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1.
J Sci Food Agric ; 103(6): 3041-3049, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36545692

RESUMO

BACKGROUND: Adding resistant starch (RS) to bread formulations is a promising way of increasing fiber content of white bread. However, the partial replacement of wheat flour (WF) by RS can lead to a decrease in technological quality. The objective of this study was to analyze the performance of hydroxypropylmethylcellulose and carboxymethylcellulose as improvers of wheat bread with a high level of replacement (30%) with maize RS. The levels of the modified celluloses were 1% and 1.5% (WF + RS basis), and a formulation without modified celluloses was used as control. Proofing time, loaf volume, crumb characteristics (porosity, texture), and bread staling parameters (hardness increase, moisture loss), among other attributes, were analyzed, and principal component analysis was applied to compare samples. RESULTS: The use of both modified celluloses was effective in improving the quality of breads. Specific volume and crumb porosity were enhanced, particularly at the 1.5% level. Breads with modified celluloses also allowed a higher retention of water and a better preservation of mechanical properties during storage. The principal component analysis projection graph for the first two principal components showed that samples with modified celluloses were clustered by the level of hydrocolloid addition rather than by the type of hydrocolloid used, although all the samples with modified celluloses were close to each other and distant from the control sample without hydrocolloids. CONCLUSION: The quality decrease resulting from the replacement of WF by a high level of RS can be greatly compensated by the use of structuring agents such as hydroxypropylmethylcellulose and carboxymethylcellulose. © 2022 Society of Chemical Industry.


Assuntos
Amido Resistente , Pão , Carboximetilcelulose Sódica/análise , Carboximetilcelulose Sódica/química , Triticum/química , Coloides , Amido/química , Derivados da Hipromelose/química
2.
Ceska Slov Farm ; 65(3): 94-98, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27854436

RESUMO

Characteristics of the buccal mucoadhesive films (film thickness, film weight, uniformity of mass and moisture content) prepared by solvent casting method were tested in this experimental study. The formulations consisted either of one mucoadhesive polymer (sodium hyaluronate of two different molecular weights and sodium carboxymethylcellulose) or combinations thereof. On the basis of the aforementioned tests, it was determined that water content was influenced by the molecular weight of sodium hyaluronate as well as by the ratio of mucoadhesive polymers in the composition. The composition of the films influences also other tested parameters.Key words: buccal mucoadhesive films solvent casting method sodium hyaluronate sodium carboxymethylcellulose water content.


Assuntos
Ácido Hialurônico/química , Mucosa Bucal/química , Carboximetilcelulose Sódica/análise , Solventes , Água/análise
3.
Neuro Endocrinol Lett ; 36 Suppl 1: 95-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26757125

RESUMO

OBJECTIVES: The aim of the study was to use methods of pharmaceutical technology, and prepare carriers in the form of pellets suitable as a filling of detection tubes for enzymatic detection of cholinesterase inhibitors. The enzymatic detection was based on enzymatic hydrolysis of acetylthiocholine iodide and the subsequent colour reaction of its hydrolysis product with Ellman's reagent. The suitable carriers should be in the form of white, regular and sufficiently mechanically resistant particles of about 1 mm allowing it to capture the enzyme during the impregnation process and ensuring its high activity for enzymatic detection. METHODS: Carriers consisting of microcrystalline cellulose, lactose, povidone, and sodium carboxymethyl cellulose were prepared using extrusion-spheronization method under three different drying conditions in either a hot air oven or a microwave oven. Subsequently, the carriers were impregnated with acetylcholinesterase and their size, shape, mechanical resistance, bulk, tapped and pycnometric density, Hausner ratio, intraparticular and total tapped porosity, and activity were measured and recorded. RESULTS: In this procedure, carriers with different physical parameters and different acetylcholinesterase activity were evaluated. It was found that higher acetylcholinesterase activity was associated not only with a higher intraparticular porosity but also with more regular particles characterized by high sphericity and low total tapped porosity. CONCLUSION: This unique finding is important for the preparation of detection tubes based on enzymatic detection which is still irreplaceable especially in the field of detection and analysis of super-toxic cholinesterase inhibitors.


