Goos-Hänchen shift in cryogenic defect photonic crystals composed of superconductor HgBa2Ca2Cu3O8+δ.

We explore theoretically Goos-Hänchen (GH) shift around the defect mode in superconducting defective photonic crystals (PCs) in cryogenic environment. The defective PCs are constructed by alternating semiconductors and superconductors. A defect mode arises in the photonic bandgap and sensitively depends on environment temperature and hydrostatic pressure. Reflection and transmission coefficient phases make an abruptly jump at the defect mode and giant GH shifts have been achieved around this mode. The maximum GH shift can get as high as 103λ (incident wavelength), which could be modulated by the values of temperature and hydrostatic pressure. This study may be utilized for pressure- or temperature-sensors in cryogenic environment.

Se-rich tea polysaccharide extracted by high hydrostatic pressure attenuated anaphylaxis by improving gut microbiota and metabolic regulation.

Selenium-rich tea polysaccharides (Se-TPS) were extracted via high hydrostatic pressure technology with a pressure of 400 MPa (200-500 MPa) for 10 min (3-20 min) at a material-to-solvent ratio of 1:40 (1:20-1:50). Subsequently, Se-TPS1-4 were isolated and purified, with Se-TPS3-4 as the main components. A spectral analysis proved that Se, which has antioxidant activity, existed. An in vitro study found that among Se-TPS, Se-TPS3-4 attenuated the release of ß-hexosaminidase, histamine, and interleukin (IL)-4. Furthermore, in vivo experiments revealed that treatment with Se-TPS downregulated IL-4 levels and upregulated TGF-ß and interferon-γ levels to improve imbalanced Th1/Th2 immunity in tropomyosin-sensitized mice. Moreover, Se-TPS promoted Lactobacillus and norank_f_Muribaculaceaek growth and upregulated metabolites such as genipin and coniferyl alcohol. Overall, these results showed the strong anti-allergy potential of Se-TPS by regulating mast cell-mediated allergic inflammatory responses and microbiota regulation, highlighting the potential of Se-TPS as a novel therapeutic agent to regulate allergy-associated metabolic disorders.

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.

Simulated Hydrostatic Pulpal Pressure Effect on Microleakage-An Initial Study.

PURPOSE: This study's purpose was to evaluate the effect of simulated in vitro hydrostatic pulpal pressure (HPP) on microleakage. METHODS AND MATERIALS: Extracted third molars (n=12) were sectioned 5 mm below the cementoenamel junction, pulp tissue removed, and the sectioned crowns mounted on a Plexiglas plate penetrated by an 18-gauge stainless steel tube. The mounted specimen mesial surface received a 2×4×6 mm Class V preparation followed by restoration with a strongly acidic, one-step dental adhesive and a flowable microfilled resin, following all manufacturers' instructions. Restorations were finished to contour, and tubing was attached to a 20-cm elevated, 0.2% rhodamine G reservoir to the specimen steel tube for 48 hours. Specimens then received a nail polish coating to within 1 mm of the restoration margins and were placed in 2% methylene blue (MB) dye for 24 hours, followed by rinsing, embedding in epoxy resin, and sectioning into 1 mm slices using a diamond saw. Controls were intact molars (n=12) processed as above but without HPP. Specimen slices were evaluated using laser confocal microscopy with images exported to ImageJ software with microleakage assessed as the MB linear penetration as a percentage of the total interfacial wall length. Mean values were evaluated with the Kruskal Wallis/Dunn test at a 95% confidence level. RESULTS: The control specimens demonstrated significantly greater (p<0.0001) MB penetration than experimental specimens with simulated HPP. Under this study's conditions, simulated HPP significantly decreased MB dye penetration. CONCLUSION: Studies accomplished without simulated HPP may overestimate microleakage results.

Hydrostatic pressure mediates epithelial-mesenchymal transition of cholangiocytes through RhoA/ROCK and TGF-ß/smad pathways.

