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Er(3+)-doped silica-hafnia films for optical waveguides and spherical resonators

RIGHINI, G. C.; BERNESCHI, S.; CONTI, G. Nunzi; PELLI, S.; MOSER, E.; RETOUX, R.; FERON, P.; GONCALVES, R. R.; SPERANZA, G.; JESTIN, Y.; FERRARI, M.; CHIASERA, A.; CHIAPPINI, A.; ARMELLINI, C.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
581.1495%
In this paper we present some result on sol-gel derived silica-hafnia systems. In particular we focus on fabrication, morphological and spectroscopic assessment of Er(3+)-activated thin films. Two examples of silica-hafnia-derived waveguiding glass ceramics, prepared by top-down and bottom-up techniques are reported, and the main optical properties are discussed. Finally, some properties of activated microspherical resonators, having a silica core, obtained by melting the end of a telecom fiber, coated with an Er(3+)-doped 70SiO(2)-30HfO(2) film, are presented. (C) 2009 Elsevier B.V. All rights reserved.

Disorder effects produced by the Mn and H incorporations on the optical absorption edge of Ga1-xMnxAs:H nanocrystalline films

Pereira, Andre L. J.; da Silva, J. H. Dias
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 5372-5377
ENG
Relevância na Pesquisa
588.37973%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 05/02249-0; Processo FAPESP: 05/03463-5; The optical absorption edges of nanocrystalline Ga1-xMnxAs:H films (0.000 <= x <= 0.081) prepared by sputtering were analyzed. The influence of Mn and hydrogen incorporations were both investigated. The energy dispersive X-ray spectroscopy and X-ray diffraction measurements show that the films are nanocrystalline and do not display any evidence of Mn segregation, or of any other secondary phase formation. The transmittance measurements in the ultraviolet-visible-near infrared range allow us to calculate the absorption coefficient, the optical gap, and the Urbach energy. The hydrogenated Ga1-xMnxAs films presented wider gaps and smaller Urbach energies than its non-hydrogenated counterparts. In the hydrogenated films a linear correlation was observed between the decrease of the optical gap and the increase of the Urbach energy, which we have attributed to potential fluctuations and disorder induced by the Mn incorporation. (C) 2008 Elsevier B.V. All rights reserved.

The use of electric fields for edible coatings and films development and production : a review

Souza, B. W. S.; Cerqueira, M. A.; Teixeira, J. A.; Vicente, A. A.
Fonte: Springer Science ; Business Media, LLC Publicador: Springer Science ; Business Media, LLC
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
620.37086%
Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. A diversity of raw materials used to produce edible coatings and films are extracted from marine and agricultural sources, including animals and plants. Electric fields processing holds advantage in producing safe, wholesome and nutritious food. Recently, the presence of a moderate electric field during the preparation of edible coatings and films was shown to influence their main properties, demonstrating its usefulness to tailor edible films and coatings for specific applications. This manuscript reviews the main aspects of the use of electric fields in the production of edible films and coatings, including the effect in their transport and mechanical properties, solubility and microstructure.; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brasil.; Fundação para a Ciência e a Tecnologia (FCT), Portugal.

Effect of moderate electric field in the physical and transport properties of chitosan coatings

Souza, B. W. S.; Cerqueira, M. A.; Casariego, A.; Martins, Joana; Teixeira, J. A.; Vicente, A. A.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 22/10/2009 ENG
Relevância na Pesquisa
615.4241%
Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. Preliminary works have shown that the presence of a moderate electric field during the preparation of chitosan coating solutions may influence e.g. their transport properties. The aim of this work was to determine the effect of field strength on functional properties of chitosan coatings (obtained from lobster of the Cuban coasts). Four different field strengths (50,100,150, 200 V·cm-1) were applied during the preparation of the film forming solution, films were cast and, for each electric treatment, the water vapor, O2 and CO2 permeabilities of the films were determined, together with their solubility in water. The films were also analysed using scanning electron microscopy (SEM) and X-ray diffractometry (XRD).The results showed that the electric field has statistically significant effects on films transport properties (which e.g. for water vapour permeability, varied from 0.3228 to 0.2667(g.(m.day.atm)-1)) and structure, a positive correlation having been found between the water vapor, O2 and CO2 permeability coefficients and the applied field strength. XRD indicated that when electrically treated...

