International Journal of Biological Macromolecules, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
International Journal of Biological Macromolecules, 2020
The development of active bilayer systems is a novel strategy for the application of active packa... more The development of active bilayer systems is a novel strategy for the application of active packaging to maintain or prolong the shelf-life of food products. A bilayer system was assembled in situ into a thermocompression unit through a two-step procedure. One of the layers was obtained by a casting process and consisted of a chitosanbased nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence of GA was designed by a thermocompression process which can be industrially scaled representing a technological progress. The formation of the bilayers was corroborated by SEM allowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of foods.
International Journal of Biological Macromolecules, 2020
Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus ... more Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus fastigiatus, is a promising compound for potential applications in the field of pharmaceuticals and food packaging. To overcome the low solubility of cabreuva EO and to protect it, a two-step process, emulsion formation compound by chitosan, SDS, and PVA, and subsequent ionic crosslinking with sodium citrate, was proposed. The formulation containing 0.75% of chitosan and 1% of SDS proved to be the most stable. An alternative to produce nanostructures and encapsulate the EO is the fiber formation through the electrospinning method. The system composed by a PVA solution assembled with crosslinked emulsions modified the viscosity, influencing the morphology of the obtained nanofibers. The advantage of the electrospun nanofibers was their ability to be an effective carrier of the cabreuva EO and the capacity of controlling the compound release that proved an effective activity against broad spectra of microorganisms (Candida albicans, E. coli, S. aureus, and S. epidermidis). The Gallagher-Corrigan model, used to fit the release profiles of matrices in contact with increasing ethanol proportion from 25:75 to 50:50 showed higher Kb in relation to k suggesting that the polymer swelling played an increasingly prominent role in the EO delivery. The developed nanostructures would be materials with potential applications in the biomedical field.
Objective: To make evaluation of quality of Argentinean sunflower oil used in high-moisture food ... more Objective: To make evaluation of quality of Argentinean sunflower oil used in high-moisture food frying through parameters indicators of oil deterioration. Methods: The results were obtained after studying the effect of temperature-time and the type of food subjected to frying through Total Polar Compounds (TPCs) determination. The type of food selected was breaded food and potato chips. From calorimetric analysis (DSC) of frying oil was obtained crystallization temperature and the crystallization enthalpy. Also was determining fatty acid composition of the frying oil by gas chromatography. Findings: It was observed during the oil heating test at various times, that the TPC content increased over time. The highest the temperatures were, the most distinctive the rises were. During the frying of breaded food and potato chips the deterioration of the oil was accelerated, observing the greatest deterioration after the breaded frying process. The thermo grams obtained by DSC showed a well-defined crystallization peak that when heating treatment times were increased, it reflected in lower temperatures and a decrease in enthalpy. A high correlation was found between the concentration of total polar compounds, and the parameters obtained from thermo grams and the concentration of palmitic and linoleic acids. Novelty/Improvement: The results obtained provide useful information for food quality control in order to avoid variations of the sensory and nutritional characteristics of sunflower oil used in high-moisture food frying.
Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus ... more Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus fastigiatus, is a promising compound for potential applications in the field of pharmaceuticals and food packaging. To overcome the low solubility of cabreuva EO and to protect it, a two-step process, emulsion formation compound by chitosan, SDS, and PVA, and subsequent ionic crosslinking with sodium citrate, was proposed. The formulation containing 0.75% of chitosan and 1% of SDS proved to be the most stable. An alternative to produce nanostructures and encapsulate the EO is the fiber formation through the electrospinning method. The system composed of a PVA solution assembled with crosslinked emulsions modified the viscosity, influencing the morphology of the obtained nanofibers. The advantage of the electrospun nanofibers was their ability to be an effective carrier of the cabreuva EO and the capacity of controlling the compound release which proved an effective activity against broad spectra of microorganisms (Candida albicans, E. coli, S. aureus, and S. epidermidis). The Gallagher-Corrigan model, used to fit the release profiles of matrices in contact with increasing ethanol proportion from 25:75 to 50:50 showed higher Kb in relation to k suggesting that the polymer swelling played an increasingly prominent role in the EO delivery. The developed nanostructures would be materials with potential applications in the biomedical field.
The development of active bilayer systems is a novel strategy for the application of active packa... more The development of active bilayer systems is a novel strategy for the application of active packaging to maintain or prolong the shelf‐life of food products. A bilayer system was assembled in situ into a thermocompression unit through a two-step procedure. One of the layers was obtained by a casting process and consisted of a chitosan-based
nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence
of GA was designed by a thermocompression process that can be industrially scaled representing technological progress. The formation of the bilayers was corroborated by SEMallowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of food.
