High Pressure Treatment Research Articles

Changes of structure properties and potential allergenicity of ovalbumin under high hydrostatic pressures

Egg proteins, notably ovalbumin (OVA), contribute to a prevalent form of food allergy, particularly in children. This study aims to investigate the impact of high hydrostatic pressure (HHP) treatment at varying levels (300, 400, 500, and 600 MPa) on the molecular structure and allergenicity of OVA. The structure of HHP-treated OVA was assessed through fluorescence spectroscopy, circular dichroism spectroscopy, and molecular dynamics (MD) simulation. HHP treatment (600 MPa) altered OVA structures, such as α-helix content decreased from 28.07 % to 19.47 %, and exogenous fluorescence intensity increased by 8.8 times compared to that of the native OVA. The free sulfhydryl groups and zeta potential value were also increased with HHP treatment (600 MPa). ELISA analysis and MD simulation unveiled a noteworthy reduction in the allergenicity of OVA when subjected to 600 MPa for 10 min. Overall, this study suggests that the conformational changes in HHP-treated OVA contribute to its altered allergenicity.

Nanofibrillated cellulose derived from rice bran, wheat bran, okara as novel dietary fibers: Structural, physicochemical, and functional properties

The structural, physicochemical, and functional properties of nanofibrillated cellulose (NFC) derived from rice bran (RB), wheat bran (WB), and okara were investigated and explored its potential as novel dietary fibers (DF). Cellulose microfibers (CMF) with cellulose purity of 87.4 % (RB), 92.1 % (WB), and 95.1 % (okara) were prepared by alkali and bleaching treatment, respectively. Subsequently, cellulose microfibers were prepared into NFCs with nanoscale diameters by dynamic high-pressure microjet treatment. Fourier transform infrared (FTIR) spectroscopy demonstrated a significant decrease in the intensity of characteristic absorption peaks of lignin and hemicellulose after chemical treatment. X-ray diffraction results indicated the order of relative crystallinity is: NFC (56.9 %) > CMF (50.8 %) > DF (26.1 %). Moreover, NFC exhibits higher water/oil holding capacity, swelling capability, nitrite/cholesterol/sodium cholate adsorption capacity than CMF and DF. Besides, NFC exhibited superior ability to inhibit starch and lipid digestion compared to DF. Consequently, NFC holds great promise as a novel dietary additive in the food industry. [Display omitted]

Novel cold and thermally pasteurized cardoon-enriched functional smoothie formulations: A zero-waste manufacturing approach

This study investigated the potential of incorporating cardoon (Cynara cardunculus L.) blades as bioactive and dietary fiber ingredients in vegetable/fruit-based smoothies, within a zero-waste approach. The smoothie formulations were pasteurized by high-pressure (550 MPa for 3 min, HPP) and thermal (90 °C for 30 s, TP) treatments and stored at 4 °C for 50 days. Cardoon-fortified smoothies exhibited higher viscosity, darker color, increased phenolic compound levels, and greater anti-inflammatory and antioxidant activities. Furthermore, the cardoon blade ingredients contributed to a more stable dietary fiber content throughout the smoothies' shelf-life. HPP-processed smoothies did not contain sucrose, suggesting enzymatic activity that resulted in sucrose hydrolysis. All beverage formulations had low or no microbial growth within European limits. In conclusion, the fortification of smoothies with cardoon blades enhanced bioactive properties and quality attributes during their shelf-life, highlighting the potential of this plant material as a potential functional food ingredient in a circular economy context.

