Características físico-químicas e propriedades funcionais tecnológicas do bagaço de mirtilo fermentado e suas farinhas

A industrialização de frutas permite que os consumidores usufruam seus benefícios funcionais; porém, na maioria das vezes, o processamento produz resíduos industriais que normalmente não são aproveitados. Desta forma, o bagaço do mirtilo é um subproduto da fermentação que geralmente é desprezado na natureza, originando poluição ambiental. Este trabalho objetivou a caracterização físico-química, a determinação da atividade antioxidante, antocianinas e polifenóis do fruto de mirtilo, bagaço de mirtilo proveniente da produção de bebidas fermentadas e da farinha obtida deste bagaço, bem como as propriedades funcionais tecnológicas e a estabilidade microbiológica destas farinhas. As farinhas do fruto e do bagaço foram obtidas a partir da desidratação em estufa a 60 ºC, por 36 h, e moídos em micromoinho refrigerado a 4 ºC. As características físico-químicas foram verificadas a partir das análises de umidade, proteína, lipídeos, cinzas, acidez, pH e sólidos solúveis. A atividade antioxidante foi determinada pelo método DPPH, e os polifenóis totais, pelo método de Folin-Ciocalteu. Os resultados demonstram que tanto o mirtilo quanto o bagaço possuem elevado conteúdo de água. O mirtilo apresentou 61,67 mg/100 g em antocianinas, 431,43 mg EAG/100 g em polifenóis e 3,83 mg/mL de atividade antioxidante, enquanto o bagaço obteve 57,32 mg/100 g; 297,20 mg EAG/100 g; 5,61 mg/mL, respectivamente. As farinhas apresentaram estabilidade microbiológica durante o armazenamento e propriedades funcionais tecnológicas adequadas, possibilitando a geração de novos produtos. Portanto, o aproveitamento de resíduos industriais de mirtilo fermentado apresenta vantagens de agregar valor e minimizar o impacto no meio ambiente.

CARACTERIZAÇÃO QUÍMICA E FÍSICA DE FRUTOS DE CURRIOLA, GABIROBA E MURICI PROVENIENTES DO CERRADO BRASILEIRO

RESUMOO bioma Cerrado apresenta uma variedade de espécies frutíferas detentoras de características sensoriais peculiares pouco exploradas científica e comercialmente. Este trabalho teve como objetivo a caracterização química, física e nutricional dos frutos de curriola (Pouteria ramiflora), gabiroba (Campomanesia cambessedeana) e murici (Byrsonima verbascifolia), nativos do Cerrado brasileiro. A gabiroba apresentou elevada quantidade de vitamina C (383,33 mg/100g), bem como uma proporção significativa de polpa (81,52%). Por sua vez, a curriola apresentou teores consideráveis de fibra bruta (8,18%), enquanto o murici apresentou uma quantidade considerável de pectina (746,81 mg/100g), lipídeos (2,31%) e um expressivo potencial antioxidante (56 mg DPPH/g fruto). Desta forma, os resultados obtidos servem como base para pesquisas futuras no sentido da comprovação da presença de compostos bioativos e elaboração de produtos visando à agregação de valor aos frutos.

Fotofísica de carotenóides e o papel antioxidante de b-caroteno

Carotenoid polyenes play a wide role in nature and their photophysical properties make of these pigments a focus of research in photochemistry, photobiology and photomedicine. Some aspects of the singlet and triplet states and, their interaction with molecular and singlet oxygen and free radicals are briefly reviewed in this article.

Caracterização química e física de vermicomposto e avaliação de sua capacidade em adsorver cobre e zinco

The physical and chemical characterization of vermicompost from bovine manure has been studied. It was examined the pH and cation exchangeable capacity (CEC), organic matter content, electric conductivity and elementary and XRD analyses, among other characteristics. The vermicompost was then applied to the retention and competition of metal micronutrients and pollutants (Cu and Zn) from metal nitrate solutions. The retention was affected by both the pH and adsorption time, while the competitive character of these metals for the substrate was relevant to each pH examined.