Edible coatings based on chitosan-beeswax emulsions

Marques, Sónia Cristina Pereira
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Dissertação de Mestrado
Publicado em //2012 ENG
Relevância na Pesquisa
817.9636%
Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica; The use of edible biopolymer-based films and coatings is an environmentally friendly technology that offers substantial advantages for increase of shelf-life of many food products including fruits and vegetables. The development of this kind of films and coatings is a technological challenge for the industry and a very active research field worldwide. In this work biodegradable edible films of chitosan with different contents of beeswax were prepared and characterized. Their hygroscopic properties and water vapour permeability, as well as their CO2 and O2 permeability, mechanical, optical and superficial properties were determined. All the obtained films are transparent with a slightly yellowish colour. They are homogeneous and dense, despite the films with beeswax presented some cracks and depressions in their structure. The incorporation of beeswax increases the films hydrophobicity, higher contact angle values, but still prevails their hydrophilic nature. Regarding the mechanical properties, these films are flexible and elastic, but the increase of beeswax content increases their brittleness. The films showed decreased water vapour permeability as well as decreased hydrophilic properties...

Inhibition of postharvest penicillium molds of oranges by antifungal hydroxypropyl methylcellulose-lipid edible composite films and coatings

Valencia-Chamorro, Silvia A.; Pérez-Gago, María B.; del Río, Miguel A.; Palou, Lluís
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Parte de Livro
Publicado em //2010 ENG
Relevância na Pesquisa
713.58164%
Proceedings of the International Conference “Environmentally friendly and safe technologies for quality of fruit and vegetables”, held in Universidade do Algarve, Faro, Portugal, on January 14-16, 2009. This Conference was a join activity with COST Action 924.; New hydroxypropyl methylcellulose (HPMC)-lipid edible composite films and coatings containing low-toxicity chemicals with antifungal properties were developed. Tested antifungal chemicals were mainly salts of organic acids, salts of parabens, and other compounds, most of them classified as food additives or generally recognized as safe (GRAS) compounds. Stand-alone edible films were used for in vitro evaluation of their antifungal activity against the pathogens Penicillium digitatum and Penicillium italicum by disk diameter tests. Selected edible coatings containing food preservatives were tested in vivo on ‘Valencia’ oranges to determine their curative (coated after fungal inoculation) and preventive (coated before fungal inoculation) activity to control citrus postharvest green and blue molds, caused by P. digitatum and P. italicum, respectively. Film disks containing parabens and the organic acid salts potassium sorbate (PS) and sodium benzoate (SB) were the most effective to inhibit both P. digitatum and P. italicum. The use of mixtures of organic acid salts did not provide any additive or synergistic effect for in vitro pathogen inhibition when compared to the use of single chemicals. On ‘Valencia’ oranges...

Study and characterization of indium oxynitride photoconductors

Sparvoli,M.; Mansano,R. D.; Chubaci,J. F. D.
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 EN
Relevância na Pesquisa
584.68156%
Multifunctional materials are a new class of thin films and coatings. These materials show interesting characteristics for application in many scientific areas, in special electronic and photonic technologies. These characteristics include sensitivity for thermal, light, mechanical, chemical and other influences, high resistivity, high electrical isolation and transparence in visible range. Recently it was obtained a new oxide type that combines oxygen, nitrogen and indium: the indium oxynitride. In this work, we study the deposition of indium oxynitride by reactive sputtering for application in photoconductor sensors. The deposition processes were performed in a home build magnetron sputtering system, using a four-inch pure In target, nitrogen and oxygen as process gases. The pressure was kept constant at 10 mtorr and the RF power (13.56 MHz) was constant at 250 W. The photoconductors were made with these thin films. The photoelectric detectors were analyzed by IxV (current versus voltage) analyses. The IxV analysis presented a low leakage current (10-8 A). The photoelectric effect was observed from the difference between the case with emitted light and dark currents. It increased around 140 times, under illumination of a halogen lamp. The Hall Effect measurements indicated that the films were n-type semiconductors. The increase in the oxygen concentration added in the plasma...

Films and edible coatings containing antioxidants - a review

Eça,Kaliana Sitonio; Sartori,Tanara; Menegalli,Florencia Cecilia
Fonte: Instituto de Tecnologia de Alimentos - ITAL Publicador: Instituto de Tecnologia de Alimentos - ITAL
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
613.89434%
The incorporation of natural antioxidants into films and edible coatings can modify their structure, improving their functionality and applicability in foods, such as in fresh-cut fruits. This paper reviews the more recent literature on the incorporation of antioxidants from several sources into films and edible coatings, for application in fruits and vegetables. The use of synthetic antioxidants in foods has been avoided due to their possible toxic effects. Instead, a wide range of natural antioxidants (such as essential oils and plant extracts, as well as pure compounds, like ascorbic acid and α-tocopherol) have been incorporated into edible films and coatings to improve their bioactive properties. Films and coatings containing added antioxidants help to preserve or enhance the sensory properties of foods and add value to the food products by increasing their shelf life.

