Molecular dynamics simulation for self-diffusion coefficients of ginger bioactive compounds in subcritical water with and without ethanol

Abstract

Molecular dynamics simulation was used to calculate the self-diffusion coefficients of ginger bioactive compounds (6-gingerol and 6-shogaol) in subcritical water with the presence of ethanol as an entrainer (0-10 mol%) at temperatures from 373.15 to 453.15 K. The all-atom optimised-potentials (OPLS/AA) were employed for the ginger bioactive compounds and ethanol. The extended simple point charge (SPC/E) model was adopted for water molecules. The self-diffusion coefficients increase from 1.00 × 10 −9 to 2.70 × 10 −9 m 2 /s with increasing temperature from 353.15 to 453.15 K. The self-diffusion coefficients also increase from 1.71 × 10 −9 to 3.00 × 10 −9 m 2 /s with increasing percentage of ethanol from 0 to 10 mol% at 413.15 K. The radial distribution functions between the ginger bioactive compounds and subcritical water (solvent) illustrate a weak interaction between the ginger bioactive compounds and solvent. The interaction increases with addition of ethanol as entrainer.

Isomerization of Paracoccus carotinifaciens-Derived Carotenoids (Astaxanthin, Adonirubin, and Adonixanthin) under Subcritical Water Conditions

“…The effect of the addition of an entrainer, ethanol (>99.5%), was also evaluated, that is, the entrainer was directly added to the P. carotinifaciens solution in the range of 1− 50% (w/w) and heated at 160−200 °C and 4 MPa for 30 min. 23,24 Moreover, the impact of the presence of an antioxidant, α-tocopherol, was investigated, that is, the antioxidant was directly added to the solution to a final concentration of 1% (w/w) and heated at 160−200 °C and 4 MPa for 30 min with or without 50% (w/w) of ethanol. The heating was conducted using an oil bath (SOS-183D, Sansho Co. Ltd., Tokyo), and pressurization in the vessel was performed with nitrogen gas through a built-in valve.…”

“…Furthermore, to improve the efficiency of the thermal isomerization of carotenoids by increasing their solubility, the effect of adding an entrainer (ethanol) to the aqueous solution was evaluated. 23,24 Enriched Z-isomers of Paracoccus carotinifaciens-derived carotenoids obtained by this nontoxic and environmentally friendly method using subcritical water should be effectively utilized in the food and feed industries.…”

“…Specifically, the effect of high temperature (140–240 °C) and high pressure (4–16 MPa) treatments to an aqueous solution dispersed with P. carotinifaciens on Z -isomerization of carotenoids was investigated. Furthermore, to improve the efficiency of the thermal isomerization of carotenoids by increasing their solubility, the effect of adding an entrainer (ethanol) to the aqueous solution was evaluated. , Enriched Z -isomers of Paracoccus carotinifaciens -derived carotenoids obtained by this nontoxic and environmentally friendly method using subcritical water should be effectively utilized in the food and feed industries.…”

Influence of hydrostatic pressure on water absorption of polyoxymethylene: experiment and molecular dynamics simulation

“…Further exploration of the microscopic adsorption mechanism of water molecules can be supplemented by molecular dynamics (MD) simulations. MD simulation, which is integrated with an iterative solution of Newton's equation of motion, is one of the most fundamental methods available for studying physical properties, typically like diffusivities and their corresponding residence times, through analyzing adequately penetrating trajectories of the atoms of a substance . In the past decades, much research based on MD simulation has been reported on the behavior and mechanism of small molecules: typically like O 2 , CO 2 , and N 2 to diffuse into polymers, metals, or minerals .…”

“…MD simulation, which is integrated with an iterative solution of Newton's equation of motion, is one of the most fundamental methods available for studying physical properties, typically like diffusivities and their corresponding residence times, through analyzing adequately penetrating trajectories of the atoms of a substance. [12][13][14] In the past decades, much research based on MD simulation has been reported on the behavior and mechanism of small molecules: typically like O 2 , CO 2 , and N 2 to diffuse into polymers, metals, or minerals. [15][16][17][18][19] In addition, MD simulation can allow observing the real-time process of water absorption and analyzing water absorption behavior of polyoxymethylene under different hydrostatic pressures.…”