Interaction of food packaging material and selected food components under high pressure

Abstract

Interactions between ethanolic solutions of p-cymene and acetophenone and different polymer packaging materials. were studied at 500 MPa and 25° C. p-Cymene solution, filled into low-density polyethylene bags, lost 30% of its aroma concentration after 24 h at 500 MPa compared to a 60% loss at atmospheric pressure. The decrease was strongest within the first 15 min. Using LDPE/HDPE/LDPE bags, losses were 20% and 30%, resp. Applying the “bag in the bag” method, p-cymene concentrations measured inside and outside the inner bag has shown sorption by the pressurized film to be one third of that by the non-pressurized. In PET/AI/LDPE bags impermeable to p-cymene, sorption was confined to the inner LDPE layer and caused higher loss in the non-pressurized sample. Acetophenone has not been found to interact with the polymer during pressure treatment, while at atmospheric pressure sorption loss in aroma concentration was nearly 70% after 60 h.     

Preparation of black soybean (Glycine max L) extract with enhanced levels of phenolic compound and estrogenic activity using high hydrostatic pressure and pre-germination

We investigated the influence of high hydrostatic pressure (HHP) treatment on the estrogenic properties and conversion of the phenolic compounds in germinated black soybean. The black soybean was germinated for two- or four-days, and then subjected to HHP at 0.1, 50, 100, or 150?MPa for 12 or 24?h. The highest total polyphenol content (3.9?mg GAE/g), flavonoid content (0.8?mg?CE/g), phenolic acid content (940?±?18.96?μg/g), and isoflavonone content (2600?μg/g) were observed after germination for four days and HHP treatment at 100?MPa for 24?h. In terms of isoflavone composition, the malonyl, acetyl and β-glycoside contents decreased, while the aglycone content increased with HHP. The highest proliferative effect (150%) is observed at four days germination and HHP treatment at 100?MPa. These results suggest that application of HHP may provide useful information regarding the utility of black soybean as alternative hormone replacement therapy.     

Diamond cleavage: importance to high pressure research

The extraordinary properties of diamond make it the number-one choice for anvils in high pressure experiments involving anvil cells. In much of the literature on the properties of diamond the only cleavage mentioned is {111}. However, experience has shown that diamond anvils made with their [001] axis oriented in line with the principal stress axis of the anvil or at a small angle to it often failed with flat faces having {110} orientations; a cleavage plane is reported in some publications. Analysis of the anisotropy of strength and Poisson ratio in diamond has shown that such orientations do, indeed, favor initial failure on {110} cleavage planes. This analysis, in conjunction with stereographic projections of the {111} and {110} cleavage planes, suggests that a 27° tilt of the [001] axis with respect to the linear stress axis by rotation around the [100] or [010] axis should provide significantly greater resistance to failure by cleaving.     

Phase transitions of sulfur at high pressure: Influence of temperature and pressure environment

Abstract

Phase transitions of orthorhombic sulfur were investigated above 10 GPa by Raman spectroscopy using red light excitation. Transitions into several phases that have been reported in previous studies using green light excitation, are confirmed. The phase behaviour is observed to depend strongly on the preparation method. In the presence of a pressure transmitting medium (methanol/ethanol, 4:1), a sequence of phases α-S₈ → [intermediate phase (“ip”) + S₆] → [S₆ + high pressure-low temperature phase (“hplt”)] is described and characterized. Without the use of a pressure transmitting medium, the phase sequence α-S₈ → [“ip” + “hplt”] + “hplt” is observed. In addition, contributions of amorphous sulfur are detected around 10 GPa, i.e. at pressures below the transformation of α-S₈ into the above-mentioned phases. Characteristic Raman spectra of the different phases are extracted and documented over a wide pressure range.     