Antimicrobial Edible Films and Coatings for Meat and Meat Products Preservation

Sánchez-Ortega, Irais; García-Almendárez, Blanca E.; Santos-López, Eva María; Amaro-Reyes, Aldo; Barboza-Corona, J. Eleazar; Regalado, Carlos
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
694.678%
Animal origin foods are widely distributed and consumed around the world due to their high nutrients availability but may also provide a suitable environment for growth of pathogenic and spoilage microorganisms. Nowadays consumers demand high quality food with an extended shelf life without chemical additives. Edible films and coatings (EFC) added with natural antimicrobials are a promising preservation technology for raw and processed meats because they provide good barrier against spoilage and pathogenic microorganisms. This review gathers updated research reported over the last ten years related to antimicrobial EFC applied to meat and meat products. In addition, the films gas barrier properties contribute to extended shelf life because physicochemical changes, such as color, texture, and moisture, may be significantly minimized. The effectiveness showed by different types of antimicrobial EFC depends on meat source, polymer used, film barrier properties, target microorganism, antimicrobial substance properties, and storage conditions. The perspective of this technology includes tailoring of coating procedures to meet industry requirements and shelf life increase of meat and meat products to ensure quality and safety without changes in sensory characteristics.

Use of Antimicrobial Films and Edible Coatings Incorporating Chemical and Biological Preservatives to Control Growth of Listeria monocytogenes on Cold Smoked Salmon

Neetoo, Hudaa; Mahomoodally, Fawzi
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
610.7372%
The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population of L. monocytogenes by a maximum of 3.3 log CFU/cm2 (films) and 2.9 log CFU/cm2 (coatings) relative to control samples after 10 days of storage at 21°C. During refrigerated storage, coatings were more effective in inhibiting growth of L. monocytogenes than their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population of L. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm2, respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development of L. monocytogenes and spoilage microflora thus enhancing the safety and quality of CSS.

Influence of counter-ions on antifogging coatings

Sundareshan, Shashank
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 38 leaves
ENG
Relevância na Pesquisa
584.62605%
The influence of different counter-ions on the superhydrophilic and antifogging behavior of polyelectrolyte multilayers was examined. Multilayers assembled with a polymer anion and amine-modified silica nanoparticles were treated with salt solutions of monovalent and divalent cations. Refraction index of the films dropped significantly when treated with monovalent cations, and increased when treated with divalent cations. It has been found that the refraction index decrease in films treated with monovalent salts may be correlated with porosity increase in treated films, and this porosity increase in turn linked with an increase in hydrophilicity. Polyelectrolyte films have yet to show long-lasting antifogging properties on the commercially valuable polycarbonate, but monovalent cations may have improved the longevity of antifogging properties of the multilayer on polycarbonate, and warrant further study.; by Shashank Sundareshan.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, June 2008.; "May 2008."; Includes bibliographical references.

Chitosan edible films and coatings - a review.

AZEREDO, H. M. C. de; BRITTO, D. de; ASSIS, O. B. G.
Fonte: In: DAVIS, S. P. (Ed.). Chitosan: Manufacture, properties, and usage. Hauppauge, NY (EUA): Nova Science Publishers, 2010. Cap. 30, p. 179-194. Publicador: In: DAVIS, S. P. (Ed.). Chitosan: Manufacture, properties, and usage. Hauppauge, NY (EUA): Nova Science Publishers, 2010. Cap. 30, p. 179-194.
Tipo: Capítulo em livro técnico-científico (ALICE)
EN
Relevância na Pesquisa
577.93277%
2011

Synthesis and Applications of Nanostructured Mesoporous Organosilica Films and Monoliths

Du, Jenny
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
602.8393%
Surfactant-templated, sol-gel based methodologies for the synthesis of tailored, nanostructured, hybrid inorganic–organic materials are incredibly powerful and versatile. Although growth in this field has been explosive in recent decades, a lot of room remains to contribute to the design and synthesis of new materials, as well as the development of advanced applications. In the work described herein, we firstly explored the synthesis of thick, mesoporous organosilica films and their application as functional coatings for solution-based, fibre-optic heavy metal sensors. Notably, sub-ppm level detection was observed for the detection of Pb(II) in mixed aqueous–organic media in short timeframes, and progress has been made toward synthesizing organotitania films that would allow for heavy metal sensing in purely aqueous solution. Furthermore, the utility of these types of surfactant-templated, organically-functionalized, mesostructured coatings has been preliminarily extended to other types of optical devices for heavy metal sensing. We have also explored the use of designer amphiphilic, alkyl oligosiloxane precursors for the tightly-controlled formation of thin, self-templated, hybrid nanostructured films. Moreover, films bearing uniaxial 2D hexagonal alignment over macroscopic length scales were obtained using polymer-treated substrates to control the interfacial interactions between the film precursors and the substrate surface. In addition...

