The use of different adsorbents for selective removal of compounds from olive residue oil miscella

The selective removal of several impurities from a solution of crude olive residue oil in n-hexane (miscella) using batch adsorption by different materials, used separately or in sequence, was investigated. The following adsorbents were tested: activated diatomaceous earths, powdered activated carbon and synthetic neutral resins ("Amberlite XAD-4, XAD-7, XAD-16). The adsorption efficiency of every group of compounds depended on the adsorbent and the ratio (amount of adsorbent/amount of oil) used. The activated earths and carbon were very much more effective in the adsorption of the compounds from the miscella than the resins. Results were similar for every resin tested. An effective removal of green pigments (chlorophylls and pheophytins) and carotenoids was achieved with every adsorbent tested. With respect to the adsorption of conjugated hydro-peroxides (HP), a removal of 50-60% was attained with activated carbon and earths, in contrast to a 20% removal by the resins. For the final oxidation products (FOP), a 60% removal was observed with powdered carbon, 20-30% with earths and 20% with resins. A removal of 20% of free fatty acids (FFA) by activated earths or powdered carbon and 40% by the resins was observed. When the adsorbents were used in sequence (carbon or earths followed by XAD-7 resin), the resin was able to adsorb the remaining FFA, HP and FOP

Selective adsorption of limonin and naringin from orange juice to natural and synthetic adsorbents

In the majority of citrus juices, bitterness is mainly ascribed to the presence of limonoids (triterpenes) and flavanone glycosides (flavonoids), namely limonin and naringin. In this study, the selective removal of limonin and naringin from citrus juice by batch adsorption to different materials was investigated. Since the removal of reducing sugars, pigments and vitamin C may also occur, the eventual adsorption of these compounds was also investigated. The following adsorbents were tested: activated diatomaceous earths, granulated activated carbon and synthetic neutral resins (Amberlite XAD-4, XAD-7 and XAD-16). Both Freundlich and Langmuir isotherm models showed a good fit to the adsorption of limonin to the resins used. Concerning naringin adsorption, a good fit of these models was only observed when the XAD-7 resin was used. Sigmoidal profiles were obtained for the adsorption of limonin to granular activated carbon. Unfavourable isotherms were also observed for limonin and naringin adsorption to activated earths. These isotherm adsorption profiles can be explained by a multilayer adsorption phenomenon. The highest adsorption efficiency for the bitter compounds was observed when synthetic neutral resin, Amberlite XAD-7 was used. The separation factor limonin/naringin varied from 16 (with earths) to 57 (with XAD-7 resin). The adsorption of sugars and pigments to the resins was low. No adsorption of vitamin C was detected for any of the adsorbents tested. The estimated affinity and separation factors show that the neutral resins tested are adequate for the selective removal of limonin from orange juices. The estimated values of free energy of adsorption, lower than -13.3 U mol(-1) K-1, indicate that a physiosorption process occurred

Kinetics of selective adsorption of impurities from a crude vegetable oil in hexane to activated earths and carbons

In this study, the selective removal of several impurities (chlorophylls and pheophytins, carotenoids, free fatty acids and oxidation products) from a solution of crude olive residue oil in n-hexane (miscella) by batch adsorption to different materials was investigated. The following adsorbents were tested: activated diatomaceous earths, powdered and granulated activated carbons. For the majority of the adsorbents used, both Freundlich and Langmuir isotherm models showed a good fit to the adsorption of pigments, free fatty acids (FFA), conjugated hydroperoxides (HP), and final oxidation products (FOP). Sigmoid profiles were observed for the adsorption of chlorophylls, carotenoids, and FOP to the 20-60 mesh carbon, suggesting the presence of pores in the intermediate range (2-50 nm). The FFA isotherm adsorption to the 8-20 mesh carbon can be explained by a multilayer adsorption phenomenon. On the basis of the estimated values for affinity and separation factors, the selective adsorption occurred in the following order for every adsorbent tested: chlorophylls and pheophytinscarotenoidshydroperoxidesfinal oxidation productsfree fatty acids. The highest adsorption efficiency was observed for the powdered activated carbon

Response surface modelling of the consumption of bitter compounds from orange juice by Acinetobacter calcoaceticus