Assuntos
Carboximetilcelulose Sódica/análise , Celulose/análise , Inibidores da Colinesterase/metabolismo , Lactose/análise , Povidona/análise , Acetiltiocolina/análogos & derivados , Acetiltiocolina/metabolismo , Ácido Ditionitrobenzoico , Teste de Materiais , Porosidade , Reagentes de Sulfidrila
4.
Biotechnol Lett ; 33(4): 787-95, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21188616

RESUMO

PURPOSE OF WORK: To show biological activity of carboxymethylated α-(1 → 3)-D-glucans isolated from the selected macromycetes fungi on human tumor and normal cells. Water-insoluble, alkali-soluble polysaccharides (WIP) were isolated from fruiting bodies of four macromycetes fungi: Lentinus edodes, Pleurotus ostreatus, Piptoporus betulinus and Laetiporus sulphureus. The structure of the polysaccharides was determined using composition analysis, methylation analysis, fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The chemical and spectroscopic investigations indicated that the polysaccharides were an α-(1 → 3)-D-glucans. A biological activity analysis of the carboxymethylated (CM) α-(1 → 3)-D-glucans was based on an assessment of their cytotoxic, mitochondrial metabolism-modulating, and free radical scavenging effects. The cytotoxic activity of the CM-glucans was concentration- and cell-type-dependent. The tested CM-glucans, generally, did not have a free radical scavenging effect. The CM-α-(1 → 3)-D-glucans isolated from the selected macromycetes fungi are biologically active and may therefore be used as diet or therapy supplements.


Assuntos
Basidiomycota/química , Carboximetilcelulose Sódica/análise , Carboximetilcelulose Sódica/farmacologia , Carpóforos/química , Glucanos/análise , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos
5.
Bioprocess Biosyst Eng ; 34(3): 357-65, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21153422

RESUMO

The cellulase production by Trichoderma viride, cultivated on different substrates, namely steam-pretreated Lespedeza, filter paper, microcrystalline cellulose (MCC) or carboxymethyl cellulose (CMC), was studied. Different cellulase systems were secreted when cultivated on different substrates. The cellulolytic enzyme from steam-pretreated Lespedeza medium performed the highest filter paper activity, exoglucanase and endoglucanase activities, while the highest ß-glucosidase activity was obtained from the enzyme produced on filter paper medium. The hydrolytic potential of the enzymes produced from different media was evaluated on steam-pretreated Lespedeza. The cellulase from steam-pretreated Lespedeza was found to have the most efficient hydrolysis capability to this specific substrate. The molecular weights of the cellulases produced on steam-pretreated Lespedeza, filter paper and MCC media were 33, 37 and 40 kDa, respectively, and the cellulase from CMC medium had molecular weights of 20 and 43 kDa. The degree of polymerization, crystallinity index and micro structure scanned by the scanning electron microscopy of degraded steam-pretreated Lespedeza residues were also studied.


Assuntos
Celulases/metabolismo , Celulose/análise , Celulose/metabolismo , Lespedeza/química , Trichoderma/enzimologia , Carboidratos/química , Carboximetilcelulose Sódica/análise , Carboximetilcelulose Sódica/metabolismo , Celulase/análise , Celulase/biossíntese , Celulase/metabolismo , Celulases/biossíntese , Celulose/ultraestrutura , Glucana 1,3-beta-Glucosidase/análise , Glucana 1,3-beta-Glucosidase/biossíntese , Glucana 1,3-beta-Glucosidase/metabolismo , Hidrólise , Lespedeza/metabolismo , Lespedeza/ultraestrutura , Papel , Polimerização , Vapor , Especificidade por Substrato , Trichoderma/metabolismo , Difração de Raios X/métodos , beta-Glucosidase/análise , beta-Glucosidase/biossíntese , beta-Glucosidase/metabolismo
6.
Caries Res ; 44(2): 127-34, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20357442

