Mercedes E. Campderrós

Selective separation of copper with Lix 864 in a hollow fiber module.

The transfer and separation of Cu(II), Co(II), Ni(II) and Zn(II) ions across a hollow fiber supported liquid membrane containing LIX 864 as the mobile carrier dissolved in kerosene solvent has been investigated. The flux and selectivity for copper has been studied as a function of the feed flow, the carrier concentration in the liquid membrane and the extraction solution acidity. A maximum copper recovery at 30% of LIX (v/v) in the diluent was obtained. The permeation experiments showed that at pH 2 in the extraction solution a highly selective separation of Cu over the other cations can be achieved. Increasing the acidity of the extraction solution copper selectivity decrease and the grade of recuperation sequence is Cu>Co>Ni>Zn. These results suggest that in selected situations, this membrane system can be competitive with the conventional liquid-liquid extraction process, in particular in leaching solutions with low metal concentration.

Mass transfer of cadmium ions in a hollow-fiber module by pertraction

Abstract The facilitated transport of Cd(Il) ions through a hollow-fiber-supported liquid membrane with bis-2-ethylhexyl phosphoric acid as carrier was studied. The mass transfer rate, expressed as permeability P , was measured as a function of mean aqueous solution velocity and carrier concentration. Characteristic ion permeabilities of 10–26 × 10 −7 m/s were measured at feed velocities between 1 × 10 −2 −19 × 10 −2 m/s at stripping velocities between 0.22 × 10 −2 −7x 10 −2 m/s with constant feed flow. The measured permeabilities were compared to generally accepted mass transfer correlations. The predicted permeabilities adequately fit the experimental data, indicating that the rate limiting step in the transport of the ion was the diffusion through both aqueous films, feed and stripping, whereas the organic resistance of the membrane was negligible. Furthermore, the proposed model allowed the prediction of the permeability of cadmium for different experimental conditions, which is useful to perform experiments to reduce metal levels in water or other effluents.

Development of reduced fat minced meats using inulin and bovine plasma proteins as fat replacers

This work deals with the effect of the addition of inulin and bovine plasma proteins as fat replacers, on the quality of minced meat. The proteins are obtained by ultrafiltration and freeze-drying. The following determinations were carried out: chemical composition, sensorial analysis (color, flavor, taste and consistency), emulsion stability and instrumental texture analysis of samples. The resulting formulations were compared with full-fat minced meat, as control. The results showed an increase of protein contents after fat replacement, while a fat reduction of 20-35% produced light products enriched with proteins and inulin as the functional ingredient. No change was observed in color, flavor, or taste among the samples. However, the sensory analysis showed that the combination of plasma protein (2.5%w/w) and inulin (2%w/w) had the best acceptability with respect to consistency, and had a lower fat drain from the emulsion. Texture profile analysis revealed that this formulation assimilated the control texture properties, being that this result is required for adequate consumer acceptance.

Improvement of gluten-free bread properties by the incorporation of bovine plasma proteins and different saccharides into the matrix

The aim of this work was to improve the quality of gluten-free bread, incorporating plasma bovine proteins concentrated by ultrafiltration and freeze-dried with saccharides (inulin and sucrose). The influence of these compounds on textural properties and final bread quality was assessed. The textural studies revealed that with the addition of proteins and inulin, homogeneous and smaller air cells were achieved improving the textural properties while the bread hardness was comparable with breads with gluten. The volume of gluten-free breads increased with increasing proteins and inulin concentrations, reaching a maximum at a protein concentration of 3.5% (w/w). The addition of the enhancers improved moisture retention of the loaves after cooking and an increase of lightness of crumb with respect to the control was observed. The sensory analysis found no statistically significant difference in sensory attributes evaluated with respect to the control, so these ingredients do not negatively affect the organoleptic properties of bread.

Stabilizing effect of saccharides on bovine plasma protein: A calorimetric study

Bovine plasma proteins provide the needed amino acids for the growth and development of an organism. With the purpose of preserving the native structure, related with the protein functional properties, the oligosaccharide inulin was used as protective agent and was compared with glucose and sucrose, during freeze-drying. In the present study, the thermal stability of protein was investigated as a function of type of saccharide in a concentration range of 5-15% (w/v), and at different pHs. The effect of these variables on phase transition, thermal stability and miscibility was assessed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results of thermal protein properties (denaturation temperature and enthalpy), demonstrated that endothermic transition shifted to higher temperatures, being the stabilizing effect: inulin>glucose>sucrose. The thermal behavior suggests compatibility or interactions between the components of blends. In this way, the micrographs showed a homogeneous distribution of the different phases, corroborating the miscibility in the matrix. The unfolding process was irreversible and could be adequately described by a two-state model.