Biomechanical cue within the tissue microenvironment is known to play a critical role in regulating cell behaviors and maintaining tissue homeostasis. As hydrostatic pressure often increases in biliary system under pathological states, we investigated the effect of the moderate elevation of the hydrostatic pressure on biliary epithelial cells, especially on the epithelial-mesenchymal transition (EMT). Human intrahepatic biliary epithelial cells were loaded to hydrostatic pressure using a commercial device. We found that loading the cells to 50 mmHg hydrostatic pressure induced obvious morphological changes and significantly upregulated vimentin, ZEB1, and pSmad2/3, fibronectin, and collagen 1α. All changes induced by hydrostatic pressure loading were effectively mitigated by either ROCK inhibitor (Y-27632) or ALK5 inhibitor (SB-431542). Our in vitro experimental data suggests that hydrostatic pressure loading induces EMT of cholangiocytes through RhoA/ROCK and TGF-ß/Smad pathways. Elevated hydrostatic pressure in biliary duct system under pathological states may promote the biliary epithelial cells shifting to profibrotic and mesenchymal characteristics.

Fluid shear force and hydrostatic pressure jointly promote osteogenic differentiation of BMSCs by activating YAP1 and NFAT2.

Natural bone tissue features a complex mechanical environment, with cells responding to diverse mechanical stimuli, including fluid shear stress (FSS) and hydrostatic pressure (HP). However, current in vitro experiments commonly employ a singular mechanical stimulus to simulate the mechanical environment in vivo. The understanding of the combined effects and mechanisms of multiple mechanical stimuli remains limited. Hence, this study constructed a mechanical stimulation device capable of simultaneously applying FSS and HP to cells. This study investigated the impact of FSS and HP on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and examined the distinctions and interactions between the two mechanisms. The results demonstrated that both FSS and HP individually enhanced the osteogenic differentiation of BMSCs, with a more pronounced effect observed through their combined application. BMSCs responded to external FSS and HP stimulation through the integrin-cytoskeleton and Piezo1 ion channel respectively. This led to the activation of downstream biochemical signals, resulting in the dephosphorylation and nuclear translocation of the intracellular transcription factors Yes Associated Protein 1 (YAP1) and nuclear factor of activated T cells 2 (NFAT2). Activated YAP1 could bind to NFAT2 to enhance transcriptional activity, thereby promoting osteogenic differentiation of BMSCs more effectively. This study highlights the significance of composite mechanical stimulation in BMSCs' osteogenic differentiation, offering guidance for establishing a complex mechanical environment for in vitro functional bone tissue construction.

Bioelectric stimulation controls tissue shape and size.

Epithelial tissues sheath organs and electro-mechanically regulate ion and water transport to regulate development, homeostasis, and hydrostatic organ pressure. Here, we demonstrate how external electrical stimulation allows us to control these processes in living tissues. Specifically, we electrically stimulate hollow, 3D kidneyoids and gut organoids and find that physiological-strength electrical stimulation of ∼ 5 - 10 V/cm powerfully inflates hollow tissues; a process we call electro-inflation. Electro-inflation is mediated by increased ion flux through ion channels/transporters and triggers subsequent osmotic water flow into the lumen, generating hydrostatic pressure that competes against cytoskeletal tension. Our computational studies suggest that electro-inflation is strongly driven by field-induced ion crowding on the outer surface of the tissue. Electrically stimulated tissues also break symmetry in 3D resulting from electrotaxis and affecting tissue shape. The ability of electrical cues to regulate tissue size and shape emphasizes the role and importance of the electrical micro-environment for living tissues.

Mechanical Stimulation of Adipose-Derived Stromal/Stem Cells for Functional Tissue Engineering of the Musculoskeletal System via Cyclic Hydrostatic Pressure, Simulated Microgravity, and Cyclic Tensile Strain.

It is critical that human adipose-derived stromal/stem cell (hASC) tissue engineering therapies possess appropriate mechanical properties in order to restore the function of the load-bearing tissues of the musculoskeletal system. In an effort to elucidate hASC response to mechanical stimulation and develop mechanically robust tissue-engineered constructs, recent research has utilized a variety of mechanical loading paradigms, including cyclic tensile strain, cyclic hydrostatic pressure, and mechanical unloading in simulated microgravity. This chapter will describe the methods for applying these mechanical stimuli to hASC to direct differentiation for functional tissue engineering of the musculoskeletal system.

