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1.
Polymers (Basel) ; 16(2)2024 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-38276683

RESUMEN

A biodegradable polymer packaging system for 'Benitaka' table grapes (Vitis vinifera L.) was developed to inhibit the development of gray mold during refrigerated storage. The system consisted of packages and sachets containing Na2S2O5 to release sulfur dioxide (SO2), both produced with biodegradable films of starch, glycerol, and poly (adipate co-butylene terephthalate) (PBAT) produced via blown extrusion. The films were characterized in terms of thickness, density, mass loss in water, water vapor permeability, sorption isotherms, and mechanical properties. The table grapes were packed with biodegradable plastic bags containing SO2-releasing sachets inside. The experimental design was completely randomized, with four repetitions and five treatments: (a) control, without sachet containing Na2S2O5 and SiO2; (b) 2 g of Na2S2O5 + 2 g of SiO2; (c) 4 g of Na2S2O5 + 1 g of SiO2; (d) 4 g of Na2S2O5 + 2 g of SiO2; and (e) 4 g of Na2S2O5 + 4 g of SiO2. The bunches were stored in a refrigerated chamber at 1 ± 1 °C and relative humidity above 90%. The treatments were evaluated 30 and 45 days after the beginning of refrigerated storage and 3 days at room temperature. The grapes were evaluated based on the incidence of gray mold, mass loss, stem browning, shattered berries, and berry bleaching. The data were subjected to the analysis of variance, and the means were compared using Tukey's test at 5%. The biodegradable films had good processability during the production via blown extrusion, with good physical properties to be used in the packaging of grapes and the production of SO2-releasing sachets. The biodegradable polymer packaging system (biodegradable plastic bags + SO2-releasing sachets) inhibited the development of gray mold on 'Benitaka' table grapes for 45 days at 1 °C, preserving their quality, with low mass loss, few shattered berries, and rachis freshness.

2.
Microorganisms ; 11(2)2023 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-36838432

RESUMEN

The subject of this review is to discuss some aspects related to the use of biopolymeric matrices as carriers for plant-growth promoting bacteria (PGPB) in agricultural systems as a possible technological solution for the establishment of agricultural production practices that result in fewer adverse impacts on the environment, reporting some promising and interesting results on the topic. Results from the encapsulation of different PGPB on alginate, starch, chitosan, and gelatin matrices are discussed, systematizing some advances made in this area of knowledge in recent years. Encapsulation of these bacteria has been shown to be an effective method for protecting them from unsuitable environments, and these new products that can act as biofertilizers and biopesticides play an important role in the establishment of a sustainable and modern agriculture. These new products are technological solutions for replacing deleterious chemical fertilizers and pesticides, maintaining soil fertility and stability, and improving crop productivity and food security. Finally, in the near future, scale-up studies will have to provide new information about the large-scale production of these materials as well as their application in the field under different biotic and abiotic stress conditions.

3.
Antibiotics (Basel) ; 12(1)2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36671379

RESUMEN

The food industry has been exploring the association of polymers with nanoparticles in packaging production, and active products are essential to increase the shelf life of food and avoid contamination. Our study developed starch-poly (adipate co-terephthalate butyl) films with silver nanoparticles produced with Fusarium oxysporum components (bio-AgNPs), intending to control foodborne pathogens. The bio-AgNPs showed activity against different Salmonella serotypes, including multidrug-resistant Salmonella Saint Paul and Salmonella Enteritidis, with minimum bactericidal concentrations ranging from 4.24 to 16.98 µg/mL. Biodegradable films with bio-AgNPs inhibited the growth of up to 106Salmonella isolates. Silver migration from the films to chicken was analyzed using electrothermal atomic absorption spectrophotometry, and the results showed migration values (12.94 mg/kg and 3.79 mg/kg) above the limits allowed by the European Food Safety Authority (EFSA) (0.05 mg/kg). Thus, it is necessary to improve the technique to avoid the migration of silver to chicken meat, since these concentrations can be harmful.