Influence of high hydrostatic pressure treatment on the soluble dietary fiber content and physicochemical characteristics of edamame

We used non-thermal high hydrostatic pressure (HHP) technology to process edamame to increase the soluble dietary fiber content of the product. We also comprehensively explored the impact of HHP on the functional properties and fiber structure of edamame. Edamame was treated at a high pressure of 600 MPa for 5-, 10-, and 15-min. Edamame treated with HHP exhibited elevated water-holding, oil-holding, and water-swelling capacities, which were attributed to alterations in the fiber structure. Scanning electron microscopy, used to assess the porous characteristics of the surface, revealed gaps that could retain liquid. This structural modification facilitated enhanced invitro performance in cholesterol adsorption and bile acid-binding force tests. X-ray diffraction analysis revealed that the broken fibers strengthened the (101) crystal plane of fiber crystal I; the reduction in crystallinity caused the fibers to form a loose structure under thermal stability, which increased the water retention and swelling properties. HHP destroyed part of the fiber structure, contributing to the altered functional properties. The findings indicate that HHP treatment adds significant value to edamame, making it a promising raw material for developing functional foods and healthcare products.

Evaluation of rapid gas decompression (RGD) resistance of sealing materials for hydrogen-doped pipeline valves

Abstract With the rapid development of hydrogen-doped natural gas pipelines, the evaluation of the applicability of hydrogen to natural gas pipeline systems is bound to gradually involve all aspects of natural gas pipelines. Targeted at the non-metallic sealing materials for valves of hydrogen-doped natural gas pipelines, this paper, according to the ISO 23936-2 standard, carried out the rapid gas decompression (RGD) tests of hydrogenated nitrile butadiene rubber (HNBR), fluorine rubber 246 (FKM246) and fluorine rubber 26 (FKM26), and the damage level of cracking failure for the rubber materials in the course of rapid release of gaseous medium was obtained (DL). The mechanical properties and volumetric dissolution rate of the three rubber materials were tested before and after the high-pressure gas mixture treatment, which explains the reason for the cracking failure of the rubber materials during the RGD test. The study obtained the influence law of high-pressure gas mixture with different hydrogen volume fractions on the RGD resistance of HNBR, FKM246, and FKM26, and selected the material with the optimal RGD resistance as FKM26, which can be used as a reference for the selection of sealing materials for the valves of hydrogen-doped natural gas pipelines in engineering.

Effects of pretreatment on the microcharacterization and fermentation of bamboo shoot shells

This study focuses on the pretreatment and characterization of natural fibers from the bamboo shoot shell (BSS) of Phyllostachys heterocycla to determine their suitability as biorefining materials. The discarded bamboo shoot shell was used as a source of fibers, which were analyzed for their physical, chemical, and microstructure properties. Fourier transform infrared spectroscopy, X-ray diffraction spectra, and scanning electron microscopy confirmed that a mixture of sodium hydroxide immersion plus high-pressure steam treatment allowed the cellulose structure to be disrupted, providing more adsorption sites for cellulases. Gas chromatography mass spectrometry (GC-MS) also showed that the pretreatment exposed the internal structure of the fibers and that high-mass silicon compounds were present in the eluted solution. After adding the cellulase produced by Trichoderma viride and Aspergillus niger, the reducing sugar yield was increased by 268% and 251%, compared to unpretreated BSS fibers. This strategy may apply to many industries, especially biorefining and lignocellulose biotransformation technology.

Comparative study on dynamic in vitro digestion characteristics of lotus seed starch-EGCG complex prepared by different processing methods

To study the effect of starch-polyphenol interaction induced by different processing methods on digestion characteristics, a dynamic in vitro human gastrointestinal system was employed to investigate the digestive characteristics of lotus seed starch–epigallocatechin gallate (EGCG) complex (LS–EGCG) prepared by different processing methods. Digestion altered crystal structure, particle size, morphology, pH, starch hydrolysis, and EGCG content. Processing broke physical barriers, reducing particle size by enzyme erosion. Enzymatic hydrolysis gradually exposed EGCG, indicated by green fluorescence. Heat and high pressure treatments enhanced starch dissolution, increasing sugar accumulation and hydrolysis. However, ultrasonic-microwave and high pressure microfluidization treatments formed dense structures, decreasing hydrolysis rates. Overall, the complex formed by high pressure microfluidization showed better enzyme resistance. The results provide a scientific basis for the development of food with quality and functional properties.