RESUMO

The aim of the present study was to evaluate the effects of experimental saliva substitutes based on carboxymethyl cellulose (CMC) differing in degrees of saturation with respect to calcium phosphates on the mineral loss of enamel in vitro. Demineralized bovine specimens (subsurface lesions) were exposed to one of six experimental CMC-based solutions with theoretical degrees of saturation with respect to octacalcium phosphate (S(OCP)) of S0, S0.5, S1, S2, S4, and S8 for 10 weeks. A previously studied saliva substitute (Glandosane) and two aqueous solutions (C0 and C1) served as controls. Mineral losses and lesion depths before and after storage were evaluated from microradiographs. Free and bound calcium as well as phosphate and fluoride concentrations were determined. According to these measurements, S(OCP) of S2, S4, and S8 was 0.3, 1.1, and 3.4, respectively. Storage in Glandosane and both negative controls resulted in significant demineralization (p < 0.05). Only S2 significantly remineralized the specimens (p < 0.05). All other solutions showed neutral effects. No significant differences in mineralization between S0 and C0 as well as between S1 and C1 could be observed (p > 0.05). It can be concluded that a CMC-based solution actually unsaturated with respect to octacalcium phosphate (S2) shows most pronounced remineralization capability under the conditions chosen. This might be explained by a more favorable balance between calcium bound to CMC in an adsorbed layer at the enamel-liquid interface and heterogeneous nucleation of calcium phosphates within a solution compared to solutions either supersaturated or having lower levels of saturation.


Assuntos
Fosfatos de Cálcio/uso terapêutico , Carboximetilcelulose Sódica/uso terapêutico , Saliva Artificial/uso terapêutico , Desmineralização do Dente/etiologia , Adsorção , Animais , Cálcio/análise , Fluoreto de Cálcio/análise , Fluoreto de Cálcio/uso terapêutico , Fosfatos de Cálcio/análise , Carboximetilcelulose Sódica/análise , Bovinos , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/patologia , Durapatita/análise , Durapatita/uso terapêutico , Fluoretos/análise , Teste de Materiais , Microrradiografia , Minerais/análise , Fosfatos/análise , Saliva Artificial/análise , Fatores de Tempo , Desmineralização do Dente/patologia , Remineralização Dentária
7.
Pediatrics ; 143(3)2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30765462

RESUMO

A 14-year-old girl developed 4 episodes of anaphylaxis of unknown etiology, which required intramuscular adrenaline administration each time. She had eaten pizza and a cheeseburger immediately before the first 2 episodes, respectively, but had not eaten anything for several hours before the last 2 episodes. It turned out that she had eaten the same ice lolly 4 hours before the first 3 episodes and a Café au lait Swirkle (a half-frozen beverage) 4 hours before the last episode. We detected carboxymethylcellulose sodium as the only common ingredient in all anaphylactic episodes. Skin prick tests were positive for carboxymethylcellulose solution and carboxymethylcellulose-containing food products. We obtained a custom-made carboxymethylcellulose sodium-free ice lolly from the manufacturer and confirmed that it did not induce anaphylactic reactions by a challenge test. Carboxymethylcellulose, an anionic water-soluble polymer derived from native cellulose, is considered to be unabsorbable from the human gut and has been widely and increasingly used in pharmaceutical preparations, cosmetics, and food. This article is the first report of anaphylaxis caused by carboxymethylcellulose-containing foods, whereas anaphylaxis to carboxymethylcellulose has been rarely associated with carboxymethylcellulose-containing pharmaceuticals. Although the exact mechanisms underlying the induction of late-onset anaphylaxis by carboxymethylcellulose remain unclear, a small minority of cellulose-digesting microbial flora in the human colon and contamination of food products with carboxymethylcellulose of low molecular weight might be involved. The induction of recurrent anaphylaxis by various products should be a clue that prompts physicians to suspect food additives as a cause for anaphylaxis.


