Suchergebnisse

Polyphenoloxidase from apple was extracted and further concentrated by cationic reversed micellar extraction. Previous to reversed micellar extraction a crude protein extract was obtained using AG2-X8 as adsorbent of phenolic compounds and the detergent Triton X-100. Forward and backward extraction conditions were optimized by using dodecyl trimethyl ammonium bromide as surfactant in the organic phase. Optimization was carried out to obtain the highest value of PPO activity recovery and the purification fold at the different experimental conditions. Under the optimum extraction conditions, PPO activity recovery was 99% and purification fold reached a value of 17, showing that reversed micellar extraction was a good technique as a first step to concentrate on a targeted enzyme. After removing some impurities by centrifuge ultrafiltration, the protein extract with PPO activity was treated by pressurized carbon dioxide and thermosonication achieving residual PPO activity values of 16 ± 3 and 9 ± 1%, respectively. Quenching experiments by iodide performed in the non-treated extract and in the treated extracts revealed conformational changes of this protein fraction reflected in the greater exposure of the fluorophore to the quencher. ; Spanish Government (MINECO) and the European Regional Development Fund (ERDF) for financial support of project CTQ2015-64396-R and AEI's contract, and to Junta de Castilla y León and ERDF for financial support of project BU301P18.

This work provides experimental fluid phase equilibrium data of the pseudo-ternary mixture CO2 + ethanol + fish oil, a system of interest in pharmaceutical and food-industry applications such as the production of omega-3-enriched lipid derivatives at mild, non-oxidative conditions. Experimental tie-lines were obtained by means of an analytical isothermal method with recirculation of the vapour phase. Measurements were carried out in the temperature range 323.15 K–343.15 K and at pressures from 10 MPa to 30 MPa. The Peng-Robinson equation of state coupled with the conventional van der Waals mixing rules with two adjustable parameters was used for experimental data correlation. ; Spanish Government through MINECO and Junta de Castilla y León for financial support of the projects CTQ2012-39131-C02-01 and BU055U16, respectively, 16 both co-financed by the European Regional Development Fund (ERDF)

Ponencia presentada en: 16th European Meeting on Supercritical Fluids, 25 a 28 de abril de 2017, Lisboa ; This work provides experimental phase equilibrium data of the pseudo-ternary system CO2 + ethanol + fish oil, a system of interest in pharmaceutical and food-industry applications such as the enzymatic production of fatty acid ethyl esters at mild, non-oxidative conditions. Measurements were carried out in a high-pressure variable-volume view cell in the temperature range 323.15-343.15 K and at pressures from 10 to 30 MPa. The Peng-Robinson equation of state was used to satisfactorily correlate experimental data. ; European Regional Development Fund (ERDF), Spanish Government (MINECO) and Junta de Castilla y León for financial support (projects CTQ2012-39131-C02-01 and BU055U16). RM acknowledges MINECO (BES-2013-063937)

The production of polyunsaturated fatty acids (PUFAs) concentrates by enzymatic catalysis has gained interest due to their stereospecificity and the milder conditions employed compared to the use of inorganic catalysts. The enzymatic glycerolysis of sardine oil by Lipozyme 435 to get PUFA concentrates in the forms of di‐ and monoacylglycerols (DAGs, MAGs) in an optimized amount of tert‐butanol as the organic solvent was studied. First, mass transfer limitation of the reaction system was analyzed. The effects of different operating variables such as lipase loading, temperature and feed composition were investigated. A semi‐empirical kinetic model based on the reversible elementary reactions of glycerolysis and hydrolysis of the glycerides was employed to correlate the experimental kinetic data. A molar ratio glycerol:oil of 3:1 was the optimum, which produced more than 84 wt% of MAG at 323 K. A comparison with other glycerolysis systems was performed using MAG yield, reaction rate and significance of kinetic parameters. ; Spanish Government through MINECO (CTQ2012‐39131‐C02‐01)