Effect of relative humidity on carvacrol release and permeation properties of chitosan based films and coating

KUREK, Mia; GUINAULT, Alain; VOILEY, Andrée; GALIC, Kata; DEBEAUFORT, Frédéric
Fonte: ELSEVIER Publicador: ELSEVIER
EN_US
Relevância na Pesquisa
581.51055%
The influence of water vapour conditions on mass transport and barrier properties of chitosan based films and coatings were studied in relation to surface and structural properties. Water contact angles, material swelling, polymer degradation temperature, barrier properties (PO2, PCO2, WVP) and aroma diffusion coefficients were determined. The solvent nature and the presence of carvacrol influenced the surface and structural properties and then the barrier performance of activated chitosan films. Increasing RH from 0% to 100% led to a significant increase in material swelling. The plasticization effect of water was more pronounced at high humid environment, while at low RH the matrix plasticization was induced by carvacrol. The deposit of a thin chitosan layer on polyethylene decreased PO2 and PCO2 both in dry and humid conditions. The carvacrol release from the chitosan matrix was strongly influenced by RH. A temperature increase from 4 to 37 C also had an impact on carvacrol diffusivity but to a lesser extent than RH.

Preparação, propriedades e aplicação de biofilmes comestiveis a base de gluten de trigo.; Preparetion, properties and application of wheat gluten-based films.

Patricia Sayuri Tanada Palmu
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/07/2003 PT
Relevância na Pesquisa
621.4538%
Recentemente surgiu um grande interesse no desenvolvimento de biofilmes comestíveis ou degradáveis biologicamente, principalmente devido à demanda por alimentos de alta qualidade e preocupações ambientais sobre o descarte de materiais não renováveis de embalagem para alimentos. Os biofilmes são geralmente produzidos com macromoléculas, como polissacarídeos, proteínas, lipídios e derivados. O objetivo desse trabalho foi o desenvolvimento e caracterização de biofilmes simples de glúten de trigo, composto e de duas camadas contendo cera de abelha e ácidos palmítico e esteárico, bem como testar a aplicação dos filmes e das coberturas em frutas frescas. A solução formadora de filme foi preparada usando glúten de trigo, etanol, glicerol e hidróxido de amônio (6N) para ajustar o pH da solução. As composições das formulações dos filmes foram calculadas segundo um planejamento fatorial 24. As propriedades funcionais utilizadas para verificar os efeitos dos fatores foram as propriedades mecânicas (resistência à tensão e elongação na ruptura), permeabilidades ao vapor d'água e ao oxigênio e solubilidade em água. A partir da formulação que apresentou as melhores propriedades funcionais, foram desenvolvidos e caracterizados os filmes compostos e de duas camadas contendo glúten de trigo...

Effect of moderate electric fields in the permeation properties of chitosan coatings

Souza, B. W. S.; Cerqueira, M. A.; Casariego, A.; Lima, A. M. P.; Teixeira, J. A.; Vicente, A. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /12/2009 ENG
Relevância na Pesquisa
616.5355%
Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. Preliminary works have shown that the presence of a moderate electric field during the preparation of chitosan coating solutions may influence e.g. their transport properties. If such effect is confirmed, moderate electric fields could be used to tailor edible films and coatings for specific applications. The aim of this work was to determine the effect of field strength on functional properties of chitosan coatings (obtained from lobster from the Cuban coasts). Four different field strengths were tested (50, 100, 150, 200 V cm−1) and, for each electric field treatment, the water vapor, oxygen and carbon dioxide permeabilities of the films formed were determined, together with their color, opacity and solubility in water. The surface microstructure of the films was analyzed using atomic force microscopy (AFM). The results showed that ohmic heating had statistically significant effects on film's physical properties and structure. In general, the most pronounced effect of the field strength was observed for treatments made at 100 V cm−1 or higher, a positive correlation being found between the water vapor...

