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Background and aim Prosopis strombulifera (Lam.) Benth is a rhizomatous shrub native from different zones of Argentine Republic. P. strombulifera aqueous extract (PsAE) has different effects and several biological activities have been reported. The goal of this study was to analyze the activity of PsAE on a murine model of cutaneous leishmaniasis caused by Leishmania amazonensis. Experimental procedure PsAE was orally administered at 150 mg/animal/day on BALB/c mice infected in the right footpad (RFP) with 1 × 105 promastigotes of L. amazonensis. As a chemotherapeutic control of treatment, animals receive a commercial form of meglumine antimoniate (MA) (Glucantime®, Aventis, Paris, France). Results and conclusion We observe that the size of RFP lesions of infected mice without treatment showed a grade of inflammation, ulceration and necrosis at the site of infection much greater than that observed with PsAE or MA treatment. Moreover, PsAE was capable of decreasing parasite burden and splenic index. Furthermore, PsAE treated mice showed a significant decrease in O.D. of total anti-Leishmania IgG antibody responses against L. amazonensis. This decrease was similar to those observed when the reference drug, MA, was used. This would indicate that PsAE treatment inhibits or delays disease progression in mice. In conclusion, our findings suggest that PsAE could be a potential candidate to be used, as a new therapeutic strategy, to treat cutaneous leishmaniasis caused by L. amazonensis.

En el presente trabajo se analiza una experiencia didáctica en el marco de la interdisciplinariedad, con base en la educación física en la formación inicial docente. La experiencia se despliega en la asignatura de metodología del fútbol, en estudiantes de tercer año de la carrera de pedagogía en educación física, considerando dos fases. La primera orientada al diseño de una planificación tradicional, mientras que en la segunda fase se plantea un desafío interdisciplinar para el diseño y ejecución de la propuesta didáctica. Entre las dificultades que surgieron en la fase uno, se logra evidenciar que los estudiantes no generan un ambiente motivador para el aprendizaje, situación que mejora considerablemente en la fase dos debido al aporte de la interdisciplinariedad. Finalmente se destacan los aspectos positivos en la utilización de estas didácticas innovadoras que logren desafiar y motivar los estudiantes, logrando así un aprendizaje significativo y permanente en el tiempo.

In gold cyanidation plants, which include a zinc cementation process, there is a progressive increase in zinc content in the solution and a higher cyanide concentration in leaching tailings. Consequently, there are opportunities to: (i) recover zinc and cyanide from these solutions, (ii) generate a saleable ZnS by-product, and (iii) reduce cyanide consumption and cyanide concentration in leaching tailings. Previous studies have proposed the use of the SART (Sulfidization, Acidification, Recycling, and Thickening) process for this purpose; however, this process has disadvantages that must be addressed. This study presents the results of the experimental assessment of an alternative process, the SuCy process, which uses an integrated membrane process. The SuCy process is composed of a metal sulfide precipitation coupled with a membrane filtration stage, a membrane contactor step to recover and concentrate cyanide, and a final neutralization and ultrafiltration stage. The flux obtained for zinc sulfide separation was around 0.01 L/m2s, with cyanide recovery of 95% at 60 min, whereas flux for ultrafiltration was 0.22 L/m2s. A comparison with an experimental study of the SART process at laboratory scale showed that the SuCy process could obtain a higher zinc recovery and can reduce the solid–liquid separation equipment by around five times. Therefore, the SuCy process could be a promising alternative for zinc and cyanide recovery in gold cyanidation.

This work aims to evaluate the effect of two natural (whey protein isolate, WPI, and soy lecithin) and a synthetic (Tween 20) emulsifier on physicochemical properties and physical stability of food grade nanoemulsions. Emulsions stabilized by these three surfactants and different sunflower oil contents (30% and 50% w/w), as the dispersed phase, were fabricated at two levels of homogenization pressure (500 and 1000 bar). Nanoemulsions were characterized for droplet size distribution, Zeta-potential, rheological properties, and physical stability. Dynamic light scattering showed that droplet size distributions and D50 values were strongly affected by the surfactant used and the oil content. WPI gave similar droplet diameters to Tween 20 and soy lecithin gave the larger diameters. The rheology of emulsions presented a Newtonian behavior, except for WPI-stabilized emulsions at 50% of oil, presenting a shear-thinning behavior. The physical stability of the emulsions depended on the surfactant used, with increasing order of stability as follows: soy lecithin < Tween 20 < WPI. From our results, we conclude that WPI is an effective natural replacement of synthetic surfactant (Tween 20) for the fabrication of food-grade nanoemulsions.

The objective of this work was to study the effect of denaturation degree of WPI dispersions used as surfactant on the microstructure, rheology, and physical stability of O/W emulsions. Emulsions with different oil contents (10%, 20% and 30% w/w) were formulated using sunflower oil, as the dispersed phase, and WPI dispersions with different degrees of denaturation (0%, 15%, 30%, 45% and 60%), as continuous phase. The emulsions were characterized in terms of (i) microstructure, quantified by optical microscopy and image analysis, (ii) rheological properties, based on flow curve tests, and (iii) physical stability, evaluated by static multiple light scattering. The diffusional migration of proteins to the oil–water interface was slightly affected by denaturation degree of proteins. Microscopy images of the emulsions revealed that droplet size distribution and mean droplet sizes were strongly affected by the denaturation degree of protein dispersions above 30% and by the oil content at 30%. The rheology of emulsions presented a shear-thinning behavior for all conditions studied. The physical stability of the emulsions increased with an aggregation degree up to 45%, presumably because of the increased apparent viscosity of the continuous phase.