The variability of times to detect growth from individual Clostridium botulinum type E endospores is differentially affected by high pressure treatments

High pressure thermal (HPT) processing is a candidate technology for the production of safe and stable food. However, little is known about the effect of HPT or high hydrostatic pressure (HHP) treatments at ambient temperature on the variability of times to detect growth from individual spores. We investigated this effect by treating Clostridium botulinum type E spores with HHP (200–600?MPa, 20°C) and HPT (600?MPa, 80°C and 800?MPa, 60°C). Our results indicate that the mean detection times increase and the frequency distribution shifts toward longer times when HHP treatment intensity is increased. HPT treatments result in a highly scattered distribution. In contrast, pressure levels ≤300?MPa decrease detection times and heterogeneity of their distribution, which could lead to an increase in the potential risk originating from C. botulinum type E spores. Data provided here could help to refine risk assessment regarding this important food intoxicator.     

Combined effects of high pressure and sodium hydrogen carbonate treatment on pork ham: improvement of texture and palatability

In this study, the combined effects of high pressure and sodium hydrogen carbonate (NaHCO₃) treatment on the physical and chemical properties, and palatability of pork ham, a tough and under-utilized meat, were investigated. Assessment of meat properties with heat treatment, after exposure to NaHCO₃ and high pressure treatment, revealed an increase in water content, and decreased weight reduction and rupture stress. The free amino acid content of meat samples increased with NaHCO₃ and high pressure treatment. The effect of high pressure processing was especially notable at a pressure of 300 MPa. Sensory evaluation showed that meat subjected to high pressure processing after NaHCO₃ treatment was tender and juicy. In addition, the sample produced minimal residue in the mouth and was characterized by a good taste.     

A high pressure Raman study of TeO2 to 30 GPa and pressure-induced phase changes

The effect of pressure on the Raman modes in TeO₂ (paratellurite) has been investigated to 30GPa, using the diamond cell and argon as pressure medium. The pressure dependence of the Raman modes indicates four pressure-induced phase transitions near 1 GPa, 4.5 GPa, 11 GPa and 22 GPa. Of these the first is the well studied second-order transition fromD ₄ ⁴ symmetry toD ₂ ⁴ symmetry, driven by a soft acoustic shear mode instability. The remarkable similarity in the Raman spectra of phases I to IV suggest that only subtle changes in the structure are involved in these phase transitions. The totally different Raman spectral features of phase V indicate major structural changes at the 22GPa transition. It is suggested that this high pressure-phase is similar to PbCl₂-type, from high pressure crystal chemical considerations. The need for a high pressure X-ray diffraction study on TeO₂ is emphasized, to unravel the structure of the various high pressure phases in the system.     

Phase transitions in CsHSO4 up to 2.5 GPa: Impedance spectroscopy under pressure

Phase transitions in CsHSO₄ at pressures up to 2.5 GPa have been studied with the help of electrical impedance measurements. The phase boundaries have been identified with the help of calculated activation energies of electrical conductivity and dielectric relaxation time. The derived temperatures of phase transition from the low conductive phase II into super ionic phase I at pressure less than 1 GPa confirm the previous results of Ponyatovski? et al. (1985) [4] and Friesel et al. (1989) [27]. The phase diagram derived in this study for pressure larger than 1 GPa differs from the data of Ponyatovski? et al. (1985) [4]. The phase transitions IV-VI and VI-I occur at higher temperatures having significantly larger Clapeyron slope. The phase VII was not identified from heating cycle and appears only under cooling between phases I and VI. The phase VIII was detected at 2.5 GPa at T<350 K and only during heating.     

Electric permittivity and dielectric loss of castor oil during its transformation to the high pressure phase

Abstract

The changes of permittivity and dielectric loss of commercially pure castor oil observed during its transition to the high pressure phase are described. Discussion about physical properties of this phase is shortly presented too.     

Combined high pressure and heavy‐ion irradiation: a novel approach

Swift heavy‐ion irradiations of a wide variety of materials have been used to modify and manipulate the properties of solids at the nanoscale. Recently, these high‐energy irradiations have been successfully combined with high‐pressure experiments. Based on results obtained for zircon (ZrSiO₄), this paper introduces this new experimental approach involving diamond anvil cells and large ion‐accelerator facilities. This technique provides a wide spectrum of geoscience applications from nanoscale simulations of fission‐track formation under crustal conditions to phase transitions of radiation‐damaged minerals resulting from meteorite impact.     

