Articles de revista
http://hdl.handle.net/2117/6306
2024-03-29T13:17:20ZRheological behaviour, freezing curve, and density of coffee solutions at temperatures close to freezing
http://hdl.handle.net/2117/85280
Rheological behaviour, freezing curve, and density of coffee solutions at temperatures close to freezing
Hernández Yáñez, Eduard; Moreno, Fabian Leonardo; Raventós Santamaria, Mercè; Santamaría, N.; Acosta, J.; Pirachican, Oscar; Torres, L.; Ruiz Pardo, Yolanda
The physical properties of coffee solutions were determined for temperatures close to the freezing point. Rheological behaviour, freezing curve, density, and their relationship between coffee mass fraction and Brix degrees were determined for coffee mass fractions between 5 and 50% (wet basis) in the -6 to 20 degrees C temperature interval. Values of viscosity varied from 1.99 to 1037 mPa center dot s and values of density from 1000 to 1236 kg center dot m(-3). The freezing curve was generated using the undercooling method, giving values within freezing curves for food fluids. The results were used to generate mathematical models to predict viscosity, freezing point depression, and density as a function of coffee mass fraction and temperature.
2016-05-13T12:07:28ZHernández Yáñez, EduardMoreno, Fabian LeonardoRaventós Santamaria, MercèSantamaría, N.Acosta, J.Pirachican, OscarTorres, L.Ruiz Pardo, YolandaThe physical properties of coffee solutions were determined for temperatures close to the freezing point. Rheological behaviour, freezing curve, density, and their relationship between coffee mass fraction and Brix degrees were determined for coffee mass fractions between 5 and 50% (wet basis) in the -6 to 20 degrees C temperature interval. Values of viscosity varied from 1.99 to 1037 mPa center dot s and values of density from 1000 to 1236 kg center dot m(-3). The freezing curve was generated using the undercooling method, giving values within freezing curves for food fluids. The results were used to generate mathematical models to predict viscosity, freezing point depression, and density as a function of coffee mass fraction and temperature.Behaviour of falling-film freeze concentration of coffee extract
http://hdl.handle.net/2117/87043
Behaviour of falling-film freeze concentration of coffee extract
Hernández Yáñez, Eduard; Raventós Santamaria, Mercè; Moreno, Fabian Leonardo; Ruiz Pardo, Yolanda
The behaviour of falling-film freeze concentration of coffee extract was studied through determining the solute inclusion in the ice produced in a single-plate freeze concentrator. The effect of the initial coffee mass fraction of the extract, the average ice growth rate and the film velocity were studied. The coffee extract at four coffee mass fractions (0.05, 0.15, 0.25 and 0.35 w/w) was freeze concentrated at three different cooling temperatures (-10, 15 and 20 degrees C) and three flow rates (5 x 10(-5), 7.5 x 10(-5) and 10 x 10(-5) m(3) s(-1)). The solute inclusion in the ice and the effect of each parameter were determined. The coffee mass fraction, ice growth rate and film velocity affected the average distribution coefficient. The coffee mass fraction had the greatest effect on average distribution coefficient. The Chen model parameters to predict the average distribution coefficient and the concentration index were found. A logistical model was proposed to predict the concentration reached in successive stages, which tended to 35% at the studied intervals. The model showed an adjusted regression coefficient of 0.98 and the experimental values were within the 95% confidence intervals. The model can be used to predict the behaviour of falling film freeze concentration of coffee extract; this technique is an economic and simple alternative to conventional freeze concentration. (C) 2014 Elsevier Ltd. All rights reserved.