Advances in Materials Science and Engineering, 2018
The incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used a... more The incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used as a strategy to obtain nanocomposite active films with different both chitosan : tripolyphosphate (CH : TPP) and nanoparticles:chitosan (N : CH) ratios. The thermal analysis carried out by modulated differential scanning calorimetry (MDSC) allowed observing the shift of an endothermic event towards higher temperatures with a greater N : CH ratio. Analyzing ATR-FTIR spectra through principal component analysis (PCA) can be inferred that the incorporation of the nanoparticles produced a discrimination of the samples into clusters when the region 1400–1700 cm−1 was considered. The decrease in crystalline size with the inclusion of nanoparticles (NA and NB) proved the existence of interactions among CH, TPP, and GA, resulting in a more amorphous structure. The positron annihilation lifetime spectroscopy (PALS) technique was adequate to correlate the glass transition temperatures (Tg) obtaine...
Chitosan (CS) films containing visible light absorbing TiO 2 nanoparticles modified with tungstop... more Chitosan (CS) films containing visible light absorbing TiO 2 nanoparticles modified with tungstophosphoric acid (TPA-TiO 2 ) at different TPA-TiO 2 :CS ratios (10%, 20%, 30% and 40% (w/w) called CS/TPA-TiO 2 -10, CS/TPA-TiO 2 -20, CS/TPA-TiO 2 -30, and CS/TPA-TiO 2 -40 respectively) were prepared. Films were characterized by DRS, SEM-EDS, XRD, ATR-FT-IR, and contact angle (CA). Materials were evaluated in malachite green (MG) photobleaching solid-gas interface reactions upon different wavelengths. SEM-EDS micrographs showed that TPA-TiO 2 nanoparticles were well dispersed through the CS film. According to ATR-FT-IR results, the interactions between TPA-TiO 2 nanoparticles and the CS functional groups were weak. Regarding the MG photobleaching reactions, CS/TPA-TiO 2 -30 film showed the highest activity upon UV-A + visible irradiation, which was even higher than that of chitosan films containing the same amount of Evonik P-25 (CS/P25-30). It was also observed by DRS that the main absorption band of malachite green underwent a hypsochromic shifting caused by oxidative reactions of N-demethylation. On the other hand, at wavelengths higher than 450 nm (Vis-1), CS/TPA-TiO 2 -30 films showed a marked dye photobleaching. Finally, upon irradiation at wavelengths above 590 nm (Vis-2), a slight color fading was observed. These results revealed that CS/TPA-TiO 2 -30 films were efficient in the photobleaching of malachite green in solid-gas interfaces through an oxidative path by photocatalytic and photosensitized routes. CS/TPA-TiO 2 -30 films showed high stability and MG photobleaching capacity after 5 reuse cycles.
This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (... more This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as and a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of interaction polymer-polymer at molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of
This work was focused on assessing the influence of the glycerol in chitosan matrices, analyzing ... more This work was focused on assessing the influence of the glycerol in chitosan matrices, analyzing the changes produced in the molecular mobility, mechanical, thermal, barrier and structural properties. The addition of glycerol in the matrix decreased the stress values, increasing the elasticity and water vapor permeability of the films, with a marked decrease in glass transition temperature; Detailed analyses of Fourier Transform IR Spectroscopy spectra supported the observed changes, especially in the spectral windows 1700-1500 cm −1 revealing the modifications at molecular level caused by hydrogen bond interactions between chitosan and water in the presence of glycerol. Positron annihilation spectroscopic (PALS) measurements allowed determining the free volume assuming spherical holes as well as monitoring the structural changes in chitosan films caused by the addition of both, glycerol and water molecules. It was possible to infer that for unplasticized matrices, a sustained increase of the radius between 0.06 and 0.2 of X water was observed, followed by a plateau up to 0.35. In the other case, with the addition of glycerol, there were two plateaus, the first between 0.25 and 0.37 of X water , and the second from 0.41 to 0.47. For higher glycerol concentrations, the plasticizer would be mainly bounded to the chitosan pack more efficiently and the water present in the system would be predominantly free in the matrix causing its swelling. Findings on molecular mobility contributed to the understanding of the role of water and glycerol in the structural arrangement and its influence on film properties.
Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic... more Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic acid delivery. In this sense, these nanostructures could be employed in different fields such as food, packaging, and pharmaceutical areas. The design parameters of chitosan-based nanoparticles functionalized with gallic acid (GA) were optimized through RSM by means of the analysis of zeta potential (ZP) and percentage encapsulation efficiency (PEE). The nanoparticles were prepared by ionotropic gelation using tripolyphosphate (TPP), at different combinations of chitosan (CH) concentration, CH:TPP ratio and GA. Global desirability methodology allowed finding the optimum formulation that included CH 0.76% (w/w), CH:TPP ratio of 5 and 37 mg GA /g CH leading to ZP of +50 mV and 82% of PEE. Analysis through QuickScan and turbidity demonstrated that the most stable nanoparticle suspensions were achieved combining concentrations of chitosan ranging between 0.5 and 0.75% with CH:TPP ratios higher than 3. These suspensions had high stability confirmed by means ZP and transmittance values which were higher than +25 mV and 0.21 on average, respectively, as well as nanoparticle diameters of about 140 nm. FTIR revealed the occurrence of both hydrogen bond and ionic interactions of CH-TPP which allowed the encapsulation and the improvement of the stability of the active agent.
