RESUMO
The study evaluated the effects of conventional pasteurization and ohmic heating (OH) at different electric fields (12, 16, 20, or 24 V/cm-1) on probiotic chocolate dairy desserts' physicochemical, microbiological, sensory properties and volatile profiles. Both treatments were analyzed for parameters such as pH, syneresis, cream stability index, rheology, bioactive compounds (total phenolics and antioxidant capacity), and probiotic viability (Lactobacillus acidophilus LA-05) over a 28-day storage period. Ohmic heating at higher electric fields (20 and 24 V/cm-1) showed comparable results to pasteurization for most parameters, with non-significant differences or even higher values for some. Sensory analysis revealed that pasteurized samples were more associated with "creamy" and "firm" textures. In contrast, OH-treated samples were linked to lumps and fluidity, particularly in OH24 and OH16, respectively. Volatile compounds such as propanal and ethyl propanoate were detected across treatments, with ethyl acetate unique to OH24. The results suggest that OH, especially at higher electric fields, is a promising technology for processing probiotic dairy desserts, offering similar or enhanced qualities compared to conventional pasteurization. These findings provide insights into the potential for OH to be routinely applied in functional dairy product production.
Assuntos
Chocolate , Lactobacillus acidophilus , Pasteurização , Probióticos , Probióticos/análise , Pasteurização/métodos , Chocolate/análise , Compostos Orgânicos Voláteis/análise , Paladar , Concentração de Íons de Hidrogênio , Microbiologia de Alimentos , Manipulação de Alimentos/métodos , Qualidade dos Alimentos , Laticínios/análise , Laticínios/microbiologia , Reologia , Fenóis/análise , Antioxidantes/análiseRESUMO
Oleogels are semi-solid systems that can function both as replacers of trans and saturated fats and/or as carriers of lipophilic bioactive compounds. However, bioactive compounds can affect the structure of the oleogel matrix and this effect depends on the properties of such compounds. Therefore, the aim of this study was to develop oleogels loaded with ß-carotene (BC) or resveratrol (R), with low concentrations of glycerol monostearate (GMS, 2-5 wt%) and sunflower oil as organic solvent. The gels were characterized by polarized light microscopy, rheological measurements, differential scanning calorimetry, oil binding capacity and Fourier transform infrared spectroscopy. At higher GMS concentrations, stronger oleogels and higher temperatures associated with transitions (sol-gel/gel-sol and crystallization/melting) were observed. The incorporation of bioactive compounds modified the gelation behavior. BC weakened the oleogel structure during the transient molecular organization of GMS, whereas R increased the dynamic moduli. BC also caused slight oil release at lower concentrations, while R improved retention. The high hydrophobicity of BC may be disturbing the solubility balance of the system, while R has phenolic hydroxyl groups that may strengthen hydrogen bonds. However, there were no considerable changes in mechanical properties after storage. We hypothesize that the molecular organization of GMS over time may be masking the modifications that bioactive compounds cause in mechanical properties. In fact, changes in the structure were revealed, as the addition of BC or R changed the morphology of the three-dimensional network crystals. Thus, the results can contribute to the rational choice of system components using low concentrations of oleogelator, as the composition of the bioactive compound exerts influence on the modulation of lipid matrices.
Assuntos
Varredura Diferencial de Calorimetria , Compostos Orgânicos , Resveratrol , Reologia , Óleo de Girassol , beta Caroteno , Resveratrol/química , Compostos Orgânicos/química , Óleo de Girassol/química , beta Caroteno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Microscopia de Polarização , Géis/química , Interações Hidrofóbicas e Hidrofílicas , Solubilidade , Glicerol/química , Fenômenos QuímicosRESUMO
The objective of this research was to assess the potential of a Pickering emulsion based on lycopene extracted from guava by sunflower oil-water and cellulose nanofibers (CNFs) isolated from banana residues as a novel ingredient for a French-style salad dressing. The aim was to determine the impact of this emulsion on the stability and rheological properties of the dressing as well as ascertain the presence of lycopene in the final product. The particle size distribution, rheological properties, and emulsion stability of the Pickering emulsion and salad dressing were evaluated. The sample exhibiting the optimal stability condition contained 0.5 wt.% of CNFs (EPI0.5). In order to prepare the French salad dressing based on this Pickering emulsion, three concentrations of vinegar were analyzed. All samples contained white salt and sugar. The findings suggest that alterations in emulsion stability may be influenced by the vinegar content and the presence of salt, particularly during the storage period, which also affects the concentration of lycopene. Notwithstanding these findings, the untrained panelists expressed a favorable opinion and acceptance of the dressings, indicating that the product could serve as an alternative means of enriching food through the incorporation of beneficial substances such as lycopene.
