scholarly journals The multifaceted effects of DMSO and high hydrostatic pressure on the kinetic constants of hydrolysis reactions catalyzed by α-chymotrypsin

2020 ◽  
Vol 22 (28) ◽  
pp. 16325-16333
Author(s):  
Lena Ostermeier ◽  
Rosario Oliva ◽  
Roland Winter
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Kinetic Constants ◽  
Antagonistic Effects ◽  
Hydrolysis Reactions

The cosolvent DMSO and high pressure have antagonistic effects on the kinetic constants of α-chymotrypsin-catalyzed hydrolysis reactions.

Effect of High Hydrostatic Pressure on Salmonella Inoculated into Creamy Peanut Butter with Modified Composition

2014 ◽  
Vol 77 (10) ◽  
pp. 1664-1668 ◽  
Author(s):  
TANYA D'SOUZA ◽  
MUKUND KARWE ◽  
DONALD W. SCHAFFNER
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Water Activity ◽  
High Hydrostatic Pressure ◽  
Peanut Butter ◽  
High Pressure Processing ◽  
Peanut Oil ◽  
Peanut Flour ◽  
Log Reduction ◽  
High Hydrostatic Pressure Processing

Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.

scholarly journals High-Pressure Inactivation of Hepatitis A Virus within Oysters

2005 ◽  
Vol 71 (1) ◽  
pp. 339-343 ◽  
Author(s):  
Kevin R. Calci ◽  
Gloria K. Meade ◽  
Robert C. Tezloff ◽  
David H. Kingsley
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Natural Conditions ◽  
Direct Evaluation ◽  
Temperature Range

ABSTRACT Previous results demonstrated that hepatitis A virus (HAV) could be inactivated by high hydrostatic pressure (HHP) (D. H. Kingsley, D. Hoover, E. Papafragkou, and G. P. Richards, J. Food Prot. 65:1605-1609, 2002); however, direct evaluation of HAV inactivation within contaminated oysters was not performed. In this study, we report confirmation that HAV within contaminated shellfish is inactivated by HHP. Shellfish were initially contaminated with HAV by using a flowthrough system. PFU reductions of >1, >2, and >3 log10 were observed for 1-min treatments at 350, 375, and 400 megapascals, respectively, within a temperature range of 8.7 to 10.3�C. Bioconcentration of nearly 6 log10 PFU of HAV per oyster was achieved under simulated natural conditions. These results suggest that HHP treatment of raw shellfish will be a viable strategy for the reduction of infectious HAV.

Effect of high pressure on various diffusion mechanisms in oxygen-deficient ReBa2Cu3O7−x (Re = Y, Ho) single crystals

2019 ◽  
Vol 33 (04) ◽  
pp. 1950039
Author(s):  
G. Ya. Khadzhai ◽  
N. R. Vovk ◽  
R. V. Vovk ◽  
I. L. Goulatis ◽  
O. V. Dobrovolskiy
Keyword(s):  
High Pressure ◽  
Electrical Resistivity ◽  
Hydrostatic Pressure ◽  
Single Crystals ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Diffusion Mechanisms ◽  
Diffusion Coalescence

The effect of high hydrostatic pressure on the relaxation of the electrical resistivity at room temperature of oxygen-nonstoichiometric [Formula: see text] (Re = Y, Ho) single crystals is investigated. The application of hydrostatic pressure has been revealed to significantly intensify the process of diffusion coalescence in the oxygen subsystem. At the same time, the intensity of the redistribution of labile oxygen is significantly changed when yttrium is replaced by holmium.

scholarly journals Alicyclobacillus acidoterrestris Strain Variability in the Inactivation Kinetics of Spores in Orange Juice by Temperature-Assisted High Hydrostatic Pressure

2020 ◽  
Vol 10 (21) ◽  
pp. 7542
Author(s):  
Patra Sourri ◽  
Anthoula A. Argyri ◽  
Efstathios Z. Panagou ◽  
George-John E. Nychas ◽  
Chrysoula C. Tassou
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Orange Juice ◽  
High Hydrostatic Pressure ◽  
Reference Strain ◽  
Wild Type Strain ◽  
Weibull Model ◽  
Inactivation Kinetics ◽  
High Pressure Level ◽  
Kinetics Of

