Navegando por Assunto "Antioxidants"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Adsorção e dessorção supercrítica de carotenos e antioxidantes do óleo de buriti (Mauritia flexuosa, Mart) em leito de γ- Alumina
(Universidade Federal do Pará, 2012-03) CUNHA, Marcos Augusto Eger da; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172; MACHADO, Nélio Teixeira; http://lattes.cnpq.br/5698208558551065
In this work we investigated the enrichment of antioxidants buriti oil (Mauritiaflexuosa Mart) adsorption process by supercritical. The adsorption was carried out experimentally by the method of frontal analysis in columns packed with y-alumina and 15, 20 e 25 MPa, 333 K, and flow of solvent QCO2 = 10,6 L/min, using an assembly of double columns of 81 cm3, tested and approved for use as a cell adsorption. The oil was buriti physic-chemically characterized according to the AOCS official methods and found to comply with the data reported in the literature. The composition of methyl esters was determined by gas chromatography (CG) and antioxidant activity by the method of capture of free radicals (DPPH). The adsorbent was characterized by fluorescence and x-ray diffraction, determining the particle size distribution, porosity and surface area by BET in each experiment, a material balance was performed in the adsorption column to calculate the mass of the adsorbed species in y-alumina in the process of supercritical adsorption. The influence of pressure on supercritical adsorption was investigated by examining the behavior of the isotherms. The Langmuir isotherm was used to model the experimental data of adsorption. The experimental results show an increased capacity adsorbent with higher pressures, showing a maximum of 90,9 ± 8,6 mg oil/g y-alumina, at 25 MPa. The adsorption supercritical buriti oil on γ-alumina using carbon dioxide as solvent appears to be an alternative method for extracting antioxidants from the includ carotenes.
Acesso aberto (Open Access)
Potencial antioxidante de compostos bioativos da chicória (eryngium foetidum L.) por métodos químicos (in vitro)
(Universidade Federal do Pará, 2022-04-29) LEITÃO, Deusa do Socorro Teixeira Costa; CHISTÉ, Renan Campos; http://lattes.cnpq.br/0583058299891937; LOPES, Alessandra Santos; http://lattes.cnpq.br/8156697119235191
Amazonian chicory (Eryngium foetidum L.), a native plant to the Amazon and Central America, is one of the main unconventional vegetables (PANCs) grown in Brazil and considered as apromising source of bioactive compounds. The main objective of this work was to determine the composition of phenolic compounds and carotenoids in amazonian chicory leaves using high performance liquid chromatography coupled to diode array detectors and mass spectrometer (HPLC-DAD-MS /MS), as well as the evaluation of the in vitro antioxidant potential. The leaves of Amazonian chicory presented high contents of water (87%), low contents of lipids (2.8%), proteins (1.99%) and low total energy value (52.23 kcal/100 g). The main phenolic compounds in the leaves were chlorogenic acid (4328 μg/g), followed by ferrulic acid derivative (3892 μg/g), while the main carotenoids were lutein (204.86 μg/g), followed by β-carotene (161 μg/g leaves). Regarding the evaluation of the in vitro antioxidant capacity, the hydromethanolic extract of Amazonian chicory leaves was able to eliminate DPPH●(91.6%, at 5 mg/mL), ABTS●+ (15.77 μM Trolox equivalent/g of extract) and exhibited high efficiency to protect tryptophan against 1O2 in a concentration-dependent manner (IC50 = 343 μg/mL). Furthermore, Amazonian chicory leaf extracts were obtained using green solvents with different polarities [H2O, EtOH/H2O, EtOH (1:1, v/v)], through ultrasound-assisted extraction. The scavenging capacity of the extracts against the main reactive oxygen (ROS) and nitrogen (RNS) species was evaluated, namely the superoxide anion radical (O2•-), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), and the peroxynitrite anion (ONOO−). The EtOH/H2O extract presented the highest phenolic compound contents (5781.00 mg/g extract) and the highest scavenging efficiency, being chlorogenic acid the major compound (38%). All the extracts were efficient in scavenging all the tested ROS and RNS in a concentration-dependent manner. The EtOH/H2O extract was the most effective (IC50 of 45.00 – 1000 μg/mL) for almost all species, with the exception of 1O2. Regarding ROO•-scavenging capacity, the most efficient extract was EtOH. Based on the results of this study, the green solvents used in this study were promising for obtaining amazonian chicory leaf extracts with a high content of bioactive compounds and antioxidant capacity. Therefore, such information have great relevance for the food, cosmetic and pharmaceutical industries, since amazonian chicory is a natural rich source of bioactive compounds to be used as potential raw material for obtaining extracts against oxidative damage both in food and physiological systems.
