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1
Murphy, Helen Elizabeth. "The influence of leaf canopy on seed and gum yield of guar (Cyamopsis tetragonoloba [L.] Taub.) /." [St. Lucia, Qld.], 1998. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16303.pdf.
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Sanchez, Gil Yaritza M. "Characterization and rheological properties of Camelina sativa gum: interactions with xanthan gum, guar gum, and locust bean gum." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/32789.
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Master of ScienceDepartment of Biological & Agricultural Engineering
Donghai Wang
Gums are water-soluble polysaccharides used in many industrial and food applications because of their functions such as thickening, gelling, emulsification, adhesion, and encapsulation. Interactions between gums are conducted to enhance functional properties of finished products and reduce processing costs. In this study, camelina gum, from the oil-seed plant Camelina sativa, is characterized by carbohydrate composition and morphological, thermal, and rheological properties. Interactions with xanthan gum, galactomannans guar gum, and locust bean gum (LBG) are also studied. Camelina gum is composed of arabinose, rhamnose, galactose, glucose, xylose and mannose; according to high-performance anion exchange chromatography analysis. Scanning electron microscopy and transmission electron microscopy images showed camelina gum with fibrillar structure and intermeshed network. Camelina gum solutions exhibited a shear thinning flow behavior in a range of concentrations (0.1% to 2.0% w/w) and shear rate (0.001 sˉ¹ to 3000 sˉ¹). Camelina gum is temperature independent at temperature ranges from 4 °C to 90 °C. The apparent viscosity increased as gum concentration increased. Mechanical properties of camelina gum demonstrated viscoelastic behavior with entangled molecular chains. Interaction of camelina gum with monovalent salt NaCl significantly reduced the viscosity of camelina gum solution at 1% when NaCl concentration increased. Camelina gum is soluble in water up to 60% ethanol content, in which the rheological properties do not significantly differ from camelina gum in water solution only. A synergy with xanthan and galactomannans was determined. All mixtures exhibited shear-thinning flow behavior, solid-like behavior at low frequencies, and liquid-like behavior at high frequencies. For camelina-galactomannans mixtures, synergistic interactions occurred in LBG-camelina mixtures at ratios of 1:1 and 3:1. For xanthan-camelina mixture, maximum synergy was observed at the ratio 1:1. Synergistic effects of gum mixtures suggest dependency on the ratios and chemical structures of the gums. The effect of temperature on apparent viscosity of mixtures is not significant. Results showed that camelina gum can be used for commercial applications.
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Al-Shehry, Jaber Mohammed. "EFFECT OF GUAR GUM ON VEGETABLE TRANSPLANT GROWTH." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275440.
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GASTONE, FRANCESCA. "Guar gum improves the stability and the mobility of iron microparticles for groundwater remediation." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2549542.
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Contaminated sites managements represents in Europe one of the most serious issues.
Recent data of the European Environmental Agency (EEA) shows how soil contamination due
to industry, garbage warehousing, mining and hydrocarbons tanks leakage represents one of
the most important threats to the environment [1].
The large volume of waste and the intense use of chemicals during past decades have
resulted in numerous contaminated sites across Europe. Contaminated sites could pose
significant environmental hazards for terrestrial and aquatic ecosystems as they are
important sources of pollution which may result in eco toxicological effects [2]. Emissions of
hazardous substances from local sources could deteriorate soil and groundwater quality. Soil
contamination is mainly located close to waste land-fills, industrial/commercial activities
diffusing heavy metals, oil industry, military camps, and nuclear power plants.
The objective of relevant EU policies is to achieve a quality of the environment applying
successful technologies. To this purpose, in the last decade EU have been financed numbers
of international, multi-partner EU projects; among them, the large scale research project
AQUAREHAB (FP7 ENV 2008.3.1.1.1.) , coordinated by VITO (Belgium) and involving 19
partners, started in May 2009 and lasted 56 months, until 2013. It aimed at developing
innovative rehabilitation technologies for soils, groundwater and surface waters
contaminated by a wide range of priority contaminants (nitrates, pesticides, chlorinated
compounds, aromatic compound, mixed pollutions, ecc.). These technologies have been
developed within 5 operative work packages (WP1-5) and the guidelines and approaches
developed have been extrapolated and applied, in WP8, to real polluted sites.
The work herein presented is included in the context of WP5 and WP8 of the AQUAREHAB
EU project, in which the group of Groundwater Engineering of the Polytechnic University of
Turin is involved; its goal is to develop and apply at the real scale an effective and costeffective in-situ rehabilitation technology based on the injection of micro-sized (100 nm-100
µm) zerovalent iron (MZVI) particles directly into a contaminated aquifer in order to create a
reactive zone which is able to treat both the plumeand the source of contamination.
Injectable MZVI particles are selected because they can overcome the major hindering
factors of the widely accepted ZVI based permeable reactive barriers (PRB) (impossibility to
treat the source of contamination and considerable excavation costs), due their high
reactivity against a wide range of contaminants thanks to their high specific surface area and
to lower costs, longer lifetime and easier handling in respect with nano-sized ZVI (NZVI)
particles. Nevertheless MZVI particles disperse in water are prone to gravitational instability
and, as a consequence, the resulting mobility is limited [3, 4]. To solve this problem, the use
of a stabilizing agent able to modify suspending fluid properties is required. In the recent
year the use of biopolymer demonstrated to be successful [5, 6] although a full
comprehension of interaction mechanisms with the porous media and a complete system
characterization is still missing.
In this work, in order to meet AQUAREHAB project requirements and to overcome
technology limitations, the use of MZVI suspended in a thickening polymer solution of guar
gum hydrocolloid is considered.
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Young, Niall William George. "The solution properties of hydrophobically modified guar gum derivatives." Thesis, University of Salford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360604.
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Husman, Stephen Herbert 1954. "IRRIGATION TIMING AND PLANTING DATE EFFECT ON GUAR SEED YIELDS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275476.
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Ma, Xiaodong. "Lyotropic ion effects in guar gum adsorption on various minerals." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31419.
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Adsorption of guar gum was studied on a number of oxide and clay minerals. The tests were performed as a function of salt concentration and pH from solutions of lithium, sodium, potassium, and cesium chlorides. The four salts allowed an assessment to be made of the significance of lyotropic ion phenomena in controlling the adsorption of the polysaccharide. The results showed that the adsorption of the polymer was independent of pH and acidity/basicity of the minerals. Therefore, no evidence of acid-base type of chemical interactions was observed and hydrogen bonding was suggested as the adsorption mechanism. It was also observed that the adsorption of guar gum on quartz, kaolinite and illite proceeded differently from lithium and sodium chloride solutions in comparison to potassium and cesium chlorides. In contrast, no significant effect of salt type and concentration was observed in guar gum adsorption on titania, hematite, and alumina. It was postulated that the presence or absence of an extensive hydration layer at the mineral-solution interface was the dominant factor and that the interfacial water created a barrier against guar gum adsorption. Therefore, the role of ions of a given lyotropic series is to destabilize the interfacial water structure and promote guar gum adsorption. On the other hand, the absence of an extensive hydration layer on titania, alumina, and hematite allowed guar gum to freely interact with the surfaces and thus no lyotropic ion effect was observed. Therefore, lyotropic ion effects are very strong only in the case of strongly hydrated quartz and, apparently, clay minerals. It was also shown that guar gum undergoes extensive aggregation in concentrated solutions of kosmotropic salts (LiCl and NaCl) while chaotropic potassium and cesium chlorides turned out to be very powerful solvents for the polymer. As a result, it can be postulated that individual guar gum molecules adsorb on minerals from concentrated KCl solutions, while entire guar gum aggregates adsorb from concentrated NaCl solutions. Such findings are of particular interest to potash flotation which is carried out in saturated salt solutions. It was stressed that any analysis of the adsorption results using traditional approaches and models must be performed with extreme caution since guar gum solutions are inherently heterogeneous due to the presence of undissolved, colloidal polymer aggregates.Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate
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Bergecliff, Terese. "Viscosity and Acid Stability in Low-fat Mayonnaise with Varying Proportions of Xanthan Gum and Guar Gum." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-57484.
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Mayonnaise is a mixture of egg yolk, vinegar, water, spices and 70-80% oil forming a semi-solid oil-in-water emulsion. When preparing a low-fat mayonnaise with an increased water content, thickening agents are required for increased viscosity and emulsion stability. The hydrocolloids xanthan gum and guar gum are sometimes used for this purpose and they act synergistically creating a viscosity increase. However, guar gum has poor acid stability, and because mayonnaise is an acidic product guar gum will eventually start to degrade causing a viscosity decrease and subsequent emulsion separation. Despite this fact, guar gum and xanthan gum are extensively used in mayonnaises today. The aim of this degree project was to explore how the synergy between guar gum and xanthan gum influences the viscosity of a low fat mayonnaise and whether high acidity will have an impact on the viscosity over a 4-week period. This was to examine if and if so, how a mayonnaise recipe can be modified to maintain a cost efficient product with the desired rheological properties in times of hydrocolloid price fluctuations. The study was conducted by preparing 15 mayonnaises with 50% fat, either at pH 3,5; 4 or 5 and a total of 0,6 % hydrocolloids with varying proportions of guar gum and xanthan gum. The mayonnaise samples were studied by measurements of viscosity, color changes and a visual comparison of their mayonnaise-like flow-properties compared to Hellmann’s Real Mayonnaise used as reference. The viscosity of the mayonnaises increased with increasing ratio of guar gum. On the other side, there were greater viscosity losses in mayonnaises with increasing ratio of guar gum 4 weeks after preparation compared to 4 days, with no apparent signs of correlation between higher acidity and hydrocolloid degradation. Mayonnaises with 20% xanthan gum and 80% guar gum had the texture most similar to the reference. In these low-fat mayonnaises, the use of more xanthan gum led to an undesired “slimy” texture and a lower viscosity – an important aspect if adjusting a low-fat mayonnaise recipe by increasing the ratio of xanthan gum. Because a commercial mayonnaise sometimes is consumed several months after manufacturing, that time frame is most likely required in order to fully measure how much the high acidity in mayonnaise will affect its viscosity. This project has shown a pattern where viscosity in the assessed mayonnaises starts to decrease a few weeks after preparation. However to find out exactly to what extent and how this would affect the overall product, and ultimately: if guar gum/xanthan gum combinations are suitable for long-term mayonnaise applications, further studies are required.Viskositet och syrastabilitet i majonnäs med låg fetthalt och olika proportioner av xantan och guarkärnmjöl Majonnäs är en blandning av äggula, vinäger, vatten, kryddor och 70-80% olja som bildar en semi-solid olja-i-vatten-emulsion. För att tillverka en lågfettsmajonnäs med högre vatteninnehåll behöver förtjockningsmedel tillsättas för viskositet och emulsionsstabilitet. Hydrokolloiderna xantangummi och guarkärnmjöl används ibland i detta syfte och de utövar en synergi som ger ökad viskositet. Dock har guarkärnmjöl dålig syrastabilitet och eftersom majonnäs är en sur produkt kommer guarkärnmjölet efter ett tag att brytas ned vilket leder till en viskositetsminskning och emulsionsseparation. Trots detta används guarkärnmjöl och xantangummi i stor utsträckning i majonnäser idag. Syftet med examensarbetet var att undersöka hur synergin mellan guarkärnmjöl och xantangummi påverkar viskositeten i en lågfettsmajonnäs och huruvida en hög syrahalt kommer att påverka viskositeten under en 4-veckorsperiod. Detta för att se om och i så fall hur ett majonnäsrecept kan modifieras för att erhålla en kostnadseffektiv produkt om priset på hydrokolloider växlar. För arbetet bereddes 15 majonnäser med 50% fetthalt, antingen med pH 3,5; 4 eller 5 och totalt 0,6% hydrokolloider med olika proportioner av guarkärnmjöl och xantangummi. Majonnäserna undersöktes genom mätning av viskositet, färgförändringar och en visuell jämförelse av deras majonnäsliknande flytegenskaper i förhållande till Hellmann’s Real Mayonnaise som användes som referens. Viskositeten i majonnäserna ökade med ökande halt guarkärnmjöl. Å andra sidan minskade viskositeten i högre grad med ökande halt guarkärnmjöl 4 veckor efter tillverkning jämfört med 4 dagar, men inga tydliga samband mellan högre syrahalt och nedbrytning av hydrokolloider syntes. Majonnäser med en blandning av 20% xantangummi och 80% guarkärnmjöl hade den konsistens som var mest lik referensen. I dessa försök med lågfettsmajonnäser ledde användandet av högre halt xantangummi till en oönskad ”slimig” textur och en lägre viskositet – en viktig aspekt om ett recept på lågfettsmajonnäs ska modifieras genom att öka halten xantangummi. Eftersom en kommersiell majonnäs ibland konsumeras flera månader efter tillverkning så är det troligtvis den tidsramen som krävs för att helt kunna mäta hur mycket den höga syrahalten i majonnäs kommer att påverka dess viskositet. Detta projekt har påvisat ett mönster där viskositeten i de analyserade majonnäserna börjar minska några veckor efter tillverkningen. Men för att få reda på exakt i vilken utsträckning och hur detta skulle påverka produkten i sin helhet, och i slutändan: om kombinationen med guarkärnmjöl och xantangummi är lämplig för majonnäser med lång hållbarhet krävs ytterligare studier.