Assuntos
Celulose , Emulsões , Licopeno , Nanofibras , Psidium , Licopeno/química , Celulose/química , Emulsões/química , Nanofibras/química , Psidium/química , Água/química , Tamanho da Partícula , Reologia , Óleo de Girassol/química , Carotenoides/química , Ácido Acético/químicaRESUMO
The aim of this study was to develop a mixture of dimethacrylate isomers (PG6EMA) as a potential monomer for dental adhesives and composites. PG6EMA was synthesized de novo and characterized in the presence of ethanol (3%, 6% or 9%). BisGMA/TEGDMA (BTEG, 50/50 wt.%) was used as the resin control. Composites were formulated with 60 wt.% of either PG6EMA or BisGMA (40 wt.% TEGDMA and 70 wt.% filler). DMPA (0.2 wt.%) and DPI-PF6 (0.4 wt.%) were added as photoinitiators, irradiated with a mercury arc lamp (320-500 nm, 500 mW/cm2; Acticure). All materials were tested for polymerization kinetics (near-infrared), viscosity (η) and storage modulus (G', oscillatory rheometry). The composites were further characterized for water sorption/solubility, wet/dry flexural strength/modulus and polymerization stress. Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05). The PG6EMA resins showed lower rates of polymerization compared with BTEG (p = 0.001) but high degrees of conversion (p = 0.002). Solvent concentration did not affect RPMAX but the 6% and 9% mixtures showed higher final DC, likely due to reduced viscosity. PG6EMA had much higher viscosity than BTEG (p <0.001) and lower G' (p = 0.003). Composites modified with PG6EMA have slower polymerization rates (p = 0.001) but higher final DC (p = 0.04) than the control. PG6EMA/TEGDMA showed lower dry/wet flexural strength and comparable dry modulus. The PG6EMA/TEGDMA composite showed a 18.4% polymerization stress reduction compared to the BTEG composite. Both base monomers had similar WS/SL and G'. Within its limitations, this study demonstrated that the newly synthesized PG6EMA was a viable alternative to BisGMA in dental composites.
Assuntos
Bis-Fenol A-Glicidil Metacrilato , Resinas Compostas , Teste de Materiais , Metacrilatos , Polimerização , Ácidos Polimetacrílicos , Resinas Compostas/química , Resinas Compostas/efeitos da radiação , Bis-Fenol A-Glicidil Metacrilato/química , Metacrilatos/química , Viscosidade , Ácidos Polimetacrílicos/química , Análise de Variância , Fatores de Tempo , Reprodutibilidade dos Testes , Valores de Referência , Resistência à Flexão , Polietilenoglicóis/química , Propriedades de Superfície , Solubilidade , Cinética , Reologia , Cimentos Dentários/química , Cura Luminosa de Adesivos Dentários/métodosRESUMO
This study evaluated the rheological properties of various hyaluronic acid (HA) gels after passing through different-sized cannulas (22-G and 25-G). Five commercial brands of highly crosslinked HA fillers were analyzed: (A) Rennova® Ultra Deep, (B) Restylane® Lyft, (C) Hialurox® - Ultra Lift, (D) Belotero® Volume, and (E) E.P.T.Q S500. Rheological characterization was conducted using an automated controlled stress rheometer. The rheological properties of the fillers were assessed both before and after passing through the cannulas. Each filler brand and cannula size was tested three times by a researcher who was blinded to the commercial brands. For data analysis, frequencies of 0.1, 0.5, and 2 Hz were employed. The rheological properties (storage modulus [G'] and loss modulus [G"]) of the high-crosslink HA fillers did not change after being passed through cannulas of different sizes (22-G and 25-G) (p > 0.109) compared to baseline measurements (no cannula). Furthermore, all fillers displayed desirable solid-like, volumizing behavior at low frequencies and strain amplitudes (<10 %). Under physiologically relevant conditions for skin and facial applications, the cannula size did not alter the rheological properties of high crosslink HA fillers.
