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Gonzalez I.,University of Barcelona | Cortes A.,University of Barcelona | Neaman A.,Pontifical Catholic University of Valparaíso | Neaman A.,Centro Regional Of Estudios En Alimentos Saludables | Rubio P.,University of Barcelona
Chemosphere | Year: 2011

Oenothera picensis plants (Fragrant Evening Primrose) grow in the acid soils contaminated by copper smelting in the coastal region of central Chile. We evaluated the effects of the biodegradable chelate MGDA (methylglycinediacetic acid) on copper extraction by O. picensis and on leaching of copper through the soil profile, using an ex situ experiment with soil columns of varying heights. MGDA was applied in four rates: 0 (control), 2, 6 and 10mmol plant -1. MGDA application significantly increased biomass production and foliar concentration, permitting an effective increase in copper extraction, from 0.09mg plant -1 in the control, to 1.3mg plant -1 in the 6 and 10mmol plant -1 treatments. With 10mmol plant -1 rate of MGDA, the copper concentration in the leachate from the 30cm columns was 20 times higher than in the control. For the 60cm columns, copper concentration was 2 times higher than the control. It can be concluded that at increased soil depths, copper leaching would be minimal and that MGDA applications at the studied rates would not pose a high risk for leaching into groundwater. It can thus be stated that applications of MGDA are an effective and environmentally safe way to improve copper extraction by O. picensis in these soils. © 2011 Elsevier Ltd.

Urtubia A.,Federico Santa María Technical University | Urtubia A.,Centro Regional Of Estudios En Alimentos Saludables | Hernandez G.,University of Valparaíso | Roger J.M.,IRSTEA
Journal of Biotechnology | Year: 2012

Three multivariate statistical techniques (Multiway Principal Component Analysis, Multiway Partial Least Squares, and Stepwise Linear Discriminant Analysis) and one artificial intelligence method (Artificial Neural Networks) were evaluated to detect and predict early abnormal behaviors of wine fermentations. The techniques were tested with data of thirty-two variables at different stages of fermentation from industrial wine fermentations of . Cabernet Sauvignon. All the techniques studied considered a pre-treatment to obtain a homogeneous space and reduce the overfitting. The results were encouraging; it was possible to classify at 72. h 100% of the fermentation correctly with three variables using Multiway Partial Least Squares and Artificial Neural Networks. Additional and complementary results were obtained with Stepwise Linear Discriminant Analysis, which found that ethanol, sugars and density measurements are able to discriminate abnormal behavior. © 2011 Elsevier B.V.

Carvajal-Rondanelli P.A.,Pontifical Catholic University of Valparaíso | Carvajal-Rondanelli P.A.,Centro Regional Of Estudios En Alimentos Saludables | Lanier T.C.,North Carolina State University
Journal of Agricultural and Food Chemistry | Year: 2010

Proteases in fish muscle often cause undesired softening of intact meat pieces during refrigerated storage or slow cooking. Several food-grade proteinaceous inhibitors can overcome this softening if properly delivered to the intracellular sites where proteases are located. Fluorescence recovery after photobleaching (FRAP) and laser scanning confocal microscopy (LSCM) were used to measure the translational diffusion of fluorescein isothiocyanate (FITC)-labeled protease inhibitors into intact muscle fibers of halibut. Diffusion coefficients (D) of α-2-macroglobulin (720 kDa), soybean trypsin inhibitor (21 kDa), and cystatin (12 kDa) were measured in both muscle fibers and dilute aqueous solutions. On the time scale of the observation (35 min), cystatin and soybean trypsin inhibitor diffused through the cell membrane (sarcolemma) and sarcoplasm, but at a considerably slower rate (>10-fold difference) than in dilute aqueous solution. α-2-Macroglobulin did not diffuse into muscle cells within the time frame of the experiment, but did completely penetrate the cell during overnight exposure. The present study thus shows a clear dependence of D on protein inhibitor size when moving within intact skeletal muscle fibers. Low molecular weight protease inhibitors such as cystatin can be effectively diffused into intact fish muscle cells to minimize proteolytic activity and meat softening. © 2010 American Chemical Society.

Gutierrez J.E.,Federico Santa María Technical University | Bejarano A.,Federico Santa María Technical University | Fuente J.C.d.l.,Federico Santa María Technical University | Fuente J.C.d.l.,Centro Regional Of Estudios En Alimentos Saludables
Journal of Chemical Thermodynamics | Year: 2010

An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at <5%. Complementary isothermal (vapour + liquid) equilibria results are reported for the (CO2 + 1-propanol), (CO2 + 2-methyl-1-propanol), (CO2 + 3-methyl-1-butanol), and (CO2 + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO2 + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) equilibria compositions were found to be in good agreement with the experimental values with deviations for the mol fractions <0.12 and <0.05 for the liquid and vapour phase, respectively. © 2009 Elsevier Ltd. All rights reserved.