Transport of niobium(V) through a TBP–Alamine 336 supported liquid membrane from chloride solutions

Abstract The transport of niobium(V) in chloride medium through a supported liquid membrane (SLM), using Alamine 336 and tributyl phosphate (TBP) as carriers, has been investigated. The work has been undertaken by first determining the liquid–liquid extraction distribution of niobium(V) between aqueous solution and different organic solutions. Optimum conditions for both extraction and stripping were established. The mixture of Alamine 336 and TBP provided the best extraction in high chloride medium, while low HCl concentration stripped the ion from the loaded organic phase. Transport experiments were carried out with a permeation cell having a continuous flow system and constant agitation. The study of the liquid membrane included the chemical conditions, i.e. carrier concentration and hydrochloric acid concentration in the feed solution. Maximum niobium recovery at 10% of Alamine 336 in TBP was obtained at HCl concentration between 6 and 7 mol/dm3. The mechanism postulated is referred to a synergistic extraction of Nb(V) by means of a co-transport process. Nb(V) can be concentrated in the stripping solution and the SLM showed a good performance for Nb–Ta separation.

Fractionation of skim milk by an integrated membrane process for yoghurt elaboration and lactose recuperation.

A combined membrane process has been used to fractionate skim milk. Microfiltration and ultrafiltration were employed to obtain concentrates with different protein/lactose ratios depending on the volume concentration ratio to produce protein enriched yoghurt. Nanofiltration has been used for lactose recovery from the ultrafiltration permeate with partial demineralization, while the permeate water of NF can be reused or recycled. Feed, permeate, concentrates and yoghurt have been physicochemical characterized and compared with commercial products. The obtained yoghurts have a smooth aroma and an agreeable taste, the protein content increased up to 50 % and the lactose content decreased approximately 50 % in comparison with commercial yoghurts, while calcium and iron were also increased, leading to a product with special characteristics and high commercial value. Lactose powder has been obtained by lyophilization; the product has good solubility and has 90% purity which can be used in different food preparations or for other applications.

Development of a Functional Beverage Formulation with High Protein Content, Inulin and Stevia

A beverage formulation with proteins of high quality, inulin, Stevia and C vitamin has been prepared. The protein source was bovine plasma which was concentrated and demineralized by a combined membrane methodologies as microfiltration, ultrafiltration and discontinues diafiltration. The use of inulin as protective agent to prevent protein concentrate denaturation during freeze-drying was assayed. The inulin is a versatile food ingredient and it also has health benefits. The powder obtained has improved sensory characteristic and high solubility. Stevia has been added as sweetness, being a low-carbohydrate, low-sugar food alternative. The formulation could be destined as protein supplement with functional properties or for special dietary use.

Coupled transport of copper through different commercial supports containing LIX 984 as carrier

The coupled transport of copper(II) ions through a supported liquid membrane containing LIX 984 as the mobile carrier dissolved in kerosene has been studied. Many commercial membrane supports were investigated at different stirrer speeds in a permeation cell. An equation describing the permeation rate has been derived, taking into account stagnant layer aqueous diffusion and liquid membrane diffusion. By means of this treatment the copper overall transfer resistance and the experimental determination of the effective porosity factor (e/τ), for each support have been performed. The Accurel® 2E-PP membrane showed a relatively high value of e/τ (0.91), which makes this membrane an adequate support when the transport properties of the supported liquid membrane are concerned.

Incorporation of Okara into Gluten-Free Cookies with High Quality and Nutritional Value

Soy products are a source of protein relatively inexpensive and recognized for their high nutritional value and functional properties. Okara is a byproduct from soy milk production. Gluten-free cookies have been developed using okara and commercial manioc flour. Four formulations were developed with different proportions of okara: 50%; 30%; 15%; and 0%. Physicochemical, physical properties, sensory analysis, and nutritional studies were performed. The use of inulin as partial replacement of sugar was evaluated. The incorporation of okara increased protein and fiber content. Furthermore, the hardness of cookies increased while the index of whiteness decreased. From the sensory evaluation, it could be concluded that the cookies presented a great acceptability. The cookies developed in this study have functional characteristics, providing added value to a waste product; furthermore the products were suitable for celiacs with acceptable quality and improved nutrition value.