Coarse-grain modelling using an equation-of-state many-body potential: application to fluid mixtures at high temperature and high pressure

ABSTRACT

A many-body, coarse-grain model, termed the product gas mixture model, is presented that accurately describes the thermodynamic behaviour of molecular mixtures. The coarse-grain model is developed by first approximating the mixture as a van der Waals one-fluid, and subsequently applying an exponential-6 equation-of-state to describe the forces and energies between particles in the spirit of the many-body model pioneered by Pagonabarraga and Frenkel. Isothermal dissipative particle dynamics simulations are carried out at thermochemical states that occur during decomposition of a prototypical energetic material, RDX (1,3,5-trinitro-1,3,5-triazinane). The product gas mixture model performance is assessed by comparing to an explicit-molecule model and a hard-core coarse-grain model based on the exponential-6 pair potential. Overall, the many-body, coarse-grain model is shown to accurately capture the structural and thermodynamic properties for the wide variety of thermochemical states considered, while the hard-core coarse-grain model cannot. The many-body, coarse-grain model overcomes the issues of transferability, scaling consistency and unphysical ordered phase behaviour that often afflict coarse-grain models. While specific thermochemical conditions related to RDX decomposition are considered, the results are generally applicable to the thermodynamic behaviour of other fluid mixtures at both moderate and extreme conditions.     

在立方氧化锆中MgO的掺入对其高压电子结构和光学性质的影响

采用基于密度泛函理论框架下的平面波超软赝势方法,分别计算了70 GPa压力下立方氧化锆理想晶体以及在其中掺入MgO时的电子结构和光学性质. 计算结果表明,掺入MgO使得立方氧化锆禁带宽度稍微减小,从而导致其吸收边发生微小红移,但不影响立方氧化锆在可见光范围内的高压光吸收性（吸收系数仍为零）. 70GPa压力下,立方氧化锆理想晶体和在其中掺入MgO时均在可见光区保持透明. 同时,在立方氧化锆中掺入MgO使得大约120nm处的反射谱主峰峰值强度有所降低,以及约120nm处的能量损失谱主峰向长波方向移动,峰值强度有明显地降低.     

在立方氧化锆中MgO的掺入对其高压电子结构和光学性质的影响

采用基于密度泛函理论框架下的平面波超软赝势方法,分别计算了70 GPa压力下立方氧化锆理想晶体以及在其中掺入MgO时的电子结构和光学性质.计算结果表明,掺入MgO使得立方氧化锆禁带宽度稍微减小,从而导致其吸收边发生微小红移,但不影响立方氧化锆在可见光范围内的高压光吸收性(吸收系数仍为零).70 GPa压力下,立方氧化锆理想晶体和在其中掺入MgO时均在可见光区保持透明.同时,在立方氧化锆中掺入MgO使得大约120 nm处的反射谱主峰峰值强度有所降低,以及约120 nm处的能量损失谱主峰向长波方向移动,峰值强度有明显地降低.     

Structural, high pressure and elastic properties of transition metal monocarbides: A FP-LAPW study

The structural, elastic and thermal properties of four transition metal monocarbides ScC, YC (group III), VC and NbC (group V) have been investigated using full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA) both at ambient and high pressure. We predict a B₁ to B₂ structural phase transition at 127.8 and 80.4 GPa for ScC and YC along with the volume collapse percentage of 7.6 and 8.4%, respectively. No phase transition is observed in case of VC and NbC up to pressure 400 and 360 GPa, respectively. The ground state properties such as equilibrium lattice constant (a₀), bulk modulus (B) and its pressure derivative (B′) are determined and compared with available data. We have computed the elastic moduli and Debye temperature and report their variation as a function of pressure.     

