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1.
Food Chem ; 399: 133967, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35998495

RESUMO

Hydrocolloids are a group of polysaccharides that act as thickeners, gelling agents, emulsion stabilizers, inhibitors of the growth and expansion of ice crystals in frozen materials, and inhibitors of the growth of sugar crystals in different industries. Hydrocolloids are used both to improve the rheological and textural properties of food products and also as fat substitutes. Also hydrocolloids are used in the production of low-calorie foods and also their beneficial nutritional properties causes their extensive application in the food industry. Food hydrocolloids or gums are high molecular weight hydrophilic biopolymers that are used as functional compounds in the food industry. Hydrocolloids are obtained from plants, animals, microorganisms, and modified biopolymers. The purpose of this article is to review hydrocolloids and their application in food, pharmaceutical and agricultural industries. Therefore, this article discusses the structure, origin, preparation methods, extraction and the applications of hydrocoloids in various industries.


Assuntos
Coloides , Polissacarídeos , Animais , Biopolímeros , Coloides/química , Indústria Alimentícia , Polissacarídeos/química , Reologia
2.
Med Eng Phys ; 107: 103874, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36068027

RESUMO

Red blood cell (RBC) deformability is an important haemorheological factor; it is impaired in many pathologies leading to microvascular complications. Several microfluidic platforms have been utilized to examine the role of deformability in RBC flows but their geometries tend to be simplified. In the present study, we extend our previous work on healthy RBC flows in micropillar arrays [1] to probe the effect of impaired RBC deformability on the velocity and haematocrit distributions in microscale RBC flows. Healthy and artificially hardened RBC suspensions at 25% haematocrit were perfused through the micropillar array at various flow rates and imaged. RBC velocities were determined by Particle Image Velocimetry (PIV) and haematocrit distributions were inferred from the image intensity distributions. The pillars divide the flow into two distinct RBC streams separated by a cell-depleted region along the centreline and in the rear/front stagnation points. RBC deformability was not found to significantly affect the velocity distributions; the shape of the velocity profiles in the interstitial space remained the same for healthy and hardened RBCs. Time-averaged and spatiotemporal intensity distributions, however, reveal differences in the dynamics and local distributions of healthy and hardened cells; hardened cells appear to enter the cell-depleted regions more frequently and their interstitial distributions are more uniform. The study highlights the importance of local RBC distributions and the impact of RBC deformability on cell transport in complex microscale flows.


Assuntos
Deformação Eritrocítica , Eritrócitos , Hematócrito , Microfluídica , Reologia
3.
Int J Mol Sci ; 23(17)2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-36077030

RESUMO

Smart hydrogels based on natural polymers present an opportunity to fabricate responsive scaffolds that provide an immediate and reversible reaction to a given stimulus. Modulation of mechanical characteristics is especially interesting in myocyte cultivation, and can be achieved by magnetically controlled stiffening. Here, hyaluronan hydrogels with carbonyl iron particles as a magnetic filler are prepared in a low-toxicity process. Desired mechanical behaviour is achieved using a combination of two cross-linking routes-dynamic Schiff base linkages and ionic cross-linking. We found that gelation time is greatly affected by polymer chain conformation. This factor can surpass the influence of the number of reactive sites, shortening gelation from 5 h to 20 min. Ionic cross-linking efficiency increased with the number of carboxyl groups and led to the storage modulus reaching 103 Pa compared to 101 Pa-102 Pa for gels cross-linked with only Schiff bases. Furthermore, the ability of magnetic particles to induce significant stiffening of the hydrogel through the magnetorheological effect is confirmed, as a 103-times higher storage modulus is achieved in an external magnetic field of 842 kA·m-1. Finally, cytotoxicity testing confirms the ability to produce hydrogels that provide over 75% relative cell viability. Therefore, dual cross-linked hyaluronan-based magneto-responsive hydrogels present a potential material for on-demand mechanically tunable scaffolds usable in myocyte cultivation.