Assuntos
Cânula , Ácido Hialurônico , Reologia , Ácido Hialurônico/química , Preenchedores Dérmicos/química , Géis/química , HumanosRESUMO
This study aimed to investigate the effects of acid or alkali modification of isolated cassava starch (ICS) on its physicochemical properties. Acetic acid concentrations of 5%, 10%, and 20% v/v (0.87, 1.73, and 3.46 M, respectively) and calcium hydroxide concentrations of 0.15%, 0.20%, and 0.30% w/w (0.02, 0.025, and 0.04 M, respectively) were tested independently and compared with untreated isolated starch. The scanning electron microscope (SEM) shows starches with polyhedral and semispherical shapes; these modifications do not change the surface of the starch granules. Nanocrystals with orthorhombic crystal structure were extracted from ICS. Transmission electron microscopy (TEM) shows crystallites with a size (two-dimensional) of 20 ± 5 nm in length and 10 ± 2 nm in width and reveals that this starch contains nanocrystals with orthorhombic crystal structure. The X-ray patterns show that these nanocrystals are unaffected by acidic or alkaline treatments. The Ca+2 and CH3COO- ions do not interact with these nanocrystals. The alkaline treatment only affects the gelatinization temperature at a Ca(OH)2 concentration of 0.30%. Low concentrations of acidic and alkaline treatments affect the ability of cassava starch to absorb water and reduce the peak and final viscosity. The infrared spectra show that the modifications lead to C-H and CâC bond formations. ICS-B 0.30 can modify the amorphous regions of the starch, and the acid treatment leads to acetylation, which was confirmed by the presence of an IR band at 1740 cm-1.
Assuntos
Manihot , Reologia , Amido , Manihot/química , Amido/química , Concentração de Íons de Hidrogênio , Difração de Raios X , Microscopia Eletrônica de Varredura , Ácido Acético/química , Nanopartículas/química , Hidróxido de Cálcio/química , Viscosidade , Microscopia Eletrônica de TransmissãoRESUMO
This study aimed to investigate the static and dynamic rheological properties of an ultra-processed powdered goat milk beverage containing carboxymethyl cellulose (CMC), guar gum (GG), and xanthan gum (XG), using a mixture design. Fourteen samples were evaluated, in addition to the original beverage. The flow curves classified the fluids as non-Newtonian and characterized all the reconstituted beverages with pseudoplastic behavior, precisely due to the addition of hydrocolloids that increased the viscosity, and the fresh beverage sample showed the behavior of a dilatant fluid. The stress sweep verified the changes in the storage module (G') and the loss module (Gâ³), the G' ranged from 1.97 to 20.36 (Pa) and the Gâ³ ranged from 5.94 to 11.30 (Pa), demonstrating that there was the formation of beverages with elastic and viscous behaviors. The results showed a synergistic effect between the texture improvers, and the formulations with GG identified a greater effect on the tension. The frequency sweep tests showed that the behavior of the samples was that of a weak gel; however, when subjected to a certain frequency, the values of G' exceeded the value of Gâ³, becoming a sample with more elastic characteristics and consequently, presenting the behavior of a stronger gel. Finally, according to the data presented, it is assumed that formulations containing GG and xanthan gum may produce desirable consumer properties for the reconstituted goat milk drink. Samples with a higher concentration of GG exhibited improved rheological performance, characterized by greater consistency, increased resistance to tension, and higher viscosity at low frequencies. PRACTICAL APPLICATION: The powdered goat milk drink is an innovative product that meets the demands of the food industry and consumers by offering a nutritious and sustainable beverage alternative.