Measurements of CO2 solubility were performed in different media, pure water, model citrate buffer solutions at different pH values and in the presence of different sugar content and in real apple and carrot juices. Solubility was determined in the pressure range from 8 to 20 MPa and in the temperature range from 308 to 318 K. CO2 solubility in citrate buffer solutions at pH = 3.8 and pH = 6.2 was slightly lower than CO2 solubility in pure water. A Chrastil-type equation according to Fornari's approach was used to fit CO2 solubility data in pure water and model solutions. A new term was introduced in this equation to account for the decrease in solubility of CO2 in the presence of sugar in the liquid media. ; Spanish Government (MINECO) and the European Regional Development Fund (ERDF) for financial support of project CTQ2015-64396-R

The extraction of polyphenoloxidase (PPO) from Litopenaeus vannamei was studied at different temperatures, pH and ionic strength conditions. Optimum extracts at pH = 7.2 were treated by hiph pressure carbon dioxide (HPCD) technology at 20 MPa and in a temperature range from 35 to 50 °C. Inactivation kinetics for PPO extracts were determined and fitted to the Weibull model. The effect of HPCD on PPO activity was also evaluated in shrimps in vivo, finding that PPO could be easier inactivated than in the crude PPO extract. Color of Litopenaeus vannamei was visually followed right after HPCD treatment and thermal treatment at the same temperature and during storage at 4 °C during a week, showing good results when shrimps were treated with HPCD in the absence of water. ; Spanish Government (MINECO) and the European Regional Development Fund for financial support of project CTQ2015-64396-R

Production of monoacylglycerols (MAGs) rich in x-3 polyunsaturated fatty acids (n-3 PUFAs) was conducted through short path distillation (SPD) of an acylglycerol mixture (containing 67% MAGs) produced by enzymatic glycerolysis of sardine oil with glycerol. A stepwise SPD process in a UIC KDL 5 system (vacuum 10 3 mbar, feeding flow 1.0 mL/min) was proceeded: the first distillation performed at evaporator temperature (TE) of 110 C to remove glycerol completely and most of FFAs; and the second distillation at optimized TE 155 C; resulting in a stream distillate with 91% purity and 94% overall recovery of MAGs. This work also demonstrated that SPD is able to concentrate n-3 PUFAs in MAG form by distilling at proper TE e.g. 125 C, where n-3 PUFAs are concentrated in the residues. Moreover, this work mapped out a complete processing diagram for scalable production of n-3 PUFAs enriched MAGs as potential food emulsifier and ingredient. ; Spanish Government through MINECO and the European Regional Development Fund (ERDF) for financial support to the project CTQ2012-39131-C02-01.

The supercritical fluid extraction (SFE) of wheat bran oil with pure supercritical carbon dioxide at different extraction pressures (25, 40, and 55 MPa) and temperatures (40, 70, and 95°C) has been studied. Since wheat bran contains important bioactive compounds such as alkylresorcinols (AR) and other phenolic compounds, the content of these compounds in the extracted oil was evaluated in order to establish oil quality. The influence of extraction pressure and temperature and wheat bran moisture on the extraction yield and oil quality was studied. Oil quality was evaluated through parameters such as AR content and profile, total polyphenols index (TPI), antioxidant activity, and fatty acids profile. SFE performed over fresh wheat bran at 55MPa and 95°C was found to provide wheat bran oil with the highest AR and phenolic content and antioxidant capacity of all the runs performed in this work. Some SFE experiments focused on oil fractionation showed that this technique can provide oil fractions enriched with AR and phenolic compounds. ; This work is part of the GALANG project (Ref.: ITC‐20113029) financed by the Spanish Government through CDTI

Supercritical carbon dioxide (SC−CO2) has been used as solvent in the ethanolysis of fish oil rich with omega-3 polyunsaturated fatty acids (n-3 PUFAs) by Lipozyme 435. The effect of experimental conditions: initial ethanol-to-oil molar ratio (MR, 6:1-76:1), pressure (10–30 MPa), and temperature (323–343 K) on the reaction performance has been studied. Experimental results have been fitted to a kinetic model based on a Ping Pong Bi Bi mechanism. High accumulation of monoacylglycerides (MAGs) has been observed in short reaction times (90 min at MR = 76:1, 10 MPa, 323 K). Subsequent purification of reaction products by supercritical fluid extraction (SFE) in the experimental range 10–28 MPa and 298–333 K yielded an extract rich with fatty acid ethyl esters (FAEE) (up to 99.46%wt.), and a raffinate with up to 82.25%wt. MAG and 49.5%wt. n-3 PUFAs. ; Spanish Government through MINECO and the European Regional Development Fund (ERDF) for financial support [grant number CTQ2012-39131-C02-01] and RM's and AEI's contracts [BES-2013-063937, CTQ2015-64396-R]. To Junta de Castilla y León and ERDF for financial support [grant number BU055U16] and ÓBR's post-doctoral contract.