Laroze L.,Pontifical Catholic University of Valparaíso | Soto C.,Centro Regional Of Estudios En Alimentos Saludables | Zuniga M.E.,Pontifical Catholic University of Valparaíso | Zuniga M.E.,Centro Regional Of Estudios En Alimentos Saludables
Electronic Journal of Biotechnology | Year: 2010

The effect of enzymatic hydrolysis on phenolic antioxidant extraction was studied in raspberry solid wastes. This by-product possesses high content of crude fiber (60%) and low values of protein, oil and ash. Raspberry fiber composition suggests that biocatalysts with cellulase, hemicellulase and pectinase activities would be useful for carrying out an enzymatically assisted antioxidant extraction. Hydro-alcoholic extraction was done using different commercial enzymes. Total phenol content and antioxidant activity of enzyme-hydrolyzed residue extracts were measured and compared with those obtained without enzyme application.All biocatalysts evaluated increased soluble solids in comparison to the non-enzymatic control. Among them, Grindamyl and Maxoliva offered the best recovery of polyphenols. Enzymatic assisted extraction with an hydro-ethanolic mixture (75:25, v/v) during 18 hrs at 50°C increased phenolic content up to 35% and antioxidant capacity around 50%, 15% and 30% according to 2,2-diphenyl-1-picrylhydrazyl = 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl) (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) methods, respectively. Use of a higher enzyme concentration significantly improved extraction of phenolic antioxidants. © 2010 by Pontificia Universidad Católica de Valparaíso, Chile.

Soto C.,Centro Regional Of Estudios En Alimentos Saludables | Soto C.,Pontifical Catholic University of Valparaíso
Electronic Journal of Biotechnology | Year: 2013

Background: Lactobacillus sp. are probiotic microorganisms, and some of them are able to produce conjugated linoleic acid (CLA) via the bio-hydrogenation of linoleic acid (LA). Both CLA and LA are polyunsaturated fatty acids commonly used in the prevention and control of cardiovascular disease, high cholesterol, and cancer, among other ailments. The carbon source is one variable that can affect the growth and characteristics of these bacteria. Molecules called prebiotics are known to benefit human health by stimulating the growth and activity of probiotic bacteria present in the intestinal microflora. The aim of this study was to evaluate how different oligosaccharides affect the growth and fatty acid profile of Lactobacillus plantarum (NRRL - B4496). L. plantarum cultivation was performed in Man-Rogosa-Sharpe (MRS) medium, and the original carbon source (glucose) in this medium was partially or totally replaced by an oligosaccharide (isomalto-oligosaccharide (IMO) or gentiooligosaccharide (GTO)). Then, the biomass concentration and fatty acid profile were determined using spectrophotometry and gas chromatography, respectively. Results: When 50% of the glucose in the MRS medium was replaced with IMO, the maximum growth was 2.6 g/L at 37°C. Under the same culture conditions, the incorporation of GTO only produced 2 g/L of biomass. At 45°C, the growth of the bacterial culture was lower than that observed at 37°C, reaching only 0.4 g/L. When cultivated at 37°C in a mixture of glucose and GTO (1:1), CLA (34%, c9t11) was obtained from cells of L. plantarum. However, when the cultivation was performed at 45°C, CLA was not obtained. When IMO was used, differences in CLA content were not observed between L. plantarum cultivated with glucose or with IMO present; however, vaccenic acid was produced. Conclusions: Lactobacillus plantarum grow well when a mixture of IMO and glucose is used as the carbon source. However, this mixture does not improve the CLA content, most likely due to high enzymatic activity that promotes the conversion of CLA to vaccenic acid. Additionally, GTO is likely less readily metabolized by this strain. Thus, the enzymatic activity is likely lower and less CLA is converted to vaccenic acid, resulting in an accumulation of CLA.

Moreno J.,University of Bío Bío | Simpson R.,Federico Santa María Technical University | Simpson R.,Centro Regional Of Estudios En Alimentos Saludables | Estrada D.,University of Bío Bío | And 4 more authors.
Innovative Food Science and Emerging Technologies | Year: 2011

The influence of pulsed vacuum (PVOD) and ohmic heating (OH) on the osmotic dehydration (OD) kinetics and structure of apples was evaluated. Apple cubes (1 cm3) were immersed in a 65 °Brix sucrose solution at 30, 40 and 50 °C for 300 min. The PVOD treatment was conducted at 5 kPa for 5 min, and the OH treatment was conducted at 100 V (electric field of 13 V/cm). The water loss, solid gain, aw, color and firmness were measured, and the microstructure was analyzed using electronic microscopy. The largest water loss was observed with the OD/OH treatment at 50 °C. The greatest amount of solute uptake and smallest firmness loss were obtained with the PVOD/OH treatment at 50 °C. Color differences were associated with the loss of clarity and corresponded to the transparency gain. OH treatments led to changes in the microstructure, cell walls and tissues of the apples due to the electroporation effect, which explained the increase of mass transference. Industrial relevance: The aim of this research was to determine the response of apple samples to osmotic dehydration using combined treatments of pulsed vacuum and ohmic heating. Two different technologies, vacuum and ohmic heating at mild temperatures, were used to determine and observe the mass transfer kinetics and microstructure of osmodehydrated apples. In several ohmic heating treatments, the time reduction reached 50% as compared to conventional heating. The increases of temperature, vacuum application and electroporation effect promoted the gain of osmotic solution into the tissue pores, thus reaching equilibrium in the sample with less water loss. Among the investigated conditions, the PVOD/OH treatment at mild temperatures was the best minimal processing method to preserve the fresh-like properties of the apples. © 2011 Elsevier Ltd. All rights reserved.