Assuntos
Manipulação de Alimentos , Galactanos , Cabras , Mananas , Leite , Gomas Vegetais , Polissacarídeos Bacterianos , Reologia , Animais , Polissacarídeos Bacterianos/química , Leite/química , Mananas/química , Gomas Vegetais/química , Viscosidade , Galactanos/química , Manipulação de Alimentos/métodos , Aditivos Alimentares , Carboximetilcelulose Sódica/química , Bebidas/análise , Pós/químicaRESUMO
External beam radiotherapy is a treatment modality that employs high doses for curative or palliative purposes. Safety in such treatments, particularly with high-precision equipment, necessitates strict adherence to quality control protocols to ensure the efficacy of oncological treatments. In this context, chemical dosimeters, particularly the Fricke gel, have emerged as valuable tools for quantitatively analysing absorbed radiation doses. These dosimeters can be applied both as tissue-equivalent phantoms and as radiation detectors in radiotherapy centers. The objective of this study was to evaluate the feasibility of new gelling matrices, comprising common materials such as CMC, GGU, and PVA, for producing ferrous sulphate dosimeters aimed at the relative quantification of radiation dose. A rheological study was conducted for different Fricke gel dosimetric formulations. Initially, the performance of these dosimeters, produced at various gel concentrations, was evaluated in terms of their consistency at room temperature. This was achieved through the straightforward process of humidification the gels with glycerine. These matrices consist of both natural and synthetic polymers that are readily accessible, easy to handle, and can be easily incorporated into the acidic ferrous sulphate solution. Parameters such as the influence of gelling matrix concentration, linearity, and stability were assessed and correlated with those previously investigated for Fricke gel produced with bloom 300 pig skin gelatine (GEL). Ferrous sulphate dosimeters fabricated with sodium carboxymethylcellulose (CMC), guar gum (GGU), and polyvinyl alcohol (PVA) exhibited a coefficient of variation of less than 1% relative to the dose response evaluated in this study. By using readily available and easily manageable materials, it is possible to replicate dosimeters with a favourable dosimetric response for high-dose measurements.
Assuntos
Estudos de Viabilidade , Compostos Ferrosos , Compostos Ferrosos/química , Dosímetros de Radiação , Polímeros/química , Géis , Humanos , ReologiaRESUMO
The heat and momentum transfer of tomato puree through a concentric-tube heat exchanger over a range of generalized Reynolds number (0.05 < Re < 66.5) was experimentally and numerically analyzed. Thermophysical and rheological properties of tomato puree (12°Brix) were measured from 20 to 60°C. The velocity, pressure, and temperature were calculated using the computational fluid dynamics (CFD) software FLUENTTM with temperature-dependent transport properties. The thermal operation of the concentric-tube exchanger was satisfactorily predicted using CFD, indicating accurate measurement of tomato puree properties with temperature variations. A concordance was found between the calculated Fanning friction factor and generalized Reynolds with the experimental correlation. A modified Sieder-Tate correlation was established, which allows properly expressing the Nusselt number as a function of the Peclet number. Simple correlations for the mechanical work and the heat transfer rate as a function of the volumetric flow rate were derived. The thermal efficiency was high at low puree flow rates but decreased with higher rates. However, at high flow rates, ceased its decline, instead showing a slight improvement. The analysis confirmed higher heat transfer rates in the concentric-tube heat exchanger compared to a plain tube at low puree flow rates. The results offer valuable insights for assessing diverse operational conditions in dairy, beverage, sauce, and concentrated food industries. Additionally, they also enhance the analysis and design of concentric-tube heat exchangers. PRACTICAL APPLICATION: The knowledge of the rheological and hydrodynamical behavior of fluids in concentric-tube heat exchangers allows to explore a set of different operating conditions to improve the yield and effectiveness on the system heating/cooling design.