In the present work, High Pressure Carbon Dioxide (HPCD) has been used to inactivate the enzymes Polyphenol Oxidase (PPO) and Pectin Methylesterase (PME). The work has been done in two stages: in the first one, fundamental knowledge about the inactivation mechanism induced by HPCD was obtained using pure commercial enzymes. The influence of the main process parameters was studied: pressure, temperature, time and ratio CO2/volume of enzymatic solution. The changes in the tertiary structure of the enzymes after the HPCD treatment were analyzed by fluorescence spectroscopy running two different tests: intrinsic fluorescence measurement and ANS binding. In the second stage, the acquired knowledge was used to study the inactivation pattern of these two enzymes in liquid and solid natural products, including fruit and vegetable juices or shrimps. The results revealed differences in the inactivation pattern of the enzymes in these substrates compared to the pure commercial enzymes, but the applicability of HPCD technology for the inactivation of enzymes in real substrates at industrial scale was also revealed. ; Spanish Government (MINECO) and the European Regional Development Fund (ERDF) for financial support of project CTQ2015-64396-R and A.E. Illera's contract. To Junta de Castilla y León and ERDF for financial support of project BU055U16 and O. Benito-Román's Post-doctoral contract.

Tomato juice, Lycopersicon esculentum cv. Canario, has been treated by high pressure carbon dioxide (HPCD) as non-thermal preservation treatment. The inactivation kinetics for pectinmethylesterase (PME) and polygalacturonase (PG) were determined at different pressures (8.5–20 MPa) and temperatures (35–55 °C). At the highest operating pressure and temperature essayed in this work, it was found that PME could be almost completely inactivated, whereas PG resulted to be more HPCD resistant at the working conditions. PME enzyme inactivation curves were properly described by a Weibull type model, while the fractional conversion model was the most appropriate for the PG with a sharp initial decrease in activity. On the contrary, high pressure processing (HPP) led to a nearly complete inactivation of PG while PME was very resistant at 600 MPa. It was also found that HPCD treatment led to a smaller particle size distribution of tomato juice. ; Spanish Government (MINECO) and the European Regional Development Fund (ERDF) for financial support of project CTQ2015-64396-R

Ponencia presentada en: 16th European Meeting on Supercritical Fluids, 25 a 28 de abril de 2017, Lisboa ; High pressure carbon dioxide (HPCD) treatment has been applied to orange juice as alternative non-thermal treatment. Kinetics inactivation for pectin methyl esterase has been determined at different operating conditions. PME residual activity was correlated succesfully to the two-fraction model. Some quality parameters such as colour, pH, calcium content, turbidity and particle size distribution (PSD) were also determined right after HPCD treatment. PSD shows that HPCD treatment results in a homogenization effect with a volume increase of small particles and a volume decrease of large particles regarding the non-treated orange juice. ; MINECO (CTQ2015-64396-R). R. Melgosa acknowledges MINECO for a grant (BES-2013-063937). ; Spanish Government through MINECO (CTQ2015-64396-R). R. Melgosa acknowledges MINECO for a grant (BES-2013-063937)