The goal of this work was to investigate the physicochemical properties of methylcellulose (MC) b... more The goal of this work was to investigate the physicochemical properties of methylcellulose (MC) based films as stabilizers of two strains of lactobacilli: Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 and Lactobacillus plantarum CIDCA 83114. The incorporation of 3% w/v fructo-oligosaccharides (FOS) into the MC film formulation improved the viability of L. delbrueckii subsp. bulgaricus CIDCA 333 after film preparation. L. plantarum CIDCA 83114 was intrinsically more resistant as no viability loss was observed upon preparation of the films in the absence of FOS. Scanning electronic microscopy images also showed a good incorporation of microorganisms without affecting the homogeneity of the films. FTIR spectroscopy provided structural information about the bacteria-loaded films. Water sorption isotherms showed an impervious behavior at low a w but on exceeding 0.7 of a w the film started to dissolve and form syrup, causing a drastic drop of bacterial viability (log N/N 0 ≤ −5). Dynamic mechanical analysis (DMA) demonstrated that the incorporation of microorganisms into the MC films had no effect on vitreous transition temperatures. FOS incorporated into the MC films had a plasticizing effect. Microorganism-loaded films were stored at relative humidities (RH) ranging from 11 to 75%. Both strains could be stored at 11% RH for 90 days. At 33 and 44% RH L. delbrueckii subsp. bulgaricus CIDCA 333 could be stored up to 15 days and L. plantarum CIDCA 83114 up to 45 days. At 75% RH only L. plantarum CIDCA 83114 could be equilibrated (log N/N 0 : −2.05 ± 0.25), but CFU/g films were undetectable after 15 days of storage. The results obtained in this work support the use of MC films containing FOS as a good strategy to immobilize lactic acid bacteria, with potential applications in the development of functional foods.
A study was undertaken to evaluate the feasibility of using chitosan active films designed to con... more A study was undertaken to evaluate the feasibility of using chitosan active films designed to control the release of an antimicrobial agent. In this context, the efficacy of propionic acid as both a medium for chitosan dissolution and an antimicrobial agent was examined. This work was focused on studying the potential application of chitosan active films developed to conserve a pastry dough product, modeling the release profile and evaluating the effectiveness of the active agent by extending the product shelf life. The kinetic release was analyzed in a simulant and in a food matrix. Fitting parameters were lower in the pastry dough than in the buffer, since the food matrix limited the active compound diffusion as well as the film swelling. The advantages of the active chitosan system were the capacity of control antimicrobial release to the pastry dough surface and their ability to be an effective carrier of propionic acid, with a consequent improvement from the technological point of view.
The aims of this work were: to develop composite, bi-layer and laminated biodegradable films base... more The aims of this work were: to develop composite, bi-layer and laminated biodegradable films based on gelatin and chitosan, to determine film barrier and mechanical properties and to characterize their microstructure. Gelatin and chitosan concentrations used were 7.5% and 1% (w/w), respectively. Glycerol (0.75%) was added as plasticizer. Physicochemical properties such as moisture content, transparency and color were analyzed. Composite and bi-layer systems showed a compact structure indicating a good compatibility between components. Water vapor permeability (WVP) was independent of film thickness up to 120 lm for gelatin films and 60 lm for chitosan ones. Both, bi-layer and laminated systems resulted effective alternatives to reduce WVP of composite films (at least 42.5%). Bi-layer systems showed better mechanical properties than laminated ones. The resistance at break increased from 54.3 for composite to 77.2 MPa for bi-layer films, whereas elongation at break values of both composite and bi-layer films were similar (2.2-5.7%).
Kefiran, an exopolysaccharide produced by microorganisms present in kefir grains, is a glucogalac... more Kefiran, an exopolysaccharide produced by microorganisms present in kefir grains, is a glucogalactan that has several health promoting properties. In the present work the effect of different sugars (glucose, galactose, sucrose) and polyols (glycerol and sorbitol) as ...
Kefiran, an exopolysaccharide produced by microorganisms present in the kefir grains, is a glucog... more Kefiran, an exopolysaccharide produced by microorganisms present in the kefir grains, is a glucogalactan that has several health promoting properties. In the present work, the ability of kefiran to form films and the effect of glycerol addition at different concentrations on film properties was evaluated. Kefiran was able to form films at concentrations ranging from 5 to 10 g/kg. The concentration 10 g/kg was selected because the films were easily removed from the plate. All film-forming solutions exhibited a pseudoplastic behavior; glycerol addition did not modify the solution rheological properties. Kefiran films exhibited differential solubility characteristics, at the different assayed temperatures. These films exhibited good water vapor barrier properties and the addition of 25 g of glycerol per 100 g of polysaccharide allowed the optimum value of 4.09 Â 10 À11 g/m s Pa to be obtained. Films without glycerol were brittle and rigid since they showed high elastic modulus and tensile strength values and low deformation at break. Glycerol addition led to extremely high elongation values, allowing flexibilities comparable to those of synthetic materials.
