Impact Of High Hydrostatic Pressure Research Articles

Effect of high-hydrostatic pressure on the digestibility of egg yolk and granule.

The impact of high hydrostatic pressure (HHP) on protein digestibility of egg yolk and egg yolk granule was evaluated by static in vitro digestion using the standardized INFOGEST 2.0 method. The degree of hydrolysis (DH) and the phospholipid content were determined during digestion, and the protein and peptide profiles were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse phase-high pressure liquid chromatography (RP-HPLC). The results showed that HHP induced protein aggregation in egg yolk and granule, mainly by disulfide bridges, which were not disrupted in the oral phase. Proteolysis during the gastric phase improved egg yolk and granule protein solubility, regardless of whether HHP was applied. However, the extent of the samples' digestibility was not affected, with DH values ranging from 15% to 20%. During the intestinal phase, the DH of egg yolk protein (∼40%) was higher than that of the granule (∼25%), probably due to the denser structure of the granule reducing the accessibility of intestinal enzymes. The DH, peptide, and protein profiles of control and HHP-treated egg yolk showed similar protein digestion behaviors for both gastric and intestinal phases. Among the different proteins, only the digestibility of β-phosvitin in HHP-treated granule was enhanced. Consequently, applying HHP to granules represents an interesting process that improves the digestibility of phosvitin with the potential to generate bioactive phosvitin-derived phosphopeptides. PRACTICAL APPLICATION: High hydrostatic pressure, mainly used as a preservation process, did not impair the nutritional quality of the egg yolk and granule proteins but improved the susceptibility of phosvitin (protein contained in egg yolk) proteolysis to produce bioactive phosphopeptides. Consequently, applying HHP to granules represents an interesting process that improves the digestibility of phosvitin.

Impact of high hydrostatic pressure and ultrasounds technologies in the autolytic process of Saccharomyces cerevisiae in a model wine system

Autolysis plays a crucial role as a technological tool in the ageing process of specific wines. This includes white, red and sparkling wines. During ageing on the lees, yeasts release different compounds that positively modify the composition of the wine. However, traditional autolytic methods can be time-consuming. This work evaluates the use of different ultrasound (US) and high hydrostatic pressure (HHP) treatments to expedite the autolytic process in Saccharomyces cerevisiae in a model wine system. The results suggest that treating yeast cells with US resulted in a faster release of nucleic acids, proteins, and total polysaccharides compared to HHP treatment. The environmental scanning electron microscopy (ESEM) of the treated lees demonstrated that the impact on the yeast cell surface was more pronounced after exposure to US compared to treatments involving HHP. In conclusion, under these conditions the US treatment effectively triggered autolysis in the wine yeast strain, facilitating the release of macromolecules in a model wine.

Assessment of structural performance of super large cross-section subsea RC shield tunnels: Emphasis on the combined effects of highly hydrostatic pressure and corrosion-induced deterioration

For the subsea reinforced concrete (RC) shield tunnels in China, the use of super large tunnel section and the presence of high hydrostatic pressure from seawater have been becoming increasingly common in practical engineering. However, owing to the combined effects of complex structural systems, extreme external loads and aggressive environments, it is a great challenge to sustain a reliable structural performance of these subsea shield tunnels within the prescribed service life. In this study, a novel approach for evaluating the structural safety of a deteriorated large-section subsea RC shield tunnel is presented with an emphasis on the spatial correlation and variation of corrosion damages and the impact of high hydrostatic pressure. Gumbel distributed random fields are established to simulate the spatial variability of steel corrosion in the segmental linings. A random field-based numerical model for the deteriorated RC segmental linings is developed in conjunction with the modeling of nonuniform steel corrosion and local-regional material degradation. In an illustrative example, the effects of the corrosion degree of internal and external steel reinforcements and the level of applied hydrostatic pressure on the structural safety of a large-section subsea RC shield tunnel are investigated.

