, and the contact angle increased over time, resulting in hydrophobicity. To explain the wettability conversion, X-Ray Photoelectron Spectroscopy (XPS) was used to observe changes in surface chemical composition and element bonding. It was observed that the level of and increased immediately after laser irradiation, resulting in surface oxidation. Since the presence of oxides has high surface energies, they contribute to super hydrophilic surfaces. Since the bond has low surface energy and the content of nonpolar bonds and increased over time, the contact angle subsequently increases over time. When the ice shape was observed after dropping a droplet on the surface, the higher contact angle specimen reduced the attached area. Therefore, the surface treatment using a nanosecond laser can produce a hydrophobic surface on the SM490A specimens so that it may solve ice adhesion problems.

Reduction of soybean globulin antigen by soybean protein isolate/γ-aminobutyric acid complexes: Effect of the different concentrations of γ-aminobutyric acid on the protein modification, antigen levels, and foaming properties

Soybean flour has received increasing attention because of its unique nutritional properties. However, potential allergies to soy protein limit its application. This study aims to investigate the impact of various concentrations of γ-aminobutyric acid (GABA) on the secondary structure, foaming properties, and antigenicity of soybean protein obtained from soybean flour under thermal sterilisation. GABA increased the content of α-helix, reduced β-turn and random coil in soybean protein. The results indicated that after heating treatment, the concentration of GABA significantly affects the spatial conformation of soybean protein isolates (SPI). When the concentration of GABA was 0.40% (w/v), the particle size, zeta potential, and surface hydrophobicity of the SPI were the lowest, whereas the disulfide bond content was the highest. Multi-spectral technologies indicated that adding 0.40% GABA could assemble the system in a relatively stable manner. Moreover, the rigid structure of the protein was destroyed. This structural change significantly reduced the foaming and allergy of the protein. Adding 0.40% GABA could reduce the β-conglycinin antigen concentration from 24.26 mg/mL to 4.43 mg/mL. This study provides new insights into the production of new low-allergenic soybean flour. Additionally, it offers an assurance for the safe consumption of soybeans by individuals with allergies.

Effects of wheat germ treated with different stabilization methods on dough characteristics and steamed bread quality

In this study, different stabilization methods (hot air, microwave, high-pressure, water bath, atmospheric pressure, ultraviolet, and microwave coupled with high-pressure) were applied to wheat germ to explore their impacts on the dough characteristics and quality of the steamed bread end-product. The stabilized lipase activity for all treatment schemes ranged from 14.05-7.24 mg/g, with the ultraviolet treatment (14.05 mg/g) being the least effective and high-pressure treatment (7.24 mg/g) being the most effective. However, the addition of high-pressure treatment increased the β-sheets content of wheat germ in the dough to 27.74%, increased dough hardness, and decreased the specific volume of the steamed bread to 1.61 mL/g. Hot air treatment improved the structural stability of the wheat germ dough, and the α-helix content and disulfide bond content increased to 29.06% and 23.10 μmol/mg, respectively, with good fermentation characteristics. This study reveals the impact of stabilized wheat germ on the dough's processing characteristics and the bread's quality, providing solutions for wheat germ stabilization methods in industrial production.

The multi-scale structure and in vitro digestive kinetics of underutilized Chinese seedless breadfruit starch.

In our previous research, the significant difference of physiochemistry properties for underutilized starches was showed between Chinese seedless breadfruit species and the other species. Based on this, the multiscale structure and digestion kinetics of Chinese seedless breadfruit of Spice and Beverage Research Institute species (SBS) and Xinglong species (XBS) was further researched. The SBS exhibited higher α-1,6 glycosylic bond content, free side-chain groups content, double-helix content, homogeneity, molecular weight, and V-type polymorphism, and fewer amorphous content, blocklet sizes, and a smaller semi-crystalline lamella thickness than XBS. Additionally, SBS showed higher final viscosity, pasting temperature, and gelatinization enthalpy than those of XBS. Consequently, SBS display lower rate constant (0.73h-1) and glycemic index (65.17) than those of XBS (0.86h-1 and 73.95). The anti-digestibility mechanism was revealed by the structure-digestibility relationship. It was found that resistant starch of SBS and XBS were significantly higher than those of starch from American and African species. This indicated that Chinese breadfruit starch could be considered as a good source of resistant starch, regulating glycemic index. In summary, XBS and XBS could be considered as a well source of resistant starch to make foods for preventing or improving type II diabetes or hyperlipemia.