Vega R.,Pontifical Catholic University of Valparaíso | Vega R.,National Major San Marcos University | Zuniga-Hansen M.E.,Pontifical Catholic University of Valparaíso | Zuniga-Hansen M.E.,Centro Regional Of Estudios En Alimentos Saludables
Food Chemistry | Year: 2015

The effect of processing conditions (temperature and degree of polymerisation, DP) on the stability of short-chain fructooligosaccharides (sc-FOS) was investigated in three reaction media (sodium citrate buffer and orange and tomato juices) in a kinetic study at pH 3.5. In addition, kinetic equations as a function of temperature and pH were developed, using published data. Pentasaccharides were more stable to heat treatment than were trisaccharides under all of the conditions tested. In addition, the sc-FOS were more stable in orange juice, followed by tomato juice and citrate buffer. The results showed that, in addition to temperature and pH, the DP and food matrix, including the type of pasteurisation, must be considered when processing foods enriched with sc-FOS. Furthermore, the continuous thermal processing simulation for each of the equivalent processes at 90 °C revealed that the percent retention of sc-FOS is greater than 95% at temperatures above 95 °C. © 2014 Elsevier Ltd.

Araus K.A.,University of Santiago de Chile | Canales R.I.,Federico Santa María Technical University | Del Valle J.M.,University of Santiago de Chile | De La Fuente J.C.,Federico Santa María Technical University | De La Fuente J.C.,Centro Regional Of Estudios En Alimentos Saludables
Journal of Chemical Thermodynamics | Year: 2011

Modification of an experimental device and methodology improved speed and reproducibility of measurement of solubility of β-carotene in pure and modified SuperCritical (SC) CO 2 at (313 to 333) K. Solubilities of β-carotene in pure CO 2 at (17 to 34) MPa ranged (0.17 to 1.06) lmol/mol and agreed with values reported in literature. The solubility of β-carotene in CO 2 modified with (1.2 to 1.6) % mol ethanol increased by a factor of 1.7 to 3.0 as compared to its solubility in pure CO 2 under equivalent conditions. The concentration of triolein in equilibrated ternary (CO 2 + β-carotene + triolein) mixtures having excess triolein reached values (0.01 to 0.39) mmol/mol corresponding to its solubility in pure SC CO 2 under equivalent conditions. Under these conditions, the solubility of β-carotene in triolein-modified CO 2 increased by a factor of up to 4.0 in relation with its solubility in pure CO 2 at comparable system temperature and pressure, reaching an uppermost value of 3.3 lmol/mol at 333 K and 32 MPa. Unlike in the case of ethanol, where enhancements in solubility where relatively independent on system conditions, solubility enhancements using triolein as co-solvent increased markedly with system pressure, being larger than using (1.2 to 1.6) % mol ethanol at about (24 to 28) MPa, depending on system temperature. The increase in the solubility β-carotene in SC CO 2 as a result of using ethanol or triolein as co-solvent apparently does not depend on the increase in density associated with the dissolution of the co-solvent in CO 2. Enhancements may be due to an increase in the polarizability of SC CO 2, which possibly growths markedly as triolein dissolves in it when the system pressure becomes higher. © 2011 Elsevier Ltd. All rights reserved.

Vega R.,Pontifical Catholic University of Valparaíso | Vega R.,National Major San Marcos University | Zuniga-Hansen M.E.,Pontifical Catholic University of Valparaíso | Zuniga-Hansen M.E.,Centro Regional Of Estudios En Alimentos Saludables
Biochemical Engineering Journal | Year: 2014

A kinetic model based on a ping-pong mechanism was developed under the steady-state hypothesis to account for the short-chain fructooligosaccharides (sc-FOS) synthesis using the commercial cellulolytic enzyme preparation, Rohapect CM. This new mechanism takes into account the interactions between the enzyme species and potential substrates (sucrose and sc-FOS) as a single complex reaction, allowing a better understanding of the reaction kinetics.The initial reaction rate laws appropriately describe the kinetic profiles of the examined substrates. Whereas sucrose exhibited Michaelis-Menten behavior with substrate inhibition, 1-kestose and nystose followed Michaelis-Menten and sigmoid enzyme kinetics. In addition, the enzyme was competitively inhibited by glucose and exhibited significant hydrolytic activity in the presence of nystose.The overall model was simultaneously fitted to experimental data from three initial sucrose concentrations (0.5, 1.5 and 2.1. M) using a multi-response regression with kinetic parameters that have biochemical relevance and are independent of the enzyme concentration. According to the model, sucrose acts almost exclusively as a fructosyl donor substrate. The mathematical development described herein is expected to be suitable for modeling similar enzymatic reaction systems. © 2013 Elsevier B.V.

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