Stability of food is a great challenge that encompasses the interaction among the constituents, processing conditions and thermal history. The frozen storage of food sometimes incurs possible harmful ...effect due to the formation of large ice crystal and destruction of the cell structure. Glass transition state is a second-order transition of matter where a system reaches a thermodynamically non-equilibrium state due to the immobility of molecules, and it is a universal phenomenon observed when liquid goes to supercooled vitreous state because of extensive cooling or change in the composition. The cryostabilisation or storage at glassy conditions has been studied widely as it can prevent the quality degradation due to freezing.
The review provides an overview of the theories and assumptions related to the concept of the glass transition and the response of different food components such as moisture, carbohydrate, protein, and lipid at the glassy state. Influences of processing conditions including moisture removal, freezing rate, annealing time on the relaxation process or the glass transition are also elaborated. In addition, the effects of novel freezing techniques such as ultrasound assisted, high pressure assisted, electric and magnetic field assisted freezing are also discussed in the current review.
The glass transition is highly dependent on the presence of moisture and carbohydrate molecules for its great affinity to make hydrogen bond and increase viscosity. The fat and protein glass transitions take place at very low temperatures, at which commercial frozen storage is not considered feasible. Conventional freeze drying and dehydrofreezing require removal of water, which increases the glass transition temperature. Storage at or below the glass transition temperature is desired to increase stability and prevent any quality deterioration. Novel freezing processes such as high pressure, ultrasound, electric and magnetic assisted freezing incur changes in microstructure and metastable glassy states. The current review provides valuable information for designing products with optimized processing techniques and conditions.
•Glass transitions for various food components are discussed.•Effects of novel freezing technologies on glass transition are elaborated.•Glass transitions have high impacts on stability and other food quality parameters.•Glass transitions are highly dependent on constituents and freezing conditions.
•Low frequency EMF changed Ca2+ATPase activity of grass carp in cold storage.•The EMF between 100 and 400 Hz inhibited protein oxidation during cold storage.•Lipid oxidation of grass carp was ...affected during low frequency EMF exposure.•Low frequency EMF reduced the relaxation of water molecules of grass carp.
This work studied the effects of electromagnetic fields (EMF) with frequencies between 100 and 400 Hz and a fixed strength of 12 mT on cold storage of grass carp at 4 °C for 30 min, and Ca2+ATPase enzyme activities, and lipid and protein oxidations in samples were measured to assess changes in intracellular Ca2+ concentration and oxidative stability. Results showed higher Ca2+ATPase activities in samples treated with EMF frequencies. Significant (p < 0.05) decreases occurred in protein oxidation for samples treated between 100 and 300 Hz, but an increase was observed for treatment with 400 Hz. However, the lipid oxidation increased for samples treated up to 200 Hz and decreased with further increase in frequency to 300 and 400 Hz. Nuclear magnetic resonance analysis showed that exposure to different frequencies of EMF could reduce the association of water molecules with protein for both bound and immobilized water. Overall, treatments of EMF between 100 and 400 Hz could improve grass carp quality during cold storage.
This study aimed to understand the effects of electromagnetic field (EMF) frequencies on the freezing of grass carp tissue. Frequencies ranging from 100 to 400 Hz with a fixed strength of 12 mT were ...applied during freezing. Results showed that the initial freezing point was significantly increased (p < 0.05) for treatment between 200 and 400 Hz compared with control, but the phase change duration was not affected. Reductions in ice areas and crystal sizes were also observed. The highest initial freezing point of −1.44 °C was obtained at 300 Hz with a 45% reduction in crystal size (19.29 μm). There were also no subsequent changes in the drip, texture, colour and pH values. These results indicated that the oscillation among ions due to applying EMF favoured ice crystallization, and frequencies between 200 and 400 Hz were suitable for improving the freezing process assisted by the electromagnetic field.