Rapidly one-step fabrication of durable superhydrophobic graphene surface with high temperature resistance and self-clean

High temperature resistant and self-cleaning superhydrophobic flexible film has potential application value in lunar exploration. In this paper, a novel method of magnetic field-assisted ultrafast laser induced plasma was proposed to fabricate strongly superhydrophobic graphene on polyimide film with multi-level micro-nano structure. The longitudinal magnetic field contributed to constrain the induced plasma in the lateral direction so as to form a plasma plume with high temperature and high energy density. The multi-level micro-nano graphene structures with better ordering and superhydrophobicity were fabricated, which had a contact angle of 163.1° and a roll-off angle of 1.5°, as well as hydrophobic CC bond content of 72.82 %. The droplets can achieve obvious bouncing at different heights of 1 cm and 5 cm on surfaces at different angles of 0°, 5° and 10°. The contact angle was still greater than 160° after 25 days of aging treatment and heating at 300 °C for 40 min. The water droplets before and after the heating of the sample can push the dust off the surface, showing excellent high temperature resistance and self-cleaning performance.

Interfacial and foaming properties of plant and microbial proteins: Comparison of structure-function behavior of different proteins

Many plant proteins are amphiphilic molecules that can adsorb to air-water interfaces and form protective coatings around gas bubbles. In this study, the composition, structure, physicochemical properties, air-water interfacial properties, and foaming properties of 16 plant and microbial proteins were characterized. We found a correlation between the composition, structure, physicochemical properties, and foaming properties of the proteins. The foaming capacity of them showed a highly significant positive correlation (p ≤ 0.01) with their foaming stability, α-helix content, surface hydrophobicity, and free sulfhydryl content. The foaming capacity and foaming stability showed highly significant negative correlations with disulfide bond content (p ≤ 0.01). We found wheat gluten protein (WGP) and mung bean protein (MBP) had higher foaming capacity (102.67 ± 8.08 % and 89.33 ± 4.72 %), which could be attributed to higher surface hydrophobicity (179.68 ± 1.40 and 130.28 ± 1.41) and larger contact angle (82.369 ± 0.016° and 82.949 ± 0.228°).

Effects of Soy Protein Isolate and Inulin Conjugate on Gel Properties and Molecular Conformation of Spanish Mackerel Myofibrillar Protein.

The gel properties and molecular conformation of Spanish mackerel myofibrillar protein (MP) induced by soy protein isolate-inulin conjugates (SPI-inulin conjugates) were investigated. The addition of SPI-inulin conjugates significantly enhanced the quality of the protein gel. An analysis of different additives was conducted to assess their impact on the gel strength, texture, water-holding capacity (WHC), water distribution, intermolecular force, dynamic rheology, Raman spectrum, fluorescence spectrum, and microstructure of MP. The results demonstrated a substantial improvement in the strength and water retention of the MP gel with the addition of the conjugate. Compared with the control group (MP), the gel strength increased from 35.18 g·cm to 41.90 g·cm, and WHC increased from 36.80% to 52.67% with the inclusion of SPI-inulin conjugates. The hydrogen bond content was notably higher than that of other groups, and hydrophobic interaction increased from 29.30% to 36.85% with the addition of SPI-inulin conjugates. Furthermore, the addition of the conjugate altered the secondary structure of the myofibrillar gel, with a decrease in α-helix content from 62.91% to 48.42% and an increase in β-sheet content from 13.40% to 24.65%. Additionally, the SPI-inulin conjugates led to a significant reduction in the endogenous fluorescence intensity of MP. Atomic force microscopy (AFM) results revealed a substantial increase in the Rq value from 8.21 nm to 20.21 nm. Adding SPI and inulin in the form of conjugates is an effective method to improve the gel properties of proteins, which provides important guidance for the study of adding conjugates to surimi products. It has potential application prospects in commercial surimi products.

Effect of Polygonatum cyrtonema Hua polysaccharides on gluten structure, in vitro digestion and shelf-life of fresh wet noodle

This study aimed to investigate the effects of raw Polygonatum cyrtonema Hua polysaccharides (RPCPs) and “zhi” P. cyrtonema Hua polysaccharides (ZPCPs) on the gluten structure, in vitro digestion, and shelf life of fresh wet noodles (FWN). The results demonstrated that incorporating PCPs improved the cooking and sensory qualities of FWN. Moreover, the shelf life of FWN was extended by 6 days with 1.5 % RPCPs (w/w) compared with the control FWN. Furthermore, incorporating 1.5 % ZPCPs led to a 1.2- and 0.2-fold increase in the disulfide bond and α-helix content, respectively, compared with the control FWN. This resulted in enhanced gluten structure, improved springiness and viscidity, and reduced cooking loss by 14.47 %–52.19 %. The scanning electron microscopy analysis revealed that the starch particles were entrapped by PCPs, leading to higher gelatinization temperature and lower setback value of FWN, thereby reducing the starch digestion ratio to 55.50 %. In summary, the findings suggested that FWN containing PCPs can extend shelf life, improve taste, and slow starch digestion staple.

