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Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Includes bibliographical references (leaves 84-91). Also available via the Internet.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência dos Alimentos. / Made available in DSpace on 2012-10-24T02:53:21Z (GMT). No. of bitstreams: 1 257467.pdf: 3529841 bytes, checksum: b02ec64317beb4c8e60e372bd2d5cf51 (MD5) / Os objetivos deste trabalho foram: avaliar a influência de polissacarídeos, nas propriedades físicas e químicas de queijos cremosos elaborados com soro de leite líquido e diferentes processos de coagulação, durante 21 dias de armazenamento; avaliar as reações promovidas pela transglutaminase nas etapas de coagulação de leite por renina, e seu impacto nas propriedades físico-químicas e físicas de queijos cremosos. Foi analisada a influência de gomas: xantana (0,2% p/p) e xantana combinada com locusta (0,1 a 0,3% p/p) e guar (0,1 a 0,3%p/p) em queijos cremosos elaborados com gel ácido e gel enzimático. Como também a influência da transglutaminase (TG) em diferentes fases da coagulação do leite por renina, na formação de géis lácteos e queijos cremosos elaborados com estes géis. Os parâmetros analisados foram os físico-químicos, índices de sinerese e de separação de soro e o comportamento reológico. Além da análise microscópica de fluorescência que foi realizada para as amostras com xantana. A xantana se mostrou eficiente no aumento de viscosidade das amostras, resultando em uma matriz protéica mais uniforme e menos porosa, e conseqüentemente dificultando a separação de soro dos queijos cremosos elaborados com géis ácidos e enzimáticos. Em relação às amostras com polissacarídeos combinados as amostras apresentaram maior índice de consistência, com comportamento pseudoplástico com tixotropia, quando utilizou-se as proporções de 0,2% xantana / 0,2% locusta e géis enzimáticos. Para os géis ácidos, os maiores valores para o índice de consistência (K) foram obtidos para os polissacarídeos nas concentrações 0,2% xantana / 0,3% locusta, assim como para a viscosidade aparente, resultados observados a partir do 15º dia de armazenamento. Para as amostras elaboradas com diferentes processos de coagulação e polissacarídeos combinados, a amostra elaborada com gel enzimático apresentou maior consistência, menor índice de sinerese e de separação de soro. Em relação às amostras adicionadas de transglutaminase, observou-se que a transglutaminase adicionada 7 minutos após a adição de renina, apresentou forte correlação (94,83%) com o teor de proteína, sólidos totais e propriedades reológicas, preservando as propriedades coagulantes da renina. Os polissacarídeos (combinados ou não) e a transglutaminase se mostraram eficientes em reduzir índices de sinerese e separação de soro, e aumentar a viscosidade das amostras de queijos cremosos adicionados de soro lácteo. The aims of this study were: to evaluate the influence of the polysaccharides, on the physical and chemical properties of the cream cheeses manufactured with milk whey and different coagulations, during 21 days of storage; to evaluate the reactions led by transglutamise on stages of renneting, and the results on physicalchemical and physical properties of the cream cheeses. It was analyzed the influence of the xanthan gum (0,2% w/w) and blend xanthan and locust (0,1 to 0,3 % w/w) and guar (0,1 to 0,3 % w/w) in cream cheeses manufactured with acid and rennet gel. As well as o the influence of the transglutaminase on different stage of renneting, on the milk gel and cream cheese manufactured with these gels. The parameters analyzed were the physicalchemicals, syneresis index and the wheying-off and rheological properties. The fluorescence microscopy analysis was done in the samples with xanthan. The xanthan was efficient on the increase of the viscosity of the samples, resulting more uniform and less porous protein matrix, and consequently decreasing the wheying-off the cream cheese elaborated wit acid and rennet gel. In relation the samples with polysaccharides blend, the samples showed higher consistency index, showing behavior pseudoplastic with tixotropy, and, when it was used 0.2 % (w/w) xanthan / 0.2 % (w/w) locust blend and rennet gel. For the acid gels samples with polysaccharides with 0.2 % (w/w) xanthan / 0.3 % (w/w) locust blend, showed higher values for the consistency index (K) and the apparent viscosity, tyhese were results observed in samples with 15 days of storage. In order to evaluate the samples with different coagulations process and polysaccharides blends, the samples manufactured with rennet showed the higher consistency, shorter syneresis index and wheying-off. With regard to samples with transglutaminase, it was observed that, the samples with transglutaminase was added 7 min after the rennet, had high correlation (94,83%) with the protein, total solids and rheological properties, maintaining renneting properties. The polysaccharides (blend or not) and the transglutaminase were efficient to decrease syneresis index and wheyingoff, and to enhance viscosity of the cream cheeses samples with milk whey.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-09T23:10:27Z No. of bitstreams: 1 MarcusViniciusGomesPaixao_DISSERT.pdf: 2020456 bytes, checksum: a95b5913fa8087068a71357d5448df6c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-11T20:04:25Z (GMT) No. of bitstreams: 1 MarcusViniciusGomesPaixao_DISSERT.pdf: 2020456 bytes, checksum: a95b5913fa8087068a71357d5448df6c (MD5) / Made available in DSpace on 2016-03-11T20:04:27Z (GMT). No. of bitstreams: 1 MarcusViniciusGomesPaixao_DISSERT.pdf: 2020456 bytes, checksum: a95b5913fa8087068a71357d5448df6c (MD5) Previous issue date: 2015-01-20 / 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%.