Assuntos
Ácido Hialurônico , Hidrogéis , Hidrogéis/química , Polímeros , Polissacarídeos , Reologia
4.
Food Res Int ; 160: 111674, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36076385

RESUMO

High shear rheometry was used to investigate the rheological behavior of high internal phase emulsions (HIPEs) stabilized by whey protein isolate (WPI). The physical stability of HIPEs was tested at extremely high shear rates generated by decreasing the gap height between parallel plates. Viscosity and yield stress, at narrow gaps, increased with protein concentration due to tighter packing of smaller droplets. Structural breakdown and recovery of HIPEs were affected by protein concentration and pH. The hysteresis behavior of HIPEs was either thixotropic or anti-thixotropic and was determined by protein concentration, whereas pH affected the magnitude of anti-thixotropy. At pH 3, emulsions showed greater stability against extreme shear and creaming due to higher deformability of oil droplets and increased interdroplet interaction compared to neutral pH. Challenging the physical integrity of concentrated emulsions under high shear is an effective way to characterize microstructural changes and stability of HIPEs in foods.


Assuntos
Emulsões , Emulsões/química , Concentração de Íons de Hidrogênio , Reologia , Viscosidade , Proteínas do Soro do Leite/química
5.
Int J Mol Sci ; 23(17)2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36077328

RESUMO

Magnetorheological elastomer (MRE) materials have the potential to be used in a wide range of applications that require long-term service in hostile environments. These widespread applications will result in the emergence of MRE-specific durability issues, where durability refers to performance under in-service environmental conditions. In response, the outdoor tropical climatic environment, combined with the effects of weathering, will be the primary focus of this paper, specifically the photodegradation of the MRE. In this study, MRE made of silicone rubber (SR) and 70 wt% micron-sized carbonyl iron particles (CIP) were prepared and subjected to mechanical and rheological testing to evaluate the effects under natural weathering. Magnetorheological elastomer samples were exposed to the natural weathering conditions of a tropical climate in Kuala Lumpur, Malaysia, for 30 days. To obtain a comprehensive view of MRE degradation during natural weathering, mechanical testing, rheology, and morphological evaluation were all performed. The mechanical and rheological properties test results revealed that after 30 days of exposure and known meteorological parameters, Young's modulus and storage modulus increased, while elongation at break decreased. The degradation processes of MRE during weathering, which are responsible for their undesirable change, were given special attention. With the help of morphological evidence, the relationship between these phenomena and the viscoelastic properties of MRE was comprehensively defined and discussed.


Assuntos
Elastômeros , Clima Tropical , Reologia , Elastômeros de Silicone , Tempo (Meteorologia)
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 3985-3988, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36086124

RESUMO

Cardiovascular disease (CVD) and especially atherosclerosis are chronic inflammatory diseases which cause the atherosclerotic plaque growth in the arterial vessels and the blood flow reduction. Stents have revolutionized the treatment of this disease to a great extent by restoring the blood flow in the vessel. The present study investigates the performance of the blood flow after stent implantation in patient-specific coronary artery and demonstrates the effect of using Newtonian vs. non-Newtonian blood fluid models in the distribution of endothelial shear stress. In particular, the Navier-Stokes and continuity equations were employed, and three non-Newtonian fluid models were investigated (Carreau, Carreau-Yasuda and the Casson model). Computational finite elements models were used for the simulation of blood flow. The comparison of the results demonstrates that the Newtonian fluid model underestimates the calculation of Endothelial Shear Stress, while the three non-Newtonian fluids present similar distribution of shear stress. Keywords: Blood flow dynamics, stented artery, non-Newtonian fluid. Clinical Relevance- This work demonstrates that when blood flow modeling is performed at stented arteries and predictive models are developed, the non-Newtonian nature of blood must be considered.


Assuntos
Vasos Coronários , Hemodinâmica , Simulação por Computador , Humanos , Reologia , Estresse Mecânico
7.
Carbohydr Polym ; 296: 119911, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36088019

RESUMO

Processing cellulose nanofibril (CNF) hydrogels with a high concentration is a solution to reduce logistics costs and drying energy and to produce CNF-based materials with good dimensional stability. However, the rheology of concentrated and highly concentrated CNF hydrogels is poorly understood due to the difficulties to characterise them using standard shear rheometers. In this study, enzymatic CNF hydrogels in the concentrated and highly concentrated regimes (3-13.6 wt%) were subjected to lubricated compression at various strain rates. At low strains, compression curves exhibited a linear regime. At higher strains and low strain rates, a heterogeneous and marked hardening of stress levels was observed and accompanied with a two-phase flow with significant fluid segregation and network consolidation. At high strain rates, a homogeneous and incompressible one-phase plateau-like regime progressively established. In this regime, a yield stress was measured and compared with literature data, showing a good agreement with them.