Quality and flavor changes in beef jerky caused by high hydrostatic pressure combined with moisture regulator treatments during storage

The impact of high hydrostatic pressure (HHP) combined with moisture regulators (MR) on the quality and flavor attributes of beef jerky during storage was investigated in this study. During storage, moisture content decreased in all the treatments, and it was significantly higher in MR + HHP samples than in HHP and control samples (<i>P</i> &lt; 0.05). At 0 and 15 days, the water activity was approximately 0.7, and at 60 days, it decreased to 0.652 for control samples and 0.678 for MR + HHP samples. During storage, the MR + HHP samples had lower shear force and thiobarbituric acid reactive substances (TBARs) value than the control and HHP samples (<i>P</i> &lt; 0.05). MR + HHP increased the formation of volatile compounds derived from spices while inhibiting the formation of volatile compounds derived from lipid oxidation. The sensory scores of MR + HHP samples for tenderness, color, taste, and flavor were significantly higher than that of the HHP and control samples (<i>P</i> &lt; 0.05). This study revealed that HHP and MR treatment reduced the quality deterioration of beef jerky during storage.

Impact of high hydrostatic pressure (HHP) pre-treatment drying cashew (Anacardium occidentale L.): drying behavior and kinetic of ultrasound-assisted extraction of total phenolics compounds

Impact of high hydrostatic pressure (HHP) pre-treatment drying cashew (Anacardium occidentale L.): drying behavior and kinetic of ultrasound-assisted extraction of total phenolics compounds

Impact of temperature and pressure on phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals

Here, we study the impact of high hydrostatic pressure (up to 11 kbar) on the conductivity in the basal ab plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals. Conversely to YBa2Cu3O7–δ single crystals, it was found that high pressure leads to phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals. The mechanisms of the influence of praseodymium and high hydrostatic pressure on the two-step resistive transition to the superconducting state are discussed.

Impact of high hydrostatic pressure on the single nucleotide polymorphism of stress-related dnaK, hrcA, and ctsR in the Lactobacillus strains

Lactic acid bacteria (LAB) are widespread in environments and can either have a positive impact because their ability to survive in harsh conditions and influence the product (probiotic properties, change of structure-EPS [exopolysaccharides], etc.), or a negative impact, (so not needed) because of their spoilage ability (beer, juices). High hydrostatic pressure (HHP), one of the non-thermal preservation methods used in the food industry, can force the LAB to activate the adaptative mechanisms. Under pressurization, the changes in the bacteria cells can occur at the transcriptional or translational level. This study evaluated the HHP on the single nucleotide polymorphism (SNP) changes in three genes, dnaK, ctsR, and hrcA, related to the stress-response mechanism in LAB. The correlation between the DNA polymorphism and the gene expression under HHP stress was assessed. The applied pressure of 300 MPa resulted in a low ratio of nonsynonymous substitutions to the synonymous substitutions (0 to 1.12), and a lower number of mutations was observed for pressurized strains (from 6 in hrcA to 11 in dnaK) than in controlled (from 3 in ctsR to 92 in hrcA). In all pressurized strains, the expression of genes was observed, whereas, in control strains, the gene expression was detected in three out of five strains. Although there was a noticeable change in stress-related gene expression after HHP, there was no correlation with SNPs. At the same time, with a high frequency of synonymous changes in nucleotide and high diversity for hrcA and dnaK, a very low diversity was found in ctsR sequences. The LAB strains stress response mechanisms are much more complex. The study requires information on the general mechanism and changes in the membranes’ composition, proteome changes, and gene expression patterns. The mutations in genes related to stress can have important implications for the strains’ fitness effect and adaptive ability of LAB strains, especially considering their food industry implication where the HHP techniques are used.

