This study investigated the effects of ionic strength, pH, gum concentration, and protein type on protein - xanthan gum interactions. Commercial soy sauce and tamari sauce as well as model systems of soy protein isolate and whey protein concentrate were the sources of protein used for evaluation with xanthan gum. Preliminary research indicated that when either soy sauce or tamari sauce were mixed with xanthan gum, stable solutions with notable viscosity synergisms resulted. The soy protein and whey protein systems were subsequently prepared with a range of 0 to 5% added sodium chloride. Results indicated that an equilibrium existed between proteins and xanthan gum such that increased sodium chloride initially increased solution stability; but when in excess, the sodium chloride led to a loss of protein - xanthan gum solution solubility and in some cases to precipitation. Precipitation was also noted at the pH extremes of 2,3, and 9 and when xanthan gum was present in excess, or at 0.25%. The effects of sodium chloride, protein type, and pH on the rheological parameters of model solutions were also examined. Higher sodium chloride levels yielded greater viscosity synergisms. Those solutions made.with intact protein were generally higher in apparent viscosity than similar solutions made with hydrolyzed protein. Solutions at pH 5 were generally higher in viscosity than were similar solutions at pH 7. Several factors that appeared to affect the stability, solubility, and the rheological parameters of protein - xanthan gum solutions were sodium chloride concentration, gum concentration, pH, and protein type. / M.S.

Di-2-piridil cetona saliciloilhidrazona (DPKSH) é uma hidrazona que forma compostos de coordenação com diversos íons metálicos. DPKSH adsorve facilmente em superficies de vidro e pode ser determinado por espectrofotometria. Estudos de adsorção do DPKSH em matrizes de sílica-gel foram efetuados em pHap 1 e 4,7 e meio 3% de etanol (v/v), a (25±1) °C. Massas conhecidas de sílica-gel foram colocadas em contato com soluções de DPKSH em concentrações conhecidas, sob agitação durante certo intervalo de tempo. A concentração de DPKSH adsorvida foi calculada considerando-se a diferença entre a concentração inicial e a concentração residual na solução sobrenadante, ambas obtidas a partir de medidas de absorbância. Estudo cinético permitiu encontrar o tempo adequado de contato sílica/DPKSH para adsorção máxima. Diferentes modelos de isotermas foram aplicados aos dados experimentais. Titulações condutométricas permitiram caracterizar as propriedades ácidas/básicas da sílica e da sílica modificada. Fez-se também um estudo preliminar sobre a retenção de íons Cu(II) na superficie de sílica-gel modificada com DPKSH. / Di-2-pyridyl ketone salicyloy1hydrazone (DPKSH) is a hydrazone that gives sensitive reactions with most of metal ions forming coulored chelates. DPKSH solutions present a visible adsorption onto glass when stored in glass bottles and can be determined by spectrophotometry. The adsorption of DPKSH onto silica gel has been investigated, at (25±l) °C and pHap 1 and 4.7 at aqueous solution containing 3%(v/v) ethanol. Masses well-known of silica gel were placed in contact with known concentration DPKSH solutions, under agitation during certain intervals of time. The quantity of DPKSH adsorbed was calculated considering the difference between the initial DPKSH concentration and the residual one in the sobrenadant solution after achieved the equilibrium, both obtained from absorbance measurements. Kinetic studies allowed to find the optimal rime for the contact silica DPKSH in order to obtain the maximum adsorption. Different models of isotherms were applied to the experimental data. Condutometric titrations led to acid/basic characteristics of silica and modified silica. A preliminary study of Cu(II) ions retention into silica gel surface modified with DPKSH was carried out.