Assuntos
Fricção , Temperatura Alta , Reologia , Solanum lycopersicum , Solanum lycopersicum/química , Manipulação de Alimentos/métodos , HidrodinâmicaRESUMO
The Portland cement industry is continuously exploring new admixture alternatives to manipulate building materials properties, including mechanical, rheological, and durability properties. Cactus mucilage is such an admixture alternative. This study reviews the literature on the use of cactus mucilage (specifically, prickly pear cactus) as a bioadmixture in building materials, particularly Portland-cement-based materials. Moreover, the influences on mechanical strength, rheology, and durability are examined. The results show that cactus mucilage, which has been used since ancient times in America, could enhance materials like lime-, Portland-cement-, and earth-based building materials.
Assuntos
Cactaceae , Materiais de Construção , Mucilagem Vegetal , Reologia , Mucilagem Vegetal/química , Cactaceae/química , Materiais de Construção/análise , Fenômenos QuímicosRESUMO
Novel thiomer/nanoclay nanocomposites based on a thiomer and montmorillonite (MMT) were prepared in order to obtain a mucoadhesive material with controlled release properties for its potential use as drug carrier. The thiomer was synthesized by immobilization of L-cysteine in alginate mediated by carbodiimide reaction and further characterized by FT-IR and Ellman's reaction. Nanocomposites with growing concentrations of thiomer and MMT were prepared and analyzed by XRD, TGA and TEM. Rheological behavior of nanocomposite in contact with mucin and intestinal mucus were studied as in vitro and in situ mucoadhesion approach, showing until â¼10-fold increasing in the complex viscosity and â¼27-fold in elastic modulus when the amount of thiomer is increased. Higuchi and Korsmeyer-Peppas kinetic models were evaluated in order to study the release of deltamethrin from nanocomposite films. Release profiles showed a retard in the migration of the drug influenced by the amount of MMT (P < 0.05). Diffusion coefficient (D) showed a significant decrease (P < 0.0001) when concentration of MMT is increased reaching D = 4.18 × 10-7 m2 h-1, which resulted â¼7-fold lower in comparison with formulation without MMT. This hybrid nanocomposite can be projected as a potential mucoadhesive drug carrier with controlled release properties.
Assuntos
Bentonita , Preparações de Ação Retardada , Portadores de Fármacos , Liberação Controlada de Fármacos , Nanocompostos , Nanocompostos/química , Portadores de Fármacos/química , Bentonita/química , Mucinas/química , Adesividade , Argila/química , Alginatos/química , Cisteína/química , Animais , Reologia , Viscosidade , Mucosa Intestinal/metabolismoRESUMO
Bacteria can synthesize a broad spectrum of multifunctional polysaccharides including extracellular polysaccharides (EPS). Bacterial EPS can be utilized in the food, pharmaceutical, and biomedical areas owing to their physical and rheological properties in addition to generally presenting low toxicity. From an ecological viewpoint, EPS are biodegradable and environment compatible, offering several advantages over synthetic compounds. This study investigated the EPS produced by Klebsiella oxytoca (KO-EPS) by chemically characterizing and evaluating its properties. The monosaccharide components of the KO-EPS were determined by HPLC coupled with a refractive index detector and GC-MS. The KO-EPS was then analyzed by methylation analysis, FT-IR and NMR spectroscopy to give a potential primary structure. KO-EPS demonstrated the ability to stabilize hydrophilic emulsions with various hydrophobic compounds, including hydrocarbons and vegetable and mineral oils. In terms of iron chelation capacity, the KO-EPS could sequester 41.9 % and 34.1 % of the most common iron states, Fe2+ and Fe3+, respectively. Moreover, KO-EPS exhibited an improvement in the viscosity of aqueous dispersion, being proportional to the increase in its concentration and presenting a non-Newtonian pseudoplastic flow behavior. KO-EPS also did not present a cytotoxic effect indicating that the KO-EPS could have potential applications as a natural thickener, bioemulsifier, and bioremediation agent.