4.
Prep Biochem Biotechnol ; 53(8): 942-953, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36592021

RESUMEN

Polysaccharides and proteins are compatible macromolecules that can be used to obtain biopolymeric hydrogels through physical interactions. In this study, an environmentally friendly strategy is being proposed to produce gelatin-xanthan gum- cellulose hydrogels, without the addition of chemical synthetic crosslinkers. Xanthan gum was employed as an alternative crosslinking agent, and cellulose was used as a potential reinforcing agent in the polymeric matrix. Firstly, the biopolymers were mixed by the extrusion process, and glycerol was used as a plasticizer. Then, the polymeric mixture was molded by thermopressing to obtain hydrogels as laminated films. All hydrogels formulations resulted in films with smooth surfaces, without pores or cracks, resulting in amorphous polymeric matrices. The obtained hydrogels had a pH-dependent degree of swelling, the highest swelling values were obtained at pH 4 (5.3-7.9 g/g) after 24 h of immersion. Cellulose acted as a reinforcing agent for hydrogels, increasing thermal stability, tensile strength, and Young's modulus of films when employed at the higher level (7%). The strategy employed in this study to obtain nontoxic hydrogels without synthetic crosslinkers was effective, resulting in materials with promising properties to be used as pharmaceutical forms to deliver active compounds in cosmetic or pharmaceutical products.


Asunto(s)
Celulosa , Gelatina , Gelatina/química , Hidrogeles/química , Polisacáridos Bacterianos/química , Polímeros/química
5.
Food Chem ; 394: 133503, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-35728472

RESUMEN

This study aimed to produce and characterized active biodegradable packages by extrusion of cassava starch, biodegradable polyester, plasticizer, and acai extract (EA 0, 1, 2, 3 and 4%) and to evaluate its effects on extra virgin olive oil (EVOO) for 120 days. All analyses were performed at the beginning (day 0) and the end of the experiment (day 120). The oil was characterized for acidity index (IA), peroxide index (IP), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD), phenolic compounds (PC) and color parameters. The incorporation of EA at the initial time caused increased thickness, mechanical properties, solubility in water and oil in all formulations. The some values of properties increased or decreased, due to the interaction of the stored product and packaging. At the end of the storage period, the values of IA and IP were below the limits established by current legislation. The EVOO showed a gradual decrease in PC from day 1 to day 120, for all treatments.


Asunto(s)
Euterpe , Aceite de Oliva/análisis , Fenoles/análisis , Extractos Vegetales , Almidón
6.
Food Chem ; 368: 130817, 2022 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-34411863

RESUMEN

Novel microcapsules containing grape peel by-product extract were obtained. In this pursuit, complex coacervation of casein/pectin bioconjugate and spray-drying were combined. We have investigated the role of the dispersion feed rate (FR), drying air inlet temperature (IT) and drying air flow rate (AR) in the drying yield, microencapsulation efficiency, total polyphenols and anthocyanins contents, antioxidant activity, and morphology of the products. Also, the first-order degradation kinetics of the phytochemicals for both the extract and dried microcapsules was assessed and compared. The loss on the phytochemicals during spray-drying was attenuated in up to 88%, and the IT was the main factor affecting the particle properties. The polyphenols on the extract interacted with the polymers, influencing the assemble of the bioconjugate and the particle's features. Such microencapsulation strategy enhanced the thermal stability of the phytochemicals and rendered biocompatible and biodegradable products of which the nutraceutical and cosmeceutical application may have potential.


Asunto(s)
Vitis , Antocianinas , Cápsulas , Caseínas , Composición de Medicamentos , Pectinas
7.
Food Chem ; 365: 130478, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34243125

RESUMEN

The growing demand for authentic products that provide sensory characteristics combined with health benefits has been the focus of current studies. This study developed a Red Ale style craft beer with spices such as turmeric (T), black pepper (P) and aroma hops (H), used isolated or in mixtures. A mixture design was employed to evaluate the total phenolic compounds and the antioxidant activity in the green and aged beers formulations. The spice extracts influenced the product's shelf-life. The addition of spices into the beers did not affect the physicochemical parameters that classify the Red Ale style, according to the hierarchical cluster analysis, except for aroma hops. A multiresponse optimization approach simultaneously maximized the antioxidant activity and the phenolic compounds in beers. The ideal formulation obtained for green beers was 25% T and 37.5% P and H; for aged beers, the formulation was 50% T, 20% P and 30% H.


