Navegando por Assunto "Filmes biodegradáveis"

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Acesso aberto (Open Access)
Desenvolvimento e caracterização de filmes de gelatina de peixe com carboximetilcelulose, álcool polivinílico e adição de nanopartículas de prata
(Universidade Federal do Pará, 2023-08-11) FERNANDES, Gleyca de Jesus Costa; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769; https://orcid.org/0000-0001-5009-8235
The general objective of this thesis was “To develop and characterize biodegradable films of fish gelatin combined with carboxymethyl cellulose and polyvinyl alcohol, added with silver nanoparticles” and is structured into three chapters. The first chapter presents a review article that serves as theoretical support for the research carried out, which is entitled “Biodegradable polymeric blends of fish gelatin, carboxymethylcellulose and polyvinyl alcohol used as active packaging: A review”. This manuscript provides an overview of the main features and shortcomings related to the application of fish gelatin in biodegradable films. It presents information that reports the production of films from the combination of biopolymers as a good strategy to overcome their limitations, highlights carboxymethylcellulose and polyvinyl alcohol as interesting polymers to form mixed films with gelatin with improved properties and considers the possibility of incorporating active compounds , particularly silver nanoparticles, to these polymeric matrices with the aim of providing antimicrobial properties to the films and extending the shelf life of packaged foods. The second chapter corresponds to the already published article entitled “Effect of polyvinyl alcohol and carboxymethyl cellulose on the technological properties of fish gelatin films”. In this study, biodegradable films were produced by mixing gelatin/carboxymethyl cellulose (FG/CMC) and gelatin/polyvinyl alcohol (FG/PVOH) in proportions 90/10, 80/20 and 70/30 with a total concentration of 3% (m/v) of solution and 10% (w/w polymers) of plasticizer, and the effect of adding these polymers on the performance of fish gelatin films was evaluated. The results showed that the mixture of gelatin with CMC and PVOH improved the mechanical strength, water vapor barrier capacity and solubility of the films. The maximum CMC concentration promoted the highest tensile strength, while the highest PVOH content produced a film with lower solubility. FG/PVOH films were more flexible and water resistant, but presented lower mechanical and thermal resistance compared to FG/CMC. The proposed mixing systems proved to be suitable for improving the properties of fish gelatin films. Chapter three presents the article “Optimization of the process for obtaining a biodegradable nanocomposite film based on fish gelatin and carboxymethylcellulose reinforced with silver nanoparticles”. The objective was to develop a biodegradable nanocomposite film from fish gelatin (FG), carboxymethylcellulose (CMC) and silver nanoparticles (NpAg). The formulation was optimized using response surface methodology to establish the best levels of FG (2–4%), CMC (0.5–1%) and NpAg(0.005–0.01%) in order to obtain a film nanocomposite (FG/CMC-NpAg) with better mechanical and barrier properties. The optimization was done based on the responses to water vapor permeability (PVA), tensile strength (RT) and elongation (E). The optimized conditions were: 3% FG, 0.54% CMC and 0.011% NpAg. The mechanical properties, PVA, solubility, optical properties and light transmission of the optimized and control films were analyzed. The optimized FG/CMC-NpAg film showed lower elongation and transparency, but on the other hand demonstrated greater tensile and water resistance, as well as improved barrier properties in relation to water vapor and ultraviolet light, when compared to the control film. Overall, the results indicated that the biodegradable nanocomposite film developed in this study may be suitable for use as packaging material.
