462 resultados para Phenols


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The aim of this study was to optimize the aqueous extraction conditions for the recovery of phenolic compounds and antioxidant capacity of lemon pomace using response surface methodology. An experiment based on Box–Behnken design was conducted to analyse the effects of temperature, time and sample-to-water ratio on the extraction of total phenolic compounds, total flavonoids, proanthocyanidins and antioxidant capacity. Sample-to-solvent ratio had a negative effect on all the dependent variables, while extraction temperature and time had a positive effect only on TPC yields and ABTS antioxidant capacity. The optimal extraction conditions were 95 oC, 15 min, and a sample-to-solvent ratio of 1:100 g/ml. Under these conditions, the aqueous extracts had the same content of TPC and TF as well as antioxidant capacity in comparison with those of methanol extracts obtained by sonication. Therefore these conditions could be applied for further extraction and isolation of phenolic compounds from lemon pomace.

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We studied the effect of Silicon (Si) on Casparian band (CB) development, chemical composition of the exodermal CB and Si deposition across the root in the Si accumulators rice and maize and the Si non-accumulator onion. Plants were cultivated in nutrient solution with and without Si supply. The CB development was determined in stained root cross-sections. The outer part of the roots containing the exodermis was isolated after enzymatic treatment. The exodermal suberin was transesterified with MeOH/BF3 and the chemical composition was measured using gas chromatography-mass spectroscopy (GC-MS) and flame ionization detector (GC-FID). Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) was used to determine the Si deposition across root cross sections. Si promoted CB formation in the roots of Si-accumulator and Si non-accumulator species. The exodermal suberin was decreased in rice and maize due to decreased amounts of aromatic suberin fractions. Si did not affect the concentration of lignin and lignin-like polymers in the outer part of rice, maize and onion roots. The highest Si depositions were found in the tissues containing CB. These data along with literature were used to suggest a mechanism how Si promotes the CB development by forming complexes with phenols.

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The objective of this study was to determine the antioxidant effect of essential oregano and alfavaca oil on the fatty acid profile of palm oil, used in industrial potato chips processing, aiming to reduce the oxidative state of palm oil. Essential oregano oil was obtained from industrial residues and commercial essential oregano oil was also acquired. The antioxidant activity of Oregano’s essential oil was taken by DPPH method. The DPPH analysis of the essential oil of oregano residue resulted in an IC50 of 797.04 mg.mL-1 and the essential oil of commercial oregano was 424.25 mg.mL-1. Regarding the content of total phenols, the essential oil of commercial oregano showed 0.167 ± 0.058 ug EAG.g-1. Based on these results, concentrations of 50, 100 e 150ug.g-1 of commercial oregano essential oil was added to palm oil and the fatty acid profile was determined by gas cromatography. Analysis were done with palm oil without being used in frying processes and without added essential oil, as well as with the different essential oil concentrations submitted at three frying processes at one single day. In the second part of the project, the effect of oreganos’s comercial essential oil compared to alfavacão essential oil, at the concentration of 100ug.g-1 in palm oil, and submitted to three frying processes during eleven cycles, was studied. The lipid profile was similar to that described in the literature, which an increase in the number of frying times caused a polyunsaturated fatty acids decrease and, therefore, a proportional increase in saturated fatty