Assuntos
Anafilaxia/induzido quimicamente , Anafilaxia/diagnóstico , Carboximetilcelulose Sódica/efeitos adversos , Carboximetilcelulose Sódica/análise , Aditivos Alimentares/efeitos adversos , Aditivos Alimentares/análise , Adolescente , Feminino , Humanos
8.
Food Funct ; 9(7): 4017-4027, 2018 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-29978871

RESUMO

The addition of dietary fibers can alleviate the deteriorated textural properties and water binding capacity (WBC) that may occur when the fat content is lowered directly in the formulas of comminuted meat products. This study investigated the effects of the addition of chitosan or carboxymethyl cellulose (CMC) (2% w/w) to a model meat product. Both dietary fibers improved the water-binding capacity (WBC), while chitosan addition resulted in a firmer texture, CMC lowered the hardness. Chitosan addition resulted in a 2-fold reduction of lipid oxidation products, whereas CMC had no significant effect on oxidation. The effect of chitosan addition on lipid oxidation was evident both in the meat system and after simulated in vitro gastrointestinal digestion. Low-field nuclear magnetic resonance (NMR) relaxometry revealed that the fibers impacted the intrinsic water differently; the addition of chitosan resulted in a faster T2 relaxation time corresponding to water entrapped in a more dense pore network. Coherent anti-Stokes Raman scattering (CARS) microscopy was for the first time applied in a meat product to study the microstructure, which revealed that the two fibers exerted different effects on the size and entrapment of fat droplets in the protein network, which probably explain the mechanisms by which chitosan reduced lipid oxidation in the system.


Assuntos
Carboximetilcelulose Sódica/análise , Quitosana/análise , Aditivos Alimentares/química , Produtos da Carne/análise , Animais , Manipulação de Alimentos , Oxirredução , Suínos , Água/análise
9.
Eur J Pharm Sci ; 96: 398-410, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27721041

RESUMO

One of the main obstacles to the successful treatment of tuberculosis is the poor and variable oral bioavailability of rifampicin (RIF), which is mainly due to its low hydrophilicity and dissolution rate. The aim of this work was to obtain a hydrophilic new material that allows a very fast dissolution rate of RIF and therefore is potentially useful in the development of oral solid dosage forms. The acid form of carboxymethylcellulose (CMC) was co-processed with RIF by solvent impregnation to obtain CMC-RIF powder, which was characterized by polarized optical microscopy, powder x-ray diffraction, DSC-TGA, hot stage microscopy, 13C and 15N solid-state NMR and FT-IR spectroscopy. In addition, the CMC-RIF matrices were subjected to water uptake and dissolution studies to assess hydrophilicity and release kinetics. CMC-RIF is a crystalline solid dispersion. Solid-state characterization indicated that no ionic interaction occurred between the components, but RIF crystallized as a zwitterion over the surface of CMC, which drastically increased the hydrophilicity of the solid. The CMC-RIF matrices significantly improved the water uptake of RIF and disintegrated in a very short period immediately releasing RIF. As CMC improves the hydrophilicity and delivery properties of RIF, CMC-RIF is very useful in the design of oral solid dosage forms with very fast dissolution of RIF, either alone or in combination with other antitubercular drugs.


