Efeitos da temperatura e da luminosidade nas características físico-químicas dos óleos de soja e de girassol durante o armazenamento

Vegetable oils are composed of a mixture of tri-, di-and monoacylglycerols, free fatty acids, glycolipids, phospholipids, sterols and other oxidizable substances so they are very susceptible to oxidation. Thus the present study aimed to evaluate the effect of temperature and luminosity on physic-chemical characteristics of soybean and sunflower oils during storage. The samples were stored at different places and characterized before its fractionation and weekly during one month. The following analyses were performed: acidity index, humidity by Karl Fischer, oxidative stability, viscosity, density, refractive index and colour. The results were statistically analyzed and their averages were compared by Tukey test (p<0.05) using the Statistica (Statsoff ) program version 10.0. It can be concluded that the storage time did not cause severe changes in the samples and that among the storage conditions studied, the samples that were exposed to the luminosity have suffered major changes. Regardless these changes, the parameters studied remained within the limits specified by law: Normative Instruction Nº 49, 22 of December, 2006, from MAPA.Os óleos vegetais são compostos por uma mistura de tri, di e monoacilgliceróis, ácidos graxos livres, glicolipídios, fosfolipídios, esteróis e outras substâncias susceptíveis à oxidação que ocorrem ao longo do tempo e como consequência geram produtos e características sensoriais indesejáveis como escurecimento, o aumento da viscosidade, desenvolvimento de sabor e aromas indesejáveis entre outros. Diante disso, o presente trabalho teve como objetivo avaliar o efeito da temperatura e da luminosidade nas características físico-químicas dos óleos de soja e girassol durante armazenamento sob diferentes condições de estocagem. Para essa avaliação ambos os óleos foram submetidos às análises de índice de acidez, umidade por Karl Fischer, estabilidade oxidativa, viscosidade cinemática, massa específica, índice de refração e cor. Os resultados obtidos foram submetidos à análise estatística e tiveram suas médias comparadas pelo teste de Tukey (p<0,05), utilizando o programa Statistica (Statsoff ) versão 10.0. De acordo com os resultados pode-se concluir que o tempo de armazenamento não ocasionou grandes alterações nas amostras analisadas e que, dentre as condições de armazenamento estudadas, as amostras que sofreram maiores alterações foram àquelas expostas à luz. Contudo, essas alterações ocorridas não ocasionaram mudanças visualmente perceptíveis em ambos os óleos. Os parâmetros estudados permaneceram dentro dos limites especificados pela Instrução Normativa Nº 49, de 22 de dezembro de 2006, do MAPA