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Hyaluronic acid (HA) is a linear, unbranched polymer, composed by simple disaccharide units, whose molar mass may range in a wide interval of distribution (104-107 Da). It is used in pharmaceutical and cosmetic applications depending on its average molecular mass. The fractionation of macromolecules of the order of magnitude of the HA may be performed by gel permeation or size-exclusion chromatography (GPC). The objective of this work is to study the characterization, purification and fractionation of microbial HA by using GPC. HA was supplied by the Department of Biotechnological Processes (DPB/FEQ/UNICAMP), having been produced by microorganisms â Streptococcus zooepidemicus â in synthetic culture media. After being centrifuged from the fermentation broth, HA was precipitated with ethanol and then dissolved in saline solution, this pre-purification procedure being performed up to four times. The presence of proteic contaminants was identified by electrophoresis in polyacrylamide gel under denaturant conditions (SDS-PAGE) and quantified by the Bradford method. For the HA sample which had been precipitated in ethanol and dissolved in 0.1 M NaNO3 four times, protein concentration was found to be nearly 100 μg/mL. The sodium salt of commercial (Sigma Aldrich - EUA) microbial HA was used as standard in order to measure a calibration curve to assess HA concentration in the samples. For the sample precipitated in ethanol and dissolved in 0.1 M NaNO3 four times, AH concentration was found to be approximately 780 μg/mL. Molar mass distribution of HA samples was assessed by GPC, both in analytical and semi-preparative scale, using refractive index (RI) and UV/Vis (280 nm) detectors, 0.1 M NaNO3 as mobile phase, flow rate 0.8 mL/min and tracers dextran and pullulan (polymers of similar hydrodynamic volume as compared to HA) as molar mass standards. The samples showed molar mass distributions in the range of 103 to 107 Da, after being precipitated and dissolved four times. For these samples, the average molar mass was found to be in the order of magnitude of 105 Da. In the semi-preparative column Superose, it was possible to separate HA fractions, with molar mass above 105 Da, and free of proteic contaminants, in an elution interval of 10 minutes / O Ãcido HialurÃnico (AH) à um polÃmero linear, nÃo ramificado, composto por unidades dissacarÃdicas simples, cuja massa molar pode se distribuir num largo intervalo (104-107 Da). à usado em aplicaÃÃes farmacÃuticas e cosmÃticas dependendo de sua massa molar mÃdia. A separaÃÃo de macromolÃculas da ordem de grandeza do AH à possÃvel atravÃs da Cromatografia de permeaÃÃo em gel (GPC). Este trabalho tem como objetivo estudar a caracterizaÃÃo, purificaÃÃo e fracionamento do AH produzido por microorganismos, utilizando GPC. O AH, cedido pelo Departamento de Processos BiotecnolÃgicos (DPB/FEQ/UNICAMP), foi obtido por cultivo de microorganismos - Streptococcus zooepidemicus - em meio de cultura sintÃtico. ApÃs centrifugaÃÃo do caldo de fermentaÃÃo, o AH foi precipitado com etanol e ressuspenso em soluÃÃo salina, sendo esta etapa de prÃ-purificaÃÃo executada atà quatro vezes. A presenÃa de contaminantes protÃicos foi identificada por eletroforese em gel de poliacrilamida sob condiÃÃes desnaturantes (SDS-PAGE) e quantificada pelo mÃtodo de Bradford, obtendo-se 97,20 μg/mL, para a amostra de AH apÃs quatro precipitaÃÃes em etanol e ressuspensÃes em NaNO3 0,1 M. Para as determinaÃÃes de concentraÃÃo de AH nas amostras estudadas, utilizou-se o sal sÃdico de AH microbial comercial (Sigma Aldrich - EUA) como padrÃo. Quantificando-se a amostra de AH apÃs quatro precipitaÃÃes em etanol e ressuspensÃes em NaNO3 0,1 M, obteve-se 783,70 μg/mL. A distribuiÃÃo da massa molar do AH foi avaliada por GPC, em escala analÃtica, utilizando coluna Shodex OHPak-SB806M-HQ e, em escala semi-preparativa, a coluna Superose 6, detectores de Ãndice de refraÃÃo e UV/Vis (280 nm), NaNO3 0,1 M como fase mÃvel, vazÃo de 0,8 mL/min e padrÃes de Dextrana e Pullulan (polÃmeros de volume hidrodinÃmico semelhante ao AH) como marcadores de massa molar (5,2x103 - 7,9x106 Da e 5,8x103 â 8,53x105 Da, respectivamente). A amostra apresentou uma distribuiÃÃo polimÃrica na faixa de 103 a 107 Da, apÃs quatro precipitaÃÃes em etanol e ressuspensÃes em NaNO3 0,1 M, sendo sua massa molar mÃdia da ordem de 105 Da. Foi possÃvel separar fraÃÃes de AH, acima de 105 Da, livre de contaminantes protÃicos, num intervalo de aproximadamente 10 minutos, na coluna Superose 6

No description available.

No description available.