In this work, the inactivation kinetics of Alicyclobacillus acidoterrestris spores by temperature-assisted high hydrostatic pressure was assessed by means of the Weibull model. Spores from two A. acidoterrestris strains (a wild-type strain and a reference strain) were inoculated in commercial orange juice and subjected to high pressure levels (500 and 600 MPa) combined with four temperature regimes (25, 45, 60 and 70 °C) for time up to 30 min. Results showed that for a given high-pressure level spore inactivation was higher as temperature progressively increased. Furthermore, the Weibull model consistently produced satisfactory fit to the inactivation data based on the values of the root mean squared error (RMSE < 0.54 log colony-forming units (CFU)/mL) and the coefficient of determination (R2 > 0.90 in most cases). The shape of inactivation curves was concave upward (p < 1) for all temperature/high pressure levels tested, indicating rapid inactivation of the sensitive cells of the bacterium whereas the remaining ones adapted to high hydrostatic pressure (HHP) treatment. The values of the shape (p) and scale (δ) parameters of the Weibull model were dependent on the applied temperature for a given high pressure level and they were further described in a secondary model using first-order fitting curves to provide predictions of the surviving spore population at 55 and 65 °C. Results revealed a systematic over-prediction for the wild-type strain regardless of temperature and high pressure applied, whereas for the reference strain under-prediction was evident after 3 log-cycles reduction of the surviving bacteria spores. Overall, the results obtained indicate that the effectiveness of high hydrostatic pressure against A. acidoterrestris spores is strain-dependent and also underline the need for temperature-assisted HPP for effective spore inactivation during orange juice processing.

Two-Parameter Semiconductor Transducer for Measuring High-Pressure and Temperature

1983 ◽  
Vol 22 ◽  
Author(s):  
W. Wlodarski
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Electronic Circuit ◽  
Block Diagram ◽  
High Pressure And Temperature ◽  
Two Parameter ◽  
Semiconductor Transducer

ABSTRACTThe paper presents the results of studies on the application of semiconductor p-n junctions as two-parameter transducers of high-hydrostatic pressure and of temperature in the area of the pressure. A block diagram of an electronic circuit intended to collaborate with a two-parameter transducer has been given.

scholarly journals Evaluating the Anti-Inflammatory and Antioxidant Effects of Broccoli Treated with High Hydrostatic Pressure in Cell Models

Foods ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 167
Author(s):  
Yi-Yuan Ke ◽  
Yuan-Tay Shyu ◽  
Sz-Jie Wu
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
High Pressures ◽  
High Pressure Processing ◽  
Total Phenolic ◽  
Anti Inflammatory ◽  
Functional Components ◽  
Antioxidant Effects ◽  
Myrosinase Activity

Isothiocyanates (ITCs) are important functional components of cruciferous vegetables. The principal isothiocyanate molecule in broccoli is sulforaphane (SFN), followed by erucin (ERN). They are sensitive to changes in temperature, especially high temperature environments where they are prone to degradation. The present study investigates the effects of high hydrostatic pressure on isothiocyanate content, myrosinase activity, and other functional components of broccoli, and evaluates its anti-inflammatory and antioxidant effects. Broccoli samples were treated with different pressures and for varying treatment times; 15 min at 400 MPa generated the highest amounts of isothiocyanates. The content of flavonoids and vitamin C were not affected by the high-pressure processing strategy, whereas total phenolic content (TPC) exhibited an increasing tendency with increasing pressure, indicating that high-pressure processing effectively prevents the loss of the heat-sensitive components and enhances the nutritional content. The activity of myrosinase (MYR) increased after high-pressure processing, indicating that the increase in isothiocyanate content is related to the stimulation of myrosinase activity by high-pressure processing. In other key enzymes, the ascorbate peroxidase (APX) activity was unaffected by high pressure, whereas peroxidase (POD) and polyphenol oxidase (PPO) activity exhibited a 1.54-fold increase after high-pressure processing, indicating that high pressures can effectively destroy oxidases and maintain food quality. With regards to efficacy evaluation, NO production was inhibited and the expression levels of inducible nitric oxide synthase (iNOS) and Cyclooxygenase-2 (COX-2) were decreased in broccoli treated with high pressures, whereas the cell viability remained unaffected. The efficacy was more significant when the concentration of SFN was 60 mg·mL−1. In addition, at 10 mg·mL−1 SFN, the reduced/oxidized glutathione (GSH/GSSG) ratio in inflammatory macrophages increased from 5.99 to 9.41. In conclusion, high-pressure processing can increase the isothiocyanate content in broccoli, and has anti-inflammatory and anti-oxidant effects in cell-based evaluation strategies, providing a potential treatment strategy for raw materials or additives used in healthy foods.