Films obtained from chitosan (CH) and methylcellulose (MC) can reduce environmental problems asso... more Films obtained from chitosan (CH) and methylcellulose (MC) can reduce environmental problems associated with synthetic packaging. The objective of the present work was to analyze the effect of an electrical field applied during drying on microstructure and macroscopic properties of films obtained with different mixtures of CH and MC. SEM and X-ray diffraction indicated that CH electrically treated film exhibited a more ordered structure and lower water vapor permeability (WVP) values than those of the control films. With regard to mechanical properties of electrical treated samples, longitudinal probes presented higher elongation values than those of transverse ones. CH treated films showed higher Young's modulus values than the control ones; in composite control samples, Young's modulus and tensile strength increased with CH concentration, leading to stronger films. Electrical field treatment would be a good alternative to improve film flexibility and water vapor barrier properties.
Abstract Urea modified TiO2 nanoparticles were synthesized at different TiO2: urea ratios (10, 30... more Abstract Urea modified TiO2 nanoparticles were synthesized at different TiO2: urea ratios (10, 30 and 60 (%wt) named UTiO2-10, 30 and 60) by sol-gel method and annealing at 400 °C during 1 h. Characterization revealed the presence of TiO2 nanoparticles with visible light absorption (between 400 and 500 nm) probably due by the formation of thermolysis urea byproducts such as melon, which may induce a TiO2/melon heterojunction. Then, modified nanoparticles were immobilized on chitosan films by adding 30% (70QS/30UTiO2) and 50% 50QS/50UTiO2) of UTiO2 nanoparticles. Functionalized films were characterized by SEM-EDS, DRS and AFM. Photo-induced degradation of malachite green stains was evaluated on these films under different wavelengths. Upon UV-A + visible light irradiation, films showed good activity even slightly better than those containing Evonik P-25 (70QS/30P-25). Upon visible light between 450 and 800 nm, films evidenced a satisfactory performance but slower than under UV-A + visible light irradiation whereas the photobleaching activity of 70QS/30P-25 was very poor. When visible light irradiation with wavelengths higher than 590 nm was used, a slight photobleaching was also observed. DRS spectra taken at different irradiation times showed that dye underwent N-demethylated oxidative reactions either upon UV–vis or visible light irradiation. ATR-FTIR measurements revealed the generation of benzophenones after 6 h of irradiation probably suggesting the formation of singlet oxygen under visible light. 70QS/30UTiO2-10 films showed a good photo-bleaching activity after 18 h of continuous UV-A + visible light irradiation.
e incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used as ... more e incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used as a strategy to obtain nanocomposite active lms with diierent both chitosan : tripolyphosphate (CH : TPP) and nanoparticles:chitosan (N : CH) ratios. e thermal analysis carried out by modulated diierential scanning calorimetry (MDSC) allowed observing the shift of an endothermic event towards higher temperatures with a greater N : CH ratio. Analyzing ATR-FTIR spectra through principal component analysis (PCA) can be inferred that the incorporation of the nanoparticles produced a discrimination of the samples into clusters when the region 1400–1700 cm −1 was considered. e decrease in crystalline size with the inclusion of nanoparticles (N A and N B) proved the existence of interactions among CH, TPP, and GA, resulting in a more amorphous structure. e positron annihilation lifetime spectroscopy (PALS) technique was adequate to correlate the glass transition temperatures (T g) obtained by usi...
International Journal of Biological Macromolecules, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
International Journal of Biological Macromolecules, 2020
The development of active bilayer systems is a novel strategy for the application of active packa... more The development of active bilayer systems is a novel strategy for the application of active packaging to maintain or prolong the shelf-life of food products. A bilayer system was assembled in situ into a thermocompression unit through a two-step procedure. One of the layers was obtained by a casting process and consisted of a chitosanbased nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence of GA was designed by a thermocompression process which can be industrially scaled representing a technological progress. The formation of the bilayers was corroborated by SEM allowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of foods.
International Journal of Biological Macromolecules, 2020
Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus ... more Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus fastigiatus, is a promising compound for potential applications in the field of pharmaceuticals and food packaging. To overcome the low solubility of cabreuva EO and to protect it, a two-step process, emulsion formation compound by chitosan, SDS, and PVA, and subsequent ionic crosslinking with sodium citrate, was proposed. The formulation containing 0.75% of chitosan and 1% of SDS proved to be the most stable. An alternative to produce nanostructures and encapsulate the EO is the fiber formation through the electrospinning method. The system composed by a PVA solution assembled with crosslinked emulsions modified the viscosity, influencing the morphology of the obtained nanofibers. The advantage of the electrospun nanofibers was their ability to be an effective carrier of the cabreuva EO and the capacity of controlling the compound release that proved an effective activity against broad spectra of microorganisms (Candida albicans, E. coli, S. aureus, and S. epidermidis). The Gallagher-Corrigan model, used to fit the release profiles of matrices in contact with increasing ethanol proportion from 25:75 to 50:50 showed higher Kb in relation to k suggesting that the polymer swelling played an increasingly prominent role in the EO delivery. The developed nanostructures would be materials with potential applications in the biomedical field.