Impact of high hydrostatic pressure on the single nucleotide polymorphism of stress-related dnaK, hrcA, and ctsR in the Lactobacillus strains

Lactic acid bacteria (LAB) are widespread in environments and can either have a positive impact because their ability to survive in harsh conditions and influence the product (probiotic properties, change of structure-EPS [exopolysaccharides], etc.), or a negative impact, (so not needed) because of their spoilage ability (beer, juices). High hydrostatic pressure (HHP), one of the non-thermal preservation methods used in the food industry, can force the LAB to activate the adaptative mechanisms. Under pressurization, the changes in the bacteria cells can occur at the transcriptional or translational level. This study evaluated the HHP on the single nucleotide polymorphism (SNP) changes in three genes, dnaK, ctsR, and hrcA, related to the stress-response mechanism in LAB. The correlation between the DNA polymorphism and the gene expression under HHP stress was assessed. The applied pressure of 300 MPa resulted in a low ratio of nonsynonymous substitutions to the synonymous substitutions (0 to 1.12), and a lower number of mutations was observed for pressurized strains (from 6 in hrcA to 11 in dnaK) than in controlled (from 3 in ctsR to 92 in hrcA). In all pressurized strains, the expression of genes was observed, whereas, in control strains, the gene expression was detected in three out of five strains. Although there was a noticeable change in stress-related gene expression after HHP, there was no correlation with SNPs. At the same time, with a high frequency of synonymous changes in nucleotide and high diversity for hrcA and dnaK, a very low diversity was found in ctsR sequences. The LAB strains stress response mechanisms are much more complex. The study requires information on the general mechanism and changes in the membranes’ composition, proteome changes, and gene expression patterns. The mutations in genes related to stress can have important implications for the strains’ fitness effect and adaptive ability of LAB strains, especially considering their food industry implication where the HHP techniques are used.

Impact of high hydrostatic pressure on the micellar structures and physicochemical stability of casein nanoemulsion loading quercetin.

Natural casein is a highly structured protein and the characteristic of self-assembly makes the formation of micelles, thus negatively limiting the applications. High hydrostatic pressure (HHP), as a novel non-thermal process, can modify the structures of protein and improve the related functionalities. In this study, micellar casein was subjected to HHP treatment from 100 to 500MPa, which then loaded quercetin and formed the nanoemulsion. The thermal, pH, ions and physical stability of nanoemulsion were comprehensively investigated. The results showed 300-500MPa could effectively disintegrate the micellar structures of natural casein by dissociating colloidal calcium phosphate, which significantly improved the emulsifying activity and encapsulation efficiency. However, 500MPa caused the nanoemulsion loading most quercetin and subsequently showed the better physical and ions stability in comparison with control and 100-400MPa. Therefore, HHP is expected to modify the high-order structure of casein, which becomes the ideal nano-vehicles for hydrophobic bioactive substances.

Profiling the water soluble pectin in clear red raspberry (Rubus idaeus L. cv. Heritage) juice: Impact of high hydrostatic pressure and high-temperature short-time processing on the pectin properties

Water soluble pectin (WSP), inherently present in the particle and serum phase of processed red raspberries, largely contributes to their overall structure organization. Nevertheless, pectin losses were preliminarily observed in hydrostatic pressure (HHP)-, and high-temperature short-time (HTST)-processed clear red raspberry juice. This study therefore aims to elucidate the process-induced pectin loss and conversion by profiling the WSP and its subdomains (homogalacturonan, HG; rhamnogalacturonan I, RG I) from differently processed red raspberry juice. First, pectin content and pectin-related enzymes (polygalacturonase [PG], pectin methyl esterase [PME], pectate lyase [PL], and β-galactosidase) in fresh, HHP-, and HTST-processed juice were analyzed. Results suggested that the pectin loss in HHP-processed juice was attributed to the residual activities of endogenous HG-modifying enzymes (PG, PME, and PL), whereas that in HTST-processed juice was due to the nonenzymatic depolymerization. Subsequently, WSP, RG I -, and HG-rich fractions were selectively isolated from differently processed juice. These fractions ranged in molecular weight (Mw, 34.03–83.69 kDa), D-(+)-galacturonic acid (GalA) content (32.22%–88.32%), and degree of esterification (3.10%–38.71%). Fourier transform infrared spectroscopy and nuclear magnetic resonance spectra confirmed the low esterified GalA-rich backbone. X-ray diffraction (XRD) patterns indicated an amorphous structure. Notably, monosaccharides composition and microscopic observations demonstrated the presence of side branches in HG-rich fractions. Differences in Mw, monosaccharides composition, and XRD revealed process-induced depolymerization occurred in the HG subdomain of WSP. However, the HG-rich fractions from processed juice showed higher thermostability. These basic findings provided novel insights into the pectin loss and conversion in processed red raspberries.