Effect of N-ethylmaleimide as a blocker of disulfide bonds formation on the properties of different protein-emulsion MP composite gels

Three different emulsions of myofibrillar protein (MP), soy protein isolate (SPI) and egg white protein isolate (EPI) were individually mixed with MP sol to form composite gels. N-ethylmaleimide (NEM) was used as a sulfhydryl group blocker to evaluate the effects of sulfhydryl and disulfide bonds on the properties of different protein–emulsion composite gels. The results show that the disulfide bond contents in the MP (SPI, EPI) emulsion composite gel decreased from the initial 2.4 ± 0.1, (2.3 ± 0.2, 1.8 ± 0.4) mol/kg to 0.6 ± 0.1, (0.5 ± 0.3, 0.7 ± 0.1) mol/kg with the NEM content increased. In addition, the microstructure showed that the interfacial protein membrane of the emulsion globules were broken in different degrees, indicating that the interaction between the emulsion and the gel matrix was weakened. Meanwhile, gel strength, water distribution and elastic modulus of the composite gels were reduced with NEM contents increased.

Comparison of the effect of vegetable oil and oleogels with different unsaturation on gel properties of Nemipterus virgatus surimi

The effect of oleogels prepared using γ-oryzanol, β-sitosterol and vegetable oils with different unsaturation on the gel properties of surimi was compared. The findings from SEM and optical microscopy demonstrated that direct addition of vegetable oils caused loose surimi gel three-dimensional network structure, which negatively impacted the water holding capacity (WHC) and texture properties. However, oleogels increased the hydrophobic interaction and disulfide bond content, facilitated the transition from α-helix to β-sheet, improving the WHC and gel strength of surimi. Among them, the surimi containing oleogels prepared by linseed oil with the highest polyunsaturated fatty acid (PUFA) content had the highest gel strength and WHC, which were 3936.067 g·mm and 66.77 %, respectively. The results of microstructure showed that linseed oil based oleogels were able to fill the gaps of gel network more uniformly with smaller holes. Therefore, oleogels enriched with PUFA were more effective in enhancing the gel properties of surimi.

Preparation and Characterization of Multi-Network Crosslinked Gels for Preventing Spontaneous Combustion of Coal

ABSTRACT In order to improve the inhibition performance of a retardant in various stages of coal spontaneous combustion, this study selected guar gum (guar) mixed with sodium tetraborate to form a multi-web gel. Then, polyethylene glycol (PEG) was added for the insertion and modification to improve the physical inhibition effect. Furthermore, we compounded the composite guar/PEG with the chemical retardant 2-hydroxyphosphonoacetic acid (HPAA) to prepare a composite retardant with the effect of full-stage inhibition. Multi-web gel composite inhibitor with a full-stage inhibition effect was prepared. Response surface analysis was used to determine the optimal solution. Scanning electron microscopy tests revealed that the surface folds of PEG/guar increased and the water retention capacity was greatly enhanced. The plugging wind experiment results show that the limiting air pressure of the gel material is 249 Pa, which can match the downhole plugging wind work. Using XRD experiments, the diffraction angle of PEG/guar was narrowed from 18.20° to 17.64°, the crystal layer spacing was increased from 4.8685 nm to 5.0218 nm, and PEG was successfully intercalated into the guar. Using Fourier-transform infrared spectroscopy, it was found that the content of free hydroxyl groups and aliphatic groups became lower, and the content of carbonyl groups and ether bonds increased, which greatly enhanced the antioxidant capacity of coal. Using thermogravimetric analysis, the characteristic temperature points of single and composite inhibitors were examined macroscopically. The results showed that the inhibition treatment could obviously chelate the transition metal ions in the coal samples, which greatly inhibited the process of coal oxidation and achieved the purpose of inhibiting the spontaneous combustion of coal.

Enhancement of ultrasonic-assisted and agitation-assisted flaxseed oil extractions: Kinetic modeling and optimization

The flaxseed oil extraction process has been investigated and enhanced by applying Ultrasonic-Assisted Extraction (UAE), and Mixer-Assisted Extraction (MAE) methods in this study. Response Surface Methodology (RSM) was also utilized to find the optimal values of the extraction parameters. The optimal conditions for UAE were determined to be 42.7 min extraction time, 0.283 mm particle size, and 2.48 W/mL power intensity, achieving the oil yield of 94.56 %. For MAE, the optimal conditions were 54.5 min extraction time, 0.274 mm particle size, 21.1 °C temperature, and 0.74 W/mL agitation intensity, resulting in the oil yield of 96.73 %. RSM showed high reliability with R2 values above 0.99 for both methods. Gas Chromatography Flame Ionization Detector (GC-FID) analysis revealed that UAE and MAE resulted in higher unsaturated fatty acids concentrations (85.8 % and 86 %, respectively) compared to CPE (78.2 %). Kinetic studies indicated that UAE and MAE are more efficient in extracting unsaturated fatty acids, with MAE showing the highest double bond content. The Kinetic models demonstrated that extraction kinetics were controlled primarily by solid-phase resistance, with the washing coefficients being significantly higher than the diffusion coefficients. The Perez model calculated diffusion coefficients of 8.03 × 10⁻12 m2/s for UAE and 1.41 × 10⁻11 m2/s for MAE, activation energies of 16.44 kJ/mol for UAE and 15.64 kJ/mol for MAE.