Assuntos
Celulose , Hidrogéis , Fenômenos Físicos , Reologia
8.
Carbohydr Polym ; 296: 119930, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36088024

RESUMO

The aim of this study was to investigate the effect of microwave heating on gel properties of low-acetyl gellan and to explore the potential mechanism of gelation behavior under microwave irradiation. Microwave heating dramatically enhanced the gel strength, hardness of low-acetyl gellan. Microwave-heated gels still formed strong network structures with 30 mM Ca2+ addition, but water bath-induced gels exhibited distinct pseudoplastic fluid behavior. Rheological analysis demonstrated that microwave heating increased the storage modulus (G') and loss modulus (G″) values of gels compared to water bath-induced gels. Low-field nuclear magnetic resonance (Lf-NMR) analysis and magnetic resonance imaging (MRI) showed that microwave heating promoted the hydration behavior of gellan, which contributed to the continuous regions in the gel network and further restricted the water mobility. These findings significantly increase our understanding of the mechanism by which microwaves improve gellan gel properties, thus facilitating the development of gel-related foods with tailored properties.


Assuntos
Micro-Ondas , Água , Géis/química , Polissacarídeos Bacterianos , Reologia
9.
Eur Phys J E Soft Matter ; 45(9): 76, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36103057

RESUMO

We developed a simple method to investigate rheological properties of soft surfaces, such as polymeric liquids and colloidal suspensions, by capturing the images of a metal micro-needle inserted into the surface. At contact, a meniscus-like deformation is formed on the surface. By relating the shape of the deformation to the balance of applied forces, local elasticity and viscosity just inside the surface are obtained. With a facile setup and rapid measurement process, the present method can be implemented to variety of systems, for instance, drying sessile drops and small volume of liquid confined in a capillary.


Assuntos
Polímeros , Reologia , Viscosidade
10.
Molecules ; 27(16)2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-36014369

RESUMO

In this study, acetic acid (AA-2% w/v), a combination of acetic acid and citric acid (AA-1% w/v + CA-1% w/w), and three different concentrations of citric acid (CA-2, 4 and 6% w/w) were used to create chitosan solution. The FTIR analysis showed the presence of residual CA in all the CA-containing samples where no trace of AA was observed. The tensile strengths of the CA-containing samples were lower than the AA samples. Whereas the values for the elongation at break of the CA samples were higher than the AA samples, which kept increasing with an increasing CA content due to the plasticizing effect from residual citric acid. The elongation at break values for 4 and 6% CA-containing samples were 98% higher than the AA samples. The samples prepared with CA showed shorter LVE regions that reduced with an increasing CA concentration compared to the AA samples. Different acid concentrations did not have a large effect on the gelation time. However, CA-containing samples showed higher viscosities as compared to the AA-containing solution, which increased with an increasing CA content. The water vapour transmission rates of the CA-containing samples were lower than the others. All the chitosan solutions suppressed the growth of the two test strains, and none of the variants reached an abs 600 nm at 0.2.


Assuntos
Quitosana , Ácido Cítrico , Reologia , Resistência à Tração , Viscosidade
11.
Mar Drugs ; 20(8)2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-36005530

RESUMO

Collagen hydrogels have been extensively applied in biomedical applications. However, their mechanical properties are insufficient for such applications. Our previous study showed improved mechanical properties when collagen was blended with alginate. The current study aims to analyze the physico-chemical properties of collagen-alginate (CA) films such as swelling, porosity, denaturation temperature (Td), and rheology properties. Collagen was prepared from discarded fish skin of Ikan Belida (Notopterus lopis) that was derived from fish ball manufacturing industries and cross-linked with alginate from brown seaweed (Sargasum polycystum) of a local species as a means to benefit the downstream production of marine industries. CA hydrogels were fabricated with ratios (v/v) of 1:1, 1:4, 3:7, 4:1, and 7:3 respectively. FTIR spectrums of CA film showed an Amide I shift of 1636.12 cm-1 to 1634.64 cm-1, indicating collagen-alginate interactions. SEM images of CA films show a porous structure that varied from pure collagen. DSC analysis shows Td was improved from 61.26 °C (collagen) to 83.11 °C (CA 3:7). CA 4:1 swelled nearly 800% after 48 h, correlated with the of hydrogels porosity. Most CA demonstrated visco-elastic solid characteristics with greater storage modulus (G') than lost modulus (G″). Shear thinning and non-Newtonian behavior was observed in CA with 0.4% to 1.0% (w/v) CaCl2. CA hydrogels that were derived from discarded materials shows promising potential to serve as a wound dressing or ink for bio printing in the future.