Assuntos
Biodegradação Ambiental , Emulsões , Klebsiella oxytoca , Polissacarídeos Bacterianos , Reologia , Klebsiella oxytoca/metabolismo , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/biossíntese , Emulsificantes/química , Emulsificantes/metabolismo , Biotecnologia/métodos , Viscosidade , Interações Hidrofóbicas e HidrofílicasRESUMO
Following consumer trends and market needs, the food industry has expanded the use of unconventional sources to obtain proteins. In parallel, 3D and 4D food printing have emerged with the potential to enhance food processing. While 3D and 4D printing technologies show promising prospects for improving the performance and applicability of unconventional sourced proteins (USP) in food, this combination remains relatively unexplored. This review aims to provide an overview of the application of USP in 3D and 4D printing, focusing on their primary sources, composition, rheological, and technical-functional properties. The drawbacks, challenges, potentialities, and prospects of these technologies in food processing are also examined. This review underscores the current necessity for greater regulation of food products processed by 3D and 4D printing. The data presented here indicate that 3D and 4D printing represent viable, sustainable, and innovative alternatives for the food industry, emphasizing the potential for further exploration of 4D printing in food processing. Additional studies are warranted to explore their application with unconventional proteins.
Assuntos
Manipulação de Alimentos , Impressão Tridimensional , Manipulação de Alimentos/métodos , Reologia , Proteínas , Indústria AlimentíciaRESUMO
In this study, a series of hydrogels were synthesized from chitosan(s) that was crosslinking with glutaraldehyde at different concentrations. Ascorbic acid in an acidic medium was used to facilitate non-covalent interactions. The chitosan(s) was obtained from shrimp cytoskeleton; while ascorbic acid was extracted from xoconostle juice. The hydrogel reaction was monitored by UV-vis spectroscopy (550 nm) to determine the reaction kinetics and reaction order at 60 °C. The hydrogels structures were characterized by NMR, FT-IR, HR-MS and SEM, while the degree of cross-linking was examined with TGA-DA. The extracellular matrices were obtained as stable hydrogels where reached maximum crosslinking was of 7 %, independent of glutaraldehyde quantity added. The rheological properties showed a behavior of weak gels and a dependence of crosslinking agent concentration on strength at different temperatures. The cytotoxicity assay showed that the gels had no adverse effects on cellular growth for all concentrations of glutaraldehyde.
Assuntos
Materiais Biocompatíveis , Quitosana , Hidrogéis , Engenharia Tecidual , Hidrogéis/química , Hidrogéis/síntese química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/farmacologia , Quitosana/química , Quitosana/farmacologia , Quitosana/síntese química , Animais , Glutaral/química , Reologia , Reagentes de Ligações Cruzadas/químicaRESUMO
It is structurally pertinent to understudy the important roles the self-compacting concrete (SCC) yield stress and plastic viscosity play in maintaining the rheological state of the concrete to flow. It is also important to understand that different concrete mixes with varying proportions of fine to coarse aggregate ratio and their nominal sizes produce different and corresponding flow- and fill-abilities, which are functions of the yield stress/plastic viscosity state conditions of the studied concrete. These factors have necessitated the development of regression models, which propose optimal rheological state behavior of SCC to ensure a more sustainable concreting. In this research paper on forecasting the rheological state properties of self-compacting concrete (SCC) mixes by using the response surface methodology (RSM) technique, the influence of nominal sizes of the coarse aggregate has been studied in the concrete mixes, which produced experimental mix entries. A total of eighty-four (84) concrete mixes were collected, sorted and split into training and validation sets to model the plastic viscosity and the yield stress of the SCC. In the field applications, the influence of the sampling sizes on the rheological properties of the concrete cannot be overstretched due to the importance of flow consistency in SCC in order to achieve effective workability. The RSM is a symbolic regression analysis which has proven to exercise the capacity to propose highly performable engineering relationships. At the end of the model exercise, it was found that the RSM proposed a closed-form parametric relationship between the outputs (plastic viscosity and yield stress) and the studied independent variables (the concrete components). This expression can be applied in the design and production of SCC with performance accuracies of above 95% and 90%, respectively. Also, the RSM produced graphical prediction of the plastic viscosity and yield stress at the optimized state conditions with respect to the measured variables, which could be useful in monitoring the performance of the concrete in practice and its overtime assessment. Generally, the production of SCC for field applications are justified by the components in this study and experimental entries beyond which the parametric relations and their accuracies are to be reverified.