Asunto(s)
Antioxidantes , Humulus , Antioxidantes/análisis , Cerveza/análisis , Fenoles/análisis , Especias
8.
Polymers (Basel) ; 13(5)2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33668081

RESUMEN

In this investigation, sludge fibre waste (SFW) and Kraft lignin powder (KLP) are introduced into polylactic acid (PLA) matrix biocomposites. These alternative materials allow for both the reuse of fibre waste from paper mill sludge and a reduction in the amount of high-cost biopolymer used in the same volume. Proportions from 10 to 40 wt.% of SFW with the addition of 2.5% and 5% of KLP are incorporated in PLA by extrusion and injection moulding. The thermogravimetric properties, water absorption, tensile and flexural properties, and morphology of the fabricated biocomposites were investigated. According to the results, KLP contributes to thermically stabilising the loss resulting from the incorporation of SFW. Flexural and tensile tests reveal a more pronounced decrease in strength with an SFW ratio above 10%. The modulus of elasticity increases significantly with an SFW ratio above 20%. The strength properties are stabilised with the addition of 5% KLP. The addition of KLP presents a tendency to reduce water absorption obtained by the incorporation of SFW into biocomposites. Scanning electron micrographs evidence that KLP improves the interfacial adhesion by reducing the voids between fibres and PLA.

9.
J Food Sci Technol ; 58(1): 197-204, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33505064

RESUMEN

Most of the food packaging is mainly petroleum-based, and new forms of food packaging have emerged, such as active, intelligent, and biodegradable packaging to extend the shelf life of fresh vegetables. The aim was to develop a biodegradable active packaging and senescence indicator label for fresh broccoli florets (Brassica oleracea L. var. italica), to increase shelf life and to monitor the decay of the vegetable. The biodegradable active packagings (BAP) were produced by blown extrusion containing zeolite as ethylene scavenger, and their mechanical properties, water vapor permeability, and water sorption isotherms were determined. Fresh broccoli florets were packed in perforated and non-perforated BAP and stored at 12 °C, and their weight loss, vitamin C content, color, and texture were evaluated during the storage. BAPs were efficient in reducing the metabolism of fresh broccoli florets stored at 12 °C, preserving the color, and vitamin C content for 7 days. The senescence indicator labels were able to detect CO2 in packages without perforations.

10.
Food Chem ; 341(Pt 1): 128193, 2021 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-33027753

RESUMEN

We report, on the successful addition of spray-dried microparticles containing roasted coffee oil, to soluble coffee (SC) and instant cappuccino (IC), to increase and tailor aroma release. Using PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometry), five parameters were defined from time series intensity for each VOC, to compare the performance of different products: total area under the curve (AUC), area under the curve of burst (AUC-burst), maximum signal intensity, final intensity (5 min), and ratio AUC-burst/AUC. Microparticles with higher loads of roasted coffee oil were effective in increasing aroma intensity in SC while, for IC, all loads of microparticles improved aroma intensity. Volatility drove the VOC release in SC, and volatility and polarity for IC. Most compounds reached maximum headspace concentration in < 16 s upon start of reconstitution. These results open new perspectives for the development of instant coffee products and demonstrate their unique aroma release characteristics.


Asunto(s)
Café/química , Odorantes/análisis , Aceites de Plantas/química , Espectrometría de Masas/métodos , Protones , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/química , Volatilización
11.
J Food Sci ; 85(9): 2832-2842, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32856302

RESUMEN

Films were produced using the blown extrusion method from blends made with cassava and pinhão thermoplastic starch, compostable polyester (poly(butylene adipate co-terephthalate, PBAT) and natural extracts (rosemary and green tea). The effect of the incorporation of the extracts and the type of starch added in the film properties were investigated following the mixture design (23 ) approach. Regression models and response surface curves were generated to predict the film properties. The effect of the cold storage (6 °C and 17% of humidity relative, for 60 days) on the film properties was also investigated in order to simulate future applications. All the properties were mainly influenced by the extract type. The incorporation of the extracts decreased the lightness parameter and the films produced with green tea extract were more opaque than those made with rosemary. Starch/rosemary blends were more flexible, while the extract type did not have a significant effect on tensile strength (TS). Film elongation (ELO) ranged from 520% to 719% and might be comparable to some synthetic polymers. The water vapor permeability was improved in approximately 14% with addition of the extracts. The storage conditions, on the one hand, increased the TS, elastic modulus, and opacity of films and, on the other hand, decreased the elongation parameter. The thermal stability of films was not modified by adding extracts or varying the starch type. The results demonstrated that pinhão/cassava/PBAT blends and the natural extracts are a good alternative matrix to produce packagings with adequate mechanical and barrier properties. PRACTICAL APPLICATION: Extruded films produced from cassava or pinhão starch, poly(butylene adipate co-terephthalate) (PBAT) and natural extracts show technological potential to be used as active packaging for food products. Pinhão starch is a great alternative substitute to cassava starch and the incorporation of the commercial compostable polymer (PBAT) is necessary in order to confer suitable mechanical properties to extrusion process. The extrusion blown method, a process widely used by plastic industries, allows the scale-up of bio-based packagings for industrial scale.