Acesso aberto (Open Access)
Principais compostos bioativos e capacidade antioxidante da polpa do camu-camu (Myrciaria dubia) em diferentes estádios de maturação
(Universidade Federal do Pará, 2014-06-25) OLIVEIRA, Thaise Cristine de Souza; MATTIETTO, Rafaella de Andrade; http://lattes.cnpq.br/7832266671782588; LOPES, Alessandra Santos; http://lattes.cnpq.br/8156697119235191
This study aimed to determine physical and physico-chemical characteristics, bioactive compounds and antioxidant capacity from camu-camu pulp of three different progenies, came from Active Germplasm Bank of camucamuzeiro, at Embrapa Amazônia Oriental, in three ripening stages. Over the ripening, the mass and the diameters varied (p ≤ 0.05) just for progeny 44 and the pulp yield increased for all the progenies, with results over 50% in the ripe stage. The ripening stage didn’t show effects in the moisture and ashes content and also pH for progeny 38; ashes for progeny 44 and fat and insoluble fibers for progeny 17. The others results varied with the ripening, but, with different behaviors to each progeny, except for the total sugar, soluble solids contents and the SS/TTA ratio, which showed a tendency to increase, and the total titratable acidity decreased in all the progenies. Overall, a higher level of vitamins C were obtained in the green stage, with a first step of degradation, as it reached the semi-ripe stage, followed by a synthesis step until the end of the ripening stage, except for the progeny 38, which showed a reduction. As for the phenolic compounds, during the ripening stage, the three progenies were characterized for synthesis and degradation processes of the total phenolic compounds; the total flavanols decreased; the flavonols content had a distinct behavior in each progeny, with an increasing in the progenies 17 and 38, and a decreasing in the progeny 44; due to a limitation of the method used to determine small quantities, It was possible to quantify anthocyanins only for progenies 17 and 44 in the ripening stage. The antioxidant capacity, determinated through the methods TEAC and DPPH, decreased in all the progenies. Besides the significant effects of the ripening stage, the results showed that the genetic variability of camu-camu influenced significantly the physical characteristics of the fruits and the continents of all compounds studied, and still the antioxidant capacity obtained through the methods mentioned.
Acesso aberto (Open Access)
Principais compostos bioativos e capacidade antioxidante no epicarpo do camu-camu (Myrciaria dubia) em função da maturação
(Universidade Federal do Pará, 2014-06-25) SOUZA, Aline Ozana de; MATTIETTO, Rafaella de Andrade; http://lattes.cnpq.br/7832266671782588; LOPES, Alessandra Santos; http://lattes.cnpq.br/8156697119235191
The presence of bioactive compounds suffers greatly influenced by environmental and genetic factors, and behave differently in each part of the plant. However, there are few studies which deal these aspects of camu-camu. Thus, this study aimed to analyze the physical, physico-chemical composition, the main bioactive compounds and antioxidant capacity of camu-camu bark, depending on the stage of ripeness in fruits of different genotypes from plant matrices Bank Active Germplasm Camucamuzeiro of Embrapa Eastern Amazon. Fruits of three genotypes, selected at random in three maturity stages were collected. Results were expressed on a dry basis and analyzed by Analysis of Variance, Comparison Test Tukey's and Pearson's Correlation Coefficient, with a confidence interval of 95%. For physico-chemical analysis, there was a different one for each progeny, depending on maturity, except that the carbohydrate content increased in all progenies behavior. For vitamin C, the progenies 38 and 44 showed a high content of ascorbic acid, comparing the green and ripe stages, and 17 progeny showed a decrease during maturation; the highest content of vitamin C has been found in 44 progeny, ripe stage (24,02 g/100g). All progenies showed an increase in the content of total phenolics and anthocyanins throughout maturation, with the highest values were demonstrated by progeny 17 (3298,98 AGE/100g mg) and 44 (165,91 mg/100g) respectively. Flavonols and carotenoids showed a distinct and statistically different behavior in each progeny, with the highest content of flavonols was found in 17 progeny in the green stage (343,63 mg QE/100g) and carotenoids in 44 progeny, ripe stage (105,88 mg/100g). Regarding the antioxidant activity based on the DPPH method, the progenies 38 and 44 showed the same behavior throughout maturation, with higher antioxidant activity half ripe and smallest stage in green, with the highest antioxidant activity was found in 17 progeny in the ripe stage (38,95 g fruit/g). Already by ABTS method, the antioxidant activity was statistically different for all progenies and in all stages of maturation, higher value submitted by 44 progeny at maturity (170,63 μM trolox/g). Evaluating the relationship between bioactive compounds and antioxidant activity, the 17 progeny won more statistically significant correlations. It can be concluded that various factors cause differences in the synthesis of various compounds during fruit ripening of camucamuzeiro.