Se presenta el uso de ámbitos estratégicos, concebidos como espacios amplios pero definidos, para la determinación de estrategias de desarrollo en universidades. A través del examen exhaustivo de información institucional y contextual, así como requisitos copulativos exigentes, se identifica un número acotado de ámbitos estratégicos que puedan generar el más alto impacto en el desarrollo de las instituciones, junto con asumir circunstancias de impredictibilidad y la diversidad de condiciones complejas. Se efectúa el análisis de un caso en una universidad chilena estatal. Es un procedimiento replicable, el cual se enmarca en el modelo adaptativo de estrategias para universidades. Los ámbitos estratégicos identificados son: (i) sistema integrado de formación, (ii) posicionamiento por integración intrainstitucional e interinstitucional, y (iii) gobernanza pertinente.

Cyanide is one of the main reagents used in gold mining that can be recovered to reduce operational costs. Gas membrane technology is an attractive method for intensifying both the stripping and absorption processes of valuable compounds, such as cyanide. However, scaling-up this technology from laboratory to industry is an unsolved challenge because it requires the improvement of the experimental methodologies that replicate lab-scale results at a larger scale. With this purpose in mind, this study compares the performance of three different hollow fiber membrane contactor modules (1.7 &times, 5.5 Mini Module, 1.7 &times, 10 Mini Module, and 2.5 &times, 8 Extra Flow). These are used for recovering cyanide from aqueous solutions at laboratory scale, using identical operational conditions. For each experimental set-up, mass-transfer correlations at the ranges of feed flows assayed were determined. The modules with the smallest and largest area of mass transfer reached similar cyanide recoveries (&gt, 95% at 60 min), which demonstrate the impact of module configuration on their operating performance. The results obtained here are limited for scaling-up the membrane module performance only because operating modules with the largest area results in a low Re number. This fact limits the extrapolation of results from the mass-transfer correlation.

Human digestion is a complex process that involves several phenomena: chemical and enzymatic reactions, absorption, hydrodynamic processes, and mass transfer. The most accurate way to determine the bioavailability of different nutrients is through human studies. However, there are ethical, economic, and technical reasons that restrict their application. Aiming at contributing with a new experimental prototype and phenomenological model to study nutrient absorption in the human small intestine, an in vitro intestinal digestion system (i-IDS), based on a hollow fiber dialysis membrane process, was constructed and tested under different operational conditions of feed flow/dialysate flow ratio. This dialysis membrane process here presented, allowed to simulate and extrapolate results of the process of glucose transfer in the human small intestine, where the glucose mass transfer reached around 90% at times ranging between 25 and 40 min. The mathematical model was validated with respect to the experimental results, obtaining a good agreement (root mean square error, %RMS, between 3% and 19%) among them. Overall permeabilities for the experimental conditions ranged between 3.85 × 10−6 and 4.86 × 10−6 m3/s. The experimental results of glucose absorption were extrapolated to those found in the human small intestine using a phenomenological model, where a good agreement among results of glucose absorption was found in human studies. This first experimental and phenomenological approach allows to acquire a better knowledge of the complex mass transfer processes found in human small intestine for nutrient absorption.

Este trabajo apunta a estudiar el efecto del grado de agregación de proteínas en las propiedades de superficie y reológicas de dispersiones de ASP con diferente concentración de proteína (80, 100 y 120 g/kg), pH (5,5 ó 6,5) o contenido de NaCl (1 ó 2 g/kg). Las dispersiones fueron tratadas térmicamente a 70, 75 y 80°C por diferentes tiempos. Mediante la mezcla de dispersiones de proteína agregada y nativa, se obtuvieron dispersiones con grados de agregación diferente. La tensión superficial de las dispersiones se determinó fue determinada por el método de la gota colgante, mientras que las propiedades reológicas se obtuvieron desde ensayos de curva de flujo. Se encontró un efecto menor del grado de agregación sobre la difusión, lo cual indica que las proteínas nativas dominaron la disminución de la tensión superficial. La reología de las dispersiones con adición de NaCl cambió desde un comportamiento Newtoniano a uno pseudoplástico para grados de agregación sobre el 20%; mientras que todas las dispersiones a pH 5,5 ó 6,5 presentaron un comportamiento pseudoplástico. This work aims to study the effect of degree of protein aggregation on the surface and rheological properties of whey protein isolate dispersions with different concentrations (80, 100 and 120 g/kg), pHs (5.5 or 6.5) or NaCl contents (1 or 2 g/kg). Dispersions were thermally treated at 70, 75 and 80°C for different times. By mixing aggregated with native protein dispersions, different degrees of aggregation (0%, 20%, 40%, 60% and 80%) were obtained. Surface tension of the dispersions was determined by the pendant drop method, whilst their rheological properties were obtained from flow curve tests. A slight effect of the degree of aggregation over diffusion was found, which indicates that native proteins dominated the decrease in surface tension. The rheological behavior of dispersions with NaCl addition changed from Newtonian to shear thinning for aggregation degrees above 20%, whilst all dispersions at pH 5.5 and 6.5 presented a shear thinning behavior.