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Barratt, Emma Elizabeth. "The isolation, purification and characterisation of an alkaline alpha-galactosidase from a thermophilic bacterial consortium." Thesis, Cranfield University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341047.
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Dziadkowiec, Joanna. "Guar Gum/Montmorillonite Nanocomposites and Their Potential Application in Drug Delivery." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33441.
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Clays are ubiquitous near the Earth’s surface. Medicinal properties of these nontoxic minerals have been intuitively recognized since ancient times. Up till now, clays have been used in pharmaceutical formulations as active agents and excipients. Currently, there is an urgent need to seek advanced, functional materials with low environmental impact. Answering to that trend, clay-biopolymer nanocomposites were synthesized in this thesis and applied in a drug delivery system. In the first part of the thesis, Portuguese clay from a bentonite deposit in Benavila (Portugal) was collected from six sampling sites and characterized. The highest content of clay fraction, approximately 30%, was found in two of the sampling sites. After purification, the smectite-rich samples were analyzed with respect to clay content, mineralogical and chemical composition, physicochemical and mechanical properties. SEM-EDS revealed that the smectite present in the ore is montmorillonite with varying Fe content. This was also indicated by the means of XRD, XRF and FTIR. The Benavila sample, which was richest in smectite, as well as the sodium Wyoming montmorillonite from the Source Clay Repository (SWy-2) were successfully used to synthesize clay-biopolymer nanocomposites. The chosen biopolymers were the plant-extracted polysaccharides – neutral guar gum and its cationic form. The obtained materials were thoroughly characterized by XRD, TGA and NMR, and the intercalated structure was reported. The prepared nanocomposites were loaded with an anti-inflammatory drug ibuprofen and tested in an in-vitro release system. The drug-loaded materials were characterized with XRD, TGA and NMR. A membrane diffusion method was chosen as a dissolution testing strategy and the drug was quantified by UV-Vis spectroscopy. The materials exhibited improved properties as a noticeable reduction of release rate was achieved.
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Garcia, Vidal Claudio Andres. "Molecular weight effects in guar gum adsorption and depression of talc." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44116.
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The effect of the molecular weight of guar gum on adsorption, talc depression, and stability of talc suspensions was studied. Four guar gum samples of different molecular weights in the range from 0.162 MDa to 1.4 MDa were used. It was also found that the intrinsic viscosities of the guar gum samples were independent of the type of background solution (NaCl, KCl, distilled water).
The adsorption density of the tested guar gum samples on talc was measured from the same background solutions at pH 9. The floatability of fine talc particles as well as their stability towards aggregation in the presence of guar gum were simultaneously determined so a direct relationship between talc depression and talc flocculation/dispersion by guar gum could be established. It was found that the effect of the molecular weight of guar gum on the adsorption density was negligible. No effect of the background electrolyte on guar gum adsorption was observed. All four guar gum samples were found to be equally strong depressants of talc flotation without any clear relationship with their molecular weights. It was determined that an adsorption density equal to about 20% of the complete surface coverage was sufficient to completely depress talc floatability. All guar gum samples also exhibited strong flocculating capabilities towards the talc particles at lower polymer dosages. As determined from turbidity data, higher molecular weight guar gum samples were more powerful flocculants than lower molecular samples. Most importantly, the strongest depression of talc flotation and the most pronounced flocculation of talc were found to occur at the same dosage. Higher doses of the polymers kept the talc particles completely depressed while simultaneously causing gradual steric redispersion of the mineral. The dispersing capabilities of the polymers were a function of the molecular weight, with the lower molecular weight samples bringing about stronger dispersion than higher molecular weight samples.
It was concluded that a high molecular weight guar gum would be the best depressant, since such a polymer would strongly depress the flotation of talc while minimizing talc dispersion and subsequent mechanical entrainment in the flotation concentrate.
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Souther, Brandy Jolene. "The Effect of Xanthan Gum and Guar Gum on Enhancing the Quality and Preventing Lipid Rancidity in Yeast Bread Supplemented with Flaxseed." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/43920.
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This study examined the effects of guar gum and xanthan gum on flax supplemented breads through objective and sensory testing. Breads containing flaxseed and gums were found to have a significantly (p<0.05) higher water activity than the control bread. Control bread was also found to have a higher (p<0.05) volume while flax breads containing guar gum had a significant (p<0.05) decrease in volume. Control bread and bread containing guar gum were significantly (p<0.05) harder in crumb texture. Breads with flax and xanthan gum displayed a significant (p<0.05) amount of springiness. While there was no significant (p>0.05) difference in peroxide values among bread samples, control bread had a lower (p<0.05) anisidine value indicating a decrease in hydroperoxide breakdown. While not significant (p>0.05), bread containing xanthan gum had a lower anisidine value than the other treatments. Sensory analysis found bread with both gums to be moister (p<0.05) and have a strong (p<0.05) yeasty aroma and fresher flavor. Control bread was found to have the least (p<0.05) yeasty aroma and taste significantly (p<0.05) less bitter but more stale.Master of Science
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Vallance, Charlene Elizabeth. "Intestinal cell proliferation and apoptosis : responses to dietary guar gum and cholesterol." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287808.
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Hurley, Samantha Jane. "The physico-chemical mechanisms underlying the physiological effects of non-starch polysaccharides: studies in ileostomy patients." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310783.
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Chityala, Pavan Kumar. "Evaluation of Xanthan/Enzymatically Modified Guar Gum Mixtures in Oil-in-Water Emulsions." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1528.
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Oil-in-water emulsions have wide range of applications in food industry because of their structure-forming properties, and as delivery systems of polyunsaturated fatty acids into foods. The thermodynamic instability of oil and water, and high susceptibility of unsaturated fatty acids to oxidation lead to physical and oxidative stability in oil-in-water emulsions. These instability processes are generally controlled by incorporating proteins and polysaccharides into oil-in-water emulsions. The objective of this study was to evaluate xanthan/enzymatically modified guar (XG/EMG) polysaccharides on the physical and oxidative stability of 2 wt% whey protein stabilized oil-in-water emulsions containing 20% v/v menhaden fish oil. Enzymatic modified guar gum was obtained by hydrolyzing native guar gum using α-galactosidase enzyme. Emulsions were prepared for guar gum (GG), xanthan gum (XG), xanthan/guar (XG/GG), and xanthan/enzymemodified guar (XG/EMG) gum mixtures using 0, 0.05, 0.1, 0.15, 0.2, and 0.3% gum concentrations. Emulsions were then evaluated for creaming, viscosity, particle size, and microstructure to evaluate the physical stability, and peroxide value, TBARS value and GC-MS solid phase micro extraction (SPME) experiments were performed to evaluate the oxidative stability. Emulsions containing XG/EMG gum mixtures exhibited better creaming stability and higher viscosity of all the emulsion types. However, XG/EMG gum concentrations did not affect the droplet size of the emulsions. The microstructures revealed decreased flocculation in emulsions with XG/EMG mixtures. The primary and secondary lipid oxidation measurements indicated that emulsions containing XG/EMG gum mixtures were more effective in preventing the lipid oxidation of all the emulsion types. From the results, it is evident that XG/EMG gum mixtures can be used as emulsifiers in oil-in-water emulsions to increase both physical and oxidative stability.
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Queiroz, Viviane Miceli Silva. "Estudo experimental do escoamento e da concentração de mistura no processo de filtração tangencial de suspensões macromoleculares." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-16102009-085558/.
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O processo de microfiltração tangencial com membranas tubulares inorgânicas e tubos microporosos, respectivamente de origem importada e nacional, foi investigado tendo-se como objeto de separação as misturas macromoleculares preparadas com os agentes polissacarídeos gomas Xantana e Guar em suspensão aquosa. São evidenciados neste processo os efeitos de sinergia compreendidos nas misturas elaboradas puras e em diferentes proporções, na concentração final de 1000 ppm. A investigação experimental acompanha o comportamento reológico de cada mistura ao longo do processo e os resultados foram investigados a partir de propriedades físico-químicas relevantes como: concentração de carbono orgânico total (Total Organic Carbon - TOC) e análise de absorbância no espectômetro de infravermelho. Resultados de TOC indicaram que em apenas um meio filtrante tubular microporoso (C1T+), o desempenho do processo na retenção dos polissacarídeos foi acima de 90%, em relação ao processo com a membrana comercial importada cuja retenção de TOC foi da ordem de 80%. De acordo com as análises de absorbância, conclui-se que as membranas com tamanho do poro nominal de 0,2 \'mü\'m e 0,4 \'mü\'m tiveram uma retenção mais eficiente do que os tubos microporosos em estudo. A temperatura foi um parâmetro significativo, pois a retenção, na maioria dos casos, foi maior na temperatura de 25ºC, independente da pressão e da velocidade média. Na análise dos procedimentos envolvendo cada mistura, foi constatada a boa sinergia entre as gomas, sem modificação de estrutura (formação de gel) ou fenômenos de superfície que impedissem o processo de microfiltração. A vazão transmembrana das misturas ficou limitada entre os máximos valores para mistura pura de Xantana e mínimos para Guar. Todas as misturas apresentaram comportamento pseudoplástico, sem mudanças na reologia, reforçando a adequada sinergia quanto a este aspecto.The present dissertation reports cross-flow microfiltration with national and imported inorganic tubular membranes and microporous tubes. The object of separation is the macromolecular mixtures prepared with polysaccharide agents Xanthan and Guar gum in aqueous solution. The process shows the synergism effects in pure and different mixture proportions, with 1000 ppm final concentration. The experiments established the rheologic behaviour of each mixture along the process and significant physical and chemical properties, such as Total Organic Carbon concentration (TOC) and absorbency analysis in infrared spectrometer were analyzed. TOC retention shows that only one microporous tubular filtering medium (C1T+) had better performance (retention 90%) than the imported commercial membrane (retention about 80%). Absorbency analysis show a better retention efficiency of membranes with pore size of 0,2 \'mü\'m and 0,4 \'mü\'m than microporous tube. The temperature was a significant parameter, as the better retention was obtained at 25ºC, independently of pressure and mean velocity. There is good synergism between Xanthan and Guar gums without structure modifications or surface phenomena that would impede the microfiltration process. The transmembrane flux of proportional mixtures has been limited between maximum values of pure Xanthan and minimum values of pure Guar mixtures. All mixtures have pseudoplastic behaviour, without changes in rheology, intensifying the good synergism.