Assuntos
Carboximetilcelulose Sódica/análise , Carboximetilcelulose Sódica/química , Rifampina/análise , Rifampina/química , Varredura Diferencial de Calorimetria/métodos , Espectroscopia de Ressonância Magnética/métodos , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Fatores de Tempo , Difração de Raios X/métodos
10.
Food Res Int ; 100(Pt 1): 858-863, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28873759

RESUMO

The understanding of the interactions between starch and cellulose hydrocolloids is crucial for equipment design and definition of operation parameters in the food industry. In the present study, the possible interactions of wheat starch (WS) with different levels (2-10%) of carboxymethyl cellulose (CMC) or microcrystalline cellulose (MCC) in short-term retrogradation were explored by dynamic rheological and Fourier transform infrared spectrum (FTIR) measurements. The chains of water-soluble CMC could creep into the continuous phase during paste gelation. It was found the amylose network structure was broken and the inter- and intra-molecular hydrogen bond of WS were weaken after gelation. Moreover, there were interactions between the chains of CMC and chains of amylose at higher CMC concentration. On other hand, water connected with COO- groups blocked the interactions between CMC chains and amylose, and the interactions among CMC chains. The amorphous phases of high crystalline MCC were just swollen during paste gelation. It results that heterogeneous microstructure with amylose and MCC domains unevenly distributed was in WS/MCC paste.


Assuntos
Carboximetilcelulose Sódica/química , Celulose/química , Amido/química , Triticum/química , Carboximetilcelulose Sódica/análise , Celulose/análise , Coloides/análise , Coloides/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier
11.
J Agric Food Chem ; 53(8): 2823-9, 2005 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-15826025

RESUMO

Guar gum, a nonionic galactomannan, is used as an economical thickener and stabilizer in the food industry and is often combined with xanthan, locust bean gum (LBG), or carboxymethylcellulose (CMC) to promote synergistic changes in viscosity or gelling behavior via intermolecular interactions; however, the adulteration of LBG with guar gum is a well-known industrial problem. The ability to identify the purity of gums and concentrations of individual gums in mixtures would be advantageous for quality control in the food industry. Fourier transform infrared spectroscopy (FTIR) methods are rapid and require minimum sample preparation. The objectives of this study were to evaluate the ability of FTIR techniques to (1) differentiate LBG with a variety of mannose/galactose (M/G) ratios, (2) differentiate guar, LBG, tara, and fenugreek gums, (3) differentiate pure guar gum from guar gum mixed with LBG, xanthan gum, or CMC, (4) quantify LBG, xanthan gum, and CMC in guar gum, and (5) quantify guar gum in LBG. Two FTIR methods were used: diffuse reflectance (DRIFT) on powdered gum samples added to KBr at 5%, w/w, and attenuated total reflectance (ATR) on 1%, w/w, gum solutions. Spectra were collected and then analyzed by multivariate statistical procedures (chemometrics). The DRIFT method provided better discrimination and quantitative results than the ATR method. Canonical variate analysis (CVA) of DRIFT spectra (1200-700 cm(-1)) was able to classify LBG with various M/G ratios, pure galactomannans, and pure versus mixtures of gums with 100% accuracy. Quantification of an individual gum in gum mixtures (0.5-15%, w/w) was possible using partial least-squares (PLS) analysis of DRIFT spectra with R2 > 0.93 and using this approach for quantifying guar gum added to LBG resulted in an R2 > 0.99, RMSEC = 0.29, and RMSEP = 3.31. Therefore, the DRIFT FTIR method could be a useful analytical tool for quality control of select gums and gum mixtures used in the food industry.


Assuntos
Contaminação de Alimentos/análise , Galactanos/análise , Mananas/análise , Polissacarídeos/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Carboximetilcelulose Sódica/análise , Indústria Alimentícia , Gomas Vegetais , Polissacarídeos Bacterianos/análise , Controle de Qualidade
12.
Waste Manag ; 38: 33-40, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25543195

RESUMO

In the present study, functionalization of mixed office waste (MOW) paper has been carried out to synthesize carboxymethyl cellulose, a most widely used product for various applications. MOW was pulped and deinked prior to carboxymethylation. The deinked pulp yield was 80.62 ± 2.0% with 72.30 ± 1.50% deinkability factor. The deinked pulp was converted to CMC by alkalization followed by etherification using NaOH and ClCH2COONa respectively, in an alcoholic medium. Maximum degree of substitution (DS) (1.07) of prepared CMC was achieved at 50 °C with 0.094 M and 0.108 M concentrations of NaOH and ClCH2COONa respectively for 3h reaction time. The rheological characteristics of 1-3% aqueous solution of optimized CMC product showed the non-Newtonian pseudoplastic behavior. Fourier transform infra red (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscope (SEM) study were used to characterize the CMC product.