Di-2-piridil cetona saliciloilhidrazona (DPKSH) é uma hidrazona que forma compostos de coordenação com diversos íons metálicos. DPKSH adsorve facilmente em superficies de vidro e pode ser determinado por espectrofotometria. Estudos de adsorção do DPKSH em matrizes de sílica-gel foram efetuados em pHap 1 e 4,7 e meio 3% de etanol (v/v), a (25±1) °C. Massas conhecidas de sílica-gel foram colocadas em contato com soluções de DPKSH em concentrações conhecidas, sob agitação durante certo intervalo de tempo. A concentração de DPKSH adsorvida foi calculada considerando-se a diferença entre a concentração inicial e a concentração residual na solução sobrenadante, ambas obtidas a partir de medidas de absorbância. Estudo cinético permitiu encontrar o tempo adequado de contato sílica/DPKSH para adsorção máxima. Diferentes modelos de isotermas foram aplicados aos dados experimentais. Titulações condutométricas permitiram caracterizar as propriedades ácidas/básicas da sílica e da sílica modificada. Fez-se também um estudo preliminar sobre a retenção de íons Cu(II) na superficie de sílica-gel modificada com DPKSH. / Di-2-pyridyl ketone salicyloy1hydrazone (DPKSH) is a hydrazone that gives sensitive reactions with most of metal ions forming coulored chelates. DPKSH solutions present a visible adsorption onto glass when stored in glass bottles and can be determined by spectrophotometry. The adsorption of DPKSH onto silica gel has been investigated, at (25±l) °C and pHap 1 and 4.7 at aqueous solution containing 3%(v/v) ethanol. Masses well-known of silica gel were placed in contact with known concentration DPKSH solutions, under agitation during certain intervals of time. The quantity of DPKSH adsorbed was calculated considering the difference between the initial DPKSH concentration and the residual one in the sobrenadant solution after achieved the equilibrium, both obtained from absorbance measurements. Kinetic studies allowed to find the optimal rime for the contact silica DPKSH in order to obtain the maximum adsorption. Different models of isotherms were applied to the experimental data. Condutometric titrations led to acid/basic characteristics of silica and modified silica. A preliminary study of Cu(II) ions retention into silica gel surface modified with DPKSH was carried out.

Konjac glucomannan (KGM), the main biologically active constituent of konjac flour extracted from corms of Amorphophallus konjac (konjac), can be used to prepare functional foods and may also have potential as a pharmaceutical product to combat obesity. The current study employed three experimental approaches to study the biology and chemistry of konjac, namely (1) glasshouse experiments to study the morphogenesis, growth and productivity of konjac plants, (2) a histological and immunocytochemical investigation of the localisation and developmental regulation of the deposition and metabolism of KGM in developing corm tissues, and (3) a comparative study of methodologies for the extraction and analysis of KGM. The current data demonstrated a morphological and functional separation between the ventral and dorsal regions of corms. The ventral region appeared to function as a source during the initial period of shoot development, while the dorsal region appeared to operate as a sink after the development of mature canopy. Once the corm reached maturity, both an inflorescence and a leaf were produced within a single season. It has also been demonstrated that the age of the ‘mother’ corm is an important factor affecting the quality of offsets produced. An anti-mannan antiserum detected a temporally regulated pattern of mannan epitope production within glucomannan idioblasts in developing corm tissues, with increased expression as the corm approached maturity/dormancy. The current observations also suggest that the mobilization of KGM initiates at the periphery of the corm and proceeds inwards towards the centre of the corm. Compositional analysis showed that the purified konjac flour (PKF) produced using a modified extraction procedure contained 92% glucomannan, with a weight average molecular weight (Mw), polydispersity index (PDI) and degree of acetylation (DA) of 9.5 ± 0.6 x 105 gmol-1, 1.2 and 2.8 wt. %. These data, plus Fourier-transform infrared spectral (FTIR) and zero shear viscosity analyses of the extract (PKF) were all consistent with the literature. Comparison of three existing methodologies for the quantitative analysis of the KGM content, namely 3,5-dinitrosalicylic acid (3,5-DNS), phenol-sulphuric acid and enzymatic colorimetric assays; indicated that the 3,5-DNS colorimetric assay was the most reproducible and accurate method, with a linear correlation coefficient of 0.997 and recoveries between 97% and 103% across three spiking levels of starch. In summary, this study has provided a better understanding of aspects of the biology and cultivation of A. konjac and has also produced methodologies which can be used as the basis for an improved good laboratory practice (GLP) for the commercial extraction and analysis of this multifunctional natural polymer.

