Navegando por Assunto "Atividade oxidante"

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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)
Extração assistida por ultrassom de compostos bioativos das matrizes vegetais (eryngium foetidum L e talinum triangulare Jacq. Willd) do bioma amazônico utilizando solventes verdes
(Universidade Federal do Pará, 2021-10-19) SANTOS FILHO, Adilson Ferreira; RODRIGUES, Antonio Manoel da Cruz; http://lattes.cnpq.br/7524720020580309
The present work aims to evaluate the extraction parameters of bioactive compounds (phenolic compounds, flavonoids, carotenoids, chlorophyll, anthocyanins, betalains and saponins) and antioxidant capacity (DPPH and FRAP) of extracts using the probe assisted extraction method ultrasound with green solvents (ethanol and olein), in samples of chicória leaves (Eryngium foetidum L.) and cariru leaves (Talinum triangulare Jacq. Willd.). Five phases of extractions were evaluated, where in each phase the effect generated individually of each variable (ethanol concentration, proportion of ethanol and olein mixture, equipment range, temperature and extraction time) on bioactive compounds and antioxidant capacity were evaluated. In the 1st extraction phase, the results obtained in this presented work was high yields of biomolecules and antioxidant capacity in relation to the levels reported in the literature of chicória and cariru. The 70% ethanol concentration was the best extraction range for the samples. In the 2nd phase, the mixture ratio of 1:3 of ethanol: olein was the best range for capturing bioactive compounds for both samples. In the 3rd extraction phase (equipment range) when it varies from 50 to 80%, it was observed that depending on the compound of interest, the range used can vary, however, the range of 70% showed the highest yield in relation to bioactive compounds and antioxidant capacity for chicória and cariru. In relation to the 4th extraction phase (temperature) it allowed an increase in the capture of the compounds, being the ideal range of 30ºC for cariru and 40ºC for chicória. In the last extraction phase where the extraction time was evaluated, it was found that for both samples the period of 15 minutes provided high yields. Regarding the applied modeling, it can be highlighted that the kinetic model of mass transfer presents the possibility to predict the experimental data and to predict values of bioactive compounds with a confidence limit of 99%. By evaluating the oxidative stability of the extracts, it can be seen that the compounds present in the optimized extracts enabled a protective action, managing to extend the olein stability index from 8 hours to 13.68 hours in the case of cariru extract and 12.79 hours for chicory. 7