2016-05-13T11:44:35ZHernández Yáñez, EduardRaventós Santamaria, MercèMoreno, Fabian LeonardoRuiz Pardo, YolandaThe behaviour of falling-film freeze concentration of coffee extract was studied through determining the solute inclusion in the ice produced in a single-plate freeze concentrator. The effect of the initial coffee mass fraction of the extract, the average ice growth rate and the film velocity were studied. The coffee extract at four coffee mass fractions (0.05, 0.15, 0.25 and 0.35 w/w) was freeze concentrated at three different cooling temperatures (-10, 15 and 20 degrees C) and three flow rates (5 x 10(-5), 7.5 x 10(-5) and 10 x 10(-5) m(3) s(-1)). The solute inclusion in the ice and the effect of each parameter were determined. The coffee mass fraction, ice growth rate and film velocity affected the average distribution coefficient. The coffee mass fraction had the greatest effect on average distribution coefficient. The Chen model parameters to predict the average distribution coefficient and the concentration index were found. A logistical model was proposed to predict the concentration reached in successive stages, which tended to 35% at the studied intervals. The model showed an adjusted regression coefficient of 0.98 and the experimental values were within the 95% confidence intervals. The model can be used to predict the behaviour of falling film freeze concentration of coffee extract; this technique is an economic and simple alternative to conventional freeze concentration. (C) 2014 Elsevier Ltd. All rights reserved.Aloe vera as an alternative to traditional edible coatings used in freshcut fruits: A case of study with kiwifruit slices
http://hdl.handle.net/2117/28144
Aloe vera as an alternative to traditional edible coatings used in freshcut fruits: A case of study with kiwifruit slices
Benítez, Sheila; Achaerandio Puente, María Isabel; Pujolà Cunill, Montserrat; Sepulcre Sánchez, Francesc
In this work, a comparative study between Aloe vera, chitosan (formulated with acetic (-AC) or citric acid
(-C)) and sodium alginate edible coatings was conducted to evaluate the effects on the quality and shelf
life of minimally processed kiwifrui
2015-06-02T12:26:27ZBenítez, SheilaAchaerandio Puente, María IsabelPujolà Cunill, MontserratSepulcre Sánchez, FrancescIn this work, a comparative study between Aloe vera, chitosan (formulated with acetic (-AC) or citric acid
(-C)) and sodium alginate edible coatings was conducted to evaluate the effects on the quality and shelf
life of minimally processed kiwifruiEffect of ultrasound on quality of fresh-cut potatoes during refrigerated storage
http://hdl.handle.net/2117/28009
Effect of ultrasound on quality of fresh-cut potatoes during refrigerated storage
Alvares Amaral, Rivia; Pujolà Cunill, Montserrat; Benedetti, Benedito Carlo; Achaerandio Puente, María Isabel; Bachelli, Mara Lígia
In the industry of fresh-cut potatoes, controlling
browning and delaying the loss of texture are important
factors to obtain a high-quality product. The use of
ultrasound can avoid these undesirable phenomena due to
its power to inactivate enzymes by breaking the cell
membranes because the cavitation activities and formation
of free radicals. For this purpose, this study aimed to
evaluate the effect of different times of contact of ultrasound
(40 kHz, 200 W for 1, 5 and 10 min) on quality
parameters (browning, firmness and total starch content) of
fresh-cut potatoes during the product shelf life (12 days;
3 ± 1 C) and cell microstructure. Ultrasound was applied
to asterix strips (rectangular, 10 9 10 mm). Results
showed that the time of sonication and storage affected
significantly to the pH of the samples. Treated samples for
5 and 10 min presented the lower values of pH. No color
degradation was noticed immediately after the application
of treatments (Hue and Chroma). However, a slight
decrease in Hue angle of fresh-cut potatoes during storage
has been observed. The use of 5 min of sonication inhibited
50 % of polyphenol oxidase (PPO) activity for the first
4 days of storage. Samples submitted to 5 and 10 min of
ultrasound also had maintained more uniform firmness after frying during storage time. However, the longest time
of immersion (10 min) caused damage in the potato cells.
