Alejandra Torres

Alejandra Torres
University of Santiago Chile | USACH · Departamento de Ciencia y Tecnología de los Alimentos (DECYTAL)

PhD

About

49
Publications
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1,258
Citations

Publications

Publications (49)
Article
Full-text available
Expanded polystyrene will account for 5.3% of total global plastic production in 2021 and is widely used for food packaging due to its excellent moisture resistance and thermal insulation. However, some of these packages are often used only once before being discarded, generating large amounts of environmentally harmful plastic waste. A very attrac...
Article
Full-text available
It is known that ethylene plays an important role in the quality characteristics of fruits, especially in storage. To avoid the deterioration of fruits caused by ethylene, titanium dioxide (TiO2) has been used due to its photocatalytic capacity. The aim of this study was to develop films based on two types of biopolymers, Mater-Bi (MB) and poly-lac...
Article
Full-text available
In the last decade, among the emerging technologies in the area of bioplastics, additive manufacturing (AM), commonly referred to as 3D printing, stands out. This technology has gained great interest in the development of new products, mainly due to its capability to easily produce customized and low-cost plastic products. This work aims to evaluat...
Preprint
Full-text available
In this work, a colorimetric indicator based on gold nanoparticles (AuNP) and a biodegradable and eco-friendly polymer (sodium alginate, Alg.), has been developed, for the real-time detection of fish spoilage products. AuNP and colorimetric indicator were characterized by: UV-Vis, FTIR spectroscopies, TGA, DSC, XRD, TEM, and colorimetry. The UV-Vis...
Article
Compounds derived from essential oils have been used in active packaging, but their volatility and degradability negatively affect stability and leads to high release rates. The present study aimed to develop PLA bio- nanocomposite foams loaded with carvacrol cocrystal by supercritical CO2 and its release into a food simulant for control release in...
Article
Full-text available
Ethylene is a phytohormone that is responsible of fruit and vegetable ripening. TiO2 has been studied as a possible solution to slowing down unwanted ripening processes, due to its photocatalytic capacity which enables it to remove ethylene. Thus, the objective of this study was to develop nanocomposites based on two types of eco-friendly materials...
Chapter
Conocer los distintos conceptos que vemos diariamente en los envases de los productos que consumimos es de suma importancia para tomar decisiones informadas con conciencia medioambiental. Hoy en día, existe una elevada preocupación relativa a la necesidad de reducir el consumo de plásticos de un solo uso provenientes del petróleo, que no se degrada...
Article
Full-text available
Among the most promising synthetic biopolymers to replace conventional plastics in numerous applications is MaterBi® (MB), a commercial biodegradable polymer based on modified starch and synthetic polymers. Actually, MB has important commercial applications as it shows interesting mechanical properties, thermal stability, processability and biodegr...
Article
Full-text available
This article proposes a foaming method using supercritical carbon dioxide (scCO2) to obtain compostable bionanocomposite foams based on PLA and organoclay (C30B) where this bionanocomposite was fabricated by a previous hot melt extrusion step. Neat PLA films and PLA/C30B films (1, 2, and 3 wt.%) were obtained by using a melt extrusion process follo...
Article
Ionic liquids have attracted widespread attention due to their low melting points, low vapor pressure, and non-flammability. However, their application at industrial scale is uncommon due to high costs and low recovering efficiency of the ionic liquids within the process. To reduce the costs and environmental effects of ionic liquids, this study pr...
Article
Full-text available
Microcellular nanocomposite foams functionalized with cinnamaldehyde (Ci) were obtained through two-step supercritical foaming and impregnation processing. PLA nanocomposite foams with different C30B concentrations (1, 2, and 3 wt.%) were obtained by foaming with scCO2 at 25 MPa and 135 °C and impregnated with Ci at 12 MPa and 40 °C. The effect of...
Article
Full-text available
Climate change is leading us to search for new materials that allow a more sustainable environmental situation in the long term. Poly(lactic acid) (PLA) has been proposed as a substitute for traditional plastics due to its high biodegradability. Various components have been added to improve their mechanical, thermal, and barrier properties. The mod...