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Abramova, N. O. "Guar gum in the treatment of irritable bowel syndrome with constipation in overweight patients." Thesis, БДМУ, 2021. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18833.
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Koek, Mehmet Samil. "Heat processing of galactomannans." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312232.
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Martins, Tatiana dos Reis. "Microencapsulation of antitubercular drugs in a matrix of partially hydrolyzed guar gum, for application in tuberculosis treatment." Master's thesis, Instituto de Tecnologia Química e Biológica António Xavier. Universidade Nova de Lisboa, 2015. http://hdl.handle.net/10362/43588.
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Trabalho realizado na Universidade do AlgarveTuberculosis (TB), despite being a completely curable disease, has reemerged due to drug resistance and deadly synergism with HIV infection, which limit the success of its management. Lung tuberculosis is the main manifestation of TB. Thus, exploring the inhalable route for a local delivery of antitubercular drugs seems a promising therapeutic approach. Partially hydrolyzed guar gum (PHGG) is a strong candidate as matrix material for antitubercular drug carriers. This is mainly due to its affinity for macrophages, the hosts of mycobacteria, which is mediated by the binding of sugar units to macrophage surface receptors. In this work, PHGG-based microparticle formulations were produced by spray-drying, evaluated for cristallinity pattern (X-ray diffraction) and ability for drug association, and in vitro drug release profiles were determined. The cytotoxicity of microparticles was also evaluated (MTT and LDH release assays). Additionally, the therapeutic effect of drug-loaded microparticles was evaluated in vitro on macrophage-like cells infected with mycobacteria strains. The results showed that microparticles exhibited suitable properties for pulmonary delivery (aerodynamic diameter between 1 and 3 μm). A favorable cytotoxic profile was evidenced, as no overt toxicity was detected in representative respiratory cell lines (A549 and Calu-3 cells), although a mild toxic effect was observed in macrophage-like cells. The in vitro response of infected macrophages to drug-loaded PHGG microparticles was considered promising, as only 20% of mycobacteria remained viable upon a single treatment with microparticles. This thesis addresses macrophages as therapeutic target, unraveling the unique role of polysaccharides on pulmonary drug delivery in the ambit of tuberculosis therapy.
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Moser, Poliana [UNESP]. "Comportamento reológico de gomas guar e xantana na presença de polióis." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/90748.
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Atualmente, os substitutos de açúcares têm ganhado destaque devido à crescente demanda do mercado mundial por alimentos que possuem baixo teor calórico e que atendam dietas específicas. Considerando que os componentes presentes nas formulações podem modificar as propriedades funcionais dos hidrocolóides, o objetivo deste trabalho foi estudar o comportamento reológico das gomas guar e xantana na presença de polióis. Soluções de goma guar (0,1, 0,5 e 1 %) e xantana (0,5 %) na presença de maltitol, sorbitol e xilitol nas concentrações de 10 à 40 % foram investigadas. O comportamento dessas misturas foi avaliado através de cisalhamento estacionário e oscilatório sob duas condições: em temperatura de 25 ºC e após o ciclo de congelamento e descongelamento. Em geral a adição dos polióis e o aumento de sua concentração elevaram a viscosidade aparente dos sistemas; somente para as soluções de guar 1 % com 40 % de poliol e xantana com 10 % de poliol a viscosidade foi reduzida. Os modelos Ostwald De Waelle e Herschel-Bulkley representaram satisfatoriamente o comportamento dos sistemas. Todas as soluções se mostraram pseudoplásticas e as soluções de guar 1 % com os polióis apresentaram tixotropia. As soluções de xantana com os polióis apresentaram tensão inicial para o escoamento. Os polióis também aumentaram os módulos dinâmicos (G’ e G’’) das soluções hidrocolóide/poliol, tornando os sistemas mais elásticos. Somente a solução de 10 % de sorbitol reduziu o valor de G’ da goma xantana, tornando o sistema menos consistente. Nas misturas de guar com 40 % de poliol, observou-se que o ângulo de fase apresentou valor ligeiramente inferior à 1 rad, com dependência da frequência, o que é característico de solução concentrada. A xantana pura possui características de solução...
Sugar substitutes have gained prominence because of the growing global market demand for foods that are low in calories and meet specific diets. Since the components present in the formulations may modify the functional properties of hydrocolloids, the aim of the present work was to study the rheological behavior of guar gum and xanthan in the presence of polyols. Solutions of guar gum (0,1, 0,5 and 1%) and xanthan (0,5%) in the presence of maltitol, sorbitol and xylitol at concentrations of 10 to 40% were investigated. The behavior of these mixtures was evaluated by steady and oscillatory shear under two conditions: at the temperature of 25 °C and after freezing and thawing cycle. In general, the addition of polyols and increasing their concentration increased the apparent viscosity of the systems; only for solutions of guar 1% with 40% polyol and xanthan with 10% polyol the viscosity was reduced. The Ostwald Waelle and Herschel-Bulkley models satisfactorily represented the behavior of systems. All solutions showed pseudoplastic behavior and guar solutions 1% with polyols showed thixotropy. Xanthan solutions with polyols showed yield stress to flow. Polyols also increased the dynamic modulus (G 'and G'') of hydrocolloid/polyol solutions, making systems more elastic. Only solution of sorbitol 10% reduced the value of G'of xanthan gum, making the system less consistent. For mixtures of guar with 40 % polyol, it was observed that the phase angle showed a value slightly lower than 1, with frequency dependence, which is characteristic of a concentrated solution. The pure xanthan has characterized concentrated solution in the presence of polyols and the value of δ was next to 0,5 rad, with little dependence on frequency, which characterizes weak gel. In solutions of guar and xanthan 0,5% polyols helped to preserve the... (Complete abstract click electronic access below)
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Moser, Poliana. "Comportamento reológico de gomas guar e xantana na presença de polióis /." São José do Rio Preto : [s.n.], 2012. http://hdl.handle.net/11449/90748.
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Orientador: Vânia Regina Nicoletti TelisBanca: Caciano P. Zapata Noreña
Banca: Renato Alexandre Ferreira Cabral
Resumo: Atualmente, os substitutos de açúcares têm ganhado destaque devido à crescente demanda do mercado mundial por alimentos que possuem baixo teor calórico e que atendam dietas específicas. Considerando que os componentes presentes nas formulações podem modificar as propriedades funcionais dos hidrocolóides, o objetivo deste trabalho foi estudar o comportamento reológico das gomas guar e xantana na presença de polióis. Soluções de goma guar (0,1, 0,5 e 1 %) e xantana (0,5 %) na presença de maltitol, sorbitol e xilitol nas concentrações de 10 à 40 % foram investigadas. O comportamento dessas misturas foi avaliado através de cisalhamento estacionário e oscilatório sob duas condições: em temperatura de 25 ºC e após o ciclo de congelamento e descongelamento. Em geral a adição dos polióis e o aumento de sua concentração elevaram a viscosidade aparente dos sistemas; somente para as soluções de guar 1 % com 40 % de poliol e xantana com 10 % de poliol a viscosidade foi reduzida. Os modelos Ostwald De Waelle e Herschel-Bulkley representaram satisfatoriamente o comportamento dos sistemas. Todas as soluções se mostraram pseudoplásticas e as soluções de guar 1 % com os polióis apresentaram tixotropia. As soluções de xantana com os polióis apresentaram tensão inicial para o escoamento. Os polióis também aumentaram os módulos dinâmicos (G' e G'') das soluções hidrocolóide/poliol, tornando os sistemas mais elásticos. Somente a solução de 10 % de sorbitol reduziu o valor de G' da goma xantana, tornando o sistema menos consistente. Nas misturas de guar com 40 % de poliol, observou-se que o ângulo de fase apresentou valor ligeiramente inferior à 1 rad, com dependência da frequência, o que é característico de solução concentrada. A xantana pura possui características de solução... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Sugar substitutes have gained prominence because of the growing global market demand for foods that are low in calories and meet specific diets. Since the components present in the formulations may modify the functional properties of hydrocolloids, the aim of the present work was to study the rheological behavior of guar gum and xanthan in the presence of polyols. Solutions of guar gum (0,1, 0,5 and 1%) and xanthan (0,5%) in the presence of maltitol, sorbitol and xylitol at concentrations of 10 to 40% were investigated. The behavior of these mixtures was evaluated by steady and oscillatory shear under two conditions: at the temperature of 25 °C and after freezing and thawing cycle. In general, the addition of polyols and increasing their concentration increased the apparent viscosity of the systems; only for solutions of guar 1% with 40% polyol and xanthan with 10% polyol the viscosity was reduced. The Ostwald Waelle and Herschel-Bulkley models satisfactorily represented the behavior of systems. All solutions showed pseudoplastic behavior and guar solutions 1% with polyols showed thixotropy. Xanthan solutions with polyols showed yield stress to flow. Polyols also increased the dynamic modulus (G 'and G'') of hydrocolloid/polyol solutions, making systems more elastic. Only solution of sorbitol 10% reduced the value of G'of xanthan gum, making the system less consistent. For mixtures of guar with 40 % polyol, it was observed that the phase angle showed a value slightly lower than 1, with frequency dependence, which is characteristic of a concentrated solution. The pure xanthan has characterized concentrated solution in the presence of polyols and the value of δ was next to 0,5 rad, with little dependence on frequency, which characterizes weak gel. In solutions of guar and xanthan 0,5% polyols helped to preserve the... (Complete abstract click electronic access below)
Mestre
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Resende, Fabrício de Souza. "Efeito do congelamento sobre a microestrutura da massa do pão." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-04112011-151945/.
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A qualidade global da massa de pão congelada por um longo período é um desafio para indústria de panificação. O uso de diferentes técnicas pode ajudar a explicar os danos sofridos à massa de pão durante o congelamento e armazenamento congelado. A presença de água na forma de cristais de gelo foi vista como a principal causa de defeitos à estrutura da massa. Gomas guar e xantana foram incorporadas às massas para contornar os danos causados pelo congelamento. Das análises térmicas conduzidas em calorímetro de varredura diferencial foi possível quantificar a quantidade de gelo presente na massa. A adição de (0,125 a 0,250) g/100g de goma guar e de (0,214 e 0,250) g/100g de goma xantana diminuíram os valores de entalpia na massa ao longo do armazenamento congelado. A fração de gelo foi menor e mais estável nas massas contendo (0,125 e 0,250) g/100g de goma guar ou xantana. O valor da atividade de água diminuiu nas massas contendo goma guar e com níveis mais altos de goma xantana, após o ciclo de congelamento e descongelamento e 170 dias de armazenamento. Alterações na estrutura das massas foram medidas e visualizadas pela análise de textura e por microscopia eletrônica de varredura (MEV). Adição de goma xantana e principalmente de goma guar às massas aumentaram a resistência à extensão após 170 dias de armazenamento congelado. A extensibilidade não foi influenciada pela adição de gomas e manteve estabilidade nos períodos de armazenamento estudados. A MEV ajudou a explicar os danos causados à rede de glúten pelos cristais de gelo ao longo do armazenamento congelado. A massa sem gomas apareceu com pequenos danos na rede de glúten com 21 dias de armazenamento e estes danos aumentaram progressivamente por até 170 dias, mostrando um glúten menos contínuo, mais rompido e separado dos grânulos de amido. As massas contendo gomas minimizaram, mas não evitaram os danos causados ao longo do armazenamento congelado.The global quality of the frozen bread dough for long periods of frozen storage is the challenge to bakery industry. The use of different techniques could help to explain the damages caused in the frozen dough during the freezing and along frozen storage time. The presence of water as ice crystals was the main cause of damage on the dough structure. In order to minimize the freezing damages, guar and xanthan gums were incorporated in the dough. From thermal analysis by DSC technique, the amount of ice present in the dough was determined. The addition of (0.125 to 0.250) g/100g guar gum and (0.214 and 0.250) g/100g xanthan gum presented lower values of fusion enthalpy. The addition of (0.125 and 0.250) g/100g of guar gum decreased or stabilized the frozen water content, suggesting minimal damage on the dough structure along frozen storage time. The water activity in the dough samples with guar gum and higher quantities of xanthan gum decreased after the freezing-thawed cycle and after a period of frozen storage of 170 days. The incorporation of xanthan gum and mainly the incorporation of guar gum increased the maximum resistance of the dough after 170 days. The extensibility was not affected by addition of gums along frozen storage time. The MEV technical helped to explain the damaged dough structure caused by ice crystals along frozen storage time. Dough samples without gums presented structure damage only after 21 days and increased after 170 days, resulting in less continuous gluten, more disrupted and separated from starch granules. The doughs with gums suffered less damage in the gluten matrix, but did not avoid the problems caused by frozen storage.