Externally initiated o-tolyl initiated poly(3-hexylthiophene) (P3HT) was synthesized according to Grignard metathesis polymerization at varying chain length to compare number average molecular weights (Mn) obtained by gel permeation chromatography (GPC) and 1H NMR end group analysis. The extent of overestimation by GPC (1.3) was determined to be lower than previously reported for low Mn polymers. However, an apparent GPC quantification limit was observed as NMR Mn correlated well to predicted results. Static light scattering studies on high Mn polymers provided evidence that the true molecular weight was more similar to GPC-derived Mn. Despite nearly 100% external initiation efficiency, at a certain Mn limit new uninitiated chains may be synthesized. It is suggested that the synthesis of externally initiated P3HT should be limited to Mn below 40 kDa to ensure fully externally initiated chains. A proposal for the synthesis of externally initiated macrocyclic P3HT will also be discussed.

In den letzten 15 Jahren wurde in einigen Mittelgebirgsregionen Zentraleuropas ein regional un-terschiedlich starker Anstieg der Konzentration gelösten organischen Kohlenstoffes (DOC) in Oberflächengewässern festgestellt. Besonders betroffen von dieser Entwicklung sind für die Trink-wasserproduktion genutzte Talsperren. Durch den erhöhten DOC-Gehalt wird die Trinkwasser-aufbereitung nicht nur kostenintensiver, sondern bekommt auch zunehmend Probleme bei der Wahrung der Trinkwasserqualität. Die Quellen des DOC sind in den Einzugsgebieten befindliche Moore und hydromorphe Nassstandorte. Die Ursachen für den in den vergangenen Jahren doku-mentierten Mehraustrag sind äußerst komplex und beinhalten sowohl klimatische als auch nut-zungsbedingte Veränderungen. Ziel der vorliegenden Arbeit ist, den Charakter des DOC näher zu bestimmen, um die für die Wasseraufbereitung problematischen Fraktionen zu benennen und Ansatzpunkte für regulierende Maßnahmen aufzuzeigen. Die Charakterisierung erfolgte an einem LC-OCD-System (Liquid Chromatography – Organic Carbon Detection) am Beispiel der drei Tal-sperrensysteme Muldenberg, Carlsfeld (Westerzgebirge) und Fláje (Osterzgebirge, Tschechien). Die Talsperren weisen unterschiedliche DOC-Gehalte auf. Die Ergebnisse zeigen, dass der DOC aller Untersuchungsgebiete sowohl in den Zuflüssen, dem Talsperrenwasser bzw. Rohwasser als auch dem Reinwasser der Wasserwerke von Huminstoffen dominiert wird. DOC-Schwankungen sind folglich auf Schwankungen der Huminstoffkonzentrationen zurückzuführen. In den Zuflüs-sen treten die höchsten Huminstoffkonzentrationen während der Schneeschmelze im Frühjahr und bei Starkniederschlägen im Sommer und Herbst auf. Niedrige Konzentrationen sind an Bo-dengefrornis oder Trockenphasen im Sommer gebunden. In den Talsperren tritt im Sommer eine Schichtung der Huminstoffe auf, bei der an der Oberfläche durch photolytischen Abbau niedrige-re Konzentrationen und in Abhängigkeit von der Talsperrentiefe durch die Einschichtung der Zuflüsse am Grund höhere Konzentrationen auftreten. Die Verteilung im Winter ist allein von der Einschichtung der Zuflüsse abhängig. Die Verteilung der Building Blocks (Huminstoffhydrolysate) ist im Sommer der der Huminstoffe entgegengesetzt, da sich beim photolytischen Abbau von Hu-minstoffen Building Blocks bilden. Während der Zirkulationen sind die Konzentrationen der Hu-minstofffraktionen im gesamten Tiefenprofil gleich. In den Talsperren Muldenberg und Carlsfeld wurde im Untersuchungszeitraum unter Berücksichtigung der technischen Gegebenheiten und anderer Wassergütekriterien der optimale Rohwasserentnahmehorizont (niedrigstmögliche Hu-minstoffkonzentration) gewählt. In der Talsperre Fláje könnte die Rohwasserqualität durch Instal-lation eines schwenkbaren Entnahmerohres erheblich verbessert werden. In den Wasserwerken sind die Huminstofffraktionen mit abnehmender Molekülgröße schwieriger zu entfernen. Die relativ niedermolekularen Building Blocks sind die am schwersten entfernbaren DOC-Bestandteile. Auf Grundlage mathematischer Beziehungen zu SAK254 bzw. DOC wurde ein Programm (DOCQuaC – DOC-Quality Calculator) entwickelt, mit dessen Hilfe die Huminstofffraktionen über diese Grundparameter ermittelt werden können. Neben der Fraktionsquantifizie-rung besteht im Programm die Möglichkeit zur Berechnung der Eliminierungsleistung, so dass beispielsweise nach der Durchführung einer Maßnahme zur Verbesserung der DOC-Entfernung eine unmittelbare Aussage über den Effekt auf die Fraktionen vorliegt. / For the last 15 years a change of Dissolved Organic Carbon (DOC) has been taking place in surface