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 ß-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.

Gut Microbiome and Metabolome Modulation by High-Hydrostatic-Pressure-Processed Tomato Juice.

High hydrostatic pressure (HHP) is a non-thermal pasteurization technology for the enhancement of food products' safety and quality. The components of tomato juice can be affected by HHP processing. Little is known about the effects of HHP-processed tomato juice on the gut microbiome and metabolism. Here, we performed high-throughput sequencing and metabolomics profiling to determine the critical differences in gut microbiota structure and metabolic profiles in mice administered with HHP-processed tomato juice. Tomato juice administration significantly increased the gut bacterial alpha diversity and the relative abundance of Bacteroides. The mice administered with HHP-processed tomato juice were characterized by the enrichment of Bacteroidetes, Alistieps, and Faecalibaculum compared with those administered with HTST-processed tomato juice. Moreover, HHP-processed tomato juice promoted SCFA levels, which were positively correlated with the enriched Alistieps. Our results show that HHP-processed tomato juice may drive healthy gut microbes and metabolites.

Competence for neural crest induction is controlled by hydrostatic pressure through Yap.

Embryonic induction is a key mechanism in development that corresponds to an interaction between a signalling and a responding tissue, causing a change in the direction of differentiation by the responding tissue. Considerable progress has been achieved in identifying inductive signals, yet how tissues control their responsiveness to these signals, known as competence, remains poorly understood. While the role of molecular signals in competence has been studied, how tissue mechanics influence competence remains unexplored. Here we investigate the role of hydrostatic pressure in controlling competence in neural crest cells, an embryonic cell population. We show that neural crest competence decreases concomitantly with an increase in the hydrostatic pressure of the blastocoel, an embryonic cavity in contact with the prospective neural crest. By manipulating hydrostatic pressure in vivo, we show that this increase leads to the inhibition of Yap signalling and impairs Wnt activation in the responding tissue, which would be required for neural crest induction. We further show that hydrostatic pressure controls neural crest induction in amphibian and mouse embryos and in human cells, suggesting a conserved mechanism across vertebrates. Our work sets out how tissue mechanics can interplay with signalling pathways to regulate embryonic competence.

High hydrostatic pressure stimulates microbial nitrate reduction in hadal trench sediments under oxic conditions.

Hadal trenches are extreme environments situated over 6000 m below sea surface, where enormous hydrostatic pressure affects the biochemical cycling of elements. Recent studies have indicated that hadal trenches may represent a previously overlooked source of fixed nitrogen loss; however, the mechanisms and role of hydrostatic pressure in this process are still being debated. To this end, we investigate the effects of hydrostatic pressure (0.1 to 115 MPa) on the chemical profile, microbial community structure and functions of surface sediments from the Mariana Trench using a Deep Ocean Experimental Simulator supplied with nitrate and oxygen. We observe enhanced denitrification activity at high hydrostatic pressure under oxic conditions, while the anaerobic ammonium oxidation - a previously recognized dominant nitrogen loss pathway - is not detected. Additionally, we further confirm the simultaneous occurrence of nitrate reduction and aerobic respiration using a metatranscriptomic dataset from in situ RNA-fixed sediments in the Mariana Trench. Taken together, our findings demonstrate that hydrostatic pressure can influence microbial contributions to nitrogen cycling and that the hadal trenches are a potential nitrogen loss hotspot. Knowledge of the influence of hydrostatic pressure on anaerobic processes in oxygenated surface sediments can greatly broaden our understanding of element cycling in hadal trenches.

Improved triamcinolone acetonide-eluting contact lenses based on cyclodextrins and high hydrostatic pressure assisted complexation.