Objective: To make evaluation of quality of Argentinean sunflower oil used in high-moisture food ... more Objective: To make evaluation of quality of Argentinean sunflower oil used in high-moisture food frying through parameters indicators of oil deterioration. Methods: The results were obtained after studying the effect of temperature-time and the type of food subjected to frying through Total Polar Compounds (TPCs) determination. The type of food selected was breaded food and potato chips. From calorimetric analysis (DSC) of frying oil was obtained crystallization temperature and the crystallization enthalpy. Also was determining fatty acid composition of the frying oil by gas chromatography. Findings: It was observed during the oil heating test at various times, that the TPC content increased over time. The highest the temperatures were, the most distinctive the rises were. During the frying of breaded food and potato chips the deterioration of the oil was accelerated, observing the greatest deterioration after the breaded frying process. The thermo grams obtained by DSC showed a well-defined crystallization peak that when heating treatment times were increased, it reflected in lower temperatures and a decrease in enthalpy. A high correlation was found between the concentration of total polar compounds, and the parameters obtained from thermo grams and the concentration of palmitic and linoleic acids. Novelty/Improvement: The results obtained provide useful information for food quality control in order to avoid variations of the sensory and nutritional characteristics of sunflower oil used in high-moisture food frying.
Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus ... more Among the essential oils (EOs), the cabreuva essential oil extracted from the wood of Myrocarpus fastigiatus, is a promising compound for potential applications in the field of pharmaceuticals and food packaging. To overcome the low solubility of cabreuva EO and to protect it, a two-step process, emulsion formation compound by chitosan, SDS, and PVA, and subsequent ionic crosslinking with sodium citrate, was proposed. The formulation containing 0.75% of chitosan and 1% of SDS proved to be the most stable. An alternative to produce nanostructures and encapsulate the EO is the fiber formation through the electrospinning method. The system composed of a PVA solution assembled with crosslinked emulsions modified the viscosity, influencing the morphology of the obtained nanofibers. The advantage of the electrospun nanofibers was their ability to be an effective carrier of the cabreuva EO and the capacity of controlling the compound release which proved an effective activity against broad spectra of microorganisms (Candida albicans, E. coli, S. aureus, and S. epidermidis). The Gallagher-Corrigan model, used to fit the release profiles of matrices in contact with increasing ethanol proportion from 25:75 to 50:50 showed higher Kb in relation to k suggesting that the polymer swelling played an increasingly prominent role in the EO delivery. The developed nanostructures would be materials with potential applications in the biomedical field.
The development of active bilayer systems is a novel strategy for the application of active packa... more The development of active bilayer systems is a novel strategy for the application of active packaging to maintain or prolong the shelf‐life of food products. A bilayer system was assembled in situ into a thermocompression unit through a two-step procedure. One of the layers was obtained by a casting process and consisted of a chitosan-based
nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence
of GA was designed by a thermocompression process that can be industrially scaled representing technological progress. The formation of the bilayers was corroborated by SEMallowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of food.
Advances in Materials Science and Engineering, 2018
The incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used a... more The incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used as a strategy to obtain nanocomposite active films with different both chitosan : tripolyphosphate (CH : TPP) and nanoparticles:chitosan (N : CH) ratios. The thermal analysis carried out by modulated differential scanning calorimetry (MDSC) allowed observing the shift of an endothermic event towards higher temperatures with a greater N : CH ratio. Analyzing ATR-FTIR spectra through principal component analysis (PCA) can be inferred that the incorporation of the nanoparticles produced a discrimination of the samples into clusters when the region 1400–1700 cm−1 was considered. The decrease in crystalline size with the inclusion of nanoparticles (NA and NB) proved the existence of interactions among CH, TPP, and GA, resulting in a more amorphous structure. The positron annihilation lifetime spectroscopy (PALS) technique was adequate to correlate the glass transition temperatures (Tg) obtaine...