This work studies the influence of two thickening agents, starch and carboxymethyl cellulose (CMC) with different structural characteristics on physical properties and lipid bioavailability of avocado oil-based nanoemulsions. Eight nanoemulsions were prepared varying oil content (5 and 15%) and thickener type and concentration (CMC: 0.5–0.75%; Starch: 6–8%). Particle size (PS) and zeta potential (ZPot) depended mainly on the thickener type; starch-based nanoemulsions showed a lower PS and ZPot values near to zero. Nanoemulsions containing the highest oil (15%) and thickener concentrations (0.75% CMC or 8% starch) were more viscous and pseudoplastic than those with 5% oil. With respect to physical stability, the CMC-thickened nanoemulsions exhibited a better stability than starch-based samples. Starch-based nanoemulsions with 15% oil showed the highest creaming index values (40–45%) after 21 days of storage. In turn, the hydrocolloid type had a significant (p

The aqueous extract of the Argentinean native plant, Prosopis strombulifera (PsAE), presents cytotoxicity against human cancer cell lines by inducing cytostasis, necrosis and apoptosis; with diminution of clonogenic survival; without genotoxic effects nor oral animal toxicity. Until now, the chemical extract composition and its in vivo antitumoral properties remain unknown; these studies are the aim of the current work. The PsAE was characterized by chemical fingerprinting and the metabolome was identified by tandem UHPLC-PDA-HESI-Q-orbitrap® mass spectrometry. Colorectal tumors were induced by DMH administration and melanomas resulted from B16-F0 S.C. cells injection; then, animals were treated orally with PsEA. To correlate in vivo results with in vitro cytotoxicity, B16-F0 cell were cultured to determine: cell proliferation and viability by dye exclusion assays, MTT and CFSE dilution; cell cycle distribution by flow cytometry; and immunoblotting of p21cip1, PCNA, cleaved caspase 3, cleaved PARP and TUBA1A. Based on UHPLC-OT-MS and PDA analysis, twenty-six compounds were identified, including: 5 simple organic acids, 4 phenolic acids, 4 procyanidins, 11 flavonoids, and 2 oxylipins. On C57BL6 mice, PsAE significantly increases the median survival on colorectal cancer and reduces the final volume and weight of melanomas. Over cultured cells, the treatment induce over-expression of p21, cytostasis by G2/M cell cycle arrest and apoptosis; while, on in vivo melanomas, treatment up-regulates p21 and slightly decreases PCNA. In conclusion, PsAE is composed by phenolic compounds which demonstrate cytotoxic and antitumoral properties when is orally administrated. Presented results support future research of PsAE as a potential phytomedicine for cancer treatment., Cancer research; Cell biology; Toxicology; Cell culture; Cell death; Cytotoxicity; Chemotherapy; UHPLC-Q-OT fingerprinting; Phenolic compounds; Colorectal cancer; Melanoma; Antitumoral plants; Prosopis.

Particle size distribution (PSD) determination is a typical practice for the characterization of the slurries generated in a precipitation plant. Furthermore, the precipitates generated in these processes form colloidal or aggregated suspensions. Nevertheless, the conventional methods used to estimate PSD (e.g., laser diffraction and/or a cyclosizer) have not been designed to measure particles that tend to aggregate or disaggregate, since they include external forces (e.g., centrifugal, agitation, pumping and sonication). These forces affect the true size of the aggregates formed in a unit operation, thereby losing representativeness in terms of aggregates particle size. This study presents an alternative method of measuring the size distribution of particles with aggregation behavior, particularly, by using non-invasive microscopy and image processing and analysis. The samples used were obtained from an experimental precipitation process by applying sulfidization to treat the cyanide-copper complexes contained in a cyanidation solution. This method has been validated with statistical tools and compared with a conventional analysis based on laser diffraction (Mastersizer). The PSD results obtained with optical microscopy show a bi-modal behavior of the precipitates. However this behavior could be not determined when using the laser diffraction technique. The PSD obtained for the sample tested by microscopy had a mean of 119.7 &mu, m, a median of 147 &mu, m and a 90% distribution reached a particle size of 312.5 &mu, m. These values differ with those obtained by the laser diffraction technique. Our results show significant differences between the methods analyzed, demonstrating that the image processing and analysis obtained by optical microscopy is an excellent and non-invasive alternative to obtain size distributions of aggregates in precipitation processes.