Avaliação da capacidade tamponante - um experimento participativo

The aim of this work is to show an experiment from which students can learn some of the main characteristics of buffer solutions. A mixture of some acid-base indicators, named as Yamada's indicator, can be used to estimate pH values in an acid-base titration of a buffer, with good approximation. In the experiment it is also possible to verify the relationship between the buffer capacity and the concentrations and the molar ratio of the components of a NH3 / NH4+ buffer solution. The shortage of experiments associated with the relative small importance given to many aspects of buffer solutions, is now explored with simplicity. In the proposed experiments, students prepare buffer solutions by themselves, calculate the pH, understand how acid-base indicators act and learn how buffer solutions work through graph constructed by sharing experimental data.

Sistema antioxidante envolvendo o ciclo metabólico da glutationa associado a métodos eletroanalíticos na avaliação do estresse oxidativo

The most relevant advances on the analytical applications of glutathione determination based on glutathione redox cycle and the antioxidant system are given. The main enzymes that participate of the glutathione metabolism are the glutathione peroxidase and glutathione reductase. The glutathione peroxidase has a major role in the removal of hydrogen peroxide and lipid peroxides from the cells. These enzymes, operating in tandem with catalase and superoxide dismutase promote a scavenging of oxyradical products in tissues minimizing damages caused by these species. Reduced glutathione is the major intracellular thiol found in mammals and changes in the glutathione concentration in biological fluids or tissues may provide a useful marker in certain disorders like hemolytic anemia, myocardial oxidative stress and in the investigation of some kinds of cancers. Particular attention is devoted to the main advantages supplied by biosensors in which there is an incorporation of bioactive materials for the glutathione determination. The correlation between stability and sensitivity of some reduced glutathione electrochemical sensors is discussed.

Adsorção de As, Cu, Pb e Cr na avaliação da capacidade de fixação de metais por resíduo de mineradoras de ferro

Two samples of residues from iron mining plants have been investigated for their retention capacity of As, Cu, Cr, and Pb. The sample with the higher content of iron oxides showed the highest capacity to retain metals. The adsorption affinity series changes from Pb>Cu>Cr~As to As>Pb>Cu>Cr or As>Cu>Cr>Pb, depending on the material and the concentration of the initial solution. In the competitive environment, the Pb adsorption decreases and the As, Cu and Cr adsorption increases. Sequential extraction procedures, carried out after adsorption batch experiments, showed that the most important adsorption process occurs in the oxide fraction and that the major part of the absorbed metal is remobilized from exchangeable and oxide fractions.

Atividade antioxidante de óleos essenciais de espécies de Croton do nordeste do Brasil

Three Croton species, C. zenhtneri, C. nepetaefolius and C. argyrophylloides, were collected at two different times, 6:00 and 13:00 h, their essential oils were extracted by steam distillation and analyzed by gas Chromatography / Mass Spectrometry. The percentage yield of oil constituents changes along the day. The oils were submitted to the antioxidant test thiobarbituric acid reactive species, using BHT and a-tocoferol as the reference compounds. All oils exhibited good antioxidant activities. In general, C. zenhtneri and C. argyrophylloides essential oils showed higher antioxidant activity than C. nepetaefolius.

Contenido de flavonoides y compuestos fenólicos de mieles chilenas e índice antioxidante

A comparison of the phenolic content of several Chilean honeys showed great variations in flavonoid concentration among the samples analysed. Higher amounts of phenolics are found in honey from dry climates. The antioxidant effect of extracts, using ORAC analysis, did not correlate with the flavonoid content or with the total phenolic concentration.

Estudo da capacidade de complexação e sua relação com algumas variáveis ambientais em cinco represas do Rio Tietê/Brasil

The copper and cadmium complexation properties in natural sediment suspensions of reservoirs of the Tietê River were studied using the solid membrane copper and cadmium ion-selective electrodes. The complexation and the average conditional stability constants were determined under equilibrium conditions at pH=6.00 ± 0.05 in a medium of 1.0 mol L-1 sodium nitrate, using the Scatchard method. The copper and cadmium electrodes presented Nernstian behavior from 1x10-6 to 1x10-3 mol L-1 of total metal concentration. Scatchard graphs suggest two classes of binding sites for both metals. A multivariate study was done to correlate the reservoirs and the variables: complexation properties, size, total organic carbon, volatile acid sulfide, E II and pH.