Improvement of texture and palatability of chicken breast: effect of high hydrostatic pressure and sodium hydrogen carbonate

Chicken breast is not preferred in Japan because it is not juicy. In this study, the effect of combined high pressure and sodium hydrogen carbonate (NaHCO₃) treatment on the texture and palatability of chicken breast was investigated. The sample used was broiler chicken breast. Meat samples were soaked in.0–.4 M NaHCO₃ solution and then pressurized at 100–400 MPa. After pressurization, the samples were heated for 30 min at 80°C and cooled down in ice-cold water. High pressure and NaHCO₃ treatment of broiler chicken breast resulted in increased water content, and decreased weight reduction and rupture stress. Moreover, meat exposed to 200 MPa pressurization and.3 M NaHCO₃ treatment was judged tender, juicy and of good taste by sensory evaluation. The combination of high pressure and NaHCO₃ treatment can be effectively used for broiler chicken breast production.     

Combined effects of high pressure and sodium hydrogen carbonate treatment on beef: improvement of texture and color

We investigated the effect of combined high pressure and sodium hydrogen carbonate (NaHCO₃) treatment on the physical properties and color of silverside Australian beef. Meat samples were pressurized at 100–500 MPa and the water content, weight reduction, rupture stress, and meat color were determined. The water content of meat treated with NaHCO₃ and high pressure (300 MPa) reached a maximum of 70.1%. Weight reduction tended to decrease with high pressure treatment at 300 MPa. Meats treated with NaHCO₃ and high pressure at 400 MPa showed a>50% decrease in hardness. Whitening of the meat was reduced by the combined high pressure and NaHCO₃ treatment. Therefore, the combined high pressure and NaHCO₃ treatment is effective for improvement of beef quality.     

Structural stability at high pressure,electronic, and magnetic properties of BaFZnAs:A new candidate of host material of diluted magnetic semiconductors

The layered semiconductor BaFZnAs with the tetragonal ZrCuSiAs-type structure has been successfully synthesized.Both the in-situ high-pressure synchrotron x-ray diffraction and the high-pressure Raman scattering measurements demonstrate that the structure of BaFZnAs is stable under pressure up to 17.5 GPa at room temperature. The resistivity and the magnetic susceptibility data show that BaFZnAs is a non-magnetic semiconductor. BaFZnAs is recommended as a candidate of the host material of diluted magnetic semiconductor.     

Phase transition,lattice dynamical and thermodynamic properties of yttrium antimonide with the rock salt structure under high pressure: first-principles investigations

We investigate the structural, electronic, first-order pressure-induced phase transition, lattice dynamical, and thermodynamic properties of yttrium antimonide (YSb) with the rock salt structure at high pressures and high temperatures using the projector-augmented wave method based on the density-functional theory. By the usual condition of equal enthalpy, we find that the rock salt-structured YSb is stable up to 31.10 GPa, and then transforms to the CsCl-type structure, this is consistent with the experiment result which begins transform from 26 GPa then ends at 36 GPa. The phonon dispersion curves of the rock salt-structured YSb are calculated under high pressure for the first time using a linear-response approach to density-functional perturbation theory successfully. Within the calculated phonon density of state and the quasi-harmonic approximation, we predict further the thermal physical properties of YSb under high temperature and high pressure systematically.     

Ionic to electronic dominant conductivity in Al2(WO4)3 at high pressure and high temperature

Electrical conduction and crystal structure of Al₂(WO₄)₃ at 400 °C have been studied as a function of pressure up to 5.5 GPa using impedance methods and synchrotron radiation X-ray diffraction, respectively. AC impedance spectroscopy and DC polarization measurements reveal an ionic to electronic dominant transition in electrical conductivity at a pressure as low as 0.9 GPa. Conductivity increases with pressure and reaches a maximum at 4.0 GPa, where the conductivity value is 5 orders of magnitude greater than the 1 atm value. Upon decompression, the conductivity retains the maximum value until the sample is cooled at 0.5 GPa. The high pressure-temperature X-ray diffraction results show that the lattice parameters decrease as pressure increases and the crystal structure undergoes an orthorhombic to tetragonal-like transformation at a pressure ∼3.0 GPa. The change of conduction mechanism from ionic to electronic may be explained by means of pressure-induced valence change of W⁶⁺→W⁵⁺, which results in electron transfer between W⁵⁺-W⁶⁺ sites at high pressure.