This study examined the effects of high hydrostatic pressure pretreatment (100–400 MPa) on the properties of heat-induced wheat gluten (WG) gels. The results showed that treatment with pressure ...higher than 100 MPa significantly increased the strength, water-holding capacity (WHC), non-freezable water (W
nf
), and storage modulus (
G
′) of heat-induced WG gels. When pressure was increased from 100 to 400 MPa, the free SH content of the heat-induced WG gels increased to 23.55 μmol/g protein, and the surface hydrophobicity (
H
0
) increased to 25.36. Fourier transform infrared spectroscopy (FTIR) analysis showed that the β-sheet and random coil content of the WG treated by high-pressure increased with pressure, while the α-helix and β-turn content decreased. Scanning electron microscopy (SEM) showed that the heat-induced WG gels had more uniform and dense three-dimensional networks after high-hydrostatic-pressure pretreatment.
•An appropriate hydrolysis allowed the compact wheat gluten structure to unfold.•The unfold structure facilitates MTGase cross-linking.•Composite modification could improve wheat gluten rheological ...behavior and thermal properties.•Excessive hydrolysis resulted in HMW-GS degrading to smaller peptides.
The rheological behavior and thermal properties of wheat gluten following partial hydrolysis using Alcalase and subsequent microbial transglutaminase (MTGase) cross-linking were investigated. The wheat gluten storage modulus (G′) and thermal denaturation temperature (Tg) were significantly increased from 2.26kPa and 54.43°C to 7.76kPa and 57.69°C, respectively, by the combined action of partial hydrolysis (DH 0.187%) and cross-linking. The free SH content, surface hydrophobicity, and secondary structure analysis suggested that an appropriate degree of Alcalase-based hydrolysis allowed the compact wheat gluten structure to unfold, increasing the β-sheet content and surface hydrophobicity. This improved its molecular flexibility and exposed additional glutamine sites for MTGase cross-linking. SEM images showed that a compact 3D network formed, while SDS–PAGE profiles revealed that excessive hydrolysis resulted in high-molecular-weight subunits degrading to smaller peptides, unsuitable for cross-linking. It was also demonstrated that the combination of Alcalase-based partial hydrolysis with MTGase cross-linking might be an effective method for modifying wheat gluten rheological behavior and thermal properties.
The effects of high hydrostatic pressure (HHP) combined with pH-shifting treatment, on the structural and emulsifying properties of soy protein isolate (SPI) were investigated. SPI was subject to ...different pH solutions (pH 7, pH 3, and pH 11) with pressure levels ranging from 0.1 MPa to 400 MPa before being neutralized to pH 7. The combination of HHP and the pH-shifting process increased the protein solubility and the surface charge of the protein molecule, and induced the formation of smaller re-aggregated protein particles. Structural changes were characterized by free sulfhydryl groups, surface hydrophobicity, ultraviolet–visible spectroscopy, and circular dichroism spectra. Emulsions fabricated with SPI treated by the combined treatment were characterized by mean droplet size, zeta potential, emulsifying activity, emulsifying stability, and fluorescence microstructure. The results suggested that the increasing pressure enhanced the effect of pH shifting, and the protein structure could be significantly unfolded by the synergistic effect of HHP and pH-shifting, further improving the emulsifying performance of SPI.
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•Structural changes of soy protein isolate were induced by high pressure and pH shifting.•Enhanced unfolding in pH shifted SPI were observed after pressurization.•High pressure aided pH shifting improved the emulsifying properties of SPI.
Myofibrillar protein (MP) gels are susceptible to oxidation, which can be prevented by complexing with hydrophilic polyphenols, but may cause gel deterioration. Sodium metabisulfite (Na2S2O5) has ...been used to induce self-assembly of MP and analyze the impact of self-assembly on the quality of composite gels containing high amounts of (−)-epigallocatechin gallate (EGCG). Hydrophobic forces were confirmed as the main driver of self-assembly. Self-assembly reduced the size of the MP–EGCG complex to approximately 670 nm and increased the gel's hydrophobic force by approximately 3.6-fold. The maximum hardness of the Na2S2O5-treated MP–EGCG composite gel was 52.43 g/kg, which was approximately 49% greater than pure MP gel. After oxidative treatment, the Na2S2O5-treated MP–EGCG composite gel had considerably lower carbonyl and dityrosine levels (2.47-μmol/g protein and 450 a.u.) than the control (8.37-μmol/g protein and 964 a.u.). Therefore, Na2S2O5 shows potential as a cost-effective additive for alleviating MP limitations in the food industry.
•Sodium metabisulfite-induced self-assembly of myofibrillar protein (MP).•Self-assembled MP formed stronger gel via increased hydrophobic interactions.•Self-assembly reduced size of MP-epigallocatechin gallate (EGCG) complexes.•Composite gels of self-assembled MP-EGCG exhibited enhanced oxidative stability.
Thermal runaway failure of power batteries will release a large amount of thermal runaway gas (TRG), causing serious environmental pollution and safety accidents. Therefore, monitoring TRG is crucial ...to battery safety. In this paper, the adsorption capacity of TRG on SnS monolayer and SnS-CuO monolayer are compared based on DFT. SnS-CuO monolayer exhibits strong adsorption for C2H4 and CO. Compared with the SnS monolayer, the Eads are improved by 285.10 % and 527.24 %, respectively. Meanwhile, the electron affinity of TRG strongly correlates with adsorption properties (SSE < 0.06, R-square > 0.9, and RMSE < 0.2), indicating that it plays a significant role in explaining the adsorption characteristics of different TRG. Furthermore, the dielectric constant of the solvent exhibits a stronger correlation with the adsorptive properties of TRG (R-square > 0.96 and RMSE < 0.004), indicating the environmental tunability of TRG adsorption. In general, this research reveals the potential of SnS-CuO monolayer as a gas sensor for C2H4 and CO and provides theoretical guidance for exploring the impact of various TRG and solvent environments on the adsorption performance of SnS-CuO monolayer. It is expected to be widely used in TRG monitoring of power batteries in the future.