Photoluminescence and light absorption edges of Bi2O2CO3 regulated by pressure-induced oxygen vacancies

In this work, Bi2O2CO3 (BOC) was subjected to high-pressure treatment using a diamond anvil cell at pressures of 0, 4.2, and 25.6 GPa to improve the photocatalytic performance. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed for in-depth analysis. The results indicated that after treatment at 25.6 GPa, oxygen vacancies were induced in the powder, and defect energy levels were formed within the band gap of the BOC, thereby expanding its absorption of visible light. The light absorption edge shifted from 377 nm to 562 nm, which have enhanced the ability of separating photogenerated electron-hole pairs. This study demonstrates that high-pressure treatment is beneficial for improving the photocatalytic performance of Bi2O2CO3.

Overcoming strength-ductility tradeoff with high pressure thermal treatment

Conventional material processing approaches often achieve strengthening of materials at the cost of reduced ductility. Here, we show that high-pressure and high-temperature (HPHT) treatment can help overcome the strength-ductility trade-off in structural materials. We report an initially strong-yet-brittle eutectic high entropy alloy simultaneously doubling its strength to 1150 MPa and its tensile ductility to 36% after the HPHT treatment. Such strength-ductility synergy is attributed to the HPHT-induced formation of a hierarchically patterned microstructure with coherent interfaces, which promotes multiple deformation mechanisms, including dislocations, stacking faults, microbands and deformation twins, at multiple length scales. More importantly, the HPHT-induced microstructure helps relieve stress concentration at the interfaces, thereby arresting interfacial cracking commonly observed in traditional eutectic high entropy alloys. These findings suggest a new direction of research in employing HPHT techniques to help develop next generation structural materials.

Effect of high-pressure treatment and germination on the functional, rheological, and microstructural characteristics of red quinoa (Chenopodium quinoa) gels

This study investigates the effect of germination and high-pressure (HP) treatment on the functional and gelling behaviour of red quinoa (RQ) (Chenopodium quinoa). The grains were subjected to germination for 48 h followed by the application of four pressures (200, 300, 400 and 500 MPa) as well as their combinations to germinated quinoa (GQ) samples. The samples were ground, and the flour was analysed for functional, rheological, and microstructural attributes. Germination and HP treatment improved the functional and gelling properties of RQ samples significantly. The degradation of protein, fat, and starch-lipid complex of the flour led to an increase in the swelling capacity of flour. The treatments increased the oil absorption capacity from 50.02 ± 0.47 to 80.86 ± 0.88 % and emulsification capacity from 57.85 ± 0.71 to 64.17 ± 0.53 %. This increase is attributed to the dissociation and unfolding of polypeptides that expose the hydrophobic sites of amino acids. The decrease in least gelling capacity from 18 to 14% signified a decrease in the amount of flour required for the gelation. Rheometric and texture profile analysis demonstrated an improved gel strength. Moreover, the SEM micrographs showed an increased structure density and reduced porosity which further support the improved gel strength. The study would help to widen the scope of accommodating RQ flour as a gelling or thickening agent in the food industries.

Green banana resistant starch: A promising potential as functional ingredient against certain maladies.

This review covers the significance of green banana resistant starch (RS), a substantial polysaccharide. The food industry has taken an interest in green banana flour due to its 30% availability of resistant starch and its approximately 70% starch content on a dry basis, making its use suitable for food formulations where starch serves as the base. A variety of processing techniques, such as heat-moisture, autoclaving, microwaving, high hydrostatic pressure, extrusion, ultrasound, acid hydrolysis, and enzymatic debranching treatments, have made significant advancements in the preparation of resistant starch. These advancements aim to change the structure, techno-functionality, and subsequently the physiological functions of the resistant starch. Green bananas make up the highest RS as compared to other foods and cereals. Many food processing industries and cuisines now have a positive awareness due to the functional characteristics of green bananas, such as their pasting, thermal, gelatinization, foaming, and textural characteristics. It is also found useful for controlling the rates of cancer, obesity, and diabetic disorders. Moreover, the use of GBRS as prebiotics and probiotics might be significantly proved good for gut health. This study aimed at the awareness of the composition, extraction and application of the green banana resistant starch in the future food products.