AVALIAÇÃO FÍSICO-QUÍMICA DA QUALIDADE DA ÁGUA DE PROPRIEDADES RURAIS DO MUNICÍPIO DE SANTA BÁRBARA, PARÁ

Water is an indispensable natural resource for living beings, it is linked directly to biological cycles, to the balance of the environment. In the rural context, water becomes a vehicle for the transmission of diseases, as well as an absence of resources in the supply system in these regions. Based on this, this research aimed to perform physical-chemical analyzes to verify the water quality of rural farms in six artesian wells and one stream located in the Expedito Ribeiro’s community, municipality of Santa Bárbara - PA. Physical-chemical analyzes were carried out in six artesian wells and one stream on the margins of the community. The parameters analyzed were: hydrogen potential (pH), dissolved oxygen (DO) in ppm, electrical conductivity (EC), total dissolved solids (TDS) and temperature (T). The analyzes revealed an acidic pH in all samples from the wells and in the stream, ranging from 4.02 to 4.98 (average 4.36). For T, the values are in accordance with the legislation of the National Environmental Council - CONAMA, as well as CE and STD, with an average variation of 29.53 °C; 26.53 μS cm-1 and 12.95 mg/L, respectively. Regarding the OD, it showed low levels, ranging between 1.76 and 4.19 ppm, with an average of 2.75, due to the decomposition processes of organic material deposited at the bottom of the wells, and a little higher in the stream, 12.29 ppm. In summary, the study showed acceptable standards for human consumption in accordance with the CONAMA resolution, with the exception of high pH acidity indices and low DO levels in all samples.Keywords: Potability; Water resource; Water supply.A água é um recurso natural indispensável aos seres vivos, estando ligada diretamente aos ciclos biológicos, ao equilíbrio do meio ambiente. No contexto rural, a água torna-se um veículo de transmissão de doenças, além de carência de recursos no sistema de abastecimento nessas regiões. Com base nisso, esta pesquisa objetivou realizar análises físico-químicas para verificar a qualidade da água de abastecimentos rurais em seis poços artesianos e um igarapé localizado na comunidade Expedito Ribeiro, município de Santa Bárbara - PA. Foram realizadas análises físico-químicas em seis poços artesianos e um igarapé às margens da comunidade. Os parâmetros analisados foram: potencial de hidrogênio (pH), oxigênio dissolvido (OD) em ppm, condutividade elétrica (CE), sólidos totais dissolvidos (STD) e temperatura (T). As análises revelaram um pH ácido em todas as amostras dos poços e no igarapé, variando entre 4,02 a 4,98 (média 4,36). Para T, os valores estão em concordância com a legislação do Conselho Nacional do Meio Ambiente - CONAMA, bem como CE e STD, com variação média de 29,53 °C; 26,53 μS cm-1 e 12,95 mg/L, respectivamente. Em relação ao OD, este apresentou baixos níveis, variando entre 1,76 e 4,19 ppm, com média de 2,75, devido aos processos de decomposição de material orgânico depositado no fundo dos poços, e um pouco mais elevado no igarapé, 12,29 ppm. Em síntese, o estudo realizado apontou padrões aceitáveis para consumo humano de acordo com a resolução do CONAMA, com exceção dos altos índices de acidez do pH e baixos níveis de OD em todas as amostras.Palavras-chave: Potabilidade, Recurso Hídrico, Abastecimento

Changes in the tobacco leaf apoplast proteome in response to salt stress

The apoplast of plant cells is a dynamic compartment involved in many processes, including maintenance of tissue shape, development, nutrition, signalling, detoxification and defence. In this work we used Nicotiana tabacum plants as a model to investigate changes in the soluble apoplast composition induced in response to salt stress. Apoplastic fluid was extracted from leaves of control plants and plants exposed to salt stress, using a vacuum infiltration procedure. Two-dimension electrophoretic analyses revealed about 150 polypeptide spots in the pH range of 3.0 to 10.0, in independent protein extracts, with a high level of reproducibility between the two sample sets. Quantitative evaluation and statistical analyses of the resolved spots in treated and untreated samples revealed 20 polypeptides whose abundance changed in response to salt stress. Mass spectroscopic peptide separation and sequencing was used to identify polypeptides affected by salt stress. While the levels of some proteins were reduced by salt-treatment, an enhanced accumulation of protein species known to be induced by biotic and abiotic stresses was observed. In particular, two chitinases and a germin-like protein increased significantly and two lipid transfer proteins were expressed entirely de novo. Some apoplastic polypeptides, involved in cell wall modifications during plant development, remained largely unchanged. The significance of these components is discussed in the context of stress responses in plants

Drag coefficient of porous and permeable microbial granules

Settling velocity of microbial aggregates, such as anaerobic and aerobic granules, in biological wastewater treatment systems is highly related to their drag coefficient. In this work a new approach, taking the porosity and the permeability into account, was established to evaluate the drag coefficient of porous and permeable microbial granules. The effectiveness of this approach was demonstrated by the experimental results with both the anaerobic and the aerobic granules. The drag coefficient of the microbial granules was found to be less than that of smooth rigid spheres and Biofilm-covered particles. In addition, this study demonstrates that the drag coefficient of microbial granules depended heavily on their permeability and porosity. A fractal-cluster model was found to be able to predict the distribution of the primary particles in the microbial granules