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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Produção de quitosana a partir de resíduo de camarão e aplicação como adsorvente do corante alimentício FD&C vermelho n° 40

Piccin, Jeferson Steffanello January 2009 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia e Ciência de Alimentos, Escola de Química e Alimentos, 2009. / Submitted by Caroline Silva (krol_bilhar@hotmail.com) on 2012-09-04T20:16:38Z No. of bitstreams: 1 20090708- dissertaojefersonpiccin.pdf: 1210293 bytes, checksum: 85497c428ae6de8e628041a39db023e5 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-09-22T17:13:20Z (GMT) No. of bitstreams: 1 20090708- dissertaojefersonpiccin.pdf: 1210293 bytes, checksum: 85497c428ae6de8e628041a39db023e5 (MD5) / Made available in DSpace on 2012-09-22T17:13:20Z (GMT). No. of bitstreams: 1 20090708- dissertaojefersonpiccin.pdf: 1210293 bytes, checksum: 85497c428ae6de8e628041a39db023e5 (MD5) Previous issue date: 2009 / Uma preocupação das indústrias de alimentos atualmente, diz respeito à geração de resíduos provenientes do processamento das matérias-primas. Estudos têm sido realizados no sentido de encontrar um destino adequado para os resíduos gerados pelas indústrias, de modo que as agressões ao meio ambiente sejam cada vez mais reduzidas. Neste contexto, a utilização de quitina, substância encontrada nos exoesqueletos de insetos, carapaças de crustáceos e parede celular de fungos, para a produção de quitosana vem sendo estudada há vários anos. O objetivo do presente trabalho consistiu no estudo do processo de obtenção da quitosana a partir de resíduos de camarão e sua aplicação como adsorvente do corante alimentício FD&C Vermelho n° 40, através da construção das isotermas de equilíbrio, cinética de adsorção, determinação dos parâmetros termodinâmicos, verificação da natureza e dos mecanismos do processo de adsorção. As análises de erro demonstraram que o modelo de isoterma de Langmuir foi mais apropriado para descrever os dados experimentais, sendo que a máxima adsorção na monocamada observada quando o pH de equilíbrio foi de 6,6, temperatura 35°C, tamanho de partícula de 0,10±0,02 mm, e grau de desacetilação 84±3% foi de 529 mg g-1. Valores negativos da entalpia (-112,7 kJ mol-1), entropia (-0,338 kJ mol-1 K-1) e Energia livre de Gibbs (-15,6 a 1,0 kJ mol-1) demonstraram que o processo de adsorção é exotérmico, espontâneo, favorável, e que a desordem do sistema diminui durante o processo de adsorção. O modelo cinético de Elovich e modelo de pseudo-segunda ordem foram os mais adequados para descrever as cinéticas de adsorção, sendo que a difusão no interior da partícula, na maioria dos casos, é o mecanismo que controla o processo de adsorção. Em condições ácidas (pH = 5,7) mais de 90% da capacidade de adsorção foi atingida em menos de 20 min. Nestas condições foi observado que a natureza do processo de adsorção é química, devido às interações entre os grupamentos aminas protonados da quitosana e o grupo sulfonado do corante. Estes resultados demonstraram que a quitosana é um promissor adsorvente de corantes alimentícios, em especial o corante alimentício FD&C Vermelho n° 40. / A current foods industries concern says respect at wastes generation of the raw materials processing. Studies are being accomplished in the sense of finding an appropriate destiny for the industrial wastes, for the environments aggressions reduction. Therefore, the use of chitin, substance found in the exoskeletons of insects, shells of crustaceans, and fungal cell walls, for chitosan production has been studied at various years. The aim of the present work was the study of production process of chitosan from shrimp wastes and your application in the adsorption of food dye FD&C Red n° 40, through the techniques of equilibrium isotherm and adsorption kinetic, determination of the thermodynamic parameters, verification of the nature and mechanisms of the adsorption process. Error analysis demonstrated that the Langmuir isotherm model was most appropriate for describing the experimental data, and the maximum monolayer adsorption value has been found to be 529 mg g-1, at pH 6.6, temperature 35°C, particle size range 0.10±0.02 mm, and deacetylation degree 84±3%. Negative enthalpy (-112.7 kJ mol-1), entropy (-0.338 kJ mol-1 K-1) and Gibbs free energy (-15.6 to 1.0 kJ mol-1) values demonstrated that the adsorption process is exothermic, spontaneous, favorable, and that randomness of the system decreases during the adsorption process. The Elovich and pseudo-second order kinetics models were most appropriate to describe the adsorption kinetics, and the intraparticle diffusion, in most of the cases, was adsorption mechanism that control the process. In acid conditions (pH = 5.7) more than 90% of the adsorption capacity were reached in less than 20 min. In these conditions was observed that the chemical adsorption process nature, due the interactions between the chitosan protonated amino group and the dye sulphonic group. These results demonstrated that the chitosan is a promising adsorbent of food dyes, especially the food dye FD&C Red n° 40.
2

Examining the Effects of Synthetic Dye Yellow No. 5 (Tartrazine) Exposure on Mouse Neuro2A Neurons In Vitro

Farnum, Jenna L 01 January 2022 (has links)
Yellow Dye No. 5, also known as tartrazine (TRZ), is widely used[1] and has an accepted daily intake (ADI) of 0-7.5 mg/kg of body weight per day[2]. Consuming TRZ dosages greater than the ADI can lead to reduced levels of antioxidant enzymes in the brain, chromosomal alterations, or neuronal dendritic changes, [3, 4] which can result in oxidative stress, impaired neuronal functioning and potential mutagenic effects. Within the ADI, there have been observed reductions of the copper zinc superoxide dismutase-1 (SOD1) enzyme levels.[5]We hypothesize that TRZ interacts pre-translationally inside the cell, resulting in the reduction of SOD1 mRNA. In this study, differentiated Neuro2A-derived neurons were exposed to TRZ for 3 or 7 days. We tested a concentration curve from 0 to 11 μg/mL. Treated cells were grown on poly-L-lysine (PLL)- and laminin-coated glass coverslips, immunostained with anti-β-tubulin III and phalloidin, imaged, and analyzed using NeuronJ/ImageJ (NIH). Neurons were traced to analyze the morphological impacts of TRZ. SOD1 mRNA was quantified using reverse transcription quantitative polymerase chain reaction (RT-qPCR). We analyzed the differences in SOD1 mRNA levels of the controls vs. experimental cells, using the 2-ΔΔCT statistical method. We found that TRZ caused an increase in neurite length and a general decreasing trend of SOD1 mRNA expression. The reduction in SOD1 mRNA expression could indicate possible pre-translational modifications, which could be a result of TRZ’s ability to bind DNA. These findings help fill the gap in understanding the mechanism of SOD1 downregulation due to TRZ exposure.

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