Mussel byssus is a by-product of mussel production and is a potential source of collagen. The goal of this study was to extract collagen from the byssus of Chilean mussel using an enzymatic method and characterize it. A pepsin-aided extraction method was employed where first an enzymatic hydrolysis at two pepsin/substrate ratios (1:50 or 4:50) and times (4 or 24 h) was done. Extraction was conducted at 80 °C for 24 h, in a 0.5 N acetic acid solution. All samples were analyzed for collagen content, amino acid profile, turbidity, viscosity, solubility, denaturation temperature and surface tension. Hydrolysis time had significant effect on collagen content, hydroxyproline content and extraction yield. Hydrolysis with a pepsin/byssus ratio of 4:50 for 24 h gave the better extraction performance with values of 69 mg/g protein, 1.8 mg/g protein and 30%, for collagen content, hydroxyproline content and extraction yield, respectively. No differences were found for the viscosity and surface tension of collagen dispersions, suggesting that the enzymatic hydrolysis did not affect the integrity of the collagen molecule. Denaturation temperature of freeze-dried byssus collagen presented a high value (83–91 °C), making this kind of collagen a very interesting material for encapsulation of bioactive molecules and for biomedical applications.

Aerated gels (AG) contain both bubbles and entrapped water in their structure, thus offering ample versatility in product development. The objective of this study was to evaluate the effect of thermal treatment of whey protein isolate (WPI) dispersions over the microstructure and textural properties of AG fabricated with these dispersions. WPI dispersions (9% w/w) with NaCl (0.4% w/w) at three pH’s (6.50, 6.75 and 7.00) were prepared. Dispersions were subjected to thermal treatment at three temperatures (70, 75 and 80 °C) at different times depending on the pH. After thermal treatment, dispersions were aerated by mechanical agitation at 2000 rpm for 3 min. Finally, aerated dispersions were cooled at 10 °C for 24 h to set the AG structure. AG were characterized in terms of their gas hold-up capacity, microstructure (bubble sizes) and textural properties. Thermal treatment temperature influenced the gas hold-up and mean diameter (DM) of air bubbles in the AG, both decreasing with an increase in temperature. Maximum gas hold-up was about 70% and DM were in the range of 530–700 μm. The increase in apparent viscosity of thermally treated dispersions produced lower air incorporation in AG structure and smaller bubble sizes. Compression stress at break decreased with an increase in the thermal treatment temperature. Control of thermal treatment conditions for WPI dispersions allows to fabricate AG with different microstructural and textural properties which can be used as innovative food matrices for obesity control or delivery of bioactives.

Gas filled membrane absorption process (GFMA), or hollow fiber gas membranes process (HFGM) can replace two units operations (absorption and stripping) in a unique stage based on membrane contactors. But its application at industrial scale is still emerging: only cases of ammonia removal and concentration have been reported. This advantage has not been enough to scale it up to pilot prototypes for different applications, probably because (i) experimental tests have been carried out with modules that do not exist at industrial scale, and the selection of the mass transfer correlation for different purposes lacks rigour with respect to the original conditions of the correlation, and (ii) industrial modules configurations focused only on gas absorption applications. The first problem limits the experimental results for scientific purposes only, making these results unreproducible for the design of a pilot or industrial plant. Furthermore, the selection of experimental modules has generally been established to validate an application, limiting the search for an optimal performance. The high quantity of mass transfer correlation also complicates the selection to design or scaling-up purposes. This work includes then a review of the first problem, by conducting an evaluation of mass transfer performance of different membranes modules configuration proposed in literature. The aim is to identify the best experimental configurations for a GFMA process that will lead a further scaling up. This evaluation was carried out using a phenomenological model of GFMA process developed for an application of cyanide recovery in the gold mining industry. The best performance was achieved in membranes modules having cross flow with center baffle and fully baffled.

National Commission for Scientific and Technological Research (CONICYT Chile) through CONICYT-PIA Project AFB180004 FONDEF/IDeA Program, FONDEF/CONICYT 2017 + ID17I10021 SNF

Cyanide recovery processes are currently an attractive technology implemented in gold mining. The reduction of operational costs, along with minimization or avoidance of the use of expensive processes in destroying cyanide, are among the main reasons that might persuade the gold mining industry to adopt these technologies. The SART and AVR processes are the most frequently implemented in the past years, although both technologies have high requirements of footprint area, equipment sizes and reagents consumption. The present work proposes a novel cyanide recovery technology based on membrane absorption to recover cyanide in gold mining. This study reports the design and cost estimation for cyanide recovery by means of the gas-filled membrane absorption (GFMA) process, which was previously characterized by experimental trials using a commercial hollow fiber contactor, and the modeling of its mass transfer was also carried out. Furthermore, preliminary economic studies of the GFMA, AVR and SART processes were done in order to evaluate the feasibility of the GFMA process. Results from this work suggest that the membrane absorption process could reduce the requirements of footprint area and energy consumption, yielding a net present value at least 35% higher than the AVR process and competitive with the SART process. Hence, the membrane absorption process here proposed is a viable and attractive alternative to current cyanide recovery processes, especially under specific operation conditions, such as low copper concentration in solutions or limitations in flow configuration, where the implementation of the SART process becomes difficult.