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Plant protein fibrils have recently attracted considerable attention as delivery vehicles for hydrophobic bioactive compounds. In this work, ultrasound treatment was applied to improve the structure ...of protein fibrils. The aim of this work was to investigate the impacts of ultrasound treatment on the structure of soy protein fibrils (SPF), and further explore the interaction between ultrasound‒treated SPF (USPF) and curcumin (Cur) to clarify the impacts of ultrasound on SPF as delivery vehicles. Thioflavin T fluorescence, SDS‒PAGE, Fourier transform infrared (FTIR) spectroscopy, and far‒UV circular dichroism spectroscopy revealed no significant changes in the primary and secondary structure of SPF after ultrasound treatment. Compared with SPF, USPF presented a more uniform particle size and higher surface hydrophobicity. Fluorescence quenching, ultraviolet–visible spectroscopy, isothermal titration calorimetry, and FTIR spectroscopy indicated USPF10 (ultrasonication for 10 min) possessed a high affinity toward curcumin via hydrophobic interactions and hydrogen bonds. The curcumin solubility in USPF10-Cur (133.19 μg/mL) complex was much higher than SPI-Cur (78.26 μg/mL) and SPF-Cur (116.22 μg/mL) complexes. The USPF10‒Cur complex exhibited good colloidal stability and thermal stability. The DPPH and ABTS scavenging capacities of the USPF10‒Cur complex were approximately 1.4 and 2.7 folds higher than those of free curcumin, respectively. An In vitro digestion assay suggested that the USPF10‒Cur complex showed a much more stable and sustainable release of curcumin and provided chances for curcumin release in the intestine. This study indicated that USPF might be promising delivery vehicles for hydrophobic bioactives as stable and functional ingredients in acidic food systems.
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•Tightly entangled SPF aggregation was de‒aggregated into shorter fibrils with uniform particle size by ultrasound.•USPF10 showed a high affinity towards curcumin through hydrophobic interactions and hydrogen bonds.•USPF10‒Cur complex showed outstanding antioxidant capacity and excellent thermal stability.•USPF10‒Cur had the potential to achieve a targeted release of curcumin in the intestine.
Gelation properties of myofibrillar protein (MP)/wheat gluten (WG) induced by glutamine transaminase (TGase) were studied. Results showed that the inclusion of transglutaminase increased the gel ...strength, water‐holding capacity (WHC), and nonfreezable water (Wnf) of MP/WG mixture. Circular dichroism (CD) analysis showed that the β‐sheet and random coil content of the MP/WG treated with TGase addition increased by 12.1% and 3.7%, while the α‐helix and β‐turn content decreased by 14.2% and 1.8%. Rheological measurements showed that TGase induced higher energy storage modulus value during the MP/WG gel heating‐cooling cycle. the hydrogen bond and hydrophobic interaction content of the MP/WG gels increased by 80 and 120 ug/L, and the disulfide bond decreased by 200 ug/L, with TGase addition was increased from 0 to 120 U/g protein. Scanning electron microscope (SEM) showed that MP/WG gel with TGase had uniform and dense network structure.
Practical Application
The properties of myofibrillar/wheat gluten gel induced by TGase crosslinking was studied. The gel structure and water holding capacity of MP/WG were improved by the cross‐linking of TGase. The study of the gel properties of MP/WG induced by TGase crosslinking also can provide a theoretical basis for analyzing the effect of TGase on the application of gluten protein in complex meat emulsion system.
Food protein fibrils are progressively recognized as promising matrixes for the preservation and delivery of bioactive compounds. In this study, soy protein fibrils (SPF) formed at 4, 8, and 12 h ...(80 °C, pH 2.0) were utilized as carriers to complex with curcumin at pH 3.2. SPF with extreme aspect ratios exhibited a higher surface hydrophobicity compared to soy protein isolate (SPI), which improved its ability to form soluble complexes with curcumin. However, a prolonged heating time of 12 h decreased the surface hydrophobicity of SPF since the formation of compact fibrillar aggregates. Further experiments revealed SPF8 (heated for 8 h) had a higher affinity for curcumin, and its predominant interactions were hydrophobic interaction and hydrogen bonding. The curcumin solubility of SPF8-Cur (405.7 μg/mL) significantly enhanced compared to that of SPI-Cur (95.6 μg/mL) at the ratio (protein/fibril to curcumin) of 12.5. The DPPH• and ABTS•+ scavenging capacities of the SPF8-Cur complex were each roughly 1.7 and 2.7 times greater than those of free curcumin. Moreover, SPF8-Cur complex presented excellent antioxidant and outstanding sustained-release properties, further offering opportunities for the release of curcumin in the intestine and improving the bioaccessibility and bioavailability of curcumin.
•Fibrillation significantly enhanced the surface hydrophobicity of SPI.•The complexation of SPF and curcumin was mainly through hydrophobic interaction and hydrogen bonding.•SPF8 showed a higher affinity to complexation with curcumin.•SPF8-Cur complex showed eminent antioxidant and outstanding sustained-release properties.