Impact of High Hydrostatic Pressure on the Gelation Behavior and Microstructure of Quinoa Protein Isolate Dispersions

Impact of High Hydrostatic Pressure on the Gelation Behavior and Microstructure of Quinoa Protein Isolate Dispersions

Impact of high hydrostatic pressure on the stability of lytic bacteriophages cocktail Salmonelex™ towards potential application on Salmonella inactivation

This work consisted in the first comprehensive study in which the potential to exploit the Salmonella lytic bacteriophages cocktail, Salmonelex™, in association with high hydrostatic pressure (HHP) towards potential application in egg matrices decontamination was evaluated. The impact of HHP (200–600 MPa) on the bacteriophages' viability pointed out a stability in the range of 200–400 MPa. From 400 MPa onwards, the inactivation was potentiated by an increase in the pressure magnitude, being matrix dependent. Salmonelex™ possessed a prominent baroresistance, requiring 600 MPa to completely lose its infectivity. Egg yolk presented the highest baroprotective effect, followed by whole egg and egg white. Transmission electron microscopy unveiled that 500 and 600 MPa elicited a detrimental impact on the bacteriophages’ structural integrity. It was noteworthy the barotolerance (200–300 MPa) of Salmonelex™, previously exposed to different pH conditions (5.0–9.0), which proved not to undermine its infectivity. Regarding the influence of ovalbumin, lysozyme, l-α-phosphatidylcholine, palmitic and oleic acids on the mild HHP-induced inactivation of Salmonelex™, a baroprotective effect was observed, particularly conferred by those compounds comprising egg yolk. The promising results highlighted the feasibility of utilizing Salmonelex™ as an adjuvant to mild HHP processing of egg matrices.

Application of high hydrostatic pressure for the reduction of STEC on raw ground beef patties and its impact on physicochemical properties: pH and color

This study on raw ground beef patties evaluated: resistance of STEC strains inoculated at 6 log CFU/g (O157:H7, O26, O45, O103, O111, O121, and O145) subjected to 350, 450 and 600 MPa, for 5 min at 10 °C; effectiveness of pressure for initial loads (2, 3 and 4 log CFU/g) of O157:H7; and general impact of high hydrostatic pressure (HHP) on raw patties. For 600 MPa treatments and 6 log CFU/g load of STEC, ~5 log CFU/g reductions were obtained with all strains. For 450 MPa, differences in baroresistance among strains became evident. When inoculating O157:H7 at different loads, counts after 600 MPa fell below quantification limits, though virulence genes were detected for the two highest loads. Additionally, HHP reduced native aerobic microbiota to <1 log CFU/g and slightly affected a* and b* color values. Montecarlo simulation was used to estimate potential initial counts of STEC that allow compliance with existing regulatory limits after applying HHP, showing that absence of STEC studied can be achieved in 65 g of patties provided initial loads are ~2 log CFU/g. Finally, HHP treatments at 600 MPa and mild temperatures can be considered a valid non-thermal processing technology to achieve 5 log CFU/g reductions.