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Khattak, Muhammad Muzaffar Ali Khan. "Modulation of large bowel fermentation and tissue lipid synthesis in rats by feeding guar gum." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241068.
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Gatenby, Susan Joy. "Guar gum : its acute metabolic effects and clinical use in the management of diabetes mellitus." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321814.
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Lynn, Miriam Elen. "Enterocyte maturity influences adhesion by lactobacillus." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481471.
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Newsholme, H. D. B. "Influence of a substituted guar gum on the adhesion of Streptococcus mutans to glass and hydroxylapatite." Thesis, University of Salford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356185.
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Cupit, Kerry. "The in vitro fermentation characteristics and prebiotic potential of samples derived from guar gum and potato fibre." Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590137.
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A range of novel and commercially available guar gums and novel potato fibre samples were investigated to see if their fermentation characteristics would make them new potential prebiotic candidates. Samples were examined using in vitro. pH controlled, 24h hatch culture fementations inoculated with human faeces. Fermentation of the guar gum samples mainly stimulated the growth of Bifidobacterium spp. and Bacteroides spp., producing considerable amounts of acetate, propionate and large amounts of gas. A direct relationship between molecular weight (MW) and fermentability was not found but instead two possible optimum molecular weight ranges - MW >500,000 Da and those with much lower MW (-34,000 Da)were suggested. Potato fibre samples produced by pectinase treatment and hemicellulase treatment gave the highest increases in bifidobacteria and lactobacilli, producing considerable amounts of acetate and propionate. Three guar gum samples and One potato fibre sample were investigated further using a three-stage human gut model. The MW of guar gum and its combination were found to affects its fermentibility, bacterial and SCFA profiles, with those containing low MW fractions (34,500 Da) giving higher increases in bifidobacteria and lactobacilli than those containing high MW fractions. Potato fibre treated with pectinase treatment 2 was found to significantly increase bifidobacteria in vessel I (VI) and vessel 2 (V2) and lactobacilli by over 1 log10 in all three vessels. Propionate was also increased significantly in all three vessels. Overall, guar gum and potato fibre derivatives have been shown to exhibit positive fermentation characteristics and prebiotic properties by increasing the beneficial bacteria such as bifidobacteria and lactobacilli and the production of SCFA. This in combination with other health promoting properties and desirable properties to food manufactures make their future use as functional food ingredients encouraging. Further investigation of these samples in human volunteer studies is required to confirm the prebiotic effect and to study potential beneficial properties
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Rebelo, Sandra da Silva. "Desenvolvimento de um modelo in vitro para avaliação de um biogel antimicrobiano com potencial para o controlo da doença periodontal canina." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2020. http://hdl.handle.net/10400.5/20210.
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Dissertação de Mestrado Integrado em Medicina VeterináriaA doença periodontal (DP) é uma das doenças mais frequentes na espécie canina, afetando cerca de 80-85% destes animais. Esta doença, de etiologia multifatorial, inicia-se com o desenvolvimento, na superfície do dente, de placa bacteriana, um biofilme composto maioritariamente por bactérias contidas numa matriz de polissacáridos extracelulares, com o potencial de inibir a ação antimicrobiana e as defesas naturais do hospedeiro. Os processos de agregação bacteriana constituem um fenómeno bastante importante na formação de biofilme ao contribuir para a interação bacteriana durante a evolução da DP. O principal objetivo do controlo da DP é controlar a formação da placa bacteriana. Estudos realizados com isolados de Enterococcus faecalis, obtidos a partir de amostras da cavidade oral canina, demonstraram atividade antimicrobiana de um gel de goma de guar suplementado com nisina (biogel de nisina) contra esta espécie bacteriana, demonstrando a sua potencial eficácia para o controlo da DP canina. Este estudo teve como objetivos o desenvolvimento de um modelo de biofilme polimicrobiano in vitro, que seja representativo da placa bacteriana presente na cavidade oral canina, e a avaliação do potencial inibitório e de erradicação do biogel de nisina relativamente ao biofilme polimicrobiano estabelecido. As espécies bacterianas incluídas foram: Porphyromonas cangingivalis, Neisseria zoodegmatis, Corynebacterium canis, Peptostreptococcus canis e E. faecalis. Durante a primeira fase deste projeto, foi avaliada a capacidade de agregação entre os cinco isolados bacterianos. Todos os isolados demonstraram capacidade de agregação, revelando o seu potencial para a formação de biofilmes polimicrobianos. De seguida, promoveu-se a formação de um biofilme polimicrobiano constituído pelas cinco espécies bacterianas em estudo. A presença das espécies bacterianas no biofilme estabelecido in vitro foi confirmada através da sua observação direta ao microscópio de fluorescência após aplicação da técnica de “Fluorescent In Situ Hybridization”. Os resultados da avaliação do potencial inibitório e de erradicação do biogel de nisina revelaram um valor de concentração mínima inibitória de biofilme de 25 μg/mL e um valor de concentração mínima de erradicação de biofilme superior a 100 μg/mL. Ambos os valores correspondem a concentrações de nisina abaixo do limite da dose diária aceitável definida pela Organização Mundial de Saúde, que corresponde a 0 – 2 mg/Kg. Este estudo demonstrou mais uma vez a eficácia do biogel de nisina para a inibição de biofilmes polmicrobianos confirmando o potencial para a sua utilização no controlo da DP canina.
ABSTRACT - Development of an in vitro model for the evaluation of an antimicrobial biogel with potential for the control of canine periodontal disease - Periodontal disease (PD) is one of the most common diseases in dogs, affecting around 80 to 85% of the canine population. It refers to a group of conditions caused by the development of a dental plaque in the tooth surface. The dental plaque is characterized by a microbial biofilm formed by a multi-species community of microorganisms enclosed in a self-producing extracellular matrix, which protects bacteria from the host immune system and reduces the action of antimicrobial therapy. It is a well-known fact that aggregation is a specific process that plays an important role in the bacterial interactions during biofilm formation. This process contributes to the changes on bacterial composition of the biofilm during the progression of PD. Periodontal therapy aims to control the formation of bacterial plaque. Previous studies have demonstrated that, when incorporated within a guar-gum biogel (nisin-biogel), antimicrobial peptide nisin can inhibit and eradicate mono-species biofilms formed by canine oral enterococci, rendering it a potential agent for PD control. The main objectives of this project were to establish a five-species biofilm model aiming to simulate dental biofilms from dogs with PD and to use the established model to evaluate the inhibitory potential of the nisin-biogel, previously developed by our research team. The bacterial species included were: Porphyromonas cangingivalis, Neisseria zoodegmatis, Corynebacterium canis, Peptostreptococcus canis and Enterococcus faecalis. During the first task, aggregation rates between all the isolates were calculated two by two and individually. All the isolates showed aggregation ability after either a 2h or 24h incubation, showing their potential to form multi-species biofilms. Later, a five-species biofilm model was successfully established and the presence of the five bacterial species was confirmed by Fluorescent In Situ Hybridization using specific probes. The susceptibility of the multi-species biofilm to the nisin-biogel was evaluated by determination of the Minimum Biofilm Inhibitory Concentration (MBIC) and of the Minimum Biofilm Eradication Concentration (MBEC). The nisin-biogel presented inhibitory activity against the polymicrobial biofilm, with a MBIC value of 25 μg/mL and a MBEC value > 100 μg/mL, both corresponding to nisin dosages lower than the acceptable daily intake, 0 – 2 mg/Kg, set by the World Health Organization. This study demonstrated that the nisin-biogel developed by our research team can inhibit the formation of multi-species biofilms, reinforcing its potential to control canine PD.
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Matuda, Tatiana Guinoza. "Estudo do congelamento da massa de pão: determinação experimental das propriedades termofísicas e desempenho de panificação." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-17112008-114317/.
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O conhecimento de propriedades termofísicas é importante na modelagem, na otimização e no projeto de equipamentos para processos como a fabricação de massa de pão congelada. Neste trabalho, as propriedades termofísicas condutividade térmica, difusividade térmica e calor específico foram determinadas experimentalmente ao longo do processo de congelamento da massa de pão, pois influenciam diretamente a cinética do processo que, por sua vez, determina a qualidade do pão produzido. Os resultados obtidos mostraram que algumas destas propriedades variaram em função do conteúdo inicial de água e principalmente devido à mudança da temperatura. O valor médio encontrado através da atividade de água das massas (aw = 0,950), para temperatura inicial de congelamento, pode explicar alguns desvios no ajuste dos dados experimentais a modelos disponíveis na literatura baseados na lei de Raoult, que são estritamente relacionados à fração de gelo formada. O uso combinado de goma guar e xantana reduziu a entalpia de fusão ao longo do tempo de armazenamento congelado (87,4 J.g-1 e 81,2 J.g-1 para a formulação sem gomas, não congelada e após 28 dias de armazenamento congelado; 84,4 J.g-1 e 76,9 J.g-1 para a formulação com 0,25% de goma guar e 0,25% de goma xantana na massa não congelada e após 28 dias de armazenamento congelado), indicando uma interação entre as gomas na capacidade de ligar água ao longo do tempo de congelamento. Porém, apesar do tempo de congelamento ter reduzido a entalpia de fusão, o processo de congelamento foi o principal fator na queda da taxa de fermentação e da produção de gás pelas leveduras independentemente do tempo de armazenamento congelado.The knowledge of thermophysical properties is important to model and optimize equipment design for frozen food processes. In this work, the thermophysical bread dough properties, such as, thermal conductivity, thermal diffusivity and specific heat were experimentally determined during freezing process, due to their influence on the kinetics process, and therefore on bread quality. The results showed that some properties varied according to the initial water content and mainly due to temperature changes. The average value of initial freezing temperature found by water activity (aw = 0.950) explains the deviations between experimental data and available models in the literature based on Raoults law, which is related to the ice mass fraction. The combined use of guar and xanthan gums reduced the fusion enthalpy along frozen storage time (87.4 J.g-1 and 81.2 J.g-1 for formulation without gum, non-frozen and after 28 frozen storage days; 84.4 J.g-1 and 76.9 J.g-1 for formulation with 0.25 % of guar gum and 0.25 % of xanthan gum in non-frozen and after 28 frozen storage days). It indicated the interaction between gums and their ability to hold water along frozen storage. Despite frozen storage reduced the fusion enthalpy, the freezing process itself was the main factor in the decrease in proofing rate and gas production by yeast cells.
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Koksel, Havva Filiz. "Effects Of Xanthan And Guar Gums On Quality And Staling Of Gluten Free Cakes Baked In Microwave-infrared Combination Oven." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610410/index.pdf.