Chitosan (CS) films containing visible light absorbing TiO 2 nanoparticles modified with tungstop... more Chitosan (CS) films containing visible light absorbing TiO 2 nanoparticles modified with tungstophosphoric acid (TPA-TiO 2 ) at different TPA-TiO 2 :CS ratios (10%, 20%, 30% and 40% (w/w) called CS/TPA-TiO 2 -10, CS/TPA-TiO 2 -20, CS/TPA-TiO 2 -30, and CS/TPA-TiO 2 -40 respectively) were prepared. Films were characterized by DRS, SEM-EDS, XRD, ATR-FT-IR, and contact angle (CA). Materials were evaluated in malachite green (MG) photobleaching solid-gas interface reactions upon different wavelengths. SEM-EDS micrographs showed that TPA-TiO 2 nanoparticles were well dispersed through the CS film. According to ATR-FT-IR results, the interactions between TPA-TiO 2 nanoparticles and the CS functional groups were weak. Regarding the MG photobleaching reactions, CS/TPA-TiO 2 -30 film showed the highest activity upon UV-A + visible irradiation, which was even higher than that of chitosan films containing the same amount of Evonik P-25 (CS/P25-30). It was also observed by DRS that the main absorption band of malachite green underwent a hypsochromic shifting caused by oxidative reactions of N-demethylation. On the other hand, at wavelengths higher than 450 nm (Vis-1), CS/TPA-TiO 2 -30 films showed a marked dye photobleaching. Finally, upon irradiation at wavelengths above 590 nm (Vis-2), a slight color fading was observed. These results revealed that CS/TPA-TiO 2 -30 films were efficient in the photobleaching of malachite green in solid-gas interfaces through an oxidative path by photocatalytic and photosensitized routes. CS/TPA-TiO 2 -30 films showed high stability and MG photobleaching capacity after 5 reuse cycles.
This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (... more This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as and a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of interaction polymer-polymer at molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of
This work was focused on assessing the influence of the glycerol in chitosan matrices, analyzing ... more This work was focused on assessing the influence of the glycerol in chitosan matrices, analyzing the changes produced in the molecular mobility, mechanical, thermal, barrier and structural properties. The addition of glycerol in the matrix decreased the stress values, increasing the elasticity and water vapor permeability of the films, with a marked decrease in glass transition temperature; Detailed analyses of Fourier Transform IR Spectroscopy spectra supported the observed changes, especially in the spectral windows 1700-1500 cm −1 revealing the modifications at molecular level caused by hydrogen bond interactions between chitosan and water in the presence of glycerol. Positron annihilation spectroscopic (PALS) measurements allowed determining the free volume assuming spherical holes as well as monitoring the structural changes in chitosan films caused by the addition of both, glycerol and water molecules. It was possible to infer that for unplasticized matrices, a sustained increase of the radius between 0.06 and 0.2 of X water was observed, followed by a plateau up to 0.35. In the other case, with the addition of glycerol, there were two plateaus, the first between 0.25 and 0.37 of X water , and the second from 0.41 to 0.47. For higher glycerol concentrations, the plasticizer would be mainly bounded to the chitosan pack more efficiently and the water present in the system would be predominantly free in the matrix causing its swelling. Findings on molecular mobility contributed to the understanding of the role of water and glycerol in the structural arrangement and its influence on film properties.
Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic... more Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic acid delivery. In this sense, these nanostructures could be employed in different fields such as food, packaging, and pharmaceutical areas. The design parameters of chitosan-based nanoparticles functionalized with gallic acid (GA) were optimized through RSM by means of the analysis of zeta potential (ZP) and percentage encapsulation efficiency (PEE). The nanoparticles were prepared by ionotropic gelation using tripolyphosphate (TPP), at different combinations of chitosan (CH) concentration, CH:TPP ratio and GA. Global desirability methodology allowed finding the optimum formulation that included CH 0.76% (w/w), CH:TPP ratio of 5 and 37 mg GA /g CH leading to ZP of +50 mV and 82% of PEE. Analysis through QuickScan and turbidity demonstrated that the most stable nanoparticle suspensions were achieved combining concentrations of chitosan ranging between 0.5 and 0.75% with CH:TPP ratios higher than 3. These suspensions had high stability confirmed by means ZP and transmittance values which were higher than +25 mV and 0.21 on average, respectively, as well as nanoparticle diameters of about 140 nm. FTIR revealed the occurrence of both hydrogen bond and ionic interactions of CH-TPP which allowed the encapsulation and the improvement of the stability of the active agent.
The goal of this work was to investigate the physicochemical properties of methylcellulose (MC) b... more The goal of this work was to investigate the physicochemical properties of methylcellulose (MC) based films as stabilizers of two strains of lactobacilli: Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 and Lactobacillus plantarum CIDCA 83114. The incorporation of 3% w/v fructo-oligosaccharides (FOS) into the MC film formulation improved the viability of L. delbrueckii subsp. bulgaricus CIDCA 333 after film preparation. L. plantarum CIDCA 83114 was intrinsically more resistant as no viability loss was observed upon preparation of the films in the absence of FOS. Scanning electronic microscopy images also showed a good incorporation of microorganisms without affecting the homogeneity of the films. FTIR spectroscopy provided structural information about the bacteria-loaded films. Water sorption isotherms showed an impervious behavior at low a w but on exceeding 0.7 of a w the film started to dissolve and form syrup, causing a drastic drop of bacterial viability (log N/N 0 ≤ −5). Dynamic mechanical analysis (DMA) demonstrated that the incorporation of microorganisms into the MC films had no effect on vitreous transition temperatures. FOS incorporated into the MC films had a plasticizing effect. Microorganism-loaded films were stored at relative humidities (RH) ranging from 11 to 75%. Both strains could be stored at 11% RH for 90 days. At 33 and 44% RH L. delbrueckii subsp. bulgaricus CIDCA 333 could be stored up to 15 days and L. plantarum CIDCA 83114 up to 45 days. At 75% RH only L. plantarum CIDCA 83114 could be equilibrated (log N/N 0 : −2.05 ± 0.25), but CFU/g films were undetectable after 15 days of storage. The results obtained in this work support the use of MC films containing FOS as a good strategy to immobilize lactic acid bacteria, with potential applications in the development of functional foods.
