scholarly journals An Overview of Molecular Dynamics Simulation for Food Products and Processes

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 119
Author(s):  
Andrea Smith ◽  
Xin Dong ◽  
Vijaya Raghavan

Molecular dynamics (MD) simulation is a particularly useful technique in food processing. Normally, food processing techniques can be optimized to favor the creation of higher-quality, safer, more functional, and more nutritionally valuable food products. Modeling food processes through the application of MD simulations, namely, the Groningen Machine for Chemical Simulations (GROMACS) software package, is helpful in achieving a better understanding of the structural changes occurring at the molecular level to the biomolecules present in food products during processing. MD simulations can be applied to define the optimal processing conditions required for a given food product to achieve a desired function or state. This review presents the development history of MD simulations, provides an in-depth explanation of the concept and mechanisms employed through the running of a GROMACS simulation, and outlines certain recent applications of GROMACS MD simulations in the food industry for the modeling of proteins in food products, including peanuts, hazelnuts, cow’s milk, soybeans, egg whites, PSE chicken breast, and kiwifruit.

Author(s):  
L. Veiller ◽  
JP. Crocombette ◽  
C. Meis ◽  
D. Ghaleb

Abstract Zirconolite (CaZrTi2O7) has been proposed as a crystalline ceramic host for the long-term disposal of actinides extracted from high-level nuclear waste (e.g. France) and from excess weapons-grade plutonium (e.g. USA). The disintegration of radionuclides induces modifications of the crystalline structure. During α-decay of actinides, localized cascades of displaced atoms occur primarily because of ballistic collisions in the material from the emitted α-recoil nuclei. Under α-decay irradiation, zirconolite undergoes a crystalline to amorphous transformation, which is associated to a volume expansion. We have focused our study on the understanding of radiation-induced structural changes at the atomic level in this ceramic. Molecular Dynamics (MD) has been used in the simulation of displacement cascades in zirconolite. Original Buckingham pair potentials have been established for zirconolite to characterize the two body short-range interactions between different ionic pairs. We present the potential parameters fitted to the structural equilibrium properties of the crystal. This fitting reproduces the characteristics of the cell parameters of zirconolite within 4% and gives reasonable values for the bulk modulus and the specific heat. The MD method is applied to determine the threshold displacement energies for the various sublattices. Finally, we have modelled the effects of displacement cascades in zirconolite, due to the α-recoil nuclei. For that purpose, two MD simulations of high recoil kinetic energies (2 and 6 keV) were performed. The preliminary results show that the complex matrix zirconolite tends to a structural disordering for high PKA energy values although a partial recrystallization step is observed during the energy dissipation.


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 286
Author(s):  
Jin Zhang ◽  
Lv Yang ◽  
Yue Wang ◽  
Huaichao Wu ◽  
Jiabin Cai ◽  
...  

Molecular dynamics (MD) simulations were conducted to investigate the interactions between a palygorskite coating and linear chain alkanes (dodecane C12, tetradecane C14, hexadecane C16, and octadecane C18), representing base oils in this study. The simulation models were built by placing the alkane molecules on the surface of the palygorskite coating. These systems were annealed and geometrically optimized to obtain the corresponding stable configurations, followed by the analysis of the structural changes occurring during the MD process. The interfacial interaction energies, mean square displacements, and self-diffusion coefficients of the systems were evaluated to characterize the interactions between base lubricant molecules and palygorskite coating. It was found that the alkanes exhibited self-arrangement ability after equilibrium. The interfacial interaction was attractive, and the electrostatic energy was the main component of the binding energy. The chain length of the linear alkanes had a significant impact on the intensity of the interfacial interactions and the molecular diffusion behavior. Moreover, the C12 molecule exhibited higher self-diffusion coefficient values than C14, C16 and C18. Therefore, it could be the best candidate to form an orderliness and stable lubricant film on the surface of the palygorskite coating. The present work provides new insight into the optimization of the structure and composition of coatings and lubricants, which will guide the experimental development of these systems for practical applications.


