Navegando por Assunto "CO2 supercrítico"

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Acesso aberto (Open Access)
Aplicação da tecnologia supercrítica e de fndição na obtenção de embalagens ativas de gelatina de peixe (Cynoscion acoupa) com óleo essencial piper divaricatum
(Universidade Federal do Pará, 2021-10-27) ALBUQUERQUE, Gilciane Américo; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748; JOELE, Maria Regina Sarkis Peixoto; http://lattes.cnpq.br/2618640380469195
Active films produced with gelatin from the skin of hake fish (Cynoscion acoupa) and essential oil (EO) Piper divaricatum were obtained by two techniques: impregnation by supercritical CO2 (scCO2) and casting. Initially, the process of impregnating the EO in the gelatin film was carried out using CO2 as a supercritical solvent, in an autoclave at 35 º C, at pressures of 100, 150 and 200 bar and times of 60, 90 and 120 min. The active film that showed the highest percentage of inhibition of antioxidant activity (IAA%) was obtained at 100 bar and 60 min (41.63±1.6%). Scanning electron microscopy (SEM) showed that the EO presented heterogeneous distribution in the film, confirming the impregnation. The scCO2 impregnation resulted in a film with lower tensile strength and thermal stability, greater flexibility and opacity when compared to the control, indicating the potential of this technique to obtain active packaging for food products. After determining the best parameter of the impregnation process, the concentrations of 10%, 20% and 30% of the EO in the gelatin film were compared by the casting and impregnation techniques by scCO2. The films obtained with the addition of 20% (71.97±1.71) and 30% (79.17±1.01) of EO produced by casting showed the highest retentions of the IAA%. Films made by scCO2 impregnation showed lower antioxidant activity, but this was improved with increasing EO content from 20% (23.57±1.45) to 30% (33.66±2.42). Through scanning electron microscopy (SEM) images, oil droplets with heterogeneous distribution were observed in films impregnated by scCO2 and homogeneous surface by the casting technique. The films impregnated with scCO2 proved to be transparent, resistant to traction, elastic and with greater thermal stability. Meanwhile, the films produced by casting showed greater resistance to moisture and greater protection from UV light. The casting technique showed greater potential for the production of active packaging, as the film showed better antioxidant potential with the incorporation of EO and the use of emulsifier in the film solution. Impregnation by scCO2 showed potential to obtain the active film, however further studies should be carried out to improve the limitations of oil retention in the film found in this
Acesso aberto (Open Access)
Diferentes métodos de secagem e desodorização por fluido supercritico de proteínas miofibrilares de resíduos de peixe para elaboração de filmes biodegradáveis
(Universidade Federal do Pará, 2021-03-16) BATISTA, Jáira Thayse Souza; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769; https://orcid.org/0000-0001-5009-8235
The present thesis consists of several connected stages and the objectives of each are: a) to study the influence of the use of different types of fish residues for the extraction of myofibrillar proteins (MP) on the technological properties of biodegradable films; b) To study the effect of different drying methods and temperatures of fish MP on the technological properties of the films; c) Deodorize fish MP using extraction with supercritical CO2, compare with solvent extraction in Soxhlet and elaborate biodegradable films with sensory properties suitable for use as food packaging. Based on these objectives, three manuscripts were prepared with the research results. In the first manuscript, carcasses with adhered muscle were used to obtain the mechanically separated meat (MSM) and the fillet toilet parings. The MP were extracted from these residues and the films produced. The results showed that the type of waste used directly influences all the analyzed properties of the films, due to the different centesimal compositions of the MP of the MSM and of the parings with significant differences mainly in the content of lipids and ash. These non-protein compounds in the protein extracted from the MSM acted as an interference in the formation of the film, generating inferior technological and thermal properties when compared to the film produced with MP extracted from the parings. Increasing the number of washes in the extraction of MP from more fatty and pigmented residues could decrease the concentration of non-protein compounds. In the second manuscript, the MP were dried by lyophilization at -60 ° C for 48 h and by convective drying of hot air at 40 °C, 60 °C at 80 °C. In convection drying, drying curves were constructed and the adjustments of the mathematical models were evaluated. The films were produced with dried proteins in different conditions and characterized. The drying times found were 540 min (40 °C), 300 min (60 °C) and 120 min (80 °C). The "logarithmic" models followed by the "diffusion approach" were the ones that best adjusted to all temperatures. The results of protein electrophoresis and the characterization of the film showed that the convective drying caused changes in the three-dimensional structure of MP, favoring the formation of a highly reticulated protein network with numerous hydrogen, hydrophobic and disulfide bonds, generating films with equal or better properties than those made with lyophilized MP. It was possible to verify that the