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The objective of this study was to determine the effects of different gums, gum concentrations and their combination on quality and staling of gluten free cakes baked in microwave-infrared combination oven and conventional oven. In the first part of the study, the effects of different gums (xanthan and guar gum) at different concentrations (0.3%, 0.6% and 1.0%) and their blend on quality of gluten free cakes baked in microwave-infrared combination and conventional oven were investigated. The gelatinization properties of the cakes were also investigated.
Among different gums, xanthan-guar gum blend addition to the cake formulation improved cake quality with increasing specific volume as well as decreasing weight loss and crumb hardness values for both types of baking methods. Gum
blend addition also improved the cake acceptability in terms of texture, taste and the crust color of the cakes. The gelatinization degrees of cakes were found to decrease as the gum concentration increased, for both types of ovens.
In the second part of the study it was focused on effects of different gums, gum concentrations and storage times on staling of cakes. Addition of gum blend decreased hardness, weight loss, retrogradation enthalpy and the change in setback viscosity values of cakes for both types of ovens and slowed down staling for 2 and 3 days for cakes baked in microwave-infrared combination and conventional oven, respectively. In microwave-infrared combination oven, it was
possible to produce gluten-free cakes with similar quality with the conventionally baked ones even in a 75% shorter baking time.
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Souza, Fernanda Carla Bombaldi de 1989. "Incorporação de alfa-bisabolol em membranas de policaprolactona e de quitosana complexada com goma guar." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266114.
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Orientador: Ângela Maria MoraesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
Made available in DSpace on 2018-08-25T01:12:46Z (GMT). No. of bitstreams: 1 Souza_FernandaCarlaBombaldide_M.pdf: 2498035 bytes, checksum: f26cf0a46c0249d60c3316fd94c93e91 (MD5) Previous issue date: 2014
Resumo: A quitosana, a goma guar e a policaprolactona são exemplos de polímeros muito usados na obtenção de curativos para a terapia de lesões de pele devido ao fato de serem biocompatíveis e biodegradáveis. A fim de aumentar a atividade biológica destes curativos, a incorporação de compostos bioativos que estimulam o processo de cura das lesões pode ser feita. Neste contexto, este trabalho teve como objetivo a obtenção de curativos biologicamente ativos, por meio da incorporação do alfa-bisabolol, um composto antioxidante e anti-inflamatório de origem natural, a membranas constituídas de quitosana combinada com goma guar (Q-G) e de policaprolactona (PCL). Dois métodos de incorporação foram utilizados: adição direta do composto ativo à mistura polimérica (AD) e impregnação do composto nas membranas por imersão em solução etanólica (IE). As membranas produzidas foram caracterizadas quanto ao seu aspecto visual, cor e opacidade, morfologia, ângulo de contato com água, propriedades mecânicas e espessura em diferentes umidades, capacidade de absorção e perda de massa em etanol e em soluções aquosas, taxa de transmissão de vapor d¿água e espectro FTIR. A eficiência de incorporação do alfa-bisabolol às membranas e a atividade antioxidante deste composto foram determinadas, e sua cinética de liberação estudada. Os resultados mostraram que tanto os filmes de Q-G como de PCL apresentaram comportamento mais adequado para a aplicação no tratamento de lesões pouco exsudativas. As propriedades mecânicas dos filmes sofreram variação significativa apenas quando estes foram expostos a condições de umidade elevada. O alfa-bisabolol utilizado nos ensaios apresentou elevado grau de pureza, porém atividade antioxidante relativamente baixa. A inserção do composto na matriz ocasionou mudanças significativas em sua aparência e alterações em sua microestrutura. Para Q-G, baixas eficiências de incorporação foram obtidas, sendo o valor máximo atingido pelo método AD igual a 1,65%, o equivalente a 4,96 mg/g, enquanto que para o método IE atingiu-se cerca de 18%, com uma retenção de aproximadamente 1080 mg/g. Já no caso da PCL, alta eficiência de incorporação foi observada (100%). A liberação mostrou-se relativamente lenta em ambos os casos e a percentagem máxima de alfa-bisabolol liberado ficou em torno de 6% e 30%, o equivalente a 12 e 300 mg/g para filmes de PCL e de Q-G, respectivamente. O tempo prolongado de liberação permitiria a troca do curativo com intervalos de tempo maiores, tornando o tratamento menos incômodo para o paciente
Abstract: Chitosan, guar gum and polycaprolactone are polymers widely used to obtain wound dressings due to their biocompatibility and biodegradability. To increase the biological activity of these dressings, bioactive compounds which accelerate wound healing can be incorporated. In this context, this work aimed the development of biologically active dressings, through the incorporation of alpha-bisabolol, a natural antioxidant and anti-inflammatory compound, to membranes made of chitosan associated with guar gum (C-G) and of polycaprolactone (PCL). The incorporation of alpha-bisabolol was performed by two distinct methods: addition directly to the polymeric mixture (AD) and absorption of the active compound from an ethanolic solution (AS). The membranes were characterized regarding to visual appearance, color and opacity, morphology, water contact angle, water vapor transmission rate, swelling capacity in ethanol and in aqueous solutions as well as mass loss in the same media, strain at break, tensile strength and thickness in different humidities conditions and FTIR spectrum. Alpha-bisabolol incorporation efficiency and its antioxidant activity were determined and the release kinetics was studied. Results showed that both films are more suitable for the use in the treatment of lesions with low exudate levels. Mechanical properties suffered significant change only after exposure of the films to high humidity conditions. The alpha-bisabolol used in this study exhibits high purity, but relatively low antioxidant activity. The addition of the compound to the matrix led to significant changes in the appearance and to modifications in the microstructure of the films. The C-G membranes presented low incorporation efficiencies, with the maximum value of 1.65%, equivalent to 4.96 mg/g, for the AD method, and 18%, approximately 1080 mg/g, for the AS method. In the case of PCL, high incorporation efficiency (100%) was observed. The release of alpha-bisabolol from the matrices was relatively slow and the maximum percentage of compound released reached about 6% and 30%, equivalent to 12 and 300 mg/g for PCL and C-G films, respectively. A prolonged release would allow less frequent dressing changes, turning the treatment more comfortable for the patient
Mestrado
Engenharia Química
Mestra em Engenharia Química
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Gusso, Ana Paula. "DIFERENTES ESPESSANTES, NÍVEIS DE GORDURA E LACTOSSORO EM CREME DE RICOTA." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/5729.
Full textAbstract:
The consumption of low-calorie foods has increased in recent decades. The industries that are
committed to health promotion have been developing technologies for food production with
reduced fat, meeting the demands of consumers. Thus, this study began with a review of the
behavior of different thickeners (guar gum, carrageenan, xanthan and tara) in experimental
ricotta cream, and compared these with commercial ricotta cream. The various thickeners
used in this study had a significant influence on instrumental and sensory firmness, being guar
gum, the selected thickener for the next phase. The second phase of this work was conducted
through the factorial planning 22 having whey and milk cream as independent variables. The
factorial planning performed was the type Central Composite Rotational Delineation (CCRD),
totaling 12 trials, being four factorial, four axial, one central point with three repetitions and
one control treatment. The treatments were subjected to physico-chemical, microbiological
and sensory analysis, as well as their stability assessed during shelflife. The use of whey as a
partial fat substitute reduced by 50% the contents of this variable for the T8 treatment when
compared to the control treatment. This reduction had no significant influence on the
concentration of fatty acids present in creams. Generally, the pH of ricotta creams were
slightly higher in the end of the storage period in relation to their averages in the beginning of
the shellife. Lipid oxidation was enhanced in the presence of whey, a synergistic element for
this analysis. Whey increased the instumental firmness of the creams when compared to the
control treatment. The response surfaces generated in sensory acceptance analysis showed the
existence of an optimal region for the best sensory grades in relation to attributes observed, in
the range of 5-15% fat and 9-21% of whey. The cream selected as preferred by judges at the
end of the sensory analyses of preference showed 5% fat and 10% whey in its composition.O consumo de alimentos de baixa caloria tem aumentado nas últimas décadas. As indústrias comprometidas com a promoção da saúde vêm desenvolvendo tecnologias para produção de alimentos com reduzido teor de gordura, atendendo assim as demandas dos consumidores. Dessa forma, este estudo iniciou-se com a avaliação do comportamento de diferentes espessantes (guar, carragena, xantana e tara) em cremes de ricota experimentais, sendo estes comparados com creme de ricota comercial. Os diferentes espessantes utilizados neste estudo tiveram influência significativa na firmeza instrumental e sensorial dos produtos, sendo, a goma guar, o espessante selecionado para a etapa seguinte. A segunda etapa do trabalho foi conduzida através do planejamento fatorial 22 tendo o lactossoro e o creme de leite como variáveis independentes. O planejamento fatorial realizado foi do tipo Delineamento Composto Central Rotacional (DCCR), totalizando 12 ensaios, sendo quatro fatoriais, quatro axiais, um ponto central com três repetições e um tratamento controle. Os tratamentos foram submetidos a análises físico-químicas, microbiológicas e sensoriais, assim como avaliada sua estabilidade durante o shelf life. A utilização do lactossoro como substituto parcial da gordura reduziu em até 50% o conteúdo desta variável para o tratamento T8 quando comparado com o tratamento controle. Esta redução não teve influencia significativa na concentração dos ácidos graxos presentes nos cremes. De maneira geral, o pH dos cremes de ricota apresentaram-se ligeiramente superiores no fim do período de armazenamento em relação a suas médias do início do shel life . A oxidação lipídica foi intensificada com a presença do lactossoro, representando este um elemento sinergístico para esta análise. O lactossoro aumentou a firmeza instrumental dos cremes quando comparados ao tratamento controle. As superfícies de respostas geradas na análise sensorial de aceitação mostraram a existência de uma região ótima para as melhores notas sensoriais em relação aos atributos observados, compreendida na faixa de 5 e 15% de gordura e 9 a 21% de lactossoro. O creme selecionado como o preferido pelos julgadores no final das análises sensoriais de preferência foi o que apresentou 5% de gordura e 10% de lactossoro em sua composição.
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Ferrari, E. "POLYMERIC MATERIALS FOR THE QUANTITATIVE AND REVERSIBLE ABSORPTION OF ORGANIC AND INORGANIC WATER CONTAMINANTS." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229550.
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Water pollution is one of the most serious environmental problems the world faces today. Due to a progressive change in environmental perception in developed countries, great attention is currently given to specific pollutants, both of natural and human origin, often labeled as organic and inorganic micropollutants. Micropollutants can have severe implications both on ecology and human health even in very low concentration in water, being potentially toxic and carcinogenic, and are included in the EU PP (Priority Pollutants) list. The current water purification treatments are affected by many limitations and do not significantly lower the concentration of micropollutants, unless the treatment is carried out, if technically possible, to such an extent to become not economically sustainable. In this context, the aim of this PhD thesis is the development and characterization of polymeric absorbing materials for the quantitative and reversible removal of organic and inorganic micro-pollutants from water. These materials are based on poly(amidoamine)s (PAAs), cyclodextrins and renewable resources such as guar gum and hemicelluloses. The synthetic procedures adopted are simple, eco-friendly and employ water as solvent. The materials proved able to absorb either inorganic (Cu(II), Co(II), Cd(II), Pb(II), Mn(II), Zn(II), Fe(II), Ni(II), Cr(VI)) or organic micropollutants (chloroform, halothane, tetrachloroethylene, o-toluidine) and were competitive with other sorbents reported in literature. They could also be regenerated and recycled without loss of absorption performance.
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Prestes, Rosa Cristina. "AVALIAÇÃO DA ADIÇÃO DE COLÁGENO HIDROLISADO, AMIDO MODIFICADO E GOMA GUAR EM PRESUNTO COZIDO DE PERU." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2008. http://tede2.uepg.br/jspui/handle/prefix/666.