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2621
Author(s):  
Seunghwa Yang

Here, we systematically interrogate the effects of grafting single-walled (SWNT) and multi-walled carbon nanotubes (MWNT) to polymer matrices by using molecular dynamics (MD) simulations. We specifically investigate key material properties that include interfacial load transfer, alteration of nanotube properties, and dispersion of nanotubes in the polymer matrix. Simulations are conducted on a periodic unit cell model of the nanocomposite with a straight carbon nanotube and an amorphous polyethylene terephthalate (PET) matrix. For each type of nanotube, either 0%, 1.55%, or 3.1% of the carbon atoms in the outermost nanotubes are covalently grafted onto the carbon atoms of the PET matrix. Stress-strain curves and the elastic moduli of nanotubes and nanocomposites are determined based on the density of covalent grafting. Covalent grafting promotes two rivalling effects with respect to altering nanotube properties, and improvements in interfacial load transfer in the nanocomposites are clearly observed. The enhanced interface enables external loads applied to the nanocomposites to be efficiently transferred to the grafted nanotubes. Covalent functionalization of the nanotube surface with PET molecules can alter the solubility of nanotubes and improve dispersibility. Finally, we discuss the current limitations and challenges in using molecular modelling strategies to accurately predict properties on the nanotube and polymers systems studied here.


2021 ◽  
pp. 1-12
Author(s):  
Haiyan Li ◽  
Zanxia Cao ◽  
Guodong Hu ◽  
Liling Zhao ◽  
Chunling Wang ◽  
...  

BACKGROUND: The ribose-binding protein (RBP) from Escherichia coli is one of the representative structures of periplasmic binding proteins. Binding of ribose at the cleft between two domains causes a conformational change corresponding to a closure of two domains around the ligand. The RBP has been crystallized in the open and closed conformations. OBJECTIVE: With the complex trajectory as a control, our goal was to study the conformation changes induced by the detachment of the ligand, and the results have been revealed from two computational tools, MD simulations and elastic network models. METHODS: Molecular dynamics (MD) simulations were performed to study the conformation changes of RBP starting from the open-apo, closed-holo and closed-apo conformations. RESULTS: The evolution of the domain opening angle θ clearly indicates large structural changes. The simulations indicate that the closed states in the absence of ribose are inclined to transition to the open states and that ribose-free RBP exists in a wide range of conformations. The first three dominant principal motions derived from the closed-apo trajectories, consisting of rotating, bending and twisting motions, account for the major rearrangement of the domains from the closed to the open conformation. CONCLUSIONS: The motions showed a strong one-to-one correspondence with the slowest modes from our previous study of RBP with the anisotropic network model (ANM). The results obtained for RBP contribute to the generalization of robustness for protein domain motion studies using either the ANM or PCA for trajectories obtained from MD.


2008 ◽  
Vol 32 ◽  
pp. 255-258
Author(s):  
Bohayra Mortazavi ◽  
Akbar Afaghi Khatibi

Molecular Dynamics (MD) are now having orthodox means for simulation of matter in nano-scale. It can be regarded as an accurate alternative for experimental work in nano-science. In this paper, Molecular Dynamics simulation of uniaxial tension of some face centered cubic (FCC) metals (namely Au, Ag, Cu and Ni) at nano-level have been carried out. Sutton-Chen potential functions and velocity Verlet formulation of Noise-Hoover dynamic as well as periodic boundary conditions were applied. MD simulations at different loading rates and temperatures were conducted, and it was concluded that by increasing the temperature, maximum engineering stress decreases while engineering strain at failure is increasing. On the other hand, by increasing the loading rate both maximum engineering stress and strain at failure are increasing.


2014 ◽  
Vol 1700 ◽  
pp. 61-66
Author(s):  
Guttormur Arnar Ingvason ◽  
Virginie Rollin

ABSTRACTAdding single walled carbon nanotubes (SWCNT) to a polymer matrix can improve the delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics (MD) simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential. This potential includes non-bonded interactions, as well as bonds, angles and dihedrals to create a MD model for a SWCNT and EPON 862/DETDA (Diethyltoluenediamine) polymer matrix. Two simulations were performed in order to test the implementation of the COMPASS parameters. The first one was a tensile test on a SWCNT, leading to a Young’s modulus of 1.4 TPa at 300K. The second one was a pull-out test of a SWCNT from an originally uncured EPON 862/DETDA matrix.


2021 ◽  
Vol 12 ◽  
Author(s):  
Trina Ekawati Tallei ◽  
Fatimawali ◽  
Afriza Yelnetty ◽  
Rinaldi Idroes ◽  
Diah Kusumawaty ◽  
...  