Contact lenses (CLs) constitute an advantageous platform for the topical release of corticosteroids due to their prolonged contact with the eye. However, the lipophilic nature of corticosteroids hampers CLs' ability to release therapeutic amounts. Two approaches to improve loading and release of triamcinolone acetonide (TA) from poly(2-hydroxyethyl methacrylate)-based hydrogels were investigated: adding 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) to the monomers solution before polymerization (HEMA/i-CD) and an hydrogels' post-treatment with HP-ß-CD (HEMA/p-CD). The effect of HP-ß-CD and sterilization by high hydrostatic pressure (HHP) on the hydrogel properties (water content, oxygen and ion permeability, roughness, transmittance, and stiffness) was evaluated. The HEMA/i-CD hydrogels had stronger affinity for TA, sustaining its release for one day. HHP sterilization promoted the formation of cyclodextrin-TA complexes within the hydrogels, improving their drug-loading capacity ¼60 %. Cytotoxicity and irritability tests confirmed the safety of the therapeutic CLs. TA released from the hydrogels permeated through ocular tissues ex vivo and showed anti-inflammatory activity. Finally, a previously validated mathematical model was used to estimate the ability of the TA-loaded CLs to deliver therapeutic drug concentrations to the posterior part of the eye. Overall, HP-ß-CD-containing CLs are promising candidates for the topical ocular application of TA as an alternative delivery system to intraocular injections.

Riboflavin-loaded soy protein isolate cold gel treated with combination of high intensity ultrasound and high hydrostatic pressure: Gel structure, physicochemical properties and gastrointestinal digestion fate.

Transglutaminase (TGase) was added to soy protein isolate (SPI) dispersion after the combination treatment of high intensity ultrasound (HIU) and high hydrostatic pressure (HHP) to catalyze the formation of cold gel, which was used to encapsulate riboflavin. The structure, physicochemical properties and in vitro digestion characteristics of riboflavin-loaded SPI cold gel were investigated. HIU-HHP combined treatment enhanced the strength, water retention, elastic property, thermal stability and protein denaturation degree of riboflavin-loaded SPI cold gels, and improved the gel network structure, resulting in a higher encapsulation efficiency of riboflavin and its chemical stability under heat and light treatment. HIU-HHP combined treatment reduced the erosion and swelling of SPI cold gel in simulated gastrointestinal fluid, and improved the sustained release effect of SPI gel on riboflavin by changing the digestion mode and rate of gel. In addition, HIU-HHP combined treated gels promoted the directional release of riboflavin in the simulated intestinal fluid, thereby improving its bioaccessibility, which was related to the secondary structure orderliness, tertiary conformation tightness and aggregation degree of protein during the gastrointestinal digestion. Therefore, HIU-HHP combined treatment technology had potential application value in improving the protection, sustained/controlled release and delivery of SPI cold gels for sensitive bioactive compounds.

Antirotaviral activity of dairy byproducts enriched in fractions from hyperimmune bovine colostrum: the effect of thermal and high hydrostatic pressure treatments.

Nowadays, rotaviruses remain a major health burden, especially in developing countries, and strategies complementary to vaccination are needed. In this view, dairy fractions have attracted great scientific interest, due to their high content of bioactive compounds. The objective of this study was to evaluate the antiviral activity of whey and buttermilk enriched in proteins from hyperimmune bovine colostrum (HBC) against rotavirus. The enriched fractions were spray-dried and subsequently tested for their neutralizing activity against the bovine rotavirus WC3 strain in vitro, using differentiated Caco-2/TC7 cells. The highest antirotaviral activity was observed when whey and buttermilk were enriched in purified immunoglobulin G (IgG), showing complete rotavirus neutralization at concentrations of 3 and 6 mg mL-1 for whey and buttermilk, respectively. Additionally, the use of a crude immunoglobulin fraction also gave satisfactory results. The inhibitory activities of all samples significantly decreased after the application of heat, except for the IgG-enriched buttermilk which showed a slight increase of activity following the application of short-time treatments (75 or 85 °C for 20 s). This sample also showed a significant increase of activity (13%) after the application of low-intensity high hydrostatic pressure treatment (400 MPa for 5 min). The maximum loss of bioactivity was observed at 600 MPa for 10 min (31 and 20% for whey- and buttermilk-based formulas, respectively). This study provides relevant information on the potential of whey, buttermilk, and HBC to be part of functional products as complementary strategies to combat rotavirus infections.

