Influence of sodium chloride and glucose on the aggregation behavior of heat-denatured ovalbumin investigated with a multiangle laser light scattering technique

ABSTRACT:  The molecular characteristics of ovalbumin aggregates formed by heating with NaCl and glucose were investigated with a multi-angle laser light scattering system. The presence of NaCl and glucose affected the formation and molecular structure of the aggregates. Specifically, glucose increased the denaturation temperature of ovalbumin due to thermal stabilization of the native state of ovalbumin, regardless of the content of added NaCl. The surface hydrophobicity of the aggregates was increased by the addition of NaCl, which induced the denaturation of ovalbumin at a lower temperature. Aggregates with a larger weight-average molar mass ( M_w ) and root mean square radius ( R_g ) formed from heat-denatured ovalbumin with NaCl and glucose. The presence of NaCl during heat denaturation caused the formation of aggregates with a larger M_w (1.9 × 10⁵ and 3.5 × 10⁶ g/mol for 0 and 10 mM NaCl, respectively) and R_g (14.8 and 80.4 nm for 0 and 10 mM NaCl, respectively). Over a certain amount of NaCl, the addition of more glucose resulted in the formation of more aggregates with greater M_w and R_g values. In sum, the thermostability of ovalbumin was affected primarily by glucose, but the molecular characteristics of the soluble aggregates formed by heat denaturation varied primarily with NaCl content.     

Influence of sodium chloride and glucose on acid-induced gelation of heat-denatured ovalbumin

ABSTRACT:  We examined the effects of NaCl and glucose on cold-set ovalbumin gelation. Cold-set gels were prepared by adding glucono-δ-lactone (GDL) to a 2% heated ovalbumin solution. For the gel prepared from ovalbumin heat-denatured with NaCl and glucose, the gel with 10 mM NaCl was most transparent and had high gel strength. Its maximum complex shear modulus ( G *) and turbidity were 2.5 times greater and 3 times lower, respectively, than those of the gel without NaCl. The turbidity of the gel with the higher NaCl content increased steeply after the addition of GDL and did not change during the experimental period. The maximum G * of the gel exhibited positive correlations with the molar mass, radius, and surface hydrophobicity of soluble aggregates and the NaCl content, but the turbidity exhibited negative correlations with these factors. The presence of glucose did not significantly affect the turbidity or rheological properties of the gel. For the gel prepared by adding NaCl and glucose with GDL, the presence of glucose did not affect the turbidity, but the maximum G * decreased in inverse proportion to the glucose content. The turbidity of the gel with higher NaCl content (≥ 50 mM) was the greatest among all samples, and the increased turbidity was maintained throughout the measurements. The gels with 50 and 100 mM NaCl exhibited thixotropy during shearing at a constant shear rate. Therefore, the presence of NaCl and glucose during cold gelation could facilitate the preparation of cold-set gels having various properties for food applications.     

Memristive Devices Based on Two-Dimensional Transition Metal Chalcogenides for Neuromorphic Computing

Two-dimensional(2D)transition metal chalcogenides(TMC)and their heterostructures are appealing as building blocks in a wide range of electronic and optoelectron...     

Application of Ag–ceramic composite electrodes to low firing piezoelectric multilayer ceramic actuators

Ag–ceramic composite materials were investigated as low-cost internal electrodes for low firing piezoelectric multilayer ceramic actuators (MLCA). Ag–ceramic pastes were prepared by adding Pb(Mg_1/3Nb_2/3)O₃–Pb(Zr_0.475,Ti_0.525)O₃ (PMNZT) ceramic powders to a commercial Ag paste in the range of 0 to 50 wt.%. PMNZT/Ag–PMNZT multilayered laminates were fabricated using tape casting and subsequently cofired at 925°C for 10 h. The addition of PMNZT into Ag electrode decreased the thermal shrinkage mismatch between the composite layers, which led to improve mass producibility of MLCA through reducing delamination probability during cofiring process.     

Control of the ferroelectric and electrical properties of Nd substituted bismuth titanate ceramics

Nd-doped bismuth titanate Bi_4?x Nd _x Ti₃O₁₂ ceramics were prepared by a solid state reaction method. The effects of Nd doping on ferroelectric and electrical properties were investigated. With Nd substitution for Bi ion, a BNdT single-phase with Bi-layered perovskite was confirmed. The Nd doping decreased the dissipation factor (tanδ) and the dc conductivity, and increased the dielectric constant and the remanent polarization. A small Nd doping on Bi₄Ti₃O₁₂ leads to a higher remanent polarization and improves the ferroelectric properties.     

DC conduction behavior of Bi3.15Nd0.85Ti3O12 thin films grown by RF-magnetron sputtering

The Bi_3.15Nd_0.85Ti₃O₁₂ (BNT) thin films were deposited on Pt(111)/Ti/SiO₂/Si substrates by using RF-magnetron sputtering method and studied the ferroelectric and leakage current charateristics. The polarization – electric field (P-E) hysteresis loops of BNT film was well saturated with the remnant polarization (2P _r ) of 29.8 μC/cm² and a coercive field (2E _c ) of 121 kV/cm. The leakage current density – electric field (J-E) characteristics of the Pt/BNT/Pt capacitor reveals the presence of two conduction region, having Ohmic behavior at low electric field (below 50 kV/cm) and Schottky-emission or Poole-Frenkel emission at high electric field (above 60 kV/cm). The barrier height and trapped level of BNT films are estimated to be 1.11 eV and 0.90 eV, respectively.     

A study on 65 % potential efficiency of the gas turbine combined cycle

Journal of Mechanical Science and Technology - This study investigates the possibility of achieving 65 % efficiency in a gas turbine combined cycle. Several options to realize it were compared. A...     

Effect of silica on the ZnS nanoparticles for stable and sustainable antibacterial application

Silica-capped Zinc Sulfide (ZnS) nanoparticles were synthesized for the use as stable and long-term antibacterial agents because silica is a very important component in food packaging applications for moisture absorption in tune with its property of biocompatibility and water solubility. The variation in morphological and optical properties of core-shell nanostructures was studied by changing the concentration of silica in a core-shell combination. The structural and morphological properties of silica-capped ZnS have been observed by powder X-ray diffraction (PXRD) and transmission electron microscopic (TEM) studies, respectively. Uncapped ZnS nanoparticles with particle size of 2-4 nm in a highly agglomerated state have been observed from TEM, which shows that they can be used only for short-term antibacterial action despite its excellent zone of inhibition (antibiotic sensitivity). However, ZnS/SiO₂ core-shell nanostructures are highly monodisperse in nature and the particle size increases up to 5-8 nm with increase in silica concentration. Fourier-transform infrared spectroscopy (FTIR) analysis confirms the formation of silica capping on the ZnS surface. The inhibition of defect-related emission by silica capping in energy-resolved photoluminescence studies also shows the formation of very stable ZnS nanoparticles. To study the antibacterial properties of the pure and silica-capped ZnS nanostructure the agar-well diffusion method was employed against both gram-positive and gram-negative bacteria. The obtained results indicate that pure ZnS shows excellent antibacterial action but it can last only for few days.