Caracterização do pão regional do distrito de Viseu e de Pão São

Dissertação de Mestrado em Qualidade e Tecnologia AlimentarO objectivo deste estudo visa a caracterização de diferentes amostras de pão Regional e pão São, procurando encontrar semelhanças e identificar os elementos diferenciadores dos mesmos. As amostras de pão Regional foram recolhidas no distrito de Viseu: Carregal do Sal, Cabanas de Viriato, Santar, Viseu, Mangualde, São Pedro do Sul e São Cipriano. No caso do pão São as amostras foram fornecidas pela empresa produtora, Fábrica do Pão localizada em Seia. Procedeu-se à caracterização física, química e sensorial, tendo sido avaliadas as diferentes propriedades em termos de média e desvio padrão das réplicas efectuadas. Posteriormente, procedeu-se a uma análise estatística, para comparação de médias e avaliação da significância das diferenças, tendo para tal sido usado o teste de Tuckey HSD. Foram ainda calculados os coeficientes de correlação de Pearson. Os resultados foram analisados recorrendo ao software SPSS para o Windows versão 19.0 e Statistic versão 6., sendo realizado o teste de análise de variância "one-way" (ANOVA). Numa fase posterior, os valores obtidos para as características do pão foram sujeitos a uma análise de componentes principais (PCA) e uma análise de Cluster. Em relação aos parâmetros químicos analisados no pão Regional, as amostras apresentaram algumas semelhanças e algumas diferenças, assim como também a nível físico e sensorial. No entanto, no que respeita à análise sensorial, as amostras foram, de modo geral, percepcionadas da mesma forma pelos provadores, não sendo detectadas diferenças significativas. Ainda assim, em termos de apreciação global a amostra preferida foi a da pastelaria Flor de Cabanas. Em relação aos parâmetros químicos, físicose sensoriais do pão São, as amostras mostraram-se semelhantes entre si, o que pode ser explicado por terem basicamente a mesma constituição em termos de ingredientes. Contudo, será de assinalar algumas diferenças em termos de fibra, hidratos de carbono, proteína e cloretos, devido à presença de farinha de tremoço numa das amostras. Quando comparadas as amostras de pão Regional com as de pão São, verificou-se que estas se apresentaram bastante diferentes, quer em termos químicos, físicos ou nível sensorial. Foi possível observar que ao nível sensorial os pães Regionais foram os preferidos pelos provadores.ABSTRACT: The aim of this study is the characterization of different samples of regional bread and healthy bread, trying to identify the similarities and contrasting elements in them. The regional bread samples were collected in the District of Viseu: Carregal do Sal, Cabanas de Viriato, Santar, Viseu, São Pedro do Sul and São Cipriano. The healthy bread samples were provided by the production company "Fábrica do Pão", located in Seia. The physical, chemical and sensory characterization was undertaken, having been avaluted the different proprerties in terms of mean value and standard deviation of the replicas made. Later, we proceeded to a statistical analysis for comparison of means and assessing the significance of the differences, having been used for this the Tukey HSD test. We also calculated the Pearson correlation coefficients. The results were analyzaed using the SPSS software version 19.0 for Windows and Statistica version 6, having been performed an analysis of variance "one way"(ANOVA). At a later stage, the values obtained for the characteristics of bread were subjected to principal components analysis (PCA) and cluster analysis. Regardind the chemical parameters analyzed in the regional bread, the samples showed some similarities and differences, as well as regarding the physical and sensory parameters. However, concerning the sensory analysis, the samples were generally perceived by the panelists in the same way, and no significant differences were observed. Still, in terms of the same way preferred by the panelists the sample from pastry "Flor de Cabanas". With respect to chemical, physical and sensory parameters of the healthy bread, the samples were similar, which can be explained by having basically the same constitution in terms of ingredients. However, there can be noted some differences in terms of fiber, carbohydrates, protein and chlorides, due to the presence of lupine flour in one sample. When comparing the regional bread samples with the healthy bread ones, it was found that they quite different, either at the chemical, physical or sensory levels. It was observed that at the sensory level the regional breads were those preferred by the tasters

Investigation on solubilization protocols in the refolding of the thioredoxin TsnC from Xylella fastidiosa by high hydrostatic pressure approach

The lack of efficient refolding methodologies must be overcome to take full advantage of the fact that bacteria express high levels of aggregated recombinant proteins. High hydrostatic pressure (HHP) impairs intermolecular hydrophobic and electrostatic interactions, dissociating aggregates, which makes HHP a useful tool to solubilize proteins for subsequent refolding. A process of refolding was set up by using as a model TsnC, a thioredoxin that catalyzes the disulfide reduction to a dithiol, a useful indication of biological activity. The inclusion bodies (IB) were dissociated at 2.4 kbar. The effect of incubation of IB suspensions at 1–800 bar, the guanidine hydrochloride concentration, the oxidized/reduced glutathione (GSH/GSSG) ratios, and the additives in the refolding buffer were analyzed. To assess the yields of fully biologically active protein obtained for each tested condition, it was crucial to analyze both the TsnC solubilization yield and its enzymatic activity. Application of 2.4 kbar to the IB suspension in the presence of 9 mM GSH, 1 mM GSSG, 0.75 M guanidine hydrochloride, and 0.5 M arginine with subsequent incubation at 1 bar furnished high refolding yield (81%). The experience gained in this study shall help to establish efficient HHP-based protein refolding processes for other proteins.This work was supported by grants from the State of São Paulo Research Foundation – FAPESP (Process 10/13353-0) and National Council for Scientific and Technological Development – CNPq (Process 479816/2007-7) and fellowship 134597/2010-9 from National Council for Scientific and Technological Development – CNPq