Assuntos
Materiais de Construção , Reologia , Reologia/métodos , Materiais de Construção/análise , Viscosidade , Teste de Materiais/métodos , Previsões/métodosRESUMO
Black liquor (BL) is the major bioproduct and biomass fuel in pulp mill processes. However, the high viscosity of BL makes it a challenging material to work with, resulting in issues with evaporators and heat exchangers during its transport and processing. The thermal and rheological properties of BLs from Pinus sp. (PBL) and Eucalyptus sp. (EBL) were studied. FTIR spectra revealed the presence of the characteristic functional groups and the chemical composition in liquors. TGA/DTG curves showed three characteristic degradation stages related to evaporation of water, pyrolysis of organic groups, and condensation of char. Rheologically, liquors are classified as non-Newtonian and with comportment pseudoplastic. Their rheological dynamic shear properties included a linear viscoelastic region up to 1% shear strain, while frequency sweeps showed that storage modulus (G') > loss modulus (G''), thus confirming the solid-like behavior of both BLs. The rheological study demonstrated that increasing the temperature and oscillatory deformations of PBL and EBL decreased their degree of viscoelasticity, which could favor their pumping and handling within the pulp mill, as well as the droplet formation and swelling characteristics in the recovery furnace.
Assuntos
Eucalyptus , Pinus , Reologia , Eucalyptus/química , Pinus/química , Viscosidade , Brasil , Finlândia , Temperatura , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The system of polysaccharides from Schizymenia dubyi (Nemastomatales) was investigated. It contains a mixture of hybrid dl galactans (SH-S) and carrageenan-like polysaccharides, which were separated by means of precipitation with KCl at high concentrations. The structural features of the carrageenan-like fraction (SH-I) were investigated by methylation analysis, desulfation, uronic acid reduction, and NMR spectroscopy. It was concluded that the structure has the typical alternance α-(1 â 3), ß-(1 â 4) of d-galactose units, with most of the 3-linked units sulfated in O-2 (and some in O-4), and most of the 4-linked units sulfated in O-3, and substituted in O-2 by single stubs of ß-d-glucuronic acid (partly sulfated in each of the three available positions). This substituent has been only seldom found in red seaweed galactans. Rheological studies of 5 % and 10 % w/v SH, SH-S and SH-I aqueous systems, either without ions, or in KCl or CaCl2 solution gave thickening behaviors. Their random coil conformations justify the pseudoplastic behavior observed in the viscosity versus shear rate curves. As SH-S and SH-I are both contained in SH, an interpenetrating network could form in SH between the glucurono-carrageenan and the agaran, as inferred from the mechanical spectra recorded in water, especially with potassium ion.