A study was undertaken to evaluate the feasibility of using chitosan active films designed to con... more A study was undertaken to evaluate the feasibility of using chitosan active films designed to control the release of an antimicrobial agent. In this context, the efficacy of propionic acid as both a medium for chitosan dissolution and an antimicrobial agent was examined. This work was focused on studying the potential application of chitosan active films developed to conserve a pastry dough product, modeling the release profile and evaluating the effectiveness of the active agent by extending the product shelf life. The kinetic release was analyzed in a simulant and in a food matrix. Fitting parameters were lower in the pastry dough than in the buffer, since the food matrix limited the active compound diffusion as well as the film swelling. The advantages of the active chitosan system were the capacity of control antimicrobial release to the pastry dough surface and their ability to be an effective carrier of propionic acid, with a consequent improvement from the technological point of view.
The aims of this work were: to develop composite, bi-layer and laminated biodegradable films base... more The aims of this work were: to develop composite, bi-layer and laminated biodegradable films based on gelatin and chitosan, to determine film barrier and mechanical properties and to characterize their microstructure. Gelatin and chitosan concentrations used were 7.5% and 1% (w/w), respectively. Glycerol (0.75%) was added as plasticizer. Physicochemical properties such as moisture content, transparency and color were analyzed. Composite and bi-layer systems showed a compact structure indicating a good compatibility between components. Water vapor permeability (WVP) was independent of film thickness up to 120 lm for gelatin films and 60 lm for chitosan ones. Both, bi-layer and laminated systems resulted effective alternatives to reduce WVP of composite films (at least 42.5%). Bi-layer systems showed better mechanical properties than laminated ones. The resistance at break increased from 54.3 for composite to 77.2 MPa for bi-layer films, whereas elongation at break values of both composite and bi-layer films were similar (2.2-5.7%).
Kefiran, an exopolysaccharide produced by microorganisms present in kefir grains, is a glucogalac... more Kefiran, an exopolysaccharide produced by microorganisms present in kefir grains, is a glucogalactan that has several health promoting properties. In the present work the effect of different sugars (glucose, galactose, sucrose) and polyols (glycerol and sorbitol) as ...
Kefiran, an exopolysaccharide produced by microorganisms present in the kefir grains, is a glucog... more Kefiran, an exopolysaccharide produced by microorganisms present in the kefir grains, is a glucogalactan that has several health promoting properties. In the present work, the ability of kefiran to form films and the effect of glycerol addition at different concentrations on film properties was evaluated. Kefiran was able to form films at concentrations ranging from 5 to 10 g/kg. The concentration 10 g/kg was selected because the films were easily removed from the plate. All film-forming solutions exhibited a pseudoplastic behavior; glycerol addition did not modify the solution rheological properties. Kefiran films exhibited differential solubility characteristics, at the different assayed temperatures. These films exhibited good water vapor barrier properties and the addition of 25 g of glycerol per 100 g of polysaccharide allowed the optimum value of 4.09 Â 10 À11 g/m s Pa to be obtained. Films without glycerol were brittle and rigid since they showed high elastic modulus and tensile strength values and low deformation at break. Glycerol addition led to extremely high elongation values, allowing flexibilities comparable to those of synthetic materials.
Films obtained from chitosan (CH) and methylcellulose (MC) can reduce environmental problems asso... more Films obtained from chitosan (CH) and methylcellulose (MC) can reduce environmental problems associated with synthetic packaging. The objective of the present work was to analyze the effect of an electrical field applied during drying on microstructure and macroscopic properties of films obtained with different mixtures of CH and MC. SEM and X-ray diffraction indicated that CH electrically treated film exhibited a more ordered structure and lower water vapor permeability (WVP) values than those of the control films. With regard to mechanical properties of electrical treated samples, longitudinal probes presented higher elongation values than those of transverse ones. CH treated films showed higher Young's modulus values than the control ones; in composite control samples, Young's modulus and tensile strength increased with CH concentration, leading to stronger films. Electrical field treatment would be a good alternative to improve film flexibility and water vapor barrier properties.