Assuntos
Colágeno , Hidrogéis , Alginatos/química , Alginatos/farmacologia , Animais , Colágeno/química , Hidrogéis/química , Porosidade , Reologia
12.
Commun Biol ; 5(1): 855, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-35995827

RESUMO

Viscoelastic properties of epithelial cells subject to shape changes were monitored by indentation-retraction/relaxation experiments. MDCK II cells cultured on extensible polydimethylsiloxane substrates were laterally stretched and, in response, displayed increased cortex contractility and loss of excess surface area. Thereby, the cells preserve their fluidity but inevitably become stiffer. We found similar behavior in demixed cell monolayers of ZO-1/2 double knock down (dKD) cells, cells exposed to different temperatures and after removal of cholesterol from the plasma membrane. Conversely, the mechanical response of single cells adhered onto differently sized patches displays no visible rheological change. Sacrificing excess surface area allows the cells to respond to mechanical challenges without losing their ability to flow. They gain a new degree of freedom that permits resolving the interdependence of fluidity ß on stiffness [Formula: see text]. We also propose a model that permits to tell apart contributions from excess membrane area and excess cell surface area.


Assuntos
Colesterol , Animais , Membrana Celular/química , Colesterol/análise , Cães , Células Madin Darby de Rim Canino , Reologia , Estresse Mecânico
13.
Carbohydr Polym ; 295: 119885, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35989020

RESUMO

Post-fibrillation endoglucanase treatment was employed to reduce the entanglement of cellulose nanofibrils (CNFs) produced with low extent of mechanical milling. The results showed that post-fibrillation endoglucanase treatment can effectively reduce the fibril degree of polymerization (DP) values and therefore entanglement. Cellulose DP was reduced from 520 for CNFs prepared by milling using a SuperMassColloider with 1 pass to 225 after endoglucanase treatment at a low dosage of 1 mg protein/g fibril for 24 h. Endoglucanase treatment can also effectively reduce the fibril mean diameter from 66 nm to 25 nm. Applying post-fibrillation endoglucanase treatment produced more uniform CNFs than the feed CNFs from pure mechanical treatment. All CNFs suspensions prepared by post-fibrillation endoglucanase treatment were non-Newtonian (except at very low concentrations below 0.5 wt%) with shear thinning behavior. Post-fibrillation endoglucanase treatment reduced the viscosity of CNF suspensions due to decreasing fibril DP values and the extent of entanglement.


Assuntos
Celulase , Nanofibras , Celulose , Reologia , Suspensões , Viscosidade
14.
Nat Commun ; 13(1): 4832, 2022 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-35977954

RESUMO

A fundamental property of higher eukaryotes that underpins their evolutionary success is stable cell-cell cohesion. Yet, how intrinsic cell rheology and stiffness contributes to junction stabilization and maturation is poorly understood. We demonstrate that localized modulation of cell rheology governs the transition of a slack, undulated cell-cell contact (weak adhesion) to a mature, straight junction (optimal adhesion). Cell pairs confined on different geometries have heterogeneous elasticity maps and control their own intrinsic rheology co-ordinately. More compliant cell pairs grown on circles have slack contacts, while stiffer triangular cell pairs favour straight junctions with flanking contractile thin bundles. Counter-intuitively, straighter cell-cell contacts have reduced receptor density and less dynamic junctional actin, suggesting an unusual adaptive mechano-response to stabilize cell-cell adhesion. Our modelling informs that slack junctions arise from failure of circular cell pairs to increase their own intrinsic stiffness and resist the pressures from the neighbouring cell. The inability to form a straight junction can be reversed by increasing mechanical stress artificially on stiffer substrates. Our data inform on the minimal intrinsic rheology to generate a mature junction and provide a springboard towards understanding elements governing tissue-level mechanics.