Emulsifying property, antioxidant activity, and bitterness of soybean protein isolate hydrolysate obtained by Corolase PP under high hydrostatic pressure

Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities. However, the problem related to the hydrolysis of proteins was the generation of the bitter taste. Recently, high hydrostatic pressure (HHP) treatment has attracted much interest and has been used in several studies on protein modification. Hence, the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments (0.1, 100, 200, and 300 MPa for 1–5 h at 50 °C) on the emulsifying property, antioxidant activity, and bitterness of soybean protein isolate hydrolysate (SPIH). As observed, the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index (47.49 m2/g) and emulsifying stability index (92.98 %), and it had higher antioxidant activities (44.77 % DPPH free radical scavenging activity, 31.12 % superoxide anion radical scavenging activity, and 61.50 % copper ion chelating activity). At the same time, the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size. In addition, the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability. This study has a broad application prospect in developing food ingredients and healthy foods.

Effects of High Temperature Short Time and High Hydrostatic Pressure Treatment on the Microbial and Physicochemical Characteristics of Red Beet Juice

Effects of High Temperature Short Time and High Hydrostatic Pressure Treatment on the Microbial and Physicochemical Characteristics of Red Beet Juice

High-pressure induces topology boosting thermoelectric performance of Bi2Te3

Decoupling conductivity (σ) and Seebeck coefficient (S) by electronic topological transitions (ETT) under high pressure (2–4 GPa) is a promising method for bismuth telluride (Bi2Te3) to optimize thermoelectric (TE) performance. However, the S cannot dramatically increase with increasing σ when ETT occurs in Bi2Te3, which impedes optimizing TE performance by utilizing ETT in Bi2Te3. A new strategy of enhanced ETT by combining lattice distortions and high pressure is proposed in this work. The lattice distortions in Bi2Te3 were introduced by high pressure and high temperature (HPHT) treatment to generate surplus dislocations. The in-situ measurements of σ and S at HPHT in Bi2Te3 with lattice distortions show an enhanced ETT effect at 2 GPa, which causes decouple σ and S with an anomalous increase in its |S| about 22%. The ETT effect causes the figure of merit ( ZT ) of Bi2Te3 can be improved to 0.275 at 1.50–2.62 GPa, 460 K, it is more than 62% compared with 0.79 GPa, at 450 K. The excellent TE performance of Bi2Te3 arising from the lattice distortions can result in local non-hydrostatic pressure which enhances ETT under high pressure. This work provides a new strategy to enhance ETT to decouple σ and S , and search for better TE materials from the pressure dimension in the future.

Combined Sous-Vide and High Hydrostatic Pressure Treatment of Pork: Is the Order of Application Decisive When Using Minimal Processing Technologies?

The aim of using minimal food processing technologies is to preserve the raw material or to achieve a special technological goal with the least possible impact. When several technologies are used together, the intensity of each treatment can be reduced according to Leistner’s hurdle principle. Does the order of application of the treatments result in a detectable difference? This research focuses on the effect of the combination of the sous-vide technology and the high hydrostatic pressure (HHP) treatment. The effect of the pressure level (300 and 600 MPa) and the influence of the treatment order was investigated on pork (longissimus thoracis and lumborum muscles (LTL)). Physico-chemical and microbiological measurements were carried out on day 0 and after 21-day storage at 2 °C and 8 °C. Significant differences were found for both the order of treatment and pressure level in weight loss (p < 0.001), CIELab color parameters a* and b* (p < 0.001), and denaturation enthalpy (p < 0.01). The texture (p < 0.001) and lipid oxidation TBARS values (p < 0.05) were only influenced by the pressure level. In the challenge test, the initial count of 105 CFU/g Listeria monocytogenes dropped below detection limit in all cases. Total aerobic and anaerobic viable numbers were below/near the detection limit in all combined-treated samples on day 0 and showed only slight or more notable growth after 21-day storage at 2 °C and 8 °C, respectively. An additional 300 MPa pressure treatment can increase the safety of sous-vide cooked pork samples while having only a minor effect on physicochemical properties. The 600 MPa pressure treatment results in a stable, albeit not shelf-stable product, but it also affects a considerable number of quality parameters such as color, texture, weight loss, and TBARS values.