Assuntos
Carboximetilcelulose Sódica/análise , Papel , Reciclagem/métodos , Gerenciamento de Resíduos/métodos , Carboximetilcelulose Sódica/química
13.
Int J Biol Macromol ; 79: 144-50, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25936282

RESUMO

Alpha-cellulose extracted from corn husks was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from husk cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA), with ethanol as the supporting medium. Characterizations of CMC were carried out by analyzing the spectra of FTIR, XRD patterns and SEM photomicrographs. Degree of substitution (DS) was determined with respect to particle size using chemical methods. Solubility, molecular weight and DS of CMC increased with decreased cellulose particle sizes. Microbiological testing of the prepared CMC was done by the pour plate method. Concentrations of heavy metals such as arsenic, lead, cadmium and mercury in the purified CMC were measured by Atomic Absorption Spectroscopy technique and found to be within the WHO/FAO recommended value. A comparative study with CMC available in the international market was conducted. The purity of the prepared CMC was higher, at 99.99% well above the purity of 99.5% for standard CMC. High purity CMC showed a yield 2.4 g/g with DS 2.41, water holding capacity 5.11 g/g, oil holding capacity 1.59 g/g. The obtained product is well suited for pharmaceutical and food additives.


Assuntos
Carboximetilcelulose Sódica/química , Celulose/química , Zea mays/química , Acetatos/química , Arsênio/análise , Cádmio/análise , Carboximetilcelulose Sódica/análise , Celulose/isolamento & purificação , Etanol/química , Análise de Alimentos , Indústria Alimentícia/métodos , Humanos , Chumbo/análise , Mercúrio/análise , Peso Molecular , Hidróxido de Sódio/química , Solubilidade , Resíduos , Água
14.
Am J Clin Nutr ; 62(6): 1252-60, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7491889

RESUMO

Eighteen healthy males with a body weight of 70.0 +/- 3.1 kg consumed three defined-formula diets that varied only in their fiber and/or lipid components: 1) 6.4% fiber (100% soy polysaccharides) and 13.1% lipid [50% medium-chain triacylglycerols (MCTs), 40% corn oil, and 10% soy oil]; 2) 3.4% fiber (75% oat fiber, 17.5% gum arabic, and 7.5% carboxymethylcellulose) and 15.6% lipid (20% MCTs, 50% canola oil, and 30% high oleic acid safflower oil); and 3) 4.4% fiber (same as diet 2) and 14.5% lipid (same as diet 1). Consumption of diet 2 resulted in slightly firmer stools and provided the greatest amount of fecal output per unit fiber intake. Total dietary fiber (TDF) digestibility was lowest for men fed diets 2 and 3, but nitrogen and lipid digestibilities and energy metabolism criteria were not different among diets. Although mineral excretion patterns differed among treatments, fiber and lipid components of the diets appeared not to be responsible for these differences. Results indicate that fecal output can be maintained with a lower intake of a blend of oat fiber, gum arabic, and carboxymethylcellulose compared with soy polysaccharides. Except for TDF digestibility, alteration of amounts and/or sources of fiber and lipid components of defined-formula diets used in this experiment did not alter nutrient digestibility, energy metabolism, or mineral retention.