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Previous issue date: 2008-02-28The main problems observed in cooked hams are bad sliceability and excessive fluids loss after cooking (purge). To reduce these problems the industry uses non-meat ingredients (proteins, polysaccharides and their interactions), but under Brazilian law, it is not allowed to add starch or modified starch in hams. In the present work three ingredients were tested: Firm Tex modified starch (0 to 2%), Grindsted Guar 178-B gum guar (0 to 0.30%) and Collagel hydrolyzed collagen (0 to 2%), following a 2 factorial design with central point. The ingredients addition changed physical characteristics and centesimal composition of the products. There was no significant difference in pH and water activity (Aw). The results showed that for losses (by cooling, freeze-thawing and cooking) the formulations with modified starch presented lower values, indicating the ability of this ingredient to retain water in the product. It seems appropriate to propose the legal permission of starch in ham or the creation of a new class of product in which starch addition would be allowed. The guar gum produced low resistance to cooking however in losses by cooling the results were adequate. The hydrolyzed collagen tested did not give satisfactory results, showing low acceptance due to formation of gel in the ham and losses higher than that of the other ingredients tested. The developed products were considered equal to the commercial product in relation to the texture (p 0.05). In assessing overall quality, the formulation F6 (2% of modified starch) was the one with the best acceptance as detected by the tasters.
Os principais problemas observados em presuntos são a má fatiabilidade e a perda excessiva de líquidos após o cozimento (sinérese). Para reduzir estes problemas a indústria utiliza ingredientes não-cárneos (proteínas, polissacarídeos e suas interações), porém segundo a legislação brasileira, não é permitida a adição de amido ou amido modificado. Neste trabalho foram testados três ingredientes, em presunto cozido de peru: amido modificado Firm Tex (0 a 2%), goma guar Grindsted Guar 178-B (0 a 0,30%) e colágeno hidrolisado Collagel (0 a 2%), seguindo um delineamento fatorial 2 com ponto central. A adição dos ingredientes testados alterou a composição centesimal e as características físicas dos produtos. Não houve diferença significativa para pH e atividade de água (Aw). Os resultados mostraram que, nas formulações com amido modificado, as perdas foram inferiores, indicando a capacidade deste ingrediente em reter água no produto. Parece-nos adequado propor a permissão legal de amido em presunto ou a criação de uma nova classe de produto para a qual se permita a utilização deste ingrediente. A goma guar apresentou baixa resistência ao reaquecimento, no entanto, nas perdas por resfriamento os resultados foram adequados. O colágeno hidrolisado testado não proporcionou resultados satisfatórios, sendo que os produtos apresentaram baixa aceitação devido a formação de gel e perdas superiores aos demais ingredientes testados. Os produtos desenvolvidos foram considerados iguais ao produto comercial em relação à textura (p0,05). Na avaliação global da qualidade, a formulação F6 (2% amido modificado) foi a que obteve melhor aceitabilidade por parte dos julgadores.
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Tomikawa, Mari Matsuoka. "Desenvolvimento de uma sobremesa a base de soja tipo petit suisse enriquecido com calcio e alto teor proteico." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255508.
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Orientador: Roberto Herminio MorettiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Produtos comerciais a base de extrato hidrossolúvel de soja em combinação com sucos de frutas têm obtido êxito no mercado, como alternativa proteica com benefícios funcionais. No entanto, a quantidade de proteína de soja nessas associações é relativamente baixa no mercado nacional, de 0,6 a 3,0%. O presente trabalho constituiu no desenvolvimento uma sobremesa a base de soja com características semelhantes aos queijos petit suisse, com teor de proteína de soja acima dos produtos a base de extrato hidrossolúvel de soja combinados com sucos de frutas encontrados hoje no mercado brasileiro, e com características sensoriais aceitas pelo consumidor. As sobremesas de soja foram desenvolvidas a partir da coagulação do extrato hidrossolúvel de soja sulfato de cálcio (CaSO4.2H2O) em concentrações de variando de 0,25 a 1%, acréscimo de goma guar em concentrações de 0,02 a 0,2% e ajuste de pH (4,0 a 4,4) com ácido lático 85%. O efeito dessas variáveis foi avaliado sobre a composição física e química, o conteúdo de cálcio, o rendimento em proteína e a firmeza das sobremesas de soja obtidas nos ensaios experimentais. Todas as variáveis foram influenciadas significativamente (p=0,05) pela concentração de CaSO4.2H2O. O teor de sólidos totais e o conteúdo de cálcio elevaram-se com o aumento da concentração de coagulante. O teor de proteína e lipídios e a firmeza apresentaram forte correlação entre si, com tendência crescente com o aumento da concentração de CaSO4.2H2O até 0,88%, seguido de um declínio dos valores dessas variáveis com o acréscimo de coagulante até 1% CaSO4.2H2O. Somente a acidez foi influenciada significativamente pelo pH, e a interação do pH com a goma guar teve efeito negativo significativo no rendimento em proteína. Nem a goma guar nem as outras interações das variáveis independentes tiveram influência significativa sobre as variáveis dependentes. Os ensaios escolhidos para a avaliação sensorial, pela composição físico-química e qualidade aparente que apresentaram, foram o ensaio com 0,88% CaSO4.2H2O; 0,05% goma guar e pH 4,3 (ensaio 6), e o ensaio com 0,63% CaSO4.2H2O, 0,02% goma guar e pH 4,2 (ensaio 11). As amostras diferiram significativamente somente no atributo 'textura', sendo o ensaio 6 mais aceito sensorialmente pelos provadores, caracterizando-se como a melhor formulação para o desenvolvimento da sobremesa de soja tipo petit suisse, dentro dos limites experimentais
Abstract: Commercial products produced from soymilk in combination with fruit juices has been successful in the market, being an alternative protein source with functional benefits. However, protein content in these soybean associations is relatively low in the national market, about 0.6 to 3.0%. The present study was the development of a soy-based dessert with similar features of petit suisse cheeses, with higher soy-protein content than the products from soymilk in combination with fruit juices found actually in the brazilian market, and with acceptable sensory characteristics by the consumer. The soy desserts were made from soymilk coagulation with calcium sulphate concentrations (CaSO4.2H2O) ranging from 0.25 to 1%, with addition of guar gum at 0.02 to 0.2% concentrations and pH correction (4.0 to 4.4) with lactic acid 85%. The effect of these variables CaSO4.2H2O, guar gum and pH) were evaluated on the physical and chemical composition, the calcium content, the protein recovery (yield in protein) and the firmness of the soy desserts obtained from the experimental trials. All variables were significantly influenced (p = 0.05) by the concentration of CaSO4.2H2O. The total solids and calcium content increased with increasing coagulant concentration. The protein and lipids content and the firmness, showed a strong relationship between them. The protein content and the firmness trend was toward an increase with increasing concentration of CaSO4.2H2O up to 0.88%, followed by a descrease at 1% CaSO4.2H2O. Only the titrable acidity was affected by pH. The pH and guar gum interaction had significant negative effect on yield in protein. Neither guar gum nor any other interactions of the independent variables, had significant influence on the dependent variables. The tests chosen for the sensory evaluation, by the physico-chemical composition and better quality apparent, were the test with CaSO4.2H2O, 0.05% guar gum and pH 4.3 (test 6), and the test with 0.63% CaSO4.2H2O, 0.02% guar gum and pH 4.2 (test 11). The samples showed difference only on the attribute of 'texture', with test 6 being the most accepted test for the sensory panelists, electing it as the best formulation for the development of soybean dessert like petit suisse cheese, within the experimental limits
Mestrado
Mestre em Tecnologia de Alimentos
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Trovão, Tiago Miguel Martins. "Eficácia in vitro de dois veículos de administração tópica de nisina a Enterococci isolados de cães com doença periodontal." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2017. http://hdl.handle.net/10400.5/14038.
Full textAbstract:
Dissertação de Mestrado Integrado em Medicina VeterináriaA doença periodontal (DP) é uma das doenças mais frequentes no cão, afetando 80 a 85% dos animais com mais de dois anos. É uma doença inflamatória crónica de etiologia multifatorial, inicia-se com o desenvolvimento de placa bacteriana que origina uma reação inflamatória do organismo, que conduz às alterações que ocorrem na gengiva e no periodonto. O Enterococcus spp. é um microrganismo frequentemente isolado a partir da cavidade oral do cão, sendo comensal do trato gastrointestinal e estanto associado a complicações sistémicas enquanto oportunista. Uma possível estratégia para prevenir e tratar a DP é a utilização de péptidos antimicrobianos (PAM) como a nisina, um composto com atividade antimicrobiana contra microrganismos gram-positivos e aprovado como aditivo alimentar (E234). O objetivo deste estudo foi avaliar se a nisina A (2,5%) mantêm a sua atividade antimicrobiana quando incorporada em dois veículos de administração. Para tal, a atividade inibitória da nisina incorporada em pasta dentífrica e gel de goma de guar foi testada numa coleção de 46 Enterococcus spp., obtidos a partir de cães com DP. O potencial da pasta dentífrica foi avaliado através de uma técnica de difusão em poço com a medição dos diâmetros dos halos de inibição de multiplicação bacteriana. A combinação de nisina com gel goma de guar foi avaliada através da determinação da concentração mínima inibitória (CMI) e da concentração mínima bactericida (CMB). Em suma, a avaliação da nisina como composto inibitório de Enterococcus spp. mostrou resultados muito promissores, uma vez que este PAM manteve a sua atividade antimicrobiana quando incorporado em qualquer um dos dois veículos de administração testados. A pasta dentífrica, demonstrou ser capaz de inibir a multiplicação de 4 dos 46 isolados (8,7 %) mesmo não estando suplementada com nisina; quando suplementada, teve a capacidade de inibir 42 dos 46 isolados (91,3 %). A solução de nisina e gel de goma de guar, apresentou uma CMI média de 0,9 mg/mL e CMB média de 2,3 mg/mL, demonstrando que a solução é eficaz em concentrações clinicamente alcançáveis. As doses de nisina correspondentes às concentrações testadas e com eficácia comprovada neste estudo são consideravelmente mais baixas que a dose diária aceitável (DDA) de 0 – 2 mg/Kg, estabelecida pela WHO.
ABSTRACT - In vitro efficacy of two topical delivery systems of nisin to Enterococci isolated from dogs with periodontal disease - Periodontal disease (PD) is one of the most frequent diseases in dogs, affecting 80 to 85% of the animals older than 2 years of age. It is a chronic inflammatory disease with a multifactorial aetiology, being promoted by the development of a bacterial plaque that causes an inflammatory reaction that leads to the alterations in the gingiva and periodontum. Enterococcus spp. is a microorganism frequently present in the oral cavity of dogs, being a commensal microorganism of the gastrointestinal tract, and being associated with systemic complications as an oportunistic bacteria. A possible strategy to prevent and treat PD is to use antimicrobial peptides such as nisin, an approved food preservative (E234) with antimicrobial activity against gram-positive bacteria. This study aimed to evaluate if nisin A (2,5%) maintains its antimicrobial activity when incorporated in two delivery systems. The inhibitory activity of nisin incorporated into a veterinary toothpaste and in guar gum gel was tested against 46 Enterococcus spp. collected from dogs with PD. The potential of the veterinary toothpaste to be used as a delivery system was evaluated by a well diffusion assay measuring inhibition halos diameters caused by the different solutions. The inhibitory potential of nisin incorporated in guar gum gel was assessed by the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). To summarize, nisin shows very promising results maintaining its antimicrobial activity when incorporated in either of the two delivery systems tested. The veterinary toothpaste by itself was capable of inhibiting the growth of 4 of the 46 isolates (8,7%) but when supplemented with nisin its inhibitory capabilities increased, being able to inhibit 42 out of the 46 isolates (91,3 %). Nisin retained its effectiveness when diluted in guar gum gel with a mean MIC value of 0,9 mg/mL and a mean MBC value of 2,3 mg/mL. This proves this solution is effective in clinical achievable concentrations. The nisin dosages corresponding to the tested concentrations, and proved effective, are much lower than the acceptable daily intake (ADI), 0 – 2 mg/Kg, set by the WHO.