Asunto(s)
Embalaje de Alimentos/instrumentación , Manihot/química , Extractos Vegetales/química , Almidón/química , Módulo de Elasticidad , Humedad , Permeabilidad , Ácidos Ftálicos/química , Poliésteres/química , Polímeros/química , Vapor , Resistencia a la Tracción
12.
Food Chem ; 317: 126455, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32109659

RESUMEN

This study presents an experimental approach to study the kinetics and fast release of volatile organic compounds (VOCs) upon reconstitution of instant coffee products. A sampling setup coupled to PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometry) for the automated and reproducible reconstitution of instant coffee products was developed to monitor the dynamic release of VOCs. A rapid release of aroma compounds was observed in the first seconds upon hot water addition ("aroma burst"), followed by subsequent decrease in headspace (HS) intensities over the course of analysis. Differences in time-intensity release profiles of individual VOCs were correlated to their Henry's Law constant, vapor pressure and water solubility. The setup and approach proposed here have shown to be sensitive and to respond to fast dynamic changes in aroma release. It allows studying VOCs release upon reconstitution and supports the development of novel technologies and formulations for instant products with improved aroma release properties.


Asunto(s)
Café/química , Análisis de los Alimentos/métodos , Odorantes/análisis , Compuestos Orgánicos Volátiles/análisis , Análisis de los Alimentos/instrumentación , Cinética , Espectrometría de Masas/instrumentación , Espectrometría de Masas/métodos , Protones , Solubilidad , Agua
13.
Food Funct ; 10(12): 7697-7706, 2019 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-31720644

RESUMEN

There is growing interest in the development of biodegradable packaging materials containing natural antioxidant extracts. In this sense, the use of extracts obtained from agro-industrial byproducts has proved to be a sustainable alternative. In this study, Pinhão extract, a byproduct of Pinhão (Araucaria angustifolia (Bertol.) Kuntze) seed consumption, was characterized by HPLC-DAD-ESI/MSn, demonstrating the presence of eight phenolic compounds, (+)-catechin and (-)-epicatechin being the most abundant molecules. TPS/PBAT films containing Pinhão extract were produced by blown extrusion and their properties (tensile properties, thermal characteristics and microstructure) were evaluated in order to determine the effect of the presence of extracts. Results suggested that the interaction between the phenolic compounds of the extract and the polymeric matrix caused the reduction in the crystallinity degree, and an increase in the starch glass transition temperature. The presence of Araucaria angustifolia (Bertol.) Kuntze extract significantly (p < 0.05) affected the color and opacity of the film. Regarding water vapor permeation, no significant difference (p > 0.05) was detected. However, the water solubility and the contact angle with water (polar solvent) and diiodomethane (non-polar solvent) significantly changed due to the extract addition. Moreover, the Pinhão extract conferred significant antioxidant capacity to the TPS/PBAT films as determined by DPPH, suggesting that this material can be applied as an active packaging material.


Asunto(s)
Araucaria/química , Embalaje de Alimentos/instrumentación , Fenoles/química , Extractos Vegetales/química , Poliésteres/química , Almidón/química , Color , Calor , Fenoles/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Polímeros/química , Semillas/química , Resistencia a la Tracción
14.
J Food Sci Technol ; 55(4): 1508-1517, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29606765

RESUMEN

The objective of this study was to optimize the extraction of protein by applying a multi-enzymatic pretreatment to okara, a byproduct from soymilk processing. The multi-enzyme complex Viscozyme, containing a variety of carbohydrases, was used to hydrolyze the okara cell walls and facilitate extraction of proteins. Enzyme-assisted extraction was carried out under different temperatures (37-53 °C), enzyme concentrations (1.5-4%) and pH values (5.5-6.5) according to a central composite rotatable design. After extraction, the protein was concentrated by isoelectric precipitation. The optimal conditions for maximum protein content and recovery in protein concentrate were 53 °C, pH 6.2 and 4% of enzyme concentration. Under these conditions, protein content of 56% (dry weight basis) and a recovery of 28% were obtained, representing an increase of 17 and 86%, respectively, compared to the sample with no enzymatic pretreatment. The multi-enzyme complex Viscozyme hydrolyzed the structural cell wall polysaccharides, improving extraction and obtaining protein concentrate from the okara. An electrophoretic profile of the protein concentrate showed two distinct bands, corresponding to the acidic and basic subunits of the protein glycinin. There were no limiting amino acids in the protein concentrate, which had a greater content of arginine.