waters of Middle European Highlands. The degree of this increase is regionally dependent. The reasons as well as the consequences of this development are of high complexity. The changes are expressed in an increase of middle DOC values and, additionally, an increase of annual changes. Reservoirs, used for drinking water production, are particularly affected, because the heightened DOC content increases the costs for drinking water treatment, and currently it is not possible to maintain a good drinking water quality. The main DOC source are peat bogs, situated in the catchments. The cause of the increasing DOC output from peat bogs are very complex and contain changes as well in climate as in land use. The aim of this presented dissertation was to gain more information about the character of DOC, so that those fractions can be determined which are problematically to remove inside the waterworks. On that base it should be possible to find some starting points for more regulating measures. The analytical characterisation was carried out by the help of a LC-OCD-System (Liquid Chromatography – Organic Carbon Detection), exemplary for the reservoir systems Muldenberg, Carlsfeld (Western Ore Mountains) and Fláje (Eastern Ore Mountains, Czech Republic). Although the DOC concentrations are very different in the reser-voirs, it was always dominated by humic substances, namely as well in the tributaries, as in the raw and treated water. Thus changes in the DOC concentration are due to changes in the concen-tration of humic substances. In spring and summer occur the highest concentrations of humic substances in the tributaries. Low concentrations are linked with frost in winter or dry periods in summer. In the reservoirs in summer a stratification of humic substances shapes up, with lower concentration near the water surface (caused by photolytical degradation) and accordingly higher concentration near the ground (layering of influxes). Distribution in winter only depends on the layering of the influxes. In summer the concentration of Building Blocks (humic substance hydro-lysates) is opposite to that of humic substances, because of the creation of Building Blocks at the photolytical degradation. During circulation the concentration of all humic substance fractions are equal in each reservoir layer. In the reservoirs Muldenberg and Carlsfeld, a further optimisation of the raw water withdrawal horizon is not possible. In the reservoir Fláje the raw water could be much improved by installing a movable withdrawal device. With decreasing molecular size the elimination of the humic fractions gets more difficult in the waterworks. Most difficult to eliminate are Building Blocks. On the basis of the mathematical cor-relation between humic fractions and the SAC254 and DOC a program (DOCQuaC – DOC-Quality Calculator) has been developed, which enables die calculation of humic concentrations by enter-ing these general parameters. In addition to the calculation of the concentrations it is possible to calculate the elimination capacity for the humic fractions. Thus the effects of measures on the humic fractions, which could be done for optimisation of the elimination capacity, can be imme-diately observed.

The degradation of wool keratin under conditions relevant to those of wool dyeing was investigated using the techniques of gel permeation chromatography (GPC), ion exchange gel chromatography, and amino acid analysis. Physical testing of the treated and untreated wool was also carried out to determine the physical changes occurring, parameters used being percentage elongation at the break, and the breaking strain of the fibre. Samples of wool keratin were immersed in various aqueous solutions at 1000C for 24 hours and the filtered, aqueous, oxidised extracts were analysed* The solutions used varied only in the dye, or dye intermediate present in the treatment solution. All treatment baths contained 10% owf 1.02 x 10 -2 MSulphuric VI acid; 10%owf 7.04x 10 -3 MSodium sulphate VI ; A 100 :1 liquor ratio was used in each case. Some of the dye intermediates showed a marked catalytic effect, particularly in their effect on breaking strain, a decrease of 40% in some cases. The GPC profiles of the extracted proteins were examined in detail and compared against previous workers' results. An explanation of the behaviour of the dyes and intermediates was proposed. The amino acid composition data of the extracted and fractionated proteins were compared against various morphological components extracted by other workers, as was the total gelatin obtained from each treatment.