•EMF treatment between 200 to 400 Hz increased freezing temperature of grass carp.•EMF treatment between 200 to 400 Hz did not affect phase change duration.•The 200–400 Hz treatment reduced ice crystal size and area covered by ice.•The 100 Hz treatment did not affect the quality parameters of grass carp tissue.•EMF treatment had no effect on water holding capacity, hardness, pH, and colour.
Biological interaction with extremely low-frequency electromagnetic fields (ELF-EMF) is complex and the 50 and 60 Hz frequencies are among a few ‘window’ frequency ranges reported with a stimulating ...effect. In the current study, ELF-EMF at frequencies from 40 to 70 Hz were examined for their possible significance in inducing biological effects during chilled storage of grass carp (Ctenopharyngodon idellus) at 4 °C for 4 and 6 h. The myofibrillar protein extracted from the grass carp was analyzed and the results indicate significant (p < 0.05) increases in Ca2+ATPase activity and pH, and a reduction in the total sulfhydryl content during the treatment of 50 and 60 Hz frequencies for both storage durations, in particular, the treatment of 50 Hz had pronounced effects with higher correlations. Therefore, the 50 Hz might be associated with the ‘window’ effect, enhancing myofibrillar protein quality during chilled storage.
•50 Hz treatment enhanced myofibrillar protein quality during chilled storage.•50 and 60 Hz treatments induced better quality compared to 40 and 70 Hz.•Low-frequency EMF treatments influenced the quality of myofibrillar protein.•Exposure duration had a stimulatory effect.•Enhanced quality at 50 Hz might be related to the ‘window’ effect of EMF.
Abstract
A multilayer perceptron neural networks (MLPNN) model is developed for robust and quick prediction of stacking fault energy (SFE) to overcome the challenges faced in the calculation of SFE
...via
experimentation and atomistic calculations in FCC medium entropy alloys (MEA). The present investigation employs a three-step hybrid feature selection approach to obtain a comprehensive understanding of the prominent features that influence the SFE, as well as the interrelationships among these features. The feature space encompasses various features related to composition, lattice stability, and elemental properties, of MEAs. The findings indicate that the estimation of SFE relies on five crucial factors: temperature, lattice stability, specific heat, ionization energy, and Allen electronegativities. Furthermore, a mathematical relationship for the estimation of the SFE is derived, considering the various influencing and prominent factors. Consequently, the MLPNN model for robust SFE prediction in MEAs is developed and the performance is evaluated using
R
2
scores, with values of 0.87 and 0.85 obtained for the training and testing datasets, respectively. This efficient strategy introduces a novel opportunity for the engineering of SFE in the extensive range of alloy chemistry of MEAs, enabling the quick prediction of SFE, and facilitating the systematic exploration of new alloys for the development of mechanisms that may accommodate deformation through octahedral/partial slip, twinning, and/or transformation.
The current research addresses the kink band-assisted grain fragmentation of (CrFeNi)
99
Si
1
medium-entropy alloy during high-pressure torsion (HPT) using combinatorial experimental and crystal ...plasticity simulations approach. The HPT experiments were carried out at room temperature with a pressure of 6 GPa for 0.2, 0.5, 1, 2, and 5 turns to achieve different levels of shear strain followed by detailed microstructural characterization using electron backscatter diffraction, transmission electron microscopy, and nanoindentation. Microstructural characterization at different length scales shows the fragmentation of grains aided by the formation of kink bands due to the activation of {111}
<
10
1
¯
>
and {111}
<
11
2
¯
>
slip system followed by gradual conversion of low-angle grain boundaries to high-angle grain boundaries by continuous dynamic recrystallization (cDRX) observed in medium and low stacking fault energy FCC metals and alloys. This aforementioned mechanism occurs over a range of length scales, scaling down the grain size over three orders of magnitude from 40 ± 5 μm to 35 ± 3 nm. Crystal plasticity simulations using the fast Fourier transform solver were employed for full-field simulations to capture the process of kink band-assisted grain fragmentation using the open-source Dusseldorf advanced material simulation kit (DAMASK) software. Finally, constitutive strength equations were developed to quantitatively predict the evolution of strength as a function of HPT deformation to establish the processing-microstructure-mechanical property in (CrFeNi)
99
Si
1
medium-entropy alloy.