Recovery of high-added-value compounds from seafood waste is a promising area of research. Mussel byssus is a by-product from mussel production for human consumption, which is a potential source of collagen. The goal of this study was to extract collagen from the byssus of Chilean mussel using two methods (acidic and enzymatic) and determine their extraction yields. Acidic extraction was performed by immersing the byssus into distilled water adjusted to pH 4 with HCl at two extraction temperatures (60 or 80 °C) and times (6 or 24 h). For enzymatic extraction, first an enzymatic hydrolysis at two times (4 or 24 h) and pepsin/substrate ratios (1:50 or 4:50) was done. Then, the extraction was conducted at 80 °C for 24 h. All samples were analyzed for total protein, amino acid profile and molecular weight of collagen extracts. Extraction time and temperature had significant effects (p

The sulfide precipitation process is currently the most successful technology for recovering cyanide and copper in cyanidation gold plants. The application of this chemical process has been implemented in the SART (Sulfidization, Acidification, Recycling, and Thickening) process. This process includes thickening and filtering unit operations to separate the solids precipitated in the sulfidization reactor. Nevertheless, solid-liquid separation in the thickener has not been optimized, resulting in the loss of copper precipitates in the overflow and, consequently, inducing a reduction in copper recovery in the overall process. This performance could be influenced by the colloidal characteristics of the particles formed in the reaction, but only a few studies have found quantifiable evidence in this regard. Moreover, the impact of the main variables of the process (e.g., pH, sulfide content, and reaction time) on the aggregation behavior has not been studied. Thus, this work attempts to reduce the current lack of scientific understanding of the SART process with respect to the industrial practice. In this context, the goal of this work was to carry out a chemical characterization, particle electrical charge (zeta potential) assessment, chemical computational simulation and settling tests of precipitates obtained from sulfide precipitation assays, in order to create a deep characterization of copper and zinc precipitates. The main results attend to understand the aggregation behavior of the precipitates, the relevance of reaction parameters (pH and sulfide addition) in the aggregation characteristics and its impact in settling results. This study is the first research focused on the characterization of sulfide metal precipitates in cyanide media and its impact in the process.

A new in vitro mechanical gastric system (IMGS) was fabricated which incorporates: a J-shaped stomach, a mechanical system with realistic peristaltic frequency and force magnitude, and a reproduction of the gastric pH curve. To evaluate the impact of a more realistic gastric peristalsis on the intestinal lipolysis of protein-stabilized O/W emulsions, the emulsions were subjected to two different in vitro digestion methodologies: (i) gastric digestion in the IMGS and intestinal digestion in a stirred beaker (SB), and (ii) gastric and intestinal digestion assays carried out in SBs. At the end of the intestinal digestion, the total amount of free fatty acids released was significantly higher for the first methodology (IMGS-SB) in comparison with the second one (27.5% vs. 23.0%), probably due to the higher physical instability induced by the IMGS in the gastric contents. These results reaffirm that O/W emulsion stability plays a crucial role in controlling the final extent of lipolysis of this kind of food-grade emulsions.

The influence of particle size on the in vitro digestion of β-lactoglobulin (BLG)-coated lipid nanoparticles was examined using simulated small intestine conditions. Nanoemulsions were prepared by high-pressure homogenization and organic solvent (hexane) evaporation. The effect of the initial organic phase composition on the size, microstructure, electrical properties, and digestion of the lipid nanoparticles was evaluated. The radius of the nanoparticles decreased (from 85 to 48nm) as the solvent concentration in the initial organic phase increased (from 0% to 95%). The lipid digestion rate initially decreased with decreasing particle radius (for r=85-59nm), but then it increased (for r=59-48nm). This dependence is contrary to the usual assumption that lipid digestion increases with increasing lipid surface area. Our results suggest that the structure of the protein layer coating the lipid nanoparticles has an important effect on lipid digestion.

The behavior of nanoemulsion-based delivery systems within the gastrointestinal tract determines their functional performance. In this study, the influence of particle radius (30–85 nm) on the in vitro digestion of nanoemulsions containing non-ionic surfactant stabilized lipid (corn oil) droplets was examined using simulated small intestine conditions. Nanoemulsions were prepared by a combination of high-pressure homogenization and solvent (hexane) displacement. Lipid droplets with different sizes were prepared by varying the oil-to-solvent ratio in the disperse phase prior to homogenization. The fraction of free fatty acids (FFA) released from emulsified triacylglycerols (TG) during digestion was measured by an in vitro model (pH-Stat titration). Nanoemulsions exhibited a lag-period before any FFA were released, which was explained by inhibition of lipase adsorption to the oil–water interface by free surfactant. After the lag-period, the digestion rate increased with decreasing oil droplet diameter (increasing specific surface area). The total amount of FFA released from the emulsions increased from 61% to 71% as the mean droplet radius decreased from 86 nm to 30 nm. The incomplete digestion of the emulsified lipids could be explained by inhibition of lipase activity by the release of fatty acids and/or by interactions between lipase and surfactants molecules.