Dual-optimization of transport properties enabled by high-pressure treatments for CuInTe2 thermoelectric materials

CuInTe2 is the focus of much research interest in I-III-VI2 diamondoid compounds due to its potentially high thermoelectric performance. However, its unmatched transport behaviors among electrical and thermal properties seriously impede enhanced thermoelectric performance. In this work, we demonstrate that high pressure can dual-optimize the electrical and thermal transport properties, leading to enhanced thermoelectric performance in CuInTe2 with cationic defects. The results indicate that the carrier concentration level is increased while greatly enhancing carrier mobility owing to the influence of high pressure on the band and electronic structures, realizing an excellent power factor of 1406 μWm−1K−2. Furthermore, high-pressure treatments and cationic defects can introduce multiple defect structures with various sizes, strongly scattering full-frequency phonons to reduce lattice thermal conductivity. With these great merits enabled by high pressure, the thermoelectric performance of CuInTe2 with cationic defects is improved and a maximum zT of 1.12 is obtained at 773 K, fully verifying the advantages of high-pressure treatments in terms of improving transport properties.

Trends in incidence and treatments of spontaneous subarachnoid hemorrhage- a 10 year hospital based study

BackgroundImproved endovascular methods make it possible to treat complex ruptured aneurysms, but surgery is still needed in certain cases. We evaluated the effects on the clinical results of the changes in aneurysm treatment.MethodsThe study cohort was 837 patients with spontaneous subarachnoid hemorrhage (SAH) and one or multiple aneurysms, admitted to Dept of Neurosurgery, Uppsala University Hospital from 2012 to 2021. Demography, location and treatment of aneurysms, neurologic condition at admission and discharge, mortality and last tier treatment of high intracranial pressure (ICP) was evaluated. Functional outcome was measured using the Extended Glasgow Outcome Scale (GOSE) Data concerning national incidences of stroke diseases was collected from open Swedish databases.ResultsEndovascular methods were used in 666 cases (79.6%). In 111 (13.3%) with stents. Surgery was performed in 115 cases (13.7%) and 56 patients (6.7%) had no aneurysm treatment. The indications for surgery were a hematoma (51 cases, 44.3%), endovascular treatment not considered safe (47 cases, 40.9%), or had been attempted without success (13 cases, 11.3%). Treatment with stent devices increased, and with surgery decreased over time. There was a trend in decrease in hemicraniectomias over time. Both the patient group admitted awake (n = 681) and unconscious (n = 156) improved significantly in consciousness between admission and discharge. Favorable outcome (GOSE 5–8) was seen in 69% for patients admitted in Hunt & Hess I-II and 25% for Hunt & Hess III-V. Mortality at one year was 10.9% and 42.7% for those admitted awake and unconscious, respectively.The number of cases decreased during the study period, which was in line with Swedish national data.ConclusionsThe incidence of patients with SAH gradually decreased in our material, in line with national data. The treatment policy in our unit has been shifting to more use of endovascular methods. During the study period the use of hemicraniectomies decreased.

Matrix effect on the Effectiveness of High Hydrostatic Pressure Treatment on Antibiotic Residues