N/A
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Liakhovych, O. D. "Peculiar features of glucose homeostasis in patients suffering from non-alcoholic steatohepatitis with comorbid obesity and osteoarthritis on the background of the use of metadoxine and guar gum." Thesis, БДМУ, 2020. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18096.
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Mansa, Rola. "Preparation and Characterization of Novel Montmorillonite Nanocomposites." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20207.
Full textAbstract:
Clay minerals have historically played a consequential role in human health. While the beginnings were rooted in geophagy, a primitive act of consuming earth, the health-related uses of clay minerals have evolved and diversified over time.
As excipients in pharmaceutical formulations, clay minerals can attribute novel properties onto intercalated compounds. Intercalating oxybenzone, a UV filter, within the interlamellar space of montmorillonite is desirable in order to minimize direct contact with skin. Intercalating resveratrol, a compound known for attributing beneficial effects onto human health, may be advantageous since this compound is susceptible to cis-trans isomerisation. The strategy of using alkylammonium–modified clay was undertaken and proved successful for the intercalation of oxybenzone.
The field of biopolymer/layered silicate nanocomposites is heavily researched for use in a multitude of applications. Novel montmorillonite nanocomposites were prepared with neutral guar gum and cationic guar gum, using an environmentally friendly process and are fully characterized.
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Cameron-Smith, David, and edu au jillj@deakin edu au mikewood@deakin edu au wildol@deakin edu au kimg@deakin. "THE INTERACTION OF DIETARY FIBRE, CARBOHYDRATE METABOLISM AND DIABETES IN THE RAT." Deakin University. School of Health and Behavioral Sciences, 1994. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20040622.171657.
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It is currently accepted that the most appropriate diet in the treatment of non-insulin-dependent diabetes mellitus "eNIDDM"e
is high in carbohydrates, high in fibre and low in fat. Dietary fibre reduces the rate of carbohydrate absorption, which may have a beneficial effect on insulin action. Furthermore, high fibre diets also increase the amount of carbohydrates which are not absorbed from the small intestine. These malabsorbed carbohydrates are fermented by the bacterial population in the large intestine, producing short chain fatty acids "eSCFA"e, including propionate, which has been shown to alter liver carbohydrate metabolism. This thesis investigated the actions of slowed carbohydrate absorption and carbohydrate malabsorption in streptozotocin-induced "eSTZ"e diabetic rats.
High carbohydrate diet supplemented with guar gum, a soluble dietary fibre, fed to STZ diabetic rats improved insulin sensitivity. investigation of the alterations in the stomach and small intestine demonstrated that guar increased the viscosity of the meal in the intestine. The action of increased fermentation, producing more propionate, was investigated by supplementing propionate into the diets of STZ diabetic rats or when perfused into isolated rat livers. No changes in insulin action or liver glucose metabolism were measured. in addition, it was shown that guar gum reduces food intake in STZ diabetic rats. Mild reductions in food intake in STZ diabetic rats were shown to increase insulin action.
In summary, STZ diabetic rats fed high carbohydrate, high fibre diets reductions in food consumption and slowed carbohydrate absorption are important factors which may lower blood glucose concentrations and increase insulin action. increased SCFA production is unlikely to contribute significantly to the improvements in insulin action.
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Paix?o, Marcus Vinicius Gomes. "Aplica??o de g?is de goma guar no processo de clarifica??o de salmouras e ?guas produzidas." Universidade Federal do Rio Grande do Norte, 2015. http://repositorio.ufrn.br/handle/123456789/20014.
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A ?gua produzida ? considerada o principal efluente da ind?stria do petr?leo, em fun??o do seu volume crescente nos campos maduros e de sua composi??o variada. O teor de ?leos e graxas (TOG) ? considerado o principal par?metro para o descarte final da ?gua produzida. Diante desse contexto, ? de grande relev?ncia o desenvolvimento de um m?todo alternativo ? base de g?is de goma guar para o tratamento de ?guas produzidas sint?ticas, tendo como diferencial a utiliza??o de um pol?mero com elevada hidrofilicidade para a clarifica??o de ?guas contaminadas com petr?leo. Dessa forma, este trabalho tem como objetivo avaliar a efici?ncia de g?is de goma guar na remo??o do ?leo presente em ?guas produzidas. A goma guar ? um pol?mero natural que, em condi??es espec?ficas, forma estruturas tridimensionais, com importantes propriedades f?sico-qu?micas. Atrav?s da reticula??o das cadeias polim?ricas por ?ons borato, na presen?a de sais, ocorre o efeito salting out, reduzindo a solubilidade do gel polim?rico em ?gua. Como resultado, tem-se a separa??o das fases com o ?leo aprisionado no gel colapsado. O TOG foi quantificado a partir da espectroscopia na regi?o do ultravioleta e vis?vel. O sistema desenvolvido mostrou-se altamente eficiente na remo??o de petr?leo disperso em ?gua produzida sint?tica, atingindo porcentagens de remo??o superiores a 90%.
Produced water is considered the main effluent of the oil industry, due to their increased volume in mature fields and its varied composition. The oil and grease content (TOG) is the main parameter for the final disposal of produced water. In this context, it is of great significance to develop an alternative method based on guar gum gel for the treatment of synthetic produced water, and using as the differential a polymer having high hydrophilicity for clarifying waters contaminated with oil. Thus, this study aims to evaluate the efficiency of guar gum gels in the remotion of oil from produced water. Guar gum is a natural polymer that, under specific conditions, forms three-dimensional structures, with important physical and chemical properties. By crosslinking the polymer chains by borate ions in the presence of salts, the effect salting out occurs, reducing the solubility of the polymer gel in water. As a result, there is phase separation with the oil trapped in the collapsed gel. The TOG was quantified from the spectroscopy in the ultraviolet and visible region. The system was proven to be highly efficient in the removal of dispersed oil from water produced synthetically, reaching removal percentages above 90%.
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Sanga, Alvin. "Superintendent Turnover in Guam." Thesis, Loyola Marymount University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10622159.
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Superintendent turnover has been rampant in the public school district in Guam, an unincorporated United States territory; there have been 18 superintendents since the 1981. This qualitative study aimed to identify and analyze potential factors affecting the superintendency in Guam. Social systems theory proposes a number of factors about the dynamics that define the relationship between an individual and a social system to help us understand the behavior of the individual within an organization. To triangulate the data, this study was comprised of individual interviews with Guam superintendents and content analysis of the Guam Public School Audit of 2009 and subsequent amendments made to board policies after the audit. Based on social systems theory, major findings suggest that superintendent turnover in Guam is influenced by the following: the Guam Education Board did not understand its roles and responsibilities and often micromanaged the superintendents; the budgetary process for the Guam Department of Education was stressful and problematic; and political pressures from the legislature and the governor encouraged superintendents to take other roles. Suggestions for improving stability within the superintendency of Guam were offered by former superintendents.
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Firouznia, Mohammadhossein. "The Hydrodynamic Interaction of Two Small Freely-moving Particles in a Couette Flow of a Yield Stress Fluid." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1502901401749626.
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Intanujit, Praichon. "Passage from Nong Gua." TopSCHOLAR®, 2002. http://digitalcommons.wku.edu/theses/601.
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I was a sophomore from a small village when Pira Sudham, the author of Monsoon Country and People of Esarn, came to speak at my university about poverty and the forgotten beauty of his people, my people, the poor people of Esarn, the Northeastern region of Thailand. Listening to his sad yet courageous stories, I was reminded over again that I, too, had stories to tell, though it would be some years before I finally sat down to puzzle them out. The result is a memoir of my childhood years in rural Surin, where the mother tongue is Khmer, where most are poor farmers and their rice fields are both their work place and their children's playgrounds. While writing this memoir I couldn't help but wonder why I had so often recalled my childhood years as among the dearest times of my life, despite all the rural hardship. There must be magic in being a child. There must be wonder in grandma's tales, the hunting of wild fruit, the swims in the pond and those walks in the woods. My village was my world, and it has much to teach largely because its being complex, difficult and painful and yet somehow simple and, above all, beautiful.
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RODRIGUES, Ana Carolina Dornelas. "Potencial da alface-d??gua (Pistia stratiotes) para descontamina??o de ?guas contaminadas por Zn e Cd." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/2346.
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FAPERJ
Nowadays water contamination by heavy metals is an increasingly common problem, mainly due to the intensity of human activities, such as industrial, which often discard these environments their effluents enriched with these elements. In this scenario, this work was to evaluate the potential of water lettuce (Pistia stratiotes) in the decontamination of water contaminated by heavy metals zinc (Zn) and Cadmium (Cd). For that, this research was divided into three chapters. In the first chapter, it was evaluated the ability to biosorption of heavy metals by dry matter of water lettuce where laboratory adsorption isotherms were carried out with five increasing doses of Zn contamination (1.8; 18; 50; 79 and 105 mg L-1) and 4 doses of Cd (0.01, 0.1, 1 and 10 mg L-1) in nine sampling times (1, 3, 6, 12, 24, 36, 48, 60 and 72 hours). The results showed that the dry biomass of water lettuce has biosorption capacity of the metals analyzed, enhanced by increasing the contact time with the solution. This conclusion was also demonstrated by determining the isothermal linear model, which indicates a high affinity of the adsorbent for the adsorbate. Changes in the morphology of the biomass were demonstrated by scanning electron microscopy images (SEM) before and after biosorption. In the second chapter it was evaluated the potential fitoextrator of water lettuce grown in increasing doses of Zn and Cd (separately) and the physiological response of the plant to this contamination. The experiment evaluated 4 doses of contamination of each metal (Zn = 0, 1.8, 18 and 180 mg L-1 and Cd = 0, 0.1, 1 and 10 mgL-1) and cultivation time 4 (24, 48, 72 and 168 hours). In each survey were analyzed: heavy metal content in the solution, root and aerial part of the plant; content of photosynthetic pigments by direct and indirect method and photosynthetic efficiency by transient fluorescence of chlorophyll a. The results showed that water lettuce has high potential to absorb and accumulate heavy metals in their tissues, preferably in the roots, thus promoting the maintenance of the pigment synthesis and photosynthetic efficiency in most doses tested. This absorption was enhanced with increasing time of cultivation, which increased the translocation of metals to shoot and carotenoid synthesis for the protection of the photosynthetic apparatus. Higher doses of the metals had their photosynthetic efficiency decreased. In the third section it was evaluated the kinetics of absorption of heavy metals by water lettuce to it have been installed to separate Zn and Cd experiments with two different concentrations of each metal (Zn = 18 and 1.8 and 0.1 Cd and 1.0 mg L-1), with three repetitions each, totaling 12 experimental units (6 units for each element). Aliquots of the solutions and measurement of pH were carried out at certain times until stabilization of the levels of metals in the solution. At the end, the biomass production, the levels of metals and the kinetic parameters of absorption (Km and Vmax) were evaluated. The results showed that the pH of the solutions was not affected by the cultivation of water lettuce and the highest Zn and Cd absorption rates were found in larger doses contamination of the solution. Biomass production was negatively affected by contamination, but these results did not affect the rate of absorption of metals by plants. Based on all the results it can be concluded that the water lettuce has potential for remediation of water bodies contaminated by heavy metals Zn and Cd, both with its dry biomass as for its in vivo cultivation.