Microstructural studies have played an important role in the comprehensive understanding of some food phenomena that occur during drying processes. The aim of this work was to study the effect of four pre-treatments (immersion in boiling water, vacuum impregnation, freezing/thawing, and uni-axial compression) on apple microstructure characterized by cell cavities size parameter and how the changes induced by these pre-treatments can affect the water loss rate during air drying. The quantitative structure analysis showed that freezing/thawing and compression pre-treatments caused more damage on the apple structure, yielding larger cell cavities in comparison to vacuum impregnation and immersion in boiling water and control. Apple slices that were frozen/thawed, compressed and immersed in boiling water displayed the higher drying rates and diffusivity coefficients than the vacuum impregnated and control samples. These results allow concluding that disruption of the cell walls can be considered as a factor that affects the drying rate.

Cyanide recovery in the gold-mining industry is a crucial step in terms of the cost of operation. Currently, a process such as AVR (acidification, volatilization and recycling), based on packed towers for stripping and absorption stages, addresses this issue with high levels of investment and operational costs. Gas-filled membrane absorption (GFMA) emerges then as an attractive alternative because the stripping and absorption stages can be performed in a single stage, reducing associated investment and operational costs. Despite the advantages of this technology, applications at industrial scale are still emerging. A possible reason is the lack of clear scaling-up methodologies where experimental data can be taken to select the optimum industrial hollow-fiber membrane contactor module (HFMC). The present study proposes a methodology to select adequately between available industrial Liqui-CelTM modules to design a process under optimal operational conditions. The methodology is based on a phenomenological model developed for recovering cyanide by using the GFMA process. Simulation of the Liqui-CelTM industrial membrane modules employed to recover cyanide in the GFMA process, both in a batch arrangement with a feed-flow rate, and in the range 10–125 m3/h, showed that in terms of cyanide recovery there are no differences between the modules tested when they work at the same feed-flow rate. The design criteria to scale-up was determined: to ensure performance at different scales, the length of the transfer unit (HTU) should be kept at different capacities of HFMC modules that comprise the equipment characteristics (mass-transfer area, stream velocities, and mass-transfer coefficient values). Additionally, the number of commercial modules Liqui-CelTM required to treat 57 m3/h and 250 m3/h ensuring a cyanide recovery of 95% was also determined. Finally, the most profitable option (lower pressure drop and module cost) resulted in the use of the 14 × 40 Liqui-CelTM module.

Kinetics of extraction of reducing sugars from potato slices was studied during blanching. Two models based on Fick’s law were used to describe loss of reducing sugars during blanching at 60, 75 and 90 °C. The first one is the classic model with a constant effective reducing sugar diffusion coefficient. The second model considers that the diffusion coefficient varies during the blanching process. The variable diffusivity model fitted the experimental data better than the constant diffusivity model (RMS average values of 8% vs. 15%, respectively). The constant effective reducing sugar diffusivity increased with blanching temperature, and the calculated activation energy for this process was 3.4 kJ/mol. The effective reducing sugar diffusion coefficient in the variable diffusivity model decreased with blanching time and temperature and behaved similarly at 75 and 90 °C, while for slices blanched at 60 °C this coefficient was considerable higher after the initial 30 s of blanching. This observation is attributed to the gelatinization of starch at temperatures above 60 °C which results in changes of original microstructure of potato, thereby making the diffusion of reducing sugars more difficult. Low temperature–long time blanching (BLTSt) gave better quality potato chips (lighter and less oily) than those blanched at high temperature–short time combination (BHTSt). No significant effect (p > 0.05) of blanching treatment conditions were observed on porosity and texture on the resultant potato chips.

The objective of this research was to study the effect of different processing conditions on physical and sensory properties of potato chips. Potato slices of Desiree and Panda varieties (diameter: 30 mm; thickness: 3 mm) were pre-treated in the following ways: (i) control or unblanched slices without pre-drying; (ii) blanched slices in hot water at 85 °C for 3.5 min and air-dried at 60 °C until a final moisture content of ∼0.6 kg water/kg dry solid; (iii) control slices soaked in a 3.5 kg/m 3 sodium metabisulphite solution at 20 °C for 3 min and pH adjusted to 3. Pre-treated slices were fried at 120 and 140 °C under vacuum conditions (5.37 kPa, absolute pressure) and under atmospheric pressure until they reached a final moisture content of ∼1.8 kg water/100 kg (wet basis). An experimental design (3 × 2 3 ) was used to analyze the effect of pre-treatment, potato variety, type of frying and frying temperature over the following responses: oil content, instrumental color and texture and sensory evaluation. Vacuum frying increased significantly ( p E , maximum breaking force, hardness and crispness and decreased L * and b * values. On the other hand, Panda potato variety improved the color of the product. A great improvement on color parameters was obtained using sulphited potato slices instead of the other pre-treatments. Although, the better flavor was obtained for control potato chips, no significant differences were found for overall quality between control and sulphited potato chips. Significant correlations ( p