2015-05-22T12:03:14ZAlvares Amaral, RiviaPujolà Cunill, MontserratBenedetti, Benedito CarloAchaerandio Puente, María IsabelBachelli, Mara LígiaIn the industry of fresh-cut potatoes, controlling
browning and delaying the loss of texture are important
factors to obtain a high-quality product. The use of
ultrasound can avoid these undesirable phenomena due to
its power to inactivate enzymes by breaking the cell
membranes because the cavitation activities and formation
of free radicals. For this purpose, this study aimed to
evaluate the effect of different times of contact of ultrasound
(40 kHz, 200 W for 1, 5 and 10 min) on quality
parameters (browning, firmness and total starch content) of
fresh-cut potatoes during the product shelf life (12 days;
3 ± 1 C) and cell microstructure. Ultrasound was applied
to asterix strips (rectangular, 10 9 10 mm). Results
showed that the time of sonication and storage affected
significantly to the pH of the samples. Treated samples for
5 and 10 min presented the lower values of pH. No color
degradation was noticed immediately after the application
of treatments (Hue and Chroma). However, a slight
decrease in Hue angle of fresh-cut potatoes during storage
has been observed. The use of 5 min of sonication inhibited
50 % of polyphenol oxidase (PPO) activity for the first
4 days of storage. Samples submitted to 5 and 10 min of
ultrasound also had maintained more uniform firmness after frying during storage time. However, the longest time
of immersion (10 min) caused damage in the potato cells.Multi-plate freeze concentration: Recovery of solutes occluded in the ice and determination of thawing time
http://hdl.handle.net/2117/27968
Multi-plate freeze concentration: Recovery of solutes occluded in the ice and determination of thawing time
Gulfo, Rafael; Auleda, Josep Maria; Moreno Moreno, Fabián Leonardo; Ruiz Pardo, Ruth Yolanda; Hernández Yáñez, Eduard; Raventós Santamaria, Mercè
The retention of solutes in the ice formed in a falling-film freeze concentrator (multi-plate freeze-concentrator) was analysed. Solutions of fructose, glucose and sucrose and a simulated juice with initial concentrations of 5, 10, 15 and 20 degrees Brix were freeze concentrated. The ice produced in the four steps of the process retains solutes at levels of 1.0-8.8 degrees Brix (expressed as solute mass fraction in the ice). The recovery of these solutes during thawing can increase overall system efficiency. All thawing steps were carried out dividing the sample in 10 fractions at 20 degrees C. The first thawed fractions showed solute concentrations that were 1.9-3.3 times higher than the mean solute mass fraction in the ice, while the last fractions of ice showed very low levels of retained solutes, less than 0.2 times the mean solute mass fraction in the ice. It was found that fractionated thawing can recover most of the solute content in the ice. The procedure presented in the present study allows the determination of the solute concentration achieved in the various thawing fractions and predicts the thawing time required for a given form factor, melting temperature and initial solute mass fraction in the ice.
2015-05-19T14:14:47ZGulfo, RafaelAuleda, Josep MariaMoreno Moreno, Fabián LeonardoRuiz Pardo, Ruth YolandaHernández Yáñez, EduardRaventós Santamaria, MercèThe retention of solutes in the ice formed in a falling-film freeze concentrator (multi-plate freeze-concentrator) was analysed. Solutions of fructose, glucose and sucrose and a simulated juice with initial concentrations of 5, 10, 15 and 20 degrees Brix were freeze concentrated. The ice produced in the four steps of the process retains solutes at levels of 1.0-8.8 degrees Brix (expressed as solute mass fraction in the ice). The recovery of these solutes during thawing can increase overall system efficiency. All thawing steps were carried out dividing the sample in 10 fractions at 20 degrees C. The first thawed fractions showed solute concentrations that were 1.9-3.3 times higher than the mean solute mass fraction in the ice, while the last fractions of ice showed very low levels of retained solutes, less than 0.2 times the mean solute mass fraction in the ice. It was found that fractionated thawing can recover most of the solute content in the ice. The procedure presented in the present study allows the determination of the solute concentration achieved in the various thawing fractions and predicts the thawing time required for a given form factor, melting temperature and initial solute mass fraction in the ice.Calculation process for the recovery of solutes retained in the ice in a multi-plate freeze concentrator: Time and concentration