Article
Full-text available
Bionanocomposites based on Polylactide (PLA) and Polyhydroxybutyrate (PHB) blends were successfully obtained through a combined extrusion and impregnation process using supercritical CO2 (scCO2). Graphene oxide (GO) and cinnamaldehyde (Ci) were incorporated into the blends as nano-reinforcement and an active compound, respectively, separately, and...
Article
Poly (lactic acid)/lignin nanocomposites (PLA/Lig-Np) containing cinnamaldehyde (Ci) were obtained by a combination of melt extrusion and supercritical impregnation process. In this work, Ci impregnation tests were carried out in a high-pressure cell at 40 °C for 3 h using 12 MPa and 1 MPa min⁻¹ of depressurization rate, obtaining impregnation yiel...
Article
Supercritical fluid extraction, using a hollow fiber membrane contactor (HFMC), is an attractive and feasible process for the food industry due to the controlled contact between the phases and the safety that the membrane processes allow. This research aimed at the extraction of vanillin from an aqueous solution with supercritical carbon dioxide (S...
Article
Nanocomposite films based on PLA with 1.0% w/w silica nanoparticles (NP) and surface-functionalized silica nanoparticles with lactic acid (NP-LA), respectively, were obtained by extrusion process. Subsequently, cinnamaldehyde (ci) was incorporated through supercritical impregnation in the films at a pressure of 12 MPa, 40 °C temperature and 1.0 MPa...
Article
Bionanocomposite films based on poly (lactic acid) (PLA) reinforced with nanoclay C30B (5.0% w/w) were impregnated with thymol (Thy) and cinnamaldehyde (Ci), incorporated through supercritical impregnation using carbon dioxide (scCO2). These assays were implemented at a pressure of 12 MPa, a constant temperature equal to 40 °C and a despressurizati...
Article
Full-text available
This work aims at the separation of n-butanol from aqueous solutions by means of pervaporation using membranes based on gelled ionic liquids(IL). These membranes were mechanically stabilized with a double silicone coating using two polydimethylsiloxane (PDMS) films. The first step of the membrane preparation considered the formation of a gelled ion...
Article
The scCO2-assisted impregnation process has arisen as an effective method to impregnate solid materials. Its multiple advantages include high diffusion, it allows to obtain free-solvent materials and to operate under low temperatures, which permits to process thermolabile solutes. These characteristics have allowed its application at industrial sca...
Article
In this work, the scCO2-assisted incorporation of thymol in LDPE nanocomposites with different concentrations of an organo-modified montmorillonite (OM-MMT) nanoclay is proposed as the preparation method of an antimicrobial food packaging system. Mass transfer characterization of thymol, for both incorporation and release processes, as a function o...
Article
Full-text available
The main objective of this work was to study the release of cinnamaldehyde (CIN) from electrospun poly lactic acid (e-PLA) mats obtained through two techniques: (i) direct incorporation of active compound during the electrospinning process (e-PLA-CIN); and (ii) supercritical carbon dioxide (scCO2) impregnation of CIN within electrospun PLA mats (e-...
Article
This work describes the procedures to obtain poly(lactic acid) (PLA) films containing natural nanofibers as well as to impregnate this material with an antimicrobial agent to be used in active food packaging. Poly(vinyl alcohol) (PV) nanofibers containing cellulose nanocrystals (CNC) were successfully prepared by electrospinning, these electrospun...
Article
LDPE nanocomposites with different concentrations of Cloisite 20A (2.5 and 5.0% (w/w)) were impregnated with thymol using supercritical carbon dioxide, with the aim of obtaining an antimicrobial packaging. Impregnation assays were carried out for 1 h at 313 K and employing two depressurization rates (10.0 and 1.0 MPa min-1) after the impregnation p...
Article
Supercritical impregnation was used to incorporate a natural compound with antibacterial activity into biopolymer-based films to develop active food packaging materials. Impregnation tests were carried out under two pressure conditions (9 and 12 MPa), and three depressurization rates (0.1, 1 and 10 MPa min− 1) in a high-pressure cell at a constant...
Article
This study deals with the improvement of the recovery performance in the solvent extraction of Cu(II) using the ionic liquid [bmim][Tf2N] and the β-diketone 1,1,1-trifluoro-2,4-pentanedione (TFA) as extractant and its stripping with supercritical carbon dioxide. This work describes a modified procedure, which shows better L-L extraction percentages...