Assuntos
Fibras na Dieta/farmacologia , Digestão/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Fezes/química , Lipídeos/farmacologia , Minerais/metabolismo , Adulto , Cálcio/análise , Cálcio/metabolismo , Carboximetilcelulose Sódica/análise , Cobre/análise , Cobre/metabolismo , Creatinina/urina , Fibras na Dieta/análise , Digestão/fisiologia , Metabolismo Energético/fisiologia , Ácidos Graxos/análise , Alimentos Formulados/análise , Goma Arábica/análise , Humanos , Ferro/análise , Ferro/metabolismo , Lipídeos/análise , Magnésio/análise , Magnésio/metabolismo , Masculino , Minerais/análise , Fósforo/análise , Fósforo/metabolismo , Polissacarídeos/análise , Potássio/análise , Potássio/metabolismo , Zinco/análise , Zinco/metabolismo
15.
J Dent Res ; 55(3): 353-6, 1976.
Artigo em Inglês | MEDLINE | ID: mdl-1063745

RESUMO

A number of fluoride gels containing a hydroxyalkyl cellulose thickening agent show non-Newtonian rheological behavior in the form of stress thinning (apparent viscosity decreasing with shear rate). Viscosities of 450 to 780 poise at low rates of shear down to 1.0 to 2.0 poise at high rates of shear were obtained. The effect of temperature on viscosity was comparatively small. One gel, containing a noncellulosic thickening agent showed a much more pronounced stress thinning (7,500 poise at low rates). Furthermore, at low rates of shear this material showed pronounced elastic behavior. This may well be clinically advantageous.


Assuntos
Fluoretos Tópicos , Carboximetilcelulose Sódica/análise , Elasticidade , Fluoretos Tópicos/análise , Géis , Metilcelulose/análise , Reologia , Viscosidade
16.
J Pharm Sci ; 77(9): 799-801, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3225776

RESUMO

An extensive study has been made of the thixotropic behavior of a microcrystalline cellulose-sodium carboxymethylcellulose gel (2% weight) and of its modification due to physical factors such as agitation time, duration of storage at rest, and temperature. An empirical function, giving thixotropic area variation rate as a function of agitation time, was obtained and found to be practically independent of storage time.


Assuntos
Carboximetilcelulose Sódica/análise , Celulose/análise , Metilcelulose/análogos & derivados , Fenômenos Químicos , Físico-Química , Géis , Reologia , Temperatura , Fatores de Tempo
17.
J Agric Food Chem ; 52(26): 8105-10, 2004 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-15612803

RESUMO

The influence of type and concentration of carboxymethyl cellulose (CMC) on flavor and textural properties of custard desserts was examined. A synthetic strawberry flavor mixture was used to flavor the custards; it comprised 15 volatile flavor compounds. The viscosity of the custards was determined using rheometric measurements. Static headspace gas chromatography and in-nose proton transfer reaction-mass spectrometry analyses were conducted to determine the custards' volatile flavor properties. Perceived odor, flavor, and textural properties were assessed in sensory analysis experiments using magnitude estimation against a fixed modulus. Both type and concentration of CMC altered the viscosity of the custards. Softer custards had higher static headspace flavor concentrations. On the contrary, firmer custards demonstrated higher in-nose flavor concentrations. In sensory analysis, firmer custards showed higher thickness and lower sweetness intensities than their low-viscosity counterparts. The thickness perception corresponded to the viscosity of the custards. Removal of sucrose from the custards affected sweetness intensity only and not the intensity of other attributes. Therefore, the influence of the viscosity of the custards on the release of sweet-tasting components is held responsible for the effect on perceived sweetness intensity. Odor intensities were generally higher for the low-viscosity custard, whereas fruity flavor intensities were higher for the firmer custards. Odor intensities correlated with static headspace concentrations and flavor intensities related reasonably well with in-nose concentrations. Opening and closing of the nasal cavity is regarded as an important factor determining the discrepancy between static and in-nose measurements.