Atualmente a contamina??o da ?gua por metais pesados ? problema cada vez mais frequente, principalmente devido a intensidade das atividades antr?picas, como as industriais, que muitas vezes descartam nesses ambientes seus efluentes enriquecidos com esses elementos. Esse trabalho teve como objetivo avaliar o potencial da Alface-d??gua (Pistia stratiotes) na descontamina??o de ?guas contaminadas pelos metais pesados zinco (Zn) e c?dmio (Cd). A pesquisa foi dividida em 3 cap?tulos. No primeiro, foi avaliada a capacidade de biossor??o de metais pesados pela mat?ria seca da Alface-d??gua, onde foram realizadas isotermas de adsor??o em laborat?rio, com cinco doses crescentes de contamina??o por Zn (1,8; 18; 50; 79 e 105 mg L-1) e 4 doses de Cd (0,01, 0,1, 1 e 10 mg L-1) em nove tempos de coleta (1, 3, 6, 12, 24, 36, 48, 60 e 72 horas). Os resultados mostraram que a biomassa seca da Alface-d??gua possui capacidade de biossor??o dos metais analisados, potencializada pelo aumento do tempo de contato com a solu??o. Tal conclus?o tamb?m foi demonstrada pela determina??o do modelo isot?rmico linear, que indica alta afinidade do adsorvente pelo adsorbato. Altera??es na morfologia da biomassa foram observadas na microscopia eletr?nica de varredura (MEV) antes e depois da biossor??o. No segundo cap?tulo foi avaliado o potencial fitoextrator da Alface-d??gua cultivada em doses crescentes de Zn e Cd (separadamente) e as resposta fisiol?gicas da planta a essa contamina??o. O experimento avaliou 4 doses de contamina??o de cada metal (Zn = 0; 1,8; 18 e 180 mg L-1 e Cd = 0; 0,1; 1 e 10 mg L-1) e 4 tempos de cultivo (24, 48, 72 e 168 horas). Em cada coleta foram analisados: teores de metais pesados na solu??o, raiz e parte a?rea da planta; teores de pigmentos fotossint?ticos por m?todo direto e indireto e efici?ncia fotossint?tica atrav?s da fluoresc?ncia transiente da clorofila ?a?. Os resultados mostraram o elevado potencial da Alface-d??gua em absorver os metais pesados e acumular em seus tecidos, preferencialmente nas ra?zes, o que favoreceu a manuten??o da s?ntese de pigmentos e a efici?ncia fotossint?tica na maioria das doses testadas. Essa absor??o foi potencializada com o tempo de cultivo, que aumentou a transloca??o dos metais para parte a?rea e a s?ntese de carotenoides para prote??o do aparato fotossint?tico. As maiores doses dos metais tiveram sua efici?ncia fotossint?tica diminu?da. No terceiro cap?tulo foi avaliada a cin?tica de absor??o dos metais pesados pela Alface-d??gua, sendo instalados experimentos separados para Zn e Cd, com duas concentra??es diferentes de cada metal (Zn =1,8 e 18 e Cd 0,1 e 1,0 mg L-1), com 3 repeti??es cada, totalizando 12 unidades experimentais (6 por elemento). Al?quotas das solu??es e aferi??o do pH foram realizadas em tempos determinados at? a estabiliza??o dos teores dos metais na solu??o. Ao final foram avaliados a produ??o de biomassa, os teores de metais e os par?metros cin?ticos de absor??o (Km e Vmax). Os resultados mostraram que o pH das solu??es n?o foi afetado pelo cultivo da Alface-d??gua e que as maiores velocidades de absor??o de Zn e Cd foram encontradas nas maiores doses de contamina??o da solu??o. A produ??o de biomassa foi afetada negativamente pela contamina??o, por?m esses resultados n?o interferiram na velocidade de absor??o dos metais pela planta. Com base em todos os resultados pode-se concluir que a Alface-d??gua apresenta potencial para remedia??o de corpos h?dricos contaminados pelos metais pesados Zn e Cd, tanto com sua biomassa seca como pelo seu cultivo in vivo.
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Salas, Marilyn Camacho. "The relationship between classroom participation structures and fourth-grade Guamanian students' reading comprehension." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185534.
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The purpose of this study was to explore the relationship between lesson interaction patterns and fourth-grade Guamanian students' reading comprehension. In the last decade, a variety of new approaches have emerged in the field of education that extend our ability to better understand the teaching-learning process. These approaches allow close and detailed examination of how teachers and their students interact in creating classroom settings, particularly as they refer to reading lessons. The present study continued the investigation of classroom participation structures and their relationship to reading comprehension in a multilingual and multicultural setting. Three reading discussion lessons were observed and audio- and videotaped in four, fourth-grade classrooms in Guam during the months of November 1989 to April 1990. Of the three discussion lessons, one was selected for in depth analyses. Students were in the Level 11 reading group of the Silver Burdette-Ginn Basal Reader Series. Teachers were instructed to teach their lessons according to their usual procedures. No attempt was made to alter delivery of instruction. From transcriptions of the audio- and videotapes, Mehan's (1979) procedures were used to describe turn-allocation and speech act procedures. In addition, retellings were analyzed utilizing the retelling profile developed by Mitchell and Irwin (1991). Although the study was conducted in schools with bilingual, multicultural and multilingual teachers and students, the participation structures found in these Guam classrooms appear no different from the participation structures found in most American classrooms. In terms of the questions being explored in this dissertation, sensitivity to the linguistic and cultural background of Guamanian students was not evident. The results of the qualitative and quantitative analyses of the data pointed to three major findings. First, variability existed in the participation structures found in the four, fourth-grade reading discussion lessons. Second, there were minimal differences in participation structures when teachers who adhered closely to basal reader material and instruction were compared with teachers who did not adhere as closely to basal reader material and instruction. Third, the study suggests that the participation structures found in the four, fourth-grade reading discussion lessons were related to the reading comprehension of these fourth-grade Guamanian students.
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Cruz, Felicity M. F. "Parents decisions regarding childcare: the Guam perspective." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/6931.
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Stephen, David V. M. "Progenic isonymy among the Chamorro of Guam." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289753.
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This study examines several methodological issues pertaining to the application of isonymy techniques to a historical population located on the island of Guam in Micronesia. Since European contact the indigenous Chamorro population of Guam has undergone a series of precipitous population declines. The Spanish colonial administration imposed a dual surname system on the Chamorro. The surname information was compiled into a demographic database representing approximately 39,000 persons traced from late 19th century vital records. Analysis using the methods of isonymy was conducted on lineages established from the four parental surnames. Values were calculated from the progeny in the database, in effect focusing on the effective breeding population. Comparisons were made with inbreeding values obtained using other methods of surname analysis both for single and dual surname systems. In contrast to the paternal lineage, the values for the other lineages were influenced by their shallow temporal depth. The non-paternal lineages showed patterns of assortative mating reflecting choices of mate selection that have the potential to influence levels of inbreeding in the population.
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Maia, Fernanda Cunha. "Qual ?gua beber: envasadas ou da torneira? O caso de Natal, Brasil." PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA SANIT?RIA, 2015. https://repositorio.ufrn.br/jspui/handle/123456789/22702.
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O consumo da ?gua envasada para beber cresceu nos ?ltimos anos. E nos pa?ses em desenvolvimento ela vem sendo uma alternativa ? ?gua distribu?da pelas concession?rias. Isso se deve pelo aumento do poder aquisitivo da popula??o e pela presun??o de que a ?gua envasada possui uma qualidade melhor que a ?gua da torneira. Dessa forma, este estudo faz uma an?lise comparativa entre a ?gua envasada comercializada e a ?gua do sistema p?blico de abastecimento, no intuito de saber se h? uma melhor op??o para o consumo humano. Foram realizadas an?lises simult?neas de amostras tanto da ?gua envasada quanto da ?gua da torneira em unidades domiciliares escolhidas aleatoriamente. As amostras da ?gua da torneira tiveram maiores concentra??es de nitrato que as amostras das ?guas envasadas e isto pode ser explicado pela expans?o territorial da cidade. Por?m, surpreendentes 38,3% (?9,5%) das amostras de ?guas envasadas apresentaram contamina??o por coliformes fecais, enquanto na ?gua da torneira verificou-se a presen?a de coliformes fecais em 7,5% (?9,5) das amostras. Para as ?guas engarrafadas, os ?rg?os de fiscaliza??o se responsabilizam pelo cumprimento dos padr?es de potabilidade do envase ao armazenamento, mas n?o h? fiscaliza??o quanto ao manuseio e consumo do produto. O fato ? que houve uma contamina??o, sem causa conhecida, e assim surge o debate se a troca da ?gua da torneira pela ?gua engarrafada ? v?lida ou n?o.
O consumo da ?gua envasada para beber cresceu nos ?ltimos anos. E nos pa?ses em desenvolvimento ela vem sendo uma alternativa ? ?gua distribu?da pelas concession?rias. Isso se deve pelo aumento do poder aquisitivo da popula??o e pela presun??o de que a ?gua envasada possui uma qualidade melhor que a ?gua da torneira. Dessa forma, este estudo faz uma an?lise comparativa entre a ?gua envasada comercializada e a ?gua do sistema p?blico de abastecimento, no intuito de saber se h? uma melhor op??o para o consumo humano. Foram realizadas an?lises simult?neas de amostras tanto da ?gua envasada quanto da ?gua da torneira em unidades domiciliares escolhidas aleatoriamente. As amostras da ?gua da torneira tiveram maiores concentra??es de nitrato que as amostras das ?guas envasadas e isto pode ser explicado pela expans?o territorial da cidade. Por?m, surpreendentes 38,3% (?9,5%) das amostras de ?guas envasadas apresentaram contamina??o por coliformes fecais, enquanto na ?gua da torneira verificou-se a presen?a de coliformes fecais em 7,5% (?9,5) das amostras. Para as ?guas engarrafadas, os ?rg?os de fiscaliza??o se responsabilizam pelo cumprimento dos padr?es de potabilidade do envase ao armazenamento, mas n?o h? fiscaliza??o quanto ao manuseio e consumo do produto. O fato ? que houve uma contamina??o, sem causa conhecida, e assim surge o debate se a troca da ?gua da torneira pela ?gua engarrafada ? v?lida ou n?o.
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Cruz, Anna Maria, and Anna Maria Cruz. "Patient Satisfaction with Nurse Practitioner Care on Guam." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/623005.
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Patient satisfaction has been identified as an indicator of quality care. There is no research on patient satisfaction with Nurse Practitioner (NP) care on Guam. Therefore, a cross sectional descriptive study was conducted to assess patient satisfaction with NP care at three primary care clinics on Guam. A convenience sample of patients 18 years and older, seen by an NP were invited to participate in completing the Nurse Practitioner Satisfaction Survey (NPSS). Data collection concluded after a one-month period (N = 108). Descriptive statistics, between group differences, and correlational analyses were conducted. Participation in the survey was voluntary and anonymity, confidentiality, and privacy were ensured. General patient satisfaction was very high for NP care on Guam. "My NP is caring" was the highest scoring item on the NPSS with a mean score of 4.43 (n=56). Participants selected the NP as providing the health education and care the patient found most satisfying. A statistically significant weak negative correlation between patient satisfaction and age and level of injury was found. Singles reported significantly higher patient satisfaction scores than widowers. Study limitations included the small sample size, convenience sampling, social desirability and selection bias. Caring is an essential tenet of NP care and patient satisfaction. Improving NP role clarity is vital to the continued success and growth of the NP profession. The value that NPs bring to primary care is substantiated by the high patient satisfaction levels consistently produced from studies across the globe. In order for NPs to significantly impact the primary care provider shortage all 50 states and the US territories must enact full practice authority (FPA).
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Torsch, Vicki L. "The elderly experience among the Chamorros of Guam /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1996.
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