Systematic enhancement of microbial decontamination efficiency in bone graft processing by means of high hydrostatic pressure using Escherichia coli as a model organism.

To obtain bone allografts that are safe for transplantation, several processing steps for decellularization and decontamination have to be applied. Currently available processing methods, although well-established, may interfere with the biomechanical properties of the bone. High hydrostatic pressure (HHP) is known to devitalize tissues effectively while leaving the extracellular matrix intact. However, little is known about the inactivation of the contaminating microorganisms by HHP. This study aims to investigate the ability of high-pressure decontamination and to establish a treatment protocol that is able to successfully inactivate microorganisms with the final goal to sterilize bone specimens. Using Escherichia coli (E. coli) as a model organism, HHP treatment parameters like temperature and duration, pressurization medium, and the number of treatment cycles were systematically adjusted to maximize the efficiency of inactivating logarithmic and stationary phase bacteria. Towards that we quantified colony-forming units (cfu) after treatment and investigated morphological changes via Field Emission Scanning Electron Microscopy (FESEM). Additionally, we tested the decontamination efficiency of HHP in bovine cancellous bone blocks that were contaminated with bacteria. Finally, two further model organisms were evaluated, namely Pseudomonas fluorescens as a Gram-negative microorganism and Micrococcus luteus as a Gram-positive representative. A HHP protocol, using 350 MPa, was able to sterilize a suspension of stationary phase E. coli, leading to a logarithmic reduction factor (log RF) of at least -7.99 (±0.43). The decontamination of bone blocks was less successful, indicating a protective effect of the surrounding tissue. Sterilization of 100% of the samples was achieved when a protocol optimized in terms of treatment temperature, duration, pressurization medium, and number and/or interval of cycles, respectively, was applied to bone blocks artificially contaminated with a suspension containing 104 cfu/mL. Hence, we here successfully established protocols for inactivating Gram-negative model microorganisms by HHP of up to 350 MPa, while pressure levels of 600 MPa were needed to inactivate the Gram-positive model organism. Thus, this study provides a basis for further investigations on different pathogenic bacteria that could enable the use of HHP in the decontamination of bone grafts intended for transplantation.

Cellular transfection using rapid decrease in hydrostatic pressure.

Of all methods exercised in modern molecular biology, modification of cellular properties through the introduction or removal of nucleic acids is one of the most fundamental. As such, several methods have arisen to promote this process; these include the condensation of nucleic acids with calcium, polyethylenimine or modified lipids, electroporation, viral production, biolistics, and microinjection. An ideal transfection method would be (1) low cost, (2) exhibit high levels of biological safety, (3) offer improved efficacy over existing methods, (4) lack requirements for ongoing consumables, (5) work efficiently at any scale, (6) work efficiently on cells that are difficult to transfect by other methods, and (7) be capable of utilizing the widest array of existing genetic resources to facilitate its utility in research, biotechnical and clinical settings. To address such issues, we describe here Pressure-jump-poration (PJP), a method using rapid depressurization to transfect even difficult to modify primary cell types such as embryonic stem cells. The results demonstrate that PJP can be used to introduce an array of genetic modifiers in a safe, sterile manner. Finally, PJP-induced transfection in primary versus transformed cells reveals a surprising dichotomy between these classes which may provide further insight into the process of cellular transformation.

Mechanical properties of artificially structured soil and Binary-medium-based constitutive model under undrained conditions.