Assuntos
Actinas , Actinas/metabolismo , Adesão Celular/fisiologia , Elasticidade , Reologia , Estresse Mecânico
15.
Food Funct ; 13(17): 8860-8870, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35920437

RESUMO

Aerated emulsions have widespread applications in the food industry. However, the poor stability of aerated emulsions remains a major challenge due to their inherent thermodynamic instability. Herein, a novel strategy to improve the foam stability of aerated emulsions using natural waxes was developed. Natural waxes including beeswax (BW), candelilla wax (CLW), carnauba wax (CW) and rice bran wax (RW), the bio-based and sustainable materials, displayed a high efficiency in improving the interfacial behavior, structural properties and foam stabilization of aerated emulsions. Compared with emulsions containing pure palm kernel stearin (PKS), the presence of waxes enhances the elastic modulus (E') of air-liquid interfacial films and the viscosity (η) of the continuous phase. Interestingly, cryo-scanning electron microscopy (cryo-SEM) images revealed that the fat droplet shape was controlled by waxes. These were related to that waxes were conducive to the formation of larger and rigid fat crystals in fat droplets and facilitated effective piercing of the interface, promoting the fat coalescence. Waxes promoted the formation of partial coalescence in the plateau borders and the interface of the aerated emulsions, thus improving the foam stability. Furthermore, whipping experiments showed that the addition of 1.0-2.0 wt% waxes resulted in a shorter optimum whipping time and a higher overrun of aerated emulsions. The microstructure images showed that aerated emulsions with waxes displayed more numerous and uniform air bubbles. Finally, rheology experiments strongly supported that waxes strengthened the interface and network structure of aerated emulsions. Our observations revealed the mechanism of interaction between the natural wax-tuned interfacial behavior and the structure of aerated emulsions.


Assuntos
Ceras , Emulsões/química , Reologia , Viscosidade , Ceras/química
16.
Water Res ; 222: 118903, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35940153

RESUMO

Due to the non-homogeneous and multiphase nature of anaerobic lagoon constituents, CFD modelling for process optimisation requires continuous functions for shear and solid-liquid separation properties across a large range of solids concentrations. Unfortunately, measurement of existing material properties of anaerobic sludges is limited to only shear or solid-liquid separation, or to a limited solids concentration. In this work, the shear properties of an anaerobic sludge were measured from 0.4 to 12.5 vol%, which corresponds to the solids concentrations seen in lagoons. The sludge showed Newtonian behaviour at 0.4 vol% and Herschel-Bulkley yield stress fluid behaviour for higher concentrations ranging from 0.5 to 12 vol%. We compared multiple approaches to determine relationships between the model fitting parameters of consistency, k, flow index, n, and shear yield stress, τy with solids volume fraction ϕ.The solid-liquid separation properties were measured from sedimentation and filtration experiments to obtain compressibility and permeability properties across all the above-mentioned concentrations, enabling development of hindered velocity sedimentation curves. Comparison to full-scale anaerobic digestate identified that the pilot lagoon sludge had faster sedimentation at a given solids concentration in comparison to the digestate. This is the first study on simultaneous rheological characterisation and solid-liquid separation behaviour of an anaerobic sludge across a wide range of concentrations, thus enabling CFD modelling of the hydrodynamics and performance of anaerobic lagoons.


Assuntos
Hidrodinâmica , Esgotos , Anaerobiose , Reologia , Viscosidade
17.
Int J Mol Sci ; 23(15)2022 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-35955893

RESUMO

Chitosan (Chit) and its composite films are widely used in biomedical, cosmetic, and packaging applications. In addition, their properties can be improved and modified using various techniques. In this study, the effect of the type of clay in Chit composites on the structure, morphology, and physical properties of Chit solution and films was tested. The liquid flow properties of Chit solution with and without clay were carried out using the steady shear test. Chit films containing clay were obtained using the solution-casting method. The morphology, structure, and physical properties of the films were characterized by scanning electron microscopy, atomic force microscopy, infrared spectroscopy, swelling behavior, and tensile tests. The results reveal that for the Chit solution with clay (C1) containing 35 wt.% dimethyl dialkyl (C14-C18) amine, the apparent viscosity is the highest, whereas Chit solutions with other clays show reduced apparent viscosity. Rheological parameters of Chit composites were determined by the power law and Cross models, indicating shear-thinning behavior. Analytical data were compared, and show that the addition of clay is favorable to the formation of intermolecular interactions between Chit and clay, which improves in the properties of the studied composites.