Ponencia presentada en: 16th European Meeting on Supercritical Fluids, 25 a 28 de abril de 2017, Lisboa ; The quality of cloudy apple juice seems to be better than the clarified juice due to the loss of phenolic compounds during processing. Enzymatic browning and cloud stability are the main problems in processing and storage of the juice. In this work, HPCD is proposed as an alternative to the traditional heat treatments that can degrade the quality of the juice. Polyphenol oxidase (PPO) and pectin methylesterase (PME) inactivation by HPCD were determined for both enzymes. The effect of stirring speed on PPO inactivation was studied; obtaining that at higher speed inactivation was also higher. Other quality parameters in the juice were also determined after HPCD treatment, such as particle size distribution, colour, turbidity and total phenolic compounds. ; (MINECO) and the European Regional Development Fund (ERDF) for financial support of project CTQ2015-64396-R and AEI's contract. R. Melgosa acknowledges MINECO for a grant (BES-2013-063937). ; Spanish Government (MINECO) and the European Regional Development Fund (ERDF) for financial support of project CTQ2015-64396-R and AEI's contract. R. Melgosa acknowledges MINECO for a grant (BES-2013-063937)

The production of monoacylglycerol rich in polyunsaturated fatty acids (PUFA) via enzymatic glycerolysis of sardine oil in a homogeneous system was evaluated. Reactions were conducted in two different tert-alcohols. Based on the phase equilibrium data, the amount of solvent added to create a homogeneous system has been calculated and optimized. The immobilized lipase used in this work was Lipozyme RM IM from Rhizomucor miehei, a water dependent lipase. The amount of water added as well as other reaction parameters were studied to evaluate the optimum conditions for monoacylglycerol obtencion. An initial reactant mole ratio glycerol to sardine oil 3:1, 12 wt% of water based on glycerol content and 10 wt% of lipase loading (based on weight of reactants), achieved a MAG yield of around 70%, with nearly 28 wt% PUFA, with low free fatty acid content (lower than 18 wt%). ; En este trabajo se ha estudiado la producción de monoacilglicéridos, ricos en ácidos grasos poliinsaturados (AGPI), mediante glicerolisis enzimática de aceite de sardina. La reacción se ha llevado a cabo en dos tert-alcoholes para conseguir de esta forma un medio homogéneo de reacción. La cantidad de disolvente añadida al medio de reacción se ha optimizado y calculado en base al equilibrio de fases de los componentes del sistema. La lipasa empleada como biocatalizador ha sido la enzima inmovilizada Lipozyme RM IM de Rhizomucor miehei, una lipasa dependiente de agua. Se ha estudiado el efecto de distintos parámetros cinéticos, así como de la cantidad de agua añadida al medio de reacción, en la producción de monoacilglicéridos. De los resultados obtenidos, se puede concluir que, para una relación molar inicial de reactantes glicerol:aceite de sardina de 3:1, un 12 % en peso de agua en base al glicerol y un 10 % en peso de lipasa, en base al peso de reactantes; se puede llegar a conseguir un rendimiento en monoacilglicéridos alrededor del 70 % en peso, con casi un 28 % en peso de AGPI y un bajo contenido en ácidos grasos libres (menor del 18 % en peso). ; Spanish Government through MINECO and the European Regional Development Fund (ERDF) for financial support to the project CTQ2012-39131-C02-01. They wish to thank Novozymes A/S for kindly supplying the enzymes. RM acknowledges MINECO for an FPI grant (reference BES-2013-063937).

Cloudy apple juice has been treated by high pressure carbon dioxide (HPCD) as non-thermal technology to inactive polyphenoloxidase and pectinmethylesterase in batch mode. Stirring speed (from 200 to 600 rpm) induced an increase in the enzyme inactivation rate while a triple cycle of pressurization/depressurization led to the same enzyme inactivation efficiency. Enzyme inactivation kinetics were determined at different temperatures (from 35 to 45 °C) and pressures (from 10 to 20 MPa). Data were described by the first order kinetic model and the Weibull model. For the first order kinetic model, decimal reduction time for HPCD treatment was found to be smaller than for mild heating, in the same temperature range. The same tendency was observed for the first decimal reduction time in the Weibull model. HPCD treatment resulted in a homogenization effect reflected in the shifting of the particle size distribution towards smaller diameters after treatment. HPCD treatment did not result in a change of water and oxalate soluble pectin content, total phenolic compounds and hidroxymethylfurfural content. ; Spanish Government (MINECO) and the European Regional Development Fund for financial support of project CTQ2015-64396-R and AEI's contract.