Acesso aberto (Open Access)
Elaboração e caracterização de filmes a partir de farinha de pupunha (Bactris gasipaes), quitosana e glicerol pelo método de casting
(Universidade Federal do Pará, 2019-06-26) COSTA, Rebeca Desireé Sousa da; RODRIGUES, Antonio Manoel da Cruz; http://lattes.cnpq.br/7524720020580309; SILVA, Luiza Helena Meller da; http://lattes.cnpq.br/2311121099883170
Environmental problems caused by packaging manufactured from non-biodegradable and renewable sources have led to increased interest and attention from industry and researchers in terms of films and edible toppings development. Films are usually obtained from polymers such as polysaccharides, proteins and lipids, used to help maintain the quality and food shelf life. Thus, the aim of this study was to develop films using the casting technique from biodegradable sources with antimicrobial activity, in addition to evaluate the mechanical, barrier, optical, structural and thermal properties as well as to analyze the rheological behavior of the different filmogenic suspensions. The films were prepared with different ratios of peach palm flour, chitosan and glycerol. The presence of chitosan led to an improvement in the mechanical, optical and morphological properties of the films; however, they did not show antimicrobial activity against foodborne pathogens as E. coli and S. aureus. The rheological study showed that all the filmogenic suspensions presented non-Newtonian fluid behavior, with dilating characteristics. The Herschel-Bulkley and Bingham models were tested, and both fit satisfactorily to the rheological data, presenting high values for the R2 factor and low values for the χ2 factor. The results obtained for the fluid behavior index (n) presented values of n> 1 for all the samples, proving the dilator behavior of the suspensions. The films obtained presented a smooth and homogeneous surface, slightly soluble, permeable to water vapor, yellow coloration due to the high content of carotenoids present in the peach palm. FTIR spectra revealed the presence of the group amide I and the films exhibited the type C X-ray pattern. After 15 days in soil, the films lost 30% of its initial weight. Therefore, films obtained exhibit properties / properties similar to conventional films, with the advantage of being biodegradable from renewable sources and can replace the current packaging.
Acesso aberto (Open Access)
Obtenção e avaliação dos extratos e óleos de canela e cipó d’ alho e aplicação em filmes biodegradáveis: estudo experimental e teórico
(Universidade Federal do Pará, 2022-08-30) NASCIMENTO, Fabiana Cristina de Araújo; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; https://orcid.org/0000-0002-1461-7306; JOELE, Maria Regina Sarkis Peixoto; http://lattes.cnpq.br/2618640380469195; https://orcid.org/0000-0001-5442-0615
Various spices such as dried fruits and food grains are prone to contamination by filamentous fungi, such as the species Aspergillus Niger, increasing the risk of ingestion of mycotoxins by the population. The production of biodegradable films added to extracts and essential oils can give the same antifungal properties. Thus, this study aimed to develop biodegradable films based on cassava starch with addition of extracts and oils of cinnamon and garlic vine and evaluate its efficiency against the fungus Aspergillus Niger. The ethanol and aqueous extracts were obtained by Soxlet extraction and maceration, respectively, while the oils were obtained by hydrodistillation. To identify the major compounds of the extracts and oils, NMR and Gas Chromatography analyzes were performed. These compounds identified were selected as ligands before the enzyme glucose oxidase produced by the fungus for the theoretical study through Molecular Docking. The extracts and oils were evaluated in antifungal diffusion tests in discs and wells, respectively. The biodegradable films were prepared with extract and oils of cinnamon and garlic vine that showed better performance in antifungal tests. All the elaborated films were evaluated in the antifungal test by means of the technique of diffusion in discs. In the theoretical study through Molecular Docking, all the ligands present in the extracts and oils showed hydrogen bonds with the key amino acid residues of the enzyme glucose oxidase being Histidine (His 559 A), Threonine (Thr 110 A) and Arginine (Arg 512 A). In the antifungal tests, the ethanolic extract of the plant species garlic vine showed a higher inhibition halo of 15mm at a concentration of 20mg/ml while the antifungal tests for oils, at volumes of 1 µl; 5 µl and 10 µl revealed the formation of inhibition halos of 25mm; 28mm and 30mm for cinnamon oil. While, in the film with the oil of the vine of garlic, the inhibition of the germination of said fungus occurred during 9 days of experiment. The antifungal tests of the films revealed that the films with surfactant containing garlic vine oil did not present sporulation halos and neither mycelial growth on films 1 and 2 during the 48h of the experiment, inhibition of the growth of the fungus through the films.