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Resumo(s)
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.
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Citação
EUROPEAN FOOD RESEARCH AND TECHNOLOGY. - Vol. 213, n. 2 (AUG 2001), p. 132-138