Assuntos
Quitosana , Quitosana/química , Argila , Microscopia de Força Atômica , Reologia/métodos , Viscosidade
18.
Sci Rep ; 12(1): 13549, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35941350

RESUMO

CLARITY is a tissue preservation and optical clearing technique whereby a hydrogel is formed directly within the architectural confines of ex vivo brain tissue. In this work, the extent of polymer gel formation and crosslinking within tissue was assessed using Raman spectroscopy and rheology on CLARITY samples prepared with a range of acrylamide monomer (AAm) concentrations (1%, 4%, 8%, 12% w/v). Raman spectroscopy of individual neurons within hybrids revealed the chemical presence and distribution of polyacrylamide within the mouse hippocampus. Consistent with rheological measurements, lower %AAm concentration decreased shear elastic modulus G', providing a practical correlation with sample permeability and protein retention. Permeability of F(ab)'2 secondary fluorescent antibody changes from 9.3 to 1.4 µm2 s-1 going from 1 to 12%. Notably, protein retention increased linearly relative to standard PFA-fixed tissue from 96.6% when AAm concentration exceeded 1%, with 12% AAm samples retaining up to ~ 99.3% native protein. This suggests that though 1% AAm offers high permeability, additional %AAm may be required to enhance protein. Our quantitative results on polymer distribution, stability, protein retention, and macromolecule permeability can be used to guide the design of future CLARITY-based tissue-clearing solutions, and establish protocols for characterization of novel tissue-polymer hybrid biomaterials using chemical spectroscopy and rheology.


Assuntos
Hidrogéis , Polímeros , Acrilamida , Animais , Materiais Biocompatíveis , Encéfalo , Hidrogéis/química , Camundongos , Reologia
19.
Bioinspir Biomim ; 17(5)2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-35931042

RESUMO

Crustacean and insect antennal scanning movements have been postulated to increase odorant capture but the exact mechanisms as well as measures of efficiency are wanting. The aim of this work is to test the hypothesis that an increase in oscillation frequency of a simplified insect antenna model translates to an increase of odorant capture, and to quantify by how much and through which mechanism. We approximate the antennal movements of bumblebees, quantified in a previous study, by a vertical oscillatory movement of a cylinder in a homogeneous horizontal flow with odorants. We test our multiphysics flow and mass transfer numerical model with dedicated experiments using particle image velocimetry. A new entire translating experimental measurement setup containing an oil tank enables us to work at appropriate Strouhal and Reynolds numbers. Increasing antennal oscillating frequency does increase the odorant capture rate, up to 200%, proving this behavior being active sensing. This result holds however only up to a critical frequency. A decrease of efficiency characterizes higher frequencies, due to molecules depletion within oversampled regions, themselves defined by overlaying boundary layers. Despite decades of work on thermal and mass transfer studies on oscillating cylinders, no analogy with published cases was found. This is due to the unique flow regimes studied here, resulting from the combination of organ small size and low frequencies of oscillations. A theory for such flow regimes is thus to be developed, with applications to fundamental research on animal perception up to bioinspired olfaction.


Assuntos
Antenas de Artrópodes , Odorantes , Animais , Insetos , Movimento , Reologia
20.
Food Res Int ; 159: 111474, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35940749

RESUMO

The aim of this study was to improve the functional properties of chickpea protein for its potential application in the food industry. The effects of low frequency high intensity ultrasound (HIU) at different power (0-300 W) and time (15-30 min) on the rheological properties, gelation, thermal stability, solubility and microstructure of chickpea protein were tested and analyzed. Based on the analysis, it was found that HIU caused the disruption of non-covalent bonds between protein chains leading to the unfolding of chickpea. The HIU-treated chickpea isolate protein aggregates were smaller and more uniformly dispersed, with increased orderly structure, thermal stability, and exposure of hydrophobic and charged groups originally buried in the interior. The experimental results also showed that the effect of HIU did not become more pronounced with increasing power and time, as the power exceeding 150 W for 30 min led to the formation of new polymers by the interactions between the exposed non-covalent groups, which were more ordered and homogeneous than those without HIU.


Assuntos
Cicer , Interações Hidrofóbicas e Hidrofílicas , Reologia , Solubilidade , Ondas Ultrassônicas
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