In certain varieties of oranges, an increase in bitterness is currently observed in juices, after extraction, restraining their industrial use. This has been explained by the conversion of the nonbitter precursor, limonoate A-ring lactone, to a bitter compound, limonin, under acidic conditions. The aim of this study was the modelling of limonin consumption in raw and sterilized orange juices by Acinetobacter calcoaceticus isolated from soil. Response Surface Methodology (RSM) was used for modelling bioconversion and optimization reaction conditions, as a function of temperature (23-37 degreesC) and limonin content (8-16 ppm). Initial rate of limonin consumption could be described, both in raw and sterilized orange juices, by concave surfaces with a minimum at 26 and 27 degreesC, respectively. In raw orange juice, after 7 h reaction time, the amount of converted limonin, increased with temperature. Also, the highest conversions (higher than 33%) were achieved at high temperature (higher than 34 degreesC) and low initial limonin content. In sterilized juice, a maximum conversion of about 23% is expected at 31 degreesC, for an initial limonin content of I I mg l(-1). Thus, limonin bioconversion may be carried out directly in raw juice, avoiding juice sterilization. In addition, no significant decrease in reducing sugars was observed. (C) 2002 Elsevier Science B.V. All rights reserved

Discursos de enfermeiras sobre morte e morrer: vontade ou verdade? Discursos de enfermeras sobre la muerte y el morir: ¿Voluntad o verdad? Nurses' speeches on death and to die: truth or will?

Propomos olhar para a morte e o morrer como uma construção social, histórica e cultural. Assim, nos aproximamos dos Estudos Culturais para conhecer discursos de enfermeiras sobre o tema. O corpus da pesquisa são artigos de dois periódicos nacionais de enfermagem. Nas análises utilizamos ferramentas propostas por Michel Foucault que possibilitaram constituir quatro categorias: a morte silenciada e ocultada; travando uma luta contra a morte; a morte em cena: multiplicidade de facetas e a morte e os cuidados paliativos: mudança de paradigma. O estudo destaca o modo como as publicações operam na produção dos saberes sobre a morte e o morrer subjetivando as enfermeiras.<br>Nos proponemos mirar la muerte y el morir como una construcción social, histórica y cultural. Así, nos aproximamos a los Estudios Culturales para conocer discursos de enfermeras sobre el tema. El corpus de la investigación son artículos de dos periódicos nacionales de enfermería. En nuestros análisis utilizamos herramientas propuestas por Michel Foucault que posibilitaran construir cuatro categorías: la muerte silenciada y ocultada; entablando una lucha contra la muerte; la muerte en escena: multiplicidad de facetas, y la muerte y los cuidados paliativos: cambio de paradigma. El estudio destaca el modo en que las publicaciones operan en la producción de los saberes sobre la muerte y el morir subjetivando a las enfermeras.<br>We consider looking at the death and dying as a social, historical and cultural construction. Thus, in we approach them to the Cultural Studies to know nurses´ speeches on the subject. The research is periodic articles of two national ones of nursing. In the analyses we use tools proposals for Michel Foucault that they make possible to constitute four categories: the silenced and occulted death; stopping one it fights against the death; the death in scene: multiplicity of faces and the palliative death and cares: paradigm change. The study detaches the way as the publications operate in the production of knowing on the death and dying to them and subjectiving the nurses

Sistema informatizado para gerenciamento de indicadores da assistência de enfermagem do Hospital São Paulo

Os indicadores são instrumentos que possibilitam definir parâmetros que serão utilizados para realizar comparações e agregar juízo de valor frente ao encontrado e ao ideal estabelecido. Este estudo tem como objetivo descrever a experiência de um grupo de enfermeiras na criação do sistema informatizado desenvolvido no Hospital São Paulo para o gerenciamento de indicadores da assistência de enfermagem. A implantação deste sistema para o gerenciamento dos indicadores foi dividida em quatro etapas: desenvolvimento do manual de indicadores da assistência de enfermagem; realização de teste piloto registrado manualmente; desenvolvimento do sistema informatizado; implementação de estudo piloto do sistema informatizado em onze unidades do hospital