Avaliação do potencial antioxidante do pólen apícola produzido na região sul do Brasil

The contents of total phenolics, flavonoids, and antioxidant activity of bee pollen ethanolic extract were determined and compared to those of commercial antioxidants. Bee pollen extract from the state of Rio Grande do Sul presented antioxidant activity statistically equal to that of α -tocopherol and higher than those of BHT and BHA. A statistically significant correlation was observed between the antioxidant activity and the total phenolics and total flavonoids contents of bee pollen extracts. HPLC technique made the identification of high contents of rutin and myricetin possible, which may partially explain the high antioxidant activity of Brazilian bee pollen.

Constituintes químicos e avaliação do potencial antiinflamatório e antioxidante de extratos das folhas de Chomelia obtusa Cham. & Schltdl. (Rubiaceae)

The phytochemical investigation of Chomelia obtusa leaves led to the isolation of four triterpenes (3-O-β-D-quinovopyranosyl-28-O-β-D-glycopyranosyl quinovic acid, 3-O-β-D-quinovopyranosyl-28-O-β-D-glycopyranosyl cincholic acid, and a mixture of ursolic and oleanolic acids), two flavonoids (3-O-β-D-glycopyranosyl quercetin, 3-O-[α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside] quercetin), besides bornesitol and a mixture of 3,5- and 4,5-O-dicaffeoyl quinic acids. The structures of the isolated compounds were assigned on the basis of spectroscopic data, including two-dimensional NMR methods. The anti-inflammatory and antioxidant activities of the crude methanolic extract and of its fractions were evaluated. This is the first report on the chemical and biological investigation of the Chomelia genus.

Isolamento de polímeros da parede celular de Saccharomyces cerevisiae e avaliação da atividade antioxidante da manana-proteína isolada

Yeast cell wall contains polymers glucan and mannan-protein that have received much attention with respect to their biological activities. Conventional isolation process involving treatments with hot alkali and acids cause degradation of these polymers. The aim of this paper was to study a low-degrading process for the isolation of glucan and mannan-protein from S. cerevisiae cell wall comprising physic and enzymatic treatments. Yeast cell glucan was obtained in a purity of 87.4% and a yield of 33.7%. The isolated mannan-protein presented antioxidant activity that was increased after thirty minutes of protease treatment. Antioxidant activity was determined by β-carotene/linoleate model system.

Compostos bioativos e atividade antioxidante do café conilon submetido a diferentes graus de torra

The bioactive compounds and antioxidant activity presented by Conilon coffee (C. Canephora) variety, produced in the Espírito Santo State, Brazil, were quantified. The light roast coffee showed the highest level of total phenols, trigonelline, caffeic and chlorogenic acids. The proanthocyanidin level was the highest for dark roast coffee, while caffeine level didn't show significative changes for the light and middle roast coffees. All the Conilon coffee extracts showed antioxidant activity depending on bioactive compounds concentration and roasting degree. The coffee samples submitted to a light roasting degree showed the highest antioxidant activity.

Atividade antioxidante do extrato de sementes de limão (Citrus limon) adicionado ao óleo de soja em teste de estocagem acelerada

The aim of this work was to evaluate antioxidant activity of lemon seeds added to soybean oil, submitted to accelerated incubator-storage test and to determine its synergistic effect with the synthetic antioxidant TBHQ. The treatments Control, TBHQ (50 mg/kg), LSE (2,400 mg/kg Lemon Seed Extract), Mixture 1 (LSE + 50 mg/kg TBHQ) and Mixture 2 (LSE + 25 mg/kg TBHQ) were prepared and subjected to the accelerated incubator-storage test at 60 ºC for 12 days; samples were taken every 3 days and analyzed regarding peroxide value and conjugated dienes. The results showed that antioxidant activity of the tested treatments were: TBHQ = Mixture 1 = Mixture 2 > LSE > Control.