Article
In this study, antioxidant food-packaging materials were developed by the incorporation of merkén, an aboriginal Chilean spice, into a biodegradable polymer matrix, poly(lactic acid). Antioxidant activity assays and the phenolic content of merkén showed interesting results compared to other condiments, such as oregano and parsley. Active materials...
Article
This study deals on the supercritical impregnation of thymol in polylactic acid (PLA) in order to obtain biodegradable antimicrobial films by means of a procedure, which is in agreement with the principles of green chemistry, reducing the environmental impact of products and of its preparation processes. The impregnation tests were carried out in a...
Chapter
Nowadays, there has been a change in the paradigm of food packaging. It is expected that food packaging will be able to enhance food quality, shelf life, and food safety. In this sense, active packaging (AP) has arisen as an alternative to provide food packaging protection.Within the different AP systems, great attention has been focused on antimic...
Article
Full-text available
The specific migration of [2,2-bis(4 hydroxyphenyl) propane] from polycarbonate films into ethanol 50 % food simulant was studied. A phenomenological model based on a resistances-in-series system was resolved through the regula falsi algorithm. The diffusion–convection model was not able to describe the BPA concentration change as a function of tim...
Article
Full-text available
Active films based on nanocomposites from linear low-density polyethylene (LLDPE) were prepared by melting extrusion incorporating Cloisite 30B (5 wt.%) and thymol as active compound at two different concentrations: 2 and 4 wt.%. A complete thermal, structural characterization and antioxidant capacity of all blends was carried out. Extraction proce...
Article
Nanocomposites based on biopolymers have been recognized as potential materials for the development of new eco-friendly food packaging. In addition, if these materials incorporate active substances in their structure, the potential applications are much higher. So, this work was oriented to develop nanocomposites with antimicrobial activity based o...
Article
Full-text available
Sulfites $$({\hbox{ SO }}_{3}^{2-})$$ or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a diffic...
Article
The coupled operation of osmotic distillation (OD) and vacuum membrane distillation (VMD) for concentration of fruit juices and simultaneous recovery of their aroma compounds was studied. The simulated aqueous fruit juices containing four common aroma compounds were concentrated using osmotic distillation where the feed solution was in contact with...
Article
The specific migration of Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (I-1076) from three-layer low-density polyethylene plastic films into a fatty food simulant was studied. The film samples, having a symmetrical structure with a contaminated core layer and virgin outer layers, were developed with a known amount of a selected migran...
Article
Unsteady fluid mechanics and natural convective heat transfer during pasteurization and sterilization for aqueous (CMC solution) and fatty (soybean oil) liquid foods were numerically predicted by means of noncommercial computational program developed in this work. This software is based on the finite volume method and the food simulants are assumed...
Article
Full-text available
The mass transfer process of additives from plastic packaging to food is of great importance and interest because of the possible harmful effects on the human health. In this work the effect of different food simulants (EtOH 10–50%) and temperatures (28–60°C) on the specific migration of Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (I...
Article
Full-text available
This work presents a theoretical and experimental study on the specific migration process, describing the mass transfer of a model migrant Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (I-1076), an antioxidant commonly used in the polyolefins processing. Film samples (LDPE), with initial concentration of Irganox between 1000 and 6000 (m...
Article
Full-text available
This work focuses on the modeling of solvent-extraction processes carried out in a hollow-fiber membrane contactor (HFC). A resistance-in-series model has been adapted to deal with a conventional solvent or a nonconventional solvent in subcritical conditions. Two kinds of applications have been chosen to test its validity: extraction of ethanol or...

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