The objective of this research was to study the kinetics of textural changes during convection drying of potato slices by using different mathematical models. The following four models were proposed to validate texture experimental data: (i) two irreversible serial chemical reactions; (ii) two irreversible serial chemical reactions with k2 = 0, which means that only the tissue softening stage is considered; (iii) fractional conversion; (iv) first-order kinetics. These models link the dimensionless textural parameter, maximum force F MAX ∗ with drying time. Experimental textural changes were followed during drying of potato slices at different air temperatures (50, 60, 70 and 80 °C). Regardless of the different drying temperatures, the trend of F MAX ∗ with drying time was almost the same, showing a progressive and significant decrease in its value as the exposure time increased. However, F MAX ∗ of potato slices during drying decreases as the moisture content and temperature decreases, reflecting a clear softening of the potato tissue. A satisfactory agreement between experimental and predicted values was observed for two irreversible serial chemical reactions, with k2 ≠ 0 and k2 = 0, and fractional conversion models, with root mean square error values (RMS’s) in the range of 4.0–9.1%, 3.0–7.4% and 2.0–7.3%, respectively. These RMS’s values are much better than 5.6–23.4% obtained with the traditional first order kinetics. The temperature dependence of model parameters was described by Arrhenius-type relationship and the activation energy for tissue softening ranged between −6565 and 3562 J/mol.

The objective of this research was to study the effect of some pre-treatments and oil temperatures in the kinetics of oil absorption and distribution in the structure of potato chips not only during the frying process but also during the posterior cooling. Pre-treated potato slices (Desiree variety, diameter: 30 mm, thickness: 3.0 mm) were fried at four constant oil temperatures (±1 °C): 120, 140, 160 and 180 °C. The tested pre-treatments were: (i) blanching in hot water at 85 °C per 3.5 min (control); (ii) blanching as in (i) and then immersion in a NaCl solution of 20 g/L per 5 min and at 200 rpm of agitation and 25 °C (salt impregnation); (iii) blanching as in (i) and then covering with an edible film solution of hydroxypropylmethylcellulose – HPMC – (16 g/L per 20 min at 70 °C). The partition of the oil absorbed was quantified during frying and the post-frying stage. Oil could penetrate in chip microstructure either during frying or during cooling when the oil wetting the potato chip surface at the end of the frying process, penetrates into the chip microstructure by vacuum forces created by evaporative cooling. Potato chips absorbed during frying at 180 °C nearly 38% of the total oil content, and almost 62% of the total oil content remained at the chip surface without penetrating into the microstructure (average values for the three pre-treatments tested). This situation reverses during the cooling stage and ∼65% of the total oil content was absorbed by potato chips and only 35% remained at the chip surface. Contrary to expected, potato chips coated with the edible film HPMC absorbed more oil than control and salt impregnated potato chips (P

Acrylamide formation in French fries was investigated in relation under different processing conditions and the content of glucose and asparagine of the strips before frying. Potato strips (0.8 × 0.8 × 5 cm) of Bintje variety were fried at 150, 170 and 190 °C until reaching moisture contents of ∼40 g water/100 g (total basis). Prior to frying, potato strips were treated in one of the following ways: (i) immersed in distilled water for 0 min (control), 60 min and 120 min; (ii) immersed in a citric acid solution of 10 g/L for an hour; (iii) immersed in a sodium pyrophosphate solution of 10 g/L for an hour; (iii) blanched in hot water at six different time-temperature combinations (50 °C for 40 and 80 min; 70 °C for 10 and 45 min; 90 °C for 3 and 10 min). Acrylamide content was determined in French fries while the glucose and asparagine content in the potato strips before frying. Immersed strips in water for 120 min showed a reduction of acrylamide formation of 33%, 21% and 27% at 150, 170 and 190 °C, respectively, when they were compared against the control. Potato strips blanched at 50 °C for 80 min had the lowest acrylamide content when compared against strips blanched at different conditions and fried at the same temperature (135, 327 and 564 μm acrylamide/kg for 150, 170 and 190 °C, respectively). Potato strip immersion in citric acid solution of 10 g/L reduced much more the acrylamide formation after frying than the strip immersion in sodium pyrophosphate solution of 10 g/L (53% vs. 17%, respectively—average values for the three temperatures tested). Acrylamide formation decreased dramatically as the frying temperature decreased from 190 to 150 °C for all the pre-treatments tested. Color represented by the total color difference showed high correlation ( r 2 of 0.854) with the acrylamide content of French fries.

A kinetic model based on 2 irreversible serial chemical reactions has been proposed to fit experimental data of texture changes during thermal processing of potato products. The model links dimensionless maximum force F*(MAX) with processing time. Experimental texture changes were obtained during frying of French fries and potato chips at different temperatures, while literature data for blanching/cooking of potato cubes have been considered. A satisfactory agreement between experimental and predicted values was observed, with root mean square values (RMSs) in the range of 4.7% to 16.4% for French fries and 16.7% to 29.3% for potato chips. In the case of blanching/cooking, the proposed model gave RMSs in the range of 1.2% to 17.6%, much better than the 6.2% to 44.0% obtained with the traditional 1st-order kinetics. The model is able to predict likewise the transition from softening to hardening of the tissue during frying.