http://hdl.handle.net/2117/27617
Calculation process for the recovery of solutes retained in the ice in a multi-plate freeze concentrator: Time and concentration
Gulfo, Rafael; Auleda Amorós, Josep Maria; Raventós Santamaria, Mercè; Hernández Yáñez, Eduard
Fractionated thawing was studied as a method to recover solutes incorporated in the ice obtained in a cryoconcentrator. Thawing times and solute concentration in the ice were determined at several thawing temperatures.; Ice sheets used for the thawing studies were obtained by cryoconcentrated solutions of sugars and simulated juice at initial concentrations of 5 to 20 degrees Brix. The ice sheets produced contained levels of solutes between 1.0 and 9.0 degrees Brix.; Fractionated thawing was performed at temperatures of 20 to 30 degrees C while maintaining geometrical similarity for the test samples. By fractionated thawing more than 60% of the solutes retained in the ice was recovered in 34%, of the total thawing time.; The procedure presented allows the determination of the solute concentration achieved in the various thawing fractions and predicts the thawing time required for a given form factor, melting temperature and the solute mass fraction in the ice.; Industrial relevance: The freeze concentration is a technology that allows eliminating water from liquid foods at temperatures below the water's freezing point, which allows obtaining products of better quality. Fractionated thawing was studied as a method to recover solutes incorporated in the ice, improving the global efficiency of a freeze concentration process by optimal recovery of the solutes retained in the ice. It also provides estimations of the energy used for thawing. This work continues the research in falling film freeze concentration technology which we have submitted and published in this journal. This work contributes to increase the global process efficiency.
2015-04-28T10:09:33ZGulfo, RafaelAuleda Amorós, Josep MariaRaventós Santamaria, MercèHernández Yáñez, EduardFractionated thawing was studied as a method to recover solutes incorporated in the ice obtained in a cryoconcentrator. Thawing times and solute concentration in the ice were determined at several thawing temperatures.; Ice sheets used for the thawing studies were obtained by cryoconcentrated solutions of sugars and simulated juice at initial concentrations of 5 to 20 degrees Brix. The ice sheets produced contained levels of solutes between 1.0 and 9.0 degrees Brix.; Fractionated thawing was performed at temperatures of 20 to 30 degrees C while maintaining geometrical similarity for the test samples. By fractionated thawing more than 60% of the solutes retained in the ice was recovered in 34%, of the total thawing time.; The procedure presented allows the determination of the solute concentration achieved in the various thawing fractions and predicts the thawing time required for a given form factor, melting temperature and the solute mass fraction in the ice.; Industrial relevance: The freeze concentration is a technology that allows eliminating water from liquid foods at temperatures below the water's freezing point, which allows obtaining products of better quality. Fractionated thawing was studied as a method to recover solutes incorporated in the ice, improving the global efficiency of a freeze concentration process by optimal recovery of the solutes retained in the ice. It also provides estimations of the energy used for thawing. This work continues the research in falling film freeze concentration technology which we have submitted and published in this journal. This work contributes to increase the global process efficiency.Eficiencia en el proceso de tratamiento de la fracción orgánica de los residuos municipales (FORM). Estudio del caso Ecoparc 2 de Montcada i Reixach, Barcelona
http://hdl.handle.net/2117/26483
Eficiencia en el proceso de tratamiento de la fracción orgánica de los residuos municipales (FORM). Estudio del caso Ecoparc 2 de Montcada i Reixach, Barcelona
Mena, Manuel; Bonmatí Blasi, August; Pujolà Cunill, Montserrat; Tarraga, Josep; Comas Angelet, Jordi
La fracción orgánica de los residuos
municipales (FORM) comprende residuos
procedentes de hogares particulares
y residuos similares de otros establecimientos
que los municipios
recogen junto con la basura doméstica.