convection drying by hot air can be used efficiently in MP used in the production of biodegradable films, reducing the time and the cost of producing the films. In the third manuscript, to deodorize the MP, supercritical CO2 was used, with global yield isotherms built at 40 and 60 ºC at 200, 300 and 400 bar. In solvent extraction in Soxhlet, petroleum ether was used at 52 ° C for 2h 30 min. The filmswere produced with MP control without deodorization and with MP deodorized with solvent in Soxhlet (due to the limitations caused by the pandemic caused by the new corona virus (SARS-CoV-2), until now it was not possible to define the best condition of deodorization with supercritical CO2 and make the film with MP deodorized by this method). The results showed that the best operational condition with supercritical CO2 was 40 ° C / 200 bar with a yield of 5.06 b.s. The best condition for supercritical extraction considering the greater efficiency in removing fish odor has not yet been determined due to the lack of analysis of aromatic compounds, it is not possible to say whether the higher oil extraction yield is directly related to greater extraction of oil other aromatic compounds such as trimethylamine and dimethylamine disulfide. The yield in relation to oil extraction was higher in solvent extraction in Soxhlet (8.04 b.s), possibly due to the low selectivity of the organic solvent that can also extract other compounds compared to the highly selective supercritical CO2. The film produced with MP that underwent solvent deodorization in Soxhlet showed all the studied properties improved in relation to the control. This indicates that the removal of lipids can solve not only the problem with the odor of fish in the films, but also provide a more isolated protein without interferences that favor the formation of films with better properties.
Acesso aberto (Open Access)
Extração de compostos bioativos de folhas de croton matourensis Aubl. com CO2 Supercrítico: determinação da composição química, atividade antioxidante e atividade biológica
(Universidade Federal do Pará, 2022-05-06) BEZERRA, Fernanda Wariss Figueiredo Bezerra; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748; https://orcid.org/0000-0002-2324-6287
The Croton matourensis species has health benefits, due to its composition, which has a high concentration of bioactive compounds such as phenolic compounds, terpenes, phenolic acids and phenylpropanoids. The most used method to obtain its extracts is hydrodistillation, however the extraction with supercritical carbon dioxide (SC-CO2) is an environmentally friendly method, with high selectivity and capable of obtaining extracts with a high concentration of larixol, an oxygenated diterpene of high economic value and with several biological activities. In this context, the present thesis aimed to use supercritical technology to obtain extracts from leaves of C. matourensis with a high concentration of larixol and to evaluate its potential anti-inflammatory, neuroprotective and antiviral activity against the COVID-19 virus. For this, in the first stage of the thesis, the extraction of C. matourensis leaves with SC-CO2 was carried out under different conditions of temperature (40 and 50 °C) and pressure (100 to 400 bar), the supercritical extraction was compared with hydrodistillation (HD) and hexane extraction (HE) through the evaluation of the mass yield, chemical composition and antioxidant activity of the extracts, then the experimental model of focal ischemia in the motor cortex of rats was carried out using the extract obtained in the best operating condition with SC-CO2. The highest yields were obtained in HE (5.73 ± 0.26%) and in the condition at 50°C/400 bar (5.60 ± 0.06%), which were statistically equal (p > 0.05), the supercritical condition was more advantageous in obtaining larixol (48.49%) compared to HE (2.93%). The extracts obtained by the different methods showed a high value of total phenolic compounds (51.81 ± 2.03 to 79.53 ± 1.19 mgGAE/g of extract), total flavonoids (2.50 ± 0.20 - 6.89 ± 0.45 mgQE/g of extract) and antioxidant activity with maximum inhibition percentage equal to 83.26 ± 0.58% at a concentration of 14 mg/mL. The focal cerebral ischemia study revealed that the animals treated with the C. matourensis extract showed a greater reduction in the lesion area than those treated with the control solution (Tween 5%), suggesting its potential anti-inflammatory and neuroprotective effect. In the second stage of the thesis, an in silico study was carried out to evaluate the interactions between the larixol ligand and four SARS-CoV-2 receptors. The molecular docking results showed that the mode of interaction played a fundamental role in the interaction with larixol, mainly in the interaction with Spike- protease. The study showed through the affinity energy that the ligand had stable conformations, forming a stable complex with the receptors, conforming to the catalytic site of the receptors. Molecular docking, molecular dynamics and Gibbs free energy data showed that larixol can bind to the binding compartment of receptors, evidencing its potential role as an antiviral agent or agent used in conjunction with other therapies that provide a line of defense against diseases associated with the coronavirus. Thus, the thesis showed that the extract of C. matourensis leaves obtained with SC-CO2 showed a high concentration of larixol, with potential anti-inflammatory, neuroprotective and antiviral activities, presenting potential to be applied as an input in the food, cosmetic and pharmaceutical industries.