The rapid spread of a novel coronavirus known as SARS-CoV-2 has compelled the entire world to seek ways to weaken this virus, prevent its spread and also eliminate it. However, no drug has been approved to treat COVID-19. Furthermore, the receptor-binding domain (RBD) on this viral spike protein, as well as several other important parts of this virus, have recently undergone mutations, resulting in new virus variants. While no treatment is currently available, a naturally derived molecule with known antiviral properties could be used as a potential treatment. Bromelain is an enzyme found in the fruit and stem of pineapples. This substance has been shown to have a broad antiviral activity. In this article, we analyse the ability of bromelain to counteract various variants of the SARS-CoV-2 by targeting bromelain binding on the side of this viral interaction with human angiotensin-converting enzyme 2 (hACE2) using molecular docking and molecular dynamics simulation approaches. We have succeeded in making three-dimensional configurations of various RBD variants using protein modelling. Bromelain exhibited good binding affinity toward various variants of RBDs and binds right at the binding site between RBDs and hACE2. This result is also presented in the modelling between Bromelain, RBD, and hACE2. The molecular dynamics (MD) simulations study revealed significant stability of the bromelain and RBD proteins separately up to 100 ns with an RMSD value of 2 Å. Furthermore, despite increases in RMSD and changes in Rog values of complexes, which are likely due to some destabilized interactions between bromelain and RBD proteins, two proteins in each complex remained bonded, and the site where the two proteins bind remained unchanged. This finding indicated that bromelain could have an inhibitory effect on different SARS-CoV-2 variants, paving the way for a new SARS-CoV-2 inhibitor drug. However, more in vitro and in vivo research on this potential mechanism of action is required.


2008 ◽  
Vol 13 (1-2) ◽  
pp. 113 ◽  
Author(s):  
F. K. GATES ◽  
B. DOBRASZCZYK

The aim of this review is to illustrate how physical properties are important to food processing and quality. Three food products, flakes, porridge and bread, in addition to oat groats are used to show the influence of water and heat-treatments on the mechanical properties. The hydrothermal history of ingredients is shown to affect product quality. Water acts as a plasticiser and solvent in these foods, whilst heat modifies the conformation and interactions of macromolecular components. Structure as well as chemical composition is shown to govern texture.;


1998 ◽  
Vol 540 ◽  
Author(s):  
J.M. Perlado ◽  
L. Malerba ◽  
T. Diaz De La Rubia

AbstractMolecular Dynamics (MD) simulations of neutron damage in β-SiC have been performed using a modified version of the Tersoff potential. The Threshold Displacement Energy (TDE) for Si and C atoms at 300 K has been determined along directions [001], [110], [111] and [ 1 1 1 ]. The existence of recombination barriers, which allow the formation of metastable, temperature-sensitive defects even below the threshold, has been observed. Displacement cascades produced by both C- and Si-recoils of energies spanning from 0.5 keV up to, respectively, 5 keV and 8 keV have also been simulated at 300 K and 1300 K. Their analysis, together with the analysis of damage accumulation (∼3.4×10-3 DPA) at 1300 K, reveals that the two sub-lattices exhibit opposite responses to irradiation: whereas only a little damage is produced on the “ductile” Si sub-lattice, many point-defects accumulate on the much more “fragile” C sub-lattice. A preliminary study of the nature and clustering tendency of these defects is performed. The possibility of disorder-induced amorphization is considered and the preliminary result is that no amorphization takes place at the dose and temperature simulated.


2015 ◽  
Vol 817 ◽  
pp. 797-802 ◽  
Author(s):  
Cai Jiang ◽  
Jian Wei Zhang ◽  
Shao Feng Lin ◽  
Su Ju ◽  
Da Zhi Jiang

Molecular dynamics (MD) simulations on three single walled carbon nanotube (SWCNT) reinforced epoxy resin composites were conducted to study the influence of SWCNT type on the glass transition temperature (Tg) of the composites. The composite matrix is cross-linked epoxy resin based on the epoxy monomers bisphenol A diglycidyl ether (DGEBA) cured by diaminodiphenylmethane (DDM). MD simulations of NPT (constant number of particles, constant pressure and constant temperature) dynamics were carried out to obtain density as a function of temperature for each composite system. The Tg was determined as the temperature corresponding to the discontinuity of plot slopes of the densityvsthe temperature. In order to understand the motion of polymer chain segments above and below the Tg, various energy components and the MSD at various temperatures of the composites were investigated and their roles played in the glass transition process were analyzed. The results show that the Tg of the composites increases with increasing aspect ratio of the embedded SWCNT


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