To investigate the mechanical properties and constitutive models of structured soil under undrained conditions, triaxial compression tests on initially anisotropic structured soil, isotropic structured soil, and remolded soil were conducted under consolidation undrained conditions at confining pressures of 25, 50, 100, and 200 kPa, respectively. The results demonstrate that the samples of structured soils with strong structural characteristics have an obvious yield strength when the consolidation stress is low. At this time, the pore water pressure in structured soils increases at the beginning of loading. As the axial strain increasing, it turns to reduce. When failure, the samples have obvious shear band. With the consolidation stress increases, the mechanical properties and deformation mechanism of structured soils are near to the remolded soil. Combining the Binary-medium theory with the analysis and discussion of the mechanical properties and deformation mechanisms of structured soil, the rationality of the corresponding Binary-medium model was verified, which shows that the constitutive model can reflect the characteristics of dilatancy and strain softening, volumetric contraction and strain hardening under the conditions of low and high confining pressure respectively. At the same time, the constitutive model can also reflect the differences in the stress-strain characteristics of the two structural soils caused by the structural differences. In general, the results agree with the experiment relative well.

Evaluation of dual modification by high hydrostatic pressure and annealing on the physicochemical properties of bean starch.

This study investigated the physical modifications by high hydrostatic pressure (HHP) at 600 MPa for 30 min/30 °C, annealing (AN) at 50 °C/24 h and the combination of both (HHP + AN and AN + HHP) applied to yellow bean starch to verify changes in morphology, X-ray diffraction, molecular order, thermal properties and pasting properties of native (NS) and modified starches. Morphological analysis showed loss of sphericity and increase in diameter with the appearance of pores on the surface after application of treatments. The AN starch showed lower values of syneresis, degree of double helix (DD), order (DO), and viscosity of the paste obtained by RVA. It exhibited a Vh-type classification with the appearance of the amylose-lipid complex. However, the gelatinization temperatures, as well as the enthalpy of gelatinization, were significantly higher. On the other hand, the starch treated with HHP showed a higher Setback (SB) value. The greatest modifications were found for the starches subjected to the combined treatments (AN + HHP) and (HHP + AN), where the order of the treatments was significant for the morpho-structural changes of yellow bean starch. According to the micrographs, the surface aspect was altered, with AN + HHP showing greater irregularities and flat yet irregular faces, as well as a larger granule diameter (147.05). The X-ray diffractogram showed a reduction in crystallinity from 28.14 % (NS) to 18.09 % (AN + HHP) and classified the starch as type "A". The double modification (HHP + AN and AN + HHP) reduced the gelatinization temperature and the enthalpy of gelatinization but had no effect on the bands of the FT-IR spectrum. There was only a reduction in the degree of order and the double helix. Finally, the treatment with AN + HHP is more effective as the gelatinization with AN facilitates the application of HHP. Both methods used are classified as physical (thermal and non-thermal), aiming to minimize environmental impacts and achieve faster and safer morpho-structural modification without leaving chemical residues in the products.

Physicochemical properties of amorphous granular starch (AGS) prepared by non-thermal gelatinization by high hydrostatic pressure (HHP) and spray drying.

Corn starch was gelatinized by high hydrostatic pressure (HHP) and spray drying to make amorphous granular starch (AGS), and their physicochemical properties were compared with the conventionally prepared (heat-gelatinized and spray dried) AGS to devise a novel AGS preparation methodology. Pressure-induced (PAGS) and heat-induced AGS (HAGS) maintained their granular shape but lost their birefringence indicating that both methods could prepare AGS. DSC (differential scanning calorimeter) and XRD (X-ray diffraction) analysis confirmed the complete loss of amylopectin double helices and crystallinity of both PAGS and HAGS. However, their swelling power, solubility, RVA pasting properties, acid/shear stability, gel forming ability and textural properties were completely different. PAGS exhibited constrained swelling, suppressed amylose leaching, and reduced viscosity. Notably, HAGS formed a gel without heating, whereas PAGS yielded a viscous paste with water-soluble attributes. Even after reheating, PAGS maintained its granular structure with comparably less swelling and weaker gel strength than HAGS. Consequently, newly developed PAGS exhibited distinctive characteristics compared to the conventional HAGS, such as lower solubility and swelling power, viscosity, textural properties, and high acid and shear stabilities, rendering it a viable option for various applications within the food industry.