Assuntos
Carragenina , Reologia , Carragenina/química , Viscosidade , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Galactanos/química , Rodófitas/química , Espectroscopia de Ressonância MagnéticaRESUMO
BACKGROUND: Treating signs of aging requires skeletal restructuring, facial contour redefinition, and sagging skin treatment. Hence, HarmonyCa® was recently introduced in the market, combining hyaluronic acid and hydroxyapatite. However, there are no studies evaluating the physicochemical properties of this material. PURPOSE: To analyze the morphology, rheology, and clinical applicability of HarmonyCa® over a 180-day follow-up. METHODS: A morphological analysis with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) and rheology measurement with a rheometer. The clinical applicability analysis included a tissue ptosis patient who received the product and was reassessed 30 and 180 days after applying HarmonyCa®. RESULTS: SEM and EDS analyses showed two distinct morphologies related to hydroxyapatite and hyaluronic acid. The rheological measurements of HarmonyCa® showed G' and Gâ³ of 51.56 and 44.01 Pa, respectively. The tan δ value was 0.8503, and G* was 108.1 Pa. The clinical outcomes were satisfactory. CONCLUSION: HarmonyCa® presents a good synergy between hyaluronic acid and hydroxyapatite. Also, the rheological analysis showed moderate viscosity for the product, with a clinical indication for subcutaneous application. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Assuntos
Durapatita , Ácido Hialurônico , Reologia , Humanos , Ácido Hialurônico/administração & dosagem , Ácido Hialurônico/química , Ácido Hialurônico/farmacologia , Durapatita/administração & dosagem , Durapatita/química , Durapatita/farmacologia , Feminino , Envelhecimento da Pele/efeitos dos fármacos , Técnicas Cosméticas , Preenchedores Dérmicos/administração & dosagem , Preenchedores Dérmicos/química , Pessoa de Meia-Idade , Microscopia Eletrônica de Varredura , Adulto , Seguimentos , Injeções SubcutâneasRESUMO
Among the emerging prebiotics, galactooligosaccharide (GOS) has a remarkable value with health-promoting properties confirmed by several studies. In addition, the application of ohmic heating has been gaining prominence in food processing, due to its various technological and nutritional benefits. This study focuses on the transformative potential of ohmic heating processing (OH, voltage values 30 and 60 V, frequencies 100, 300, and 500 Hz, respectively) in prebiotic chocolate milk beverage (3.0 %w/v galactooligosaccharide) processing. Chemical stability of GOS was assessed along all the ohmic conditions. In addition, microbiological analysis (predictive modeling), physical analysis (color and rheology), thermal load indicators assessment, bioactivity values, and volatile compound was performed. HPAEC-PAD analysis confirmed GOS stability and volatile compound evaluation supported OH's ability to preserve flavor-associated compounds. Besides, OH treatments demonstrated superior microbial reduction and decreased thermal load indicators as well as the assessment of the bioactivity. In conclusion, OH presented was able to preserve the GOS chemical stability on chocolate milk beverages processing with positive effects of the intrinsic quality parameters of the product.
Assuntos
Chocolate , Manipulação de Alimentos , Leite , Oligossacarídeos , Oligossacarídeos/química , Oligossacarídeos/análise , Chocolate/análise , Manipulação de Alimentos/métodos , Leite/química , Animais , Prebióticos/análise , Temperatura Alta , Bebidas/análise , Reologia , Cacau/química , Compostos Orgânicos Voláteis/análiseRESUMO
Hydrogels based on natural polysaccharides have demonstrated efficacy in epithelial recovery from cutaneous burn wounds. Here, we prepared a double-network hydrogel consisting of galactomannan (from Cassia grandis seeds) and κ-carrageenan (commercially sourced), cross-linked with CaCl2, as a matrix for immobilizing lactoferrin and/or Cramoll, aiming at its applicability as dressings for second-degree burn wounds. The formulations obtained [H - hydrogel, HL - hydrogel + lactoferrin, HC - hydrogel + Cramoll and HLC - hydrogel + lactoferrin + Cramoll] were analyzed rheologically as well as in terms of their stability (pH, color, microbial contamination) for 90 days. The burn was created with an aluminum bar (97 ± 3 °C) in the dorsal region of Wistar rats and subsequently treated with hydrogels (H, HL, HC, HLC) and control saline solution (S). The burn was monitored for 3, 7 and 14 days to evaluate the efficacy of the hydrogels in promoting wound healing. The hydrogels did not reveal significant pH or microbiological changes; there was an increase in brightness and a reduction in opacity for H. The rheological analysis confirmed the gel-like viscoelastic signature of the systems without substantial modification of the basic rheological characteristics, however HLC proved to be more rigid, due to rheological synergy when combining protein biomolecules. Macroscopic analyses confirmed centripetal healing with wound contraction: S < H < HC < HL < HLC. Histopathological analyses showed that hydrogel-treated groups reduced inflammation, tissue necrosis and fibrosis, while promoting re-epithelialization with focal acanthosis, especially in HLC due to a positive synergistic effect, indicating its potential as a promising therapy in the repair of burns.