Revestimentos comestíveis à base de quitosano e cera de abelha: aplicação na conservação de uva de mesa; Edible coatings based on chitosan and beeswax: their usage on the conservation of table grapes

Fonseca, João Paulo Caria Gerald Queiroz
Fonte: ISA/UTL Publicador: ISA/UTL
Tipo: Dissertação de Mestrado
Publicado em //2012 POR
Relevância na Pesquisa
613.6871%
Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia; For this study we produced three different formulations to obtain edible films and coatings based on chitosan, incorporated with beeswax, glycerol and a surfactant (Tween 80). It was studied the effect of beeswas concentration (0%, 10% e 20% wax mass per polymer mass) in the properties of the films obtained. Regarding the mechanical properties of the films, the results show that the tensile strength, elongation, Young's modulus, perforation tension and deformation were not significantly affected by the wax concentration used. The Water Vapor Permeability (WVP) and hydrophilicity of the films decreased with wax incorporation. The WVP decreased about 99% due to the permeability of the films without wax. During the performance evaluation of edible coatings, on the study of grapes preservation, it was found that the application of such coatings favors the dehydration of the fruit; as they do not significantly affect the grapes properties (color, texture, brix and pH) compared to the control sample. The sensory and multivariate analysis performed showed that the chitosan coating embedded with wax is not the most suitable for usage on grapes.

Fabrication and characterization of thin films and coatings

Miller, Timothy James
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
600.2866%
Teplyakov, Andrew V.; Surface and interfacial chemistry is a major, well-researched topic in science. From microelectronics to biosensors to catalysis, surface chemistry research is applicable to many different areas. This dissertation focuses on three of these areas: photovoltaics, protective coatings, and a novel nanoparticle deposition procedure. These three areas are all related through energy-related research. An additional focus is placed on the understanding of the systems' chemistries at the molecular level. Several surface spectroscopic and microscopic techniques are utilized to understand the systems. Spectroscopic techniques include Fourier-transfrom infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and X-ray diffraction (XRD). Surface microscopic techniques include scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM). Additionally, nanoindentation measurements are used to determine Young's modulus for the protective coatings. For some studies, density functional theory models were used to complement experimental results, and predict pathways.; University of Delaware, Department of Chemistry and Biochemistry; Ph.D.

Significant improvement of adhesion between gold thin films and a polymer

Li, Wei; Charters, Robbie; Luther-Davies, Barry; Mar, L
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
586.80562%
A novel technique was demonstrated for realizing extremely strong adhesion between gold thin films and a polysiloxane based polymer. The surface of the polymer was modified by using a plasma treatment. The variation of the wettability and topography of the polymer surface with the plasma conditions were investigated through water contact angle measurement and scanning electron microscope observation, respectively. It was found that the polymer surface was roughened greatly, and its water contact angle was reduced from 81 to 0° by using 1min of O2/CF4 plasma treatment. The pull-off strength of the Au film from the polymer was enhanced from 1.2 to 8.5N/mm 2 after the plasma treatment. Further improvement of the adhesion was achieved by sputter-coating two adhesion layers, Al2O 3/Al, on the polymer before coating the Au film and annealing the films at 150°C for 2h. The pull-off strength of the Au film from such a polymer/Al2O3/Al/Au system was over 35N/mm2. The extremely strong bonding between the Au and the rest layers of the system was explained mainly by the formation of Au-Al alloys at the interface between the Al and Au layers based on an analysis using chemical etch and energy dispersive X-ray spectroscopy.

Edible films and coatings for cheese; Filmes e revestimentos comestíveis para queijos

Orosa, Maria Inês Franco
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
805.78164%
Over the last years there has been an increasing interest to replace synthetic materials by biodegradable ones, due to the ecological problems. Edible and biodegradable films can be produced using polysaccharides, lipids, proteins and composites, and act as a package without damaging the environment. By choosing a suitable coating composition it is possible to preserve several desired properties of a certain food product. Important properties should be considered, such as mechanical, functional and barrier properties. The main goal of this study was to evaluate edible films and coatings from plant proteins (pea, soy), with incorporated natural antimicrobial and antioxidant agents, to potentially protect cheese from physico-chemical and microbial deterioration and to preserve the organoleptic characteristics, especially of sliced cheeses. The work performed focused mainly on the preparation and characterization of pea protein films, with added chitooligosaccharides (COs) (0.5%, 1% and 2%) and two types of essential oils at 1%, bay and thyme oils. Films with 0.5% of COs showed the highest values of Young’s modulus, tensile strength and elongation. Regarding the barrier properties, the film with 1% of COs showed the lower permeability value. Addition of small amounts of COs may be advantageous to improve the mechanical properties of the PPI films...