Estos residuos constituyen entre el 30 y
50% de la masa total de los residuos sólidos
municipales
2015-02-24T12:02:56ZMena, ManuelBonmatí Blasi, AugustPujolà Cunill, MontserratTarraga, JosepComas Angelet, JordiLa fracción orgánica de los residuos
municipales (FORM) comprende residuos
procedentes de hogares particulares
y residuos similares de otros establecimientos
que los municipios
recogen junto con la basura doméstica.
Estos residuos constituyen entre el 30 y
50% de la masa total de los residuos sólidos
municipalesA process to concentrate coffee extract by the integration of falling film and block freeze-concentration
http://hdl.handle.net/2117/21253
A process to concentrate coffee extract by the integration of falling film and block freeze-concentration
Moreno, Fabián Leonardo; Hernández Yáñez, Eduard; Raventós Santamaria, Mercè; Robles, C.; Ruíz, Y.
2014-01-16T14:27:50ZMoreno, Fabián LeonardoHernández Yáñez, EduardRaventós Santamaria, MercèRobles, C.Ruíz, Y.Estimation of the freezing point of concentrated fruit juices for application in freeze concentration
http://hdl.handle.net/2117/12486
Estimation of the freezing point of concentrated fruit juices for application in freeze concentration
Auleda Amorós, Josep Maria; Raventós Santamaria, Mercè; Sánchez Machado, José; Hernández Yáñez, Eduard
In freeze concentration operations the fluids remain at temperatures below 0 °C. For a good study of this concentration operation is very important to know the values of freezing point. The aim of this work was to establish a model that predicts the freezing point of fruit juices at various concentrations within the range of interest for freeze concentration (10–40 °Brix). The model proposed relates the freezing point of a juice with the concentrations of main sugars present in the juice: sucrose, glucose and fructose. The freezing point of apple juice, pear juice and peach juice was determined experimentally at various concentrations, and experimental results were well correlated with model calculations.
2011-05-05T16:36:14ZAuleda Amorós, Josep MariaRaventós Santamaria, MercèSánchez Machado, JoséHernández Yáñez, EduardIn freeze concentration operations the fluids remain at temperatures below 0 °C. For a good study of this concentration operation is very important to know the values of freezing point. The aim of this work was to establish a model that predicts the freezing point of fruit juices at various concentrations within the range of interest for freeze concentration (10–40 °Brix). The model proposed relates the freezing point of a juice with the concentrations of main sugars present in the juice: sucrose, glucose and fructose. The freezing point of apple juice, pear juice and peach juice was determined experimentally at various concentrations, and experimental results were well correlated with model calculations.A new method to obtain information about the pore size distribution in microporous polymeric membranes
http://hdl.handle.net/2117/11248
A new method to obtain information about the pore size distribution in microporous polymeric membranes
Llorens, Joan; Marco, P.; Sabaté Reboll, José; Pujolà Cunill, Montserrat; Felip, I; Plumed, E
Transport measurements of selected fluids through porous membranes provide information on precise statistical
moments of the membrane pore-size distribution (PSD). It is assumed that membrane porosity, ~T,is
distributed on different pores sizes which are statistically distributed. Mean pore sizes are determined on the
basis of statistical moment analysis. This paper focuses in the special case of determining PSD in microfiltration
(MF) membranes from a collectíon of experíments that include porosity and bubble point determinations
and liquid and gas permeations.
2011-02-01T15:13:00ZLlorens, JoanMarco, P.Sabaté Reboll, JoséPujolà Cunill, MontserratFelip, IPlumed, ETransport measurements of selected fluids through porous membranes provide information on precise statistical
moments of the membrane pore-size distribution (PSD). It is assumed that membrane porosity, ~T,is
distributed on different pores sizes which are statistically distributed. Mean pore sizes are determined on the
basis of statistical moment analysis. This paper focuses in the special case of determining PSD in microfiltration
(MF) membranes from a collectíon of experíments that include porosity and bubble point determinations
and liquid and gas permeations.