Doctor of Philosophy / Food Science Program / Fadi M. Aramouni / Thomas J. Herald / Dynamic viscoelastic and intrinsic viscosity properties of native xanthan, deacetylated xanthan, guar, and their mixtures in dilute solutions were investigated by using an oscillating capillary rheometer. Influence of mixing temperature, deacetylation, and salt concentration on xanthan conformation and interaction with guar were studied in order to provide additional evidence that can be used to elucidate the mechanism of the intermolecular interaction between the two biopolymers, and build up a more detailed rheological understanding of molecular interactions between xanthan and guar gum in dilute solutions. Synergistic interaction was found at mixing temperatures of 25 and 80 °C, but a stronger synergistic interaction was observed at mixing temperature of 80 °C. The differences in viscosity and elasticity measurements between the two mixing temperatures could be attributed to the degree of disordering of xanthan. For both mixing temperatures, the relative viscosity and elasticity of xanthan and guar blends were higher than the relative viscosity and elasticity calculated for blends assuming no interaction, indicating that intermolecular binding occurred between galactomannans backbone and disordered segments of xanthan. Deacetylated xanthan exhibited a stronger synergistic interaction with guar than native xanthan. The intrinsic viscosities of deacetylated xanthan-guar mixtures were higher than those calculated from the weight averages of the two individually, whereas the intrinsic viscosities of native xanthan-guar mixtures were lower than those calculated from weight averages of the two individually, demonstrating that intermolecular binding occurred between xanthan and guar gum. Synergistic interaction for both native xanthan-guar mixtures and deacetylated xanthan-guar mixtures in the dilute regime was observed in water and 2 mM NaCl but not in 40 mM NaCl. The results suggest that intermolecular interaction has occurred between xanthan and guar mixtures in water and 2 mM NaCl, but may not occur in 40 mM NaCl and mutual incompatibility may take place. These results also suggest that degree of disordering of xanthan played a critical role in xanthan-guar interaction and may explain the differences in viscosity, elasticity, and intrinsic viscosity measurements between 2 and 40 mM NaCl, and hence, the intermolecular interaction occurred between the backbone of guar gum and the disordered segments of xanthan.

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The purpose of this research was to determine whether all-purpose flour could be partially replaced with locust bean gum (LBG) and guar gum, and produce an acceptable bread product. A pilot study determined that up to 4% gum replacement for flour was feasible. All bread treatments were evaluated objectively by standing height, texture, color, and cell size. Moisture determinations were obtained for each bread variation. Sensory quality was examined by consumer testing. The amount of heat required to break the hydrogen bonds in amylopectin, indicative of bread staling, was measured by differential scanning calorimetry (DSC) for all bread treatments. Two percent LBG replacement significantly increased standing height. Firmness of bread increased with an increase in gum; the 4% guar bread was significantly firmer. Crumb color was not significantly different for any of the five bread treatments. Crust color, however, was significantly lighter for the control in comparison to the 2 and 4% guar, and 4% LBG breads. Two percent guar produced a more even cell size distribution throughout the bread crumb. For all 5 bread formulations moistures were not significantly different. Sensory evaluation determined a significant difference between the control and 4% LBG. The 4% LBG bread was preferred, although not significantly. Both gums were found to retard bread staling and 2% LBG was the most effective in lengthening the shelf life of the bread product. Objective and sensory evaluation indicated both gums produced acceptable bread products for consumer consumption and possible use in further research. / Master of Science