15.
Mater Sci Eng C Mater Biol Appl ; 78: 932-941, 2017 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-28576069

RESUMEN

The production of biodegradable plastic materials using natural resources has aroused increased attention due to environmental concerns. This study aimed to manufacture novel, commercially feasible, biodegradable sheets by flat die extrusion-calendering process produced with thermoplastic starch/plasticized cellulose acetate (TPS/PCA) and thermoplastic starch/plasticized cellulose acetate/poly (butylene adipate-co-terephthalate) (TPS/PCA/PBAT) blends, and to investigate the effects of composition and processing conditions, morphological characteristics, and thermal properties. The results showed that TPS/PCA and TPS/PCA/PBAT biodegradable sheets properties were highly dependent upon both composition and processing temperature. The morphological characteristics and thermal properties of the sheets demonstrated the good compatibility between TPS and PCA in TPS/PCA blends, mainly at higher processing temperatures, whereas TPS/PCA/PBAT sheets present a heterogeneous structure due to the poor compatibility between the components. TPS/PCA biodegradable sheets presented suitable processability and handleability characteristics that allow them to be considered as a novel eco-friendly, economically feasible alternative to conventional plastic materials.


Asunto(s)
Almidón/química , Celulosa/análogos & derivados , Poliésteres , Temperatura
16.
J Food Sci Technol ; 52(9): 5866-73, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26345002

RESUMEN

The aim of this study was to develop a gluten-free formulation of quinoa (Chenopodium quinoa Willd.)-based cookies using experimental design of mixture to optimize a ternary mixture of quinoa flour, quinoa flakes and corn starch for parameters of colour, specific volume and hardness. Nutritional and sensory aspects of the optimized formulation were also assessed. Corn starch had a positive effect on the lightness of the cookies, but increased amounts of quinoa flour and quinoa flakes in the mixture resulted in darker product. Quinoa flour showed a negative effect on the specific volume, producing less bulky cookies, and quinoa flour and quinoa flakes had a positive synergistic effect on the hardness of the cookies. According the results and considering the desirability profile for colour, hardness and specific volume in gluten-free cookies, the optimized formulation contains 30 % quinoa flour, 25 % quinoa flakes and 45 % corn starch. The quinoa-based cookie obtained was characterized as a product rich in dietary fibre, a good source of essential amino acids, linolenic acid and minerals, with good sensory acceptability. These findings reports for the first time the application of quinoa processed as flour and flakes in mixture with corn starch as an alternative ingredient for formulations of gluten-free cookies-type biscuits.

17.
Mater Sci Eng C Mater Biol Appl ; 56: 274-9, 2015 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-26249590

RESUMEN

There is an increasing interest in the use of polysaccharides and proteins for the production of biodegradable films. Visible and near-infrared (VIS-NIR) spectroscopy is a reliable analytical tool for objective analyses of biological sample attributes. The objective is to investigate the potential of VIS-NIR spectroscopy as a process analytical technology for compositional characterization of biodegradable materials and correlation to their mechanical properties. Biofilms were produced by single-screw extrusion with different combinations of polybutylene adipate-co-terephthalate, whole oat flour, glycerol, magnesium stearate, and citric acid. Spectral data were recorded in the range of 400-2498nm at 2nm intervals. Partial least square regression was used to investigate the correlation between spectral information and mechanical properties. Results show that spectral information is influenced by the major constituent components, as they are clustered according to polybutylene adipate-co-terephthalate content. Results for regression models using the spectral information as predictor of tensile properties achieved satisfactory results, with coefficients of prediction (R(2)C) of 0.83, 0.88 and 0.92 (calibration models) for elongation, tensile strength, and Young's modulus, respectively. Results corroborate the correlation of NIR spectra with tensile properties, showing that NIR spectroscopy has potential as a rapid analytical technology for non-destructive assessment of the mechanical properties of the films.