Acesso aberto (Open Access)
Obtenção de extratos com potencial bioativo a partir da polpa do piquiá (caryocar villosum (aubl.) pers.) utilizando dióxido de carbono no estado supercrítico
(Universidade Federal do Pará, 2024-09-30) CORDEIRO, Renato Macedo; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748; https://orcid.org/0000-0002-4433-6580
In a context of increasing demand for substances with health-beneficial properties, extracts from certain plant species found in the Amazon are a promising source of bioactive compounds. Caryocar villosum (Aubl.) Pers., a native fruit of the Amazon region commonly known as piquiá, is regarded as a source of bioactive compounds. This study investigated the supercritical extraction process of piquiá pulp to evaluate the process parameters, overall yield, extraction kinetics, fatty acid profile, α-tocopherol content, functional quality, and physicochemical characterization. The influence of extraction temperature, pressure, and solvent density on the extraction yield was considered. The quality of the obtained extracts was assessed in terms of fatty acid profile, functional quality indices, physicochemical characterization, and α-tocopherol content. A kinetic study of the piquiá extraction with supercritical fluid was conducted using experimental data and mathematical models. The extraction yield was found to increase with pressure at each isotherm, with the highest yield reaching 62.74% and the lowest at 44.01%. The kinetic mathematical models of Martinez and Barton demonstrated good performance in correlating the extraction process of piquiá pulp. The primary fatty acids observed in the extracts obtained under all operational conditions were oleic and palmitic acids. The extract obtained at the operational condition of 60 °C and 250 bar exhibited the highest α-tocopherol content compared to the other experimental conditions in this study. The results indicated that the extracts from piquiá pulp obtained through supercritical CO₂ extraction present significant potential for the industry due to their functional quality.
Acesso aberto (Open Access)
Obtenção do óleo e da polpa sem gordura do açaí (euterpe oleracea) por extração supercrítica: caracterização físico-química, estudo da citotoxicidade e vida de prateleira
(Universidade Federal do Pará, 2025-01-06) SIQUEIRA, Letícia Maria Martins; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; https://orcid.org/0000-0002-1461-7306; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748; https://orcid.org/0000-0002-4433-6580
Açaí is a very important product for the development of the state of Pará, for the bioeconomy and the market has been growing. And currently the majority of the state’s production is just fruit pulp, hence the importance of new products with added value and the need to invest in new sustainable processes for the region’s development. Therefore, the objective of this work was to obtain the oil and pulp without açaí fat by supercritical extraction, determine the main bioactive compounds, evaluate the possible cytotoxicity in MRC-5 and VERO cells in vitro and evaluate the shelf life of the products. The freezedried açaí pulp was subjected to extraction with supercritical CO2, under the conditions 323,15 K at 35 MPa, 333,15 K at 42 MPa and 343,15 K at 49 MPa. The highest yield (51,74 %), carotenoids (277,09 μg/g), DPPH (2,55 μmol TE/g), ABTS (2,60 μmol TE/g) and FRAP (15,25 μm ferrous sulfate/g) from oil and ABTS (644,23 μmol TE/g) from pulp without fat were found at 343,15 K at 49 MPa condition. The highest contents of phenolic compounds (150,20 mg GAE/g d.b.), DPPH (414,99 μmol TE/g d.b.) and FRAP (746,2 μm ferrous sulfate/g) from pulp without fat were found at 323,15 K at 35 MPa condition. The pulp without fat presented high levels of anthocyanins without significant variation. The products did not present cytotoxicity. The half-life of the freeze-dried pulp and the fat-free pulp in the presence of light (Becker) was shorter than that of the packaging materials. The sealed packaging achieved a longer half-life compared to vacuum-sealed packaging for the freeze-dried pulp. However, for the fat-free pulp, the vacuum-sealed packaging showed a longer half-life compared to the sealed one. The results of the stability of açaí oil qualify it as a table oil rather than a frying oil, as it degrades more rapidly at higher temperatures. The results demonstrated that the products have potential applications in the industry.