Effect of high hydrostatic pressure on the enzymic hydrolysis of β-lactoglobulin B by trypsin, thermolysin and pepsin

1996 ◽  
Vol 63 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Henrik Stapelfeldt ◽  
Per Hjort Petersen ◽  
Kristian Rotvig Kristiansen ◽  
Karsten Bruun Qvist ◽  
Leif H. Skibsted
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Pressure Effect ◽  
Ambient Pressure ◽  
Apparent Volume ◽  
Enzymic Hydrolysis ◽  
Ambient Conditions ◽  
Β Lactoglobulin ◽  
Hydrolysis Of

SummaryHydrolysis of β-lactoglobulin B (β-lg B) by pepsin, a process slow at ambient conditions, is facilitated at a moderately high hydrostatic pressure such as 300 MPa, corresponding to an apparent volume of activation ΔV# = −63 ml mol−1 at pH 2·5, 30 °C and Γ/2=0·16. Digestion of β-lg by trypsin and thermolysin is likewise enhanced by pressure, and the pressure effect has been traced to pressure denaturation of β-lg B, which by high-pressure fluorescence spectroscopy has been shown to have a large negative volume of reaction, ΔV° = −98 ml mol−1, at pH 6·7, 30 °C and Γ/2 = 0·16. Pressure denaturation is only slowly reversed following release of pressure and the enhanced digestibility is maintained at ambient pressure for several hours.

scholarly journals THE INFLUENCE OF HIGH HYDROSTATIC PRESSURE ON COCAINE AND VERATRINE ACTION IN A VERTEBRATE NERVE

1959 ◽  
Vol 42 (3) ◽  
pp. 647-653 ◽  
Author(s):  
Norman L. Gershfeld ◽  
Abraham M. Shanes
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Sciatic Nerve ◽  
Action Potential ◽  
High Hydrostatic Pressure ◽  
Elevated Pressure

The application of high hydrostatic pressure to toad sciatic nerve causes a gain in sodium and a loss of potassium which are not affected by cocaine. However, cocaine action is enhanced by high pressure when counteracting veratrine depolarization and when blocking the action potential. Various effects of elevated pressure on the after-potentials are presented and the role of ions in these processes is discussed.

scholarly journals Pressure tunablity in ReX4based SMMs; A magnetostructural study

2014 ◽  
Vol 70 (a1) ◽  
pp. C903-C903
Author(s):  
Christopher Woodall ◽  
Francisco Jose Martinez Lillo ◽  
Martin Míšek ◽  
Alessandro Prescimone ◽  
Dave Allan ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Susceptibility ◽  
Hydrostatic Pressure ◽  
Single Molecule ◽  
High Hydrostatic Pressure ◽  
Magnetic Behaviour ◽  
Magnetic Interactions ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
Single Molecule Magnets

Since the discovery of Single-Molecule Magnets (SMMs) in 1993 there has been extensive interest in understanding, developing and tuning the nature of magnetic interactions within SMMs with the intention of gaining greater insight into the nature of these interactions.[1] Typically this is done synthetically using variations in ligand geometry and co-ordination environment to vary magnetic behaviour. More recently it has been demonstrated that high hydrostatic pressure are also an effective mechanism for "tuning" properties such as magnetic susceptibility in a variety of SMMs.[2] The number of studies utilising high hydrostatic pressure to investigate molecular magnetism is extremely limited due to their inherent difficulty however we report a new study investigating the pressure tunabilty of Re(IV) based SMMs. 4d and 5d metal ions such as Re are of interest due their enhanced magnetic exchanges relative to their 3d analogues and Re(IV) based complexes are of particular interest. Previous studies into [ReX6]2-(X = Cl, Br and I) anions demonstrate significant antiferromagnetic coupling, not transmitted through chemical interactions but rather through weak Re-X...X interactions in the solid state which may be easily perturbed at high pressure. [3] Therefore we report an investigation into the tunability of magnetic susceptibility in a variety of [ReX4] based compounds using high pressure magnetic susceptibility measurements and correlate the results with structure observations taken from high pressure single crystal X-ray diffraction experiments. The effects of the removal of solvent trapped in the lattice using temperature and vacuum and the corresponding effect on magnetic behaviour and chemical structure are also reported.

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