Asunto(s)
Biopolímeros/química , Módulo de Elasticidad , Membranas Artificiales , Análisis Espectral
18.
Rev. bras. farmacogn ; 25(3): 284-291, May-June 2015. tab, ilus
Artículo en Inglés | LILACS | ID: lil-757432

RESUMEN

AbstractPhytopharmaceutical products are being used in the treatment and prevention of health problems. Nowadays, the development and evaluation of novel pharmaceutical products is expensive and time consuming. A statistical approach is a good tool for optimal development processes. Nectandra falcifolia (Nees) J.A. Castigl. ex Mart. Crov. & Piccinini, Lauraceae, a Brazilian species, is reported as anti-inflammatory, anti-leishmanial and anti-microbial. However, there is little known about its chemical composition. For other species of Nectandra genus, the presence of antioxidant compounds is reported. In order to optimize the process of obtaining extract with high antioxidant activity, different extraction conditions were tested following a statistical approach. Two sequential experimental designs were used – first, a factorial 23 design, followed by central composite 22. The extracts manufactured by these experimental statistical matrixes had their antioxidant activity and phenolic contents quantified and the response surface plots were fitted in quadratic models and they predicted the best extraction condition for the best antioxidant activity. This standardized extract and its antioxidant activity were better evaluated by two complementary tests (ABTS and Burst respiratory). A topical formulation containing 1% (w/w) of standardized extract was prepared and used for an in vivo skin permeation study using a two-dose application. The photoacoustic spectroscopy was used to analyze the samples from the permeation study and the composition profile of standardized extract. In rat skin samples, the data demonstrated that for the higher dose of topical formulation (5 g/cm2), the standardized extract could cross skin and be seen in epidermis and dermis. This was not the case for the lower dose (2 g/cm2) which was only present in the epidermis. This information suggests that this novel standardized extract of N. falcifoliacould be explored for skin damage prevention or treatment for diseases developed by oxidative damage.

19.
Mater Sci Eng C Mater Biol Appl ; 33(7): 4112-7, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23910321

RESUMEN

Biodegradable films were produced using the blown extrusion method from blends that contained cassava thermoplastic starch (TPS), poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) with two different extrusion processes. The choice of extrusion process did not have a significant effect on the mechanical properties, water vapor permeability (WVP) or viscoelasticity of the films, but the addition of PLA decreased the elongation, blow-up ratio (BUR) and opacity and increased the elastic modulus, tensile strength and viscoelastic parameters of the films. The films with 20% PLA exhibited a lower WVP due to the hydrophobic nature of this polymer. Morphological analyses revealed the incompatibility between the polymers used.


Asunto(s)
Ácido Láctico/química , Poliésteres/química , Polímeros/química , Almidón/química , Temperatura , Elasticidad , Humedad , Microscopía Electrónica de Rastreo , Permeabilidad , Vapor , Viscosidad
20.
Mater Sci Eng C Mater Biol Appl ; 33(7): 4331-6, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23910350

RESUMEN

Nowadays, the production of biodegradable starch-based films is of great interest because of the growing environmental concerns regarding pollution and the need to reduce dependence on the plastics industry. A broad view of the role of different components, added to starch-based films to improve their properties, is required to guide the future development. The self-organizing maps (SOMs) provide comparisons that initially were complicated due to the large volume of the data. Furthermore, the construction of a model capable of predicting the mechanical and barrier properties of these films will accelerate the development of films with improved characteristics. The water vapor permeability (WVP) analysis using the SOM algorithm showed that the presence of glycerol is very important for films with low amounts of poly (butylene adipate co-terephthalate) and confirms the role of the equilibrium relative humidity in the determination of WVP. Considering the mechanical properties, the SOM analysis emphasizes the important role of poly (butylene adipate co-terephthalate) in thermoplastic starch based films. The properties of biodegradable films were predicted and optimized by using a multilayer perceptron coupled with a genetic algorithm, presenting a great correlation between the experimental and theoretical values with a maximum error of 24%. To improve the response of the model and to ensure the compatibility of the components more information will be necessary.


Asunto(s)
Fenómenos Mecánicos , Redes Neurales de la Computación , Almidón/química , Algoritmos , Biodegradación Ambiental , Permeabilidad , Plásticos/química , Poliésteres/química , Vapor , Temperatura
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