Clathrin-mediated endocytosis plays an important role in the maintenance of neuronal integrity in the synaptic terminals. Here we studied the effect of anomalous polyglutamine expansion in huntingtin on the interaction of coat proteins with membranes, in areas of mouse brain or in cultured striatal cells. We observed that this anomaly induces a redistribution of AP-2, but not other coat proteins, from the membrane to the cytosol in the striatum, and in the cultured striatal cells. It was also noted that huntingtin associates with AP-2, and that this association decreases due to the mutation in huntingtin. This decreased receptor-mediated endocytosis, measured by the internalization of transferrin in the mutated cells. It was also confirmed that huntingtin mutation made the cells more vulnerable to the action of quinolinic acid, with an increasing degradation of the AP-2 alpha subunits. On the basis of these results, we conclude that abnormal polyglutamine expansion in huntingtin affects clathrin-mediated endocytosis, and may be one of the pathogenic mechanisms of neurodegeneration. © 2012 Elsevier Inc., SeCTyP (Grant 06/J413); Universidad Nacional de Cuyo; Spanish Ministry of Science; Fundación Ramón Areces

Increasing epidemiological evidence has linked the prevalence of diseases, such as obesity, cardiovascular disease, hypertension, type II diabetes mellitus, and even cancer, to dietary factors. Besides, overweight and obesity are major risk factors to the prevalence of the mentioned diet-related diseases. The obesity epidemic around the world has been attributed to energy imbalance, mainly because of increased food consumption and/or sedentary lifestyle. Changes in eating behavior and the massive amount of high-calorie foods readily available has allowed obesity to reach epidemic proportions around the world. The logical strategy to attack the obesity problem is lowering the total energy intake along with a reduction in fat and sugar/digestible carbohydrate intake, which can have a substantial impact on body weight (American Dietetic Association [ADA], 2005). In past years, the food industry developed “light” products by diminishing or replacing the amount of fat and/or sugar from high-calorie products. However, the replacement of fat and sugar decreases the palatability of foods and for consumers foods must be simultaneously safe, healthy, delicious and convenient (German & Watzke, 2004). Hence, the challenge for the food industry is much more complex than simply providing healthy foods; to provide healthy and delicious foods is the real challenge. The control of digestion and the release of nutrients from the food matrix is an alternative approach to attack the obesity problem and other diet-related diseases. The concept of a food matrix points to the fact that nutrients are contained into a larger continuous medium that may be of cellular origin (i.e., fruits and vegetables) or a structure produced by processing, where nutrients interact at different length scales with the components and structures of the medium (Aguilera & Stanley, 1999). Research on human digestion has often been undertaken with a view to changing the rates of digestion and delivery sites of macronutrients that might affect satiety and thus caloric intake. Several aspects of human eating behavior and food digestion may be relevant for identifying effective measures to treat or prevent diet-related diseases. Although most of people in developed and developing countries eat an unbalanced diet, an increasing part of the consumers are progressively more aware of the relationship between diet and health. Thus, the demand for functional food products that address specific health benefits is growing steadily (Palzer, 2009). The food industry is currently responding by reformulating its products, especially looking at

The rheological behavior of oil-in-water (O/W) emulsions stabilized by whey protein isolate (WPI) and its relationship with the microstructural changes caused by shearing was studied. O/W emulsions (50, 55, and 60 g oil/100 g) were made using ultrasound and their rheological properties were determined by: flow curve test, constant shear rate test, and hysteresis loop test. Microstructural changes were evaluated in terms of droplet size and droplet size distribution. Emulsions containing 50 and 55 g oil/100 g showed a Newtonian behavior, whereas those with 60 g oil/100 g exhibited shear-thinning behavior. Under constant deformation, the apparent viscosity of the emulsions decreased with time. The hysteresis loop test revealed that increasing oil content increased the degree of thixotropy of the emulsions. Moreover, before and after the constant deformation test droplet size distributions did not show differences, indicating that the decrease in the apparent viscosity may be promoted by breakdown and further deformation and/or reorganization of oil droplets flocs. In turn, experimental data obtained from the constant shear rate test was fitted to a structural kinetic model. The rate constant values showed no particular trend with oil content and shear rate, implying that probably wall slip occurred at high shear rates and high oil contents.

The objective of this research was to determine the kinetics of water loss and oil uptake during frying of pre-treated potato slices under vacuum and atmospheric pressure. Potato slices (diameter: 30 mm; width: 3 mm) were pre-treated in the following ways: (i) raw potato slices “control”; (ii) control slices were blanched in hot water at 85 °C for 3.5 min; (iii) blanched slices were dried in hot air until reaching a moisture content of ∼0.6 g water/g dry basis. The slices were fried under vacuum (5.37 kPa, absolute pressure, at 120, 130 and 140 °C) and atmospheric conditions (at 180 °C). Two models based on the Fick's law were used to describe water loss: (i) with a constant effective diffusive coefficient; and (ii) with a variable effective diffusive coefficient. Oil uptake data were fitted to an empirical model, with a linear behavior for short times whereas the model was time independent for long times. The variable diffusivity model better fitted experimental water loss, giving values of effective diffusivity between 4.73 × 10−9 and 1.80 × 10−8 m2/s. The proposed model for the study of the kinetics of oil uptake fitted the experimental data properly. Control and blanched vacuum fried potato chips increased their final oil contents to 57.1% and 75.4% respectively, when compared with those fried at atmospheric pressure. However, the oil absorption of dried vacuum fried potato chips diminished by ∼30%.