Graphical abstract
Energy intensive commercial abrasive-friction rice polishing systems with heavy moving parts induces considerable breakage of rice. Jet polishing, used for metals with high speed air-abrasive ...particles, could be adopted to develop a simple pneumatic rice polishing system without any moving parts. Its construction is similar to a gas-cyclone system. The effect of four abrasive surfaces, viz., coarse (CR, 483 μm), medium (MD, 254 μm), fine (FN,122 μm) and very fine (VF, 89 μm) on degree of polishing (DP) and broken yield (Br) was studied. Particle-trajectory, particle-abrasive surface interaction, grain rotation pattern and progress of bran removal were also studied. DP and Br increased linearly with number of passes for all the abrasive surfaces. Higher DP (8.49 ± 0.2 and 8.49 ± 0.3%) with CR and MD was attributed to removal of bran layer along with endosperm fractions while FN and VF removed proportionally more bran layer (DP, 6.27 ± 0.3 and 8.31 ± 0.4%) with negligible endosperm fraction. Br was least (24.13 ± 0.5%) with VF and highest (34.0 ± 2.2%) with CR.
•A new cyclone type pneumatic polisher has been developed for polishing of rice.•System with no moving parts is very simple in construction and maintenance.•Device separates bran and polished rice continuously.•Uniform and control degree of polishing is possible with this system.•Yield of broken kernels is much less than commercial abrasive polishing system.
Herein, copper sulfide covellite nanoplates were developed by precipitating Cu2+ cations in an aqueous solution using H2S gas. The polygonal CuS nanoplates were further coated with polydopamine and ...chitosan for the development of a stimuli-responsive nanoplatform for cancer cell ablation. The intense absorption in the Near Infrared (NIR) region (700–1100 nm) has been fundamental for the application of the CuS & PDA nanoplates in photothermal therapy. Furthermore, 5-Fluorouracil was chosen as the model chemotherapeutic drug and encapsulated in the polydopamine layer to achieve synergistic chemo-photothermal therapy. To improve the biocompatibility, chitosan was introduced into the nanosystem and lastly folic acid was attached to the nanoplatform to target breast cancer cells so likely reducing damage to healthy tissues. The photothermal conversion efficiency of the nanoconjugate was examined using a NIR laser (808 nm). The in vitro cytotoxicity test and hemocompatibility tests of the nanoconjugate showed excellent biocompatibility and photothermal conversion efficiency under an 808 nm laser irradiation. Visualization of the nanoconjugate treated MCF-7 cells, using a fluorescence microscope displayed that the synthesized photothermal system is efficient in cancer therapy. In summary, the final conjugate CuS-5-FU-PDA@CS-FA with laser treatment shows cancer-killing properties by chemo-photothermal cancer ablation.
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Significant advancements in the field of power electronics have created an ideal opportunity to introduce various topologies of multilevel inverters. These multilevel inverter topologies comprise ...different notable characteristics, such as staircase sinusoidal output voltage with high quality, a lowered number of power switches, no filter requirement, etc. In this literature, a new asymmetrical MLI topology is proposed to reduce the number of components of the inverter with admirable voltage-step creation. The proposed topology provides a 17-level, staircase-type, nearly sinusoidal output voltage waveform. The number of switches required for the proposed multilevel inverter topology is fewer compared to the existing topology for the same level. A carrier-based sinusoidal pulse-width modulation technique is used for the proposed topology at a switching frequency of 3 kHz. The functioning of the proposed inverter topology is thoroughly examined. A 17-level asymmetrical inverter is executed; both the MATLAB/SIMULINK as well as the experimental results using dSPACE-1103 controller. The simulation results are verified using the experimental results for the proposed 17-level multilevel inverter for modulation indexes of 1 and 0.6.