The use of antibiotics in agriculture and livestock poses health risks to consumers. Treatments such as High Hydrostatic Pressure (HHP) have been shown to reduce antibiotic and pesticide residues in food. This study aims to investigate the matrix effect on the effectiveness of HHP on hydrochloride tetracycline (HTC) and sulfathiazole (STZ) residues in spiked food matrices. The effect of viscosity, as well as carbohydrate, protein, and fat content on the effectiveness of HHP on antibiotic residues, was investigated. The studied matrices were full-fat and fat-free bovine milk and model food systems consisting of aqueous solutions of sugars, aqueous solutions of proteins, and oil in water emulsions. Model food systems were also used to study the viscosity effect. These systems consisted of aqueous solutions of honey, aqueous solutions of apple puree, and aqueous solutions of glycerol. The HHP processing (580 MPa, 6 min, 25 °C) took place under industrial conditions. For both antibiotics, the concentration of sugars and proteins was found to affect the effectiveness of treatment. The concentration of oils affected treatment efficacy only for HTC. Reduction of antibiotics by HHP was also affected by the type of carbohydrate and the viscosity. In conclusion, the composition and the viscosity of the food matrix exert a variable effect on the studied antibiotic residues reduction by HHP indicating different underlying mechanisms of the interactions between food constituents and antibiotics under the same process conditions.

Preparation and Characterization of a Hypoglycemic Complex of Gallic Acid-Antarctic Krill Polypeptide Based on Polylactic Acid-Hydroxyacetic Acid (PLGA) and High-Pressure Microjet Microencapsulation.

Gallic acid-Antarctic krill peptides (GA-AKP) nanocapsules (GA-AKP-Ns) were prepared using a dual delivery system with complex emulsion as the technical method, a high-pressure microjet as the technical means, polylactic acid-hydroxyacetic acid (PLGA) as the drug delivery vehicle, and GA-AKP as the raw material for delivery. This study aimed to investigate the effects of microjet treatment and the concentration of PLGA on the physicochemical properties and stability of the emulsion. Under optimal conditions, the physicochemical properties and hypoglycemic function of nano-microcapsules prepared after lyophilization by the solvent evaporation method were analyzed. Through the microjet treatment, the particle size of the emulsion was reduced, the stability of the emulsion was improved, and the encapsulation rate of GA-AKP was increased. The PLGA at low concentrations decreased the particle size of the emulsion, while PLGA at high concentrations enhanced the encapsulation efficiency of the emulsion. Additionally, favorable results were obtained for emulsion preparation through high-pressure microjet treatment. After three treatment cycles with a PLGA concentration of 20 mg/mL and a microjet pressure of 150 MPa (manometric pressure), the emulsion displayed the smallest particle size (285.1 ± 3.0 nm), the highest encapsulation rates of GA (71.5%) and AKP (85.2%), and optimal physical stability. GA-AKP was uniformly embedded in capsules, which can be slowly released in in vitro environments, and effectively inhibited α-amylase, α-glucosidase, and DPP-IV at different storage temperatures. This study demonstrated that PLGA as a carrier combined with microjet technology can produce excellent microcapsules, especially nano-microcapsules, and these microcapsules effectively improve the bioavailability and effectiveness of bioactive ingredients.

Changes in properties of myofibrillar protein and myofibrillar protein gel from freshwater fish after low-temperature and high-pressure collaborative treatment

This study investigated the effects of low-temperature and high-pressure collaborative and conventional air freezing (CAF) on myofibrillar protein (MP) characteristics from grass carp. Turbidity, solubility, and particle size analysis showed that the pressure shift freezing (PSF) treatment could inhibit the formation of large MP aggregates to a certain extent during freezing. Chemical interaction studies unveiled that PSF treatment not only mitigates damage to the inherent structure of MP during freezing but also enhances its crosslinking ability. Microstructure analysis revealed a densely woven fibrous protein network structure within the MP gel in the PSF group. MP gel with fiber shape network structure in the PSF group exhibited stronger water-holding capacity and mechanical properties compared to the CAF group having an incomplete protein network structure. This suggests that the combined application of low-temperature and high-pressure treatment holds promising potential for utilization in the surimi gel processing industry and aquatic products processing.Industrial relevance: The quality and safety of food are closely related to the commodity value of food. Combined low-temperature and high-pressure treatment can enhance the commodity value of low-value freshwater fish products and has potential in surimi gel new product development. This study provides theoretical guidance for high-pressure and low-temperature collaborative processing and industrial production of related aquatic products.