New Insights into Physical, Morphological, Thermal, and Pasting Properties of HHP‐Treated Starches: Effect of Starch Type and Industry‐Scale Concentration

AbstractThe impact of high hydrostatic pressure (HHP) (600 MPa‐20 min) on the physical, morphological, pasting, and thermal properties of waxy corn starch (WCS), normal corn starch (NCS), and wheat starch (WS) at different concentrations (10%, 15%, and 20% w/w) was examined. By applying the HHP, water absorption capacity (WAC) and oil absorption capacity (OAC) of the native starches increased tremendously; however, augmenting the concentration of starches from 10% to 20% w/w cause a slight decrease (for WS and NCS) or increase (for WCS) in WAC and a considerable increase in OAC of the HHP‐treated starches. Morphological analysis shows that by increasing the concentration of HHP‐treated starches, the destruction of starch granules is quite detectable; however, this destruction is lower for NCS and the granules show high resistance to degradation and higher inflation than that of WCS and WS. By employing HHP and augmenting the concentration, the zeta potential of the selected starches increased considerably. Rapid visco analysis revealed that HHP and increasing starch concentration from 10% to 20% caused a remarkable decrease in peak, trough, breakdown, final, and setback viscosities of the starches. The native starches depict higher gelatinization, peak, and conclusion temperatures likewise gelatinization enthalpy than the HHP‐treated starches.

Measurement and comparison of multi-scale structure in heat and pressure treated corn starch granule under the same degree of gelatinization

In order to popularize the application of high hydrostatic pressure (HHP) in staple food, the different impact of HHP (from 300 to 600 MPa) and heat treatment (from 60 to 75 °C) on corn starch (80 wt%) under the same DG was investigated. Granule morphology, crystalline characteristics, short-range ordered structure and lamellae structure was examined with a combination of SEM, CLSM, XRD, ATR-FTIR, and SAXS. Results obtained demonstrated Heat-Treated starch appeared endo- and exo-corrosion with more collapses and destructiveness, whereas just endo-corrosion with a dense periphery was induced by HHP. Under the same degree of gelatinization (DG), the long-range and short-range structure sustained more ordered in Pressure-Treated starch than Heat-Treated starch. Further, Heat-Treated starch exhibited more flawed semi-crystalline lamellae. The larger DG, the thicker amorphous lamellae thickness (da) of Heat-Treated starch and Pressure-Treated starch was. Moreover, when DG up to 70%, the increase of da in Heat-Treated starch was more obvious. Heat treatment was shown to be more severe than HHP to disrupt the lamellae. The loss of semi-crystalline structure order occurs more violent than crystalline structure for corn starch. It is of value to reveal that heat and HHP treatment led to similar change trend for multi-scale structural features, whereas the change extent was quite various. This study was potential to provide a theoretical basis to improve the quality of novel starch-based food.

The Effect of Equal Channel Angular Extrusion and Hydrostatic Pressure on the Elastic and Microplastic Properties of a Cu–0.2 wt % Zr Alloy

The effect of severe plastic deformation and the subsequent impact of high hydrostatic pressure on the elastic and microplastic properties of Cu–0.2 wt % Zr alloy has been studied and analyzed. The influence of nanoporosity, which is formed in the process of equal-channel angular pressing and is fixed by applying hydrostatic pressure, has been evaluated.

Application of high pressure processing to improve digestibility, reduce allergenicity, and avoid protein oxidation in cod (Gadus morhua)

In this study, comprehensive analysis was performed to evaluate the impact of high hydrostatic pressure (HHP) and traditional thermal processing methods (baking and steaming) on cod proteins. Results showed that HHP, but not baking or steaming, was able to increase the content of soluble protein nitrogen (1.42-fold), compared with control. Total peptide contents of HHP-treated samples were also significantly higher than baked and steamed ones. In addition, protein oxidation was greatly increased after baking (1.56-fold) and steaming (1.97-fold), whereas HHP did not exhibit any appreciable effect. Furthermore, the allergenicity of cod was significantly reduced after HHP as reflected by the attenuated IgE and IgG-binding capacities (67–84% relative to control), while baking and steaming resulted in higher allergenicity. This study strongly supports the potential of HHP for reducing allergenicity, avoiding protein oxidation, and improving digestibility of cod and other protein-rich foods susceptible to quality deterioration during thermal processing.