Assuntos
Carboximetilcelulose Sódica/análise , Análise de Alimentos , Sensação , Paladar , Aromatizantes/análise , Fragaria , Humanos , Olfato , Viscosidade , Volatilização
18.
Int J Pharm ; 263(1-2): 61-8, 2003 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-12954181

RESUMO

The studies reported here have been undertaken to assess the potential use of isothermal microcalorimetry in studying the antimicrobial efficacy of wound dressings that contain antimicrobial agents. The microcalorimetric technique allows non-invasive and non-destructive analysis to be performed directly on a test sample, regardless of whether it is homogeneous or heterogeneous in nature. Microcalorimetry is an established procedure that offers quantitative measurements and has the distinct advantage over traditional antimicrobial test methodologies in that calorimetric measurements are made continuously over real-time, thus the dynamic response of microorganisms to an antimicrobial agent is observed in situ. The results described in this paper are for interaction of two silver-containing wound care products AQUACEL Ag Hydrofiber (ConvaTec, Deeside, UK) and Acticoat 7 with SILCRYST (Smith and Nephew Healthcare, UK) with the wound pathogenic organisms Staphylococcus aureus and Pseudomonas aeruginosa. Both dressings are shown, microcalorimetrically, to have the capacity to kill these common wound pathogens within 1-2 h of contact. A dose-response study was conducted with the AQUACEL Ag dressing. Microcalorimetry is shown to be rapid, simple and effective in the study of the antimicrobial properties of gel forming wound dressings.


Assuntos
Anti-Infecciosos/análise , Bandagens , Carboximetilcelulose Sódica/análise , Poliésteres/análise , Polietilenos/análise , Compostos de Prata/análise , Anti-Infecciosos/farmacologia , Bandagens/microbiologia , Calorimetria/métodos , Carboximetilcelulose Sódica/farmacologia , Poliésteres/farmacologia , Polietilenos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Compostos de Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
19.
J Pharm Biomed Anal ; 27(3-4): 577-85, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-11755758

RESUMO

Enantiomer separations of various drugs by capillary electrophoresis (CE) were investigated utilizing carboxymethyl (CM) derivatives of some polysaccharides. Three types of CM-polysaccharides, namely CM-dextran, -amylose and -cellulose were employed as chiral selectors in the CE enantiomer separation. Capability of enantiomer separation by these CM-polysaccharides was compared with that by polysaccharides without CM residues (i.e. native or neutral polysaccharides). Among three selectors employed, CM-dextran and -cellulose showed a relatively wide capability of enantiomer separation. Modification of polysaccharides seems to lead to the enhancement of the capability of enantiomer separation. Degree of substitution greatly affected the capability of enantiomer separation of these polysaccharide derivatives as in the beta-cyclodextrins derivatives.


Assuntos
Amilose/análogos & derivados , Amilose/análise , Carboximetilcelulose Sódica/análise , Dextranos/análise , Polissacarídeos/análise , Amilose/química , Carboximetilcelulose Sódica/química , Dextranos/química , Eletroforese Capilar/métodos , Polissacarídeos/química , Estereoisomerismo
20.
J Pharm Biomed Anal ; 7(12): 1641-9, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2490553

RESUMO

A sensitive method for the identification of polysaccharides in pharmaceuticals is described. Polysaccharides are isolated by gel filtration and subsequently hydrolysed. The monomeric carbohydrates obtained are transformed into oxime-trimethylsilyl derivatives and analysed by capillary gas chromatography. Profiles of 13 different natural or semi-synthetic polysaccharides are discussed. The profiles of the hydrolysis products can be used to identify the polysaccharides mentioned above. Possible interferences by other polymers are given. The method can be used to identify most polysaccharides used as pharmaceutical adjuvants.


Assuntos
Polissacarídeos/análise , Álcoois/análise , Amilose/análogos & derivados , Amilose/análise , Carboidratos/análise , Carboximetilcelulose Sódica/análise , Celulose/análogos & derivados , Celulose/análise , Cromatografia Gasosa , Cromatografia em Gel , Emulsões , Hidrólise , Indicadores e Reagentes , Pomadas , Ácidos Sulfúricos/análise , Compostos de Trimetilsilil/análise , Compostos de Trimetilsilil/química , Ácidos Urônicos/análise
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