Abstract Urea modified TiO2 nanoparticles were synthesized at different TiO2: urea ratios (10, 30... more Abstract Urea modified TiO2 nanoparticles were synthesized at different TiO2: urea ratios (10, 30 and 60 (%wt) named UTiO2-10, 30 and 60) by sol-gel method and annealing at 400 °C during 1 h. Characterization revealed the presence of TiO2 nanoparticles with visible light absorption (between 400 and 500 nm) probably due by the formation of thermolysis urea byproducts such as melon, which may induce a TiO2/melon heterojunction. Then, modified nanoparticles were immobilized on chitosan films by adding 30% (70QS/30UTiO2) and 50% 50QS/50UTiO2) of UTiO2 nanoparticles. Functionalized films were characterized by SEM-EDS, DRS and AFM. Photo-induced degradation of malachite green stains was evaluated on these films under different wavelengths. Upon UV-A + visible light irradiation, films showed good activity even slightly better than those containing Evonik P-25 (70QS/30P-25). Upon visible light between 450 and 800 nm, films evidenced a satisfactory performance but slower than under UV-A + visible light irradiation whereas the photobleaching activity of 70QS/30P-25 was very poor. When visible light irradiation with wavelengths higher than 590 nm was used, a slight photobleaching was also observed. DRS spectra taken at different irradiation times showed that dye underwent N-demethylated oxidative reactions either upon UV–vis or visible light irradiation. ATR-FTIR measurements revealed the generation of benzophenones after 6 h of irradiation probably suggesting the formation of singlet oxygen under visible light. 70QS/30UTiO2-10 films showed a good photo-bleaching activity after 18 h of continuous UV-A + visible light irradiation.
e incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used as ... more e incorporation of suspensions of nanoparticles functionalized with gallic acid (GA) was used as a strategy to obtain nanocomposite active lms with diierent both chitosan : tripolyphosphate (CH : TPP) and nanoparticles:chitosan (N : CH) ratios. e thermal analysis carried out by modulated diierential scanning calorimetry (MDSC) allowed observing the shift of an endothermic event towards higher temperatures with a greater N : CH ratio. Analyzing ATR-FTIR spectra through principal component analysis (PCA) can be inferred that the incorporation of the nanoparticles produced a discrimination of the samples into clusters when the region 1400–1700 cm −1 was considered. e decrease in crystalline size with the inclusion of nanoparticles (N A and N B) proved the existence of interactions among CH, TPP, and GA, resulting in a more amorphous structure. e positron annihilation lifetime spectroscopy (PALS) technique was adequate to correlate the glass transition temperatures (T g) obtained by usi...
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Papers by Adriana Artano
indicators of oil deterioration. Methods: The results were obtained after studying the effect of temperature-time and the
type of food subjected to frying through Total Polar Compounds (TPCs) determination. The type of food selected was
breaded food and potato chips. From calorimetric analysis (DSC) of frying oil was obtained crystallization temperature
and the crystallization enthalpy. Also was determining fatty acid composition of the frying oil by gas chromatography.
Findings: It was observed during the oil heating test at various times, that the TPC content increased over time. The
highest the temperatures were, the most distinctive the rises were. During the frying of breaded food and potato chips the
deterioration of the oil was accelerated, observing the greatest deterioration after the breaded frying process. The thermo
grams obtained by DSC showed a well-defined crystallization peak that when heating treatment times were increased, it
reflected in lower temperatures and a decrease in enthalpy. A high correlation was found between the concentration of
total polar compounds, and the parameters obtained from thermo grams and the concentration of palmitic and linoleic
acids. Novelty/Improvement: The results obtained provide useful information for food quality control in order to avoid
variations of the sensory and nutritional characteristics of sunflower oil used in high-moisture food frying.
nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence
of GA was designed by a thermocompression process that can be industrially scaled representing technological progress. The formation of the bilayers was corroborated by SEMallowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of food.
indicators of oil deterioration. Methods: The results were obtained after studying the effect of temperature-time and the
type of food subjected to frying through Total Polar Compounds (TPCs) determination. The type of food selected was
breaded food and potato chips. From calorimetric analysis (DSC) of frying oil was obtained crystallization temperature
and the crystallization enthalpy. Also was determining fatty acid composition of the frying oil by gas chromatography.
Findings: It was observed during the oil heating test at various times, that the TPC content increased over time. The
highest the temperatures were, the most distinctive the rises were. During the frying of breaded food and potato chips the
deterioration of the oil was accelerated, observing the greatest deterioration after the breaded frying process. The thermo
grams obtained by DSC showed a well-defined crystallization peak that when heating treatment times were increased, it
reflected in lower temperatures and a decrease in enthalpy. A high correlation was found between the concentration of
total polar compounds, and the parameters obtained from thermo grams and the concentration of palmitic and linoleic
acids. Novelty/Improvement: The results obtained provide useful information for food quality control in order to avoid
variations of the sensory and nutritional characteristics of sunflower oil used in high-moisture food frying.
nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence
of GA was designed by a thermocompression process that can be industrially scaled representing technological progress. The formation of the bilayers was corroborated by SEMallowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of food.