Reduction of β-ODAP and IP6 contents in Lathyrus sativus L. seed by high hydrostatic pressure

Grass pea (Lathyrus sativus L.) seeds contain an endogenous neurotoxic non-proteinogenic amino acid, β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP), a major limiting factor-for their human consumption. Furthermore, phytate (IP6), a well-known antinutrient is present in concentration capable of hindering bioavailability of iron (Fe), zinc (Zn), calcium (Ca), phosphorus (P) and other micronutrients from the seeds. Due to the reported capability of high hydrostatic pressure (HHP) to reduce the content of certain antinutritional/toxic agents in seeds and grains, the impact of HHP on the reduction of β-ODAP and IP6 were investigated. The contents of β-ODAP of accessions from different regions in Ethiopia were found to be in the range of 51.94 to 806.52 mg/100 g. Accession (GF1- Alemu, AK) exhibiting the highest β-ODAP content was selected for HHP treatment in soaked and batter forms using Central Composite Face Centered Design of experiments. The best HHP conditions in respect to β-ODAP reduction were also applied to the accession (GP-240038) with the lowest β-ODAP-content, a genetically improved variety (Wassie) and a variety from Germany (GR). The HHP treatment at 600 MPa for 25 min of seeds soaked for 6 h and 12 h exhibited the maximum reduction of β-ODAP (232.11 mg/100 g) and IP6 (21.11 mg/100 g) respectively. The combined incremental effect of pressure and soaking time resulted in a more significant (p ≤ .001) reduction in both compounds than the interaction of pressure with holding time (p ≤ .05). A reduction of β-ODAP from 36.00 to 71.22% by soaked-HHP treatment was observed. β-ODAP reductions were always higher for soaked compared to batter grass pea seeds. IP6 contents after HHP treatment ranged from 33.65 mg/100 g to nill. It can be concluded that pressure, soaking and holding time as well as the grass pea seed accession/variety had great impact on molecular structure changes, enhancement of enzyme activity and reduction in β-ODAP and IP6 content.

Phenomena Occurring in Nanostructured Stainless Steel 316LVM during Annealing under High Hydrostatic Pressure

The aim of the study is to demonstrate the impact of high hydrostatic pressure annealing on the grain boundary character, precipitation rate, and susceptibility to intergranular corrosion of nanostructured austenitic stainless steel 316LVM. To this end, samples of an austenitic stainless steel are deformed by high pressure torsion and subsequently annealed at 900 °C for 10 min under a pressure of 2, 6 GPa and, for comparison, under atmospheric pressure. The resulting microstructures are examined using electron beam scattering diffraction, and transmission and scanning electron microscopy. It is shown that the pressure applied during annealing leads to a higher percentage of high‐angle grain boundaries than does atmospheric pressure. Moreover, it promotes the coexistence of two orientations, &lt;111&gt; and &lt;100&gt;, whereas atmospheric supports mainly &lt;111&gt;. High pressure hinders the growth of carbides, but drastically increases their number compared with atmospheric pressure annealing. As a consequence, the highest number of Cr23C6 carbides are present in the sample annealed under 6 GPa, making this sample susceptible to intergranular corrosion.

Impact of High Hydrostatic Pressure on the Shelling Efficacy, Physicochemical Properties, and Microstructure of Fresh Razor Clam (Sinonovacula constricta).

High hydrostatic pressure (HHP) is now well known as a nonthermal processing technology and becoming increasingly acknowledged. However, it has not been widely applied to shell seafood due to its uncertain influence on its quality and shelling property. This study could provide valuable information regarding the shelling efficacy, physicochemical properties, and microstructure of razor clam treated by HHP. And it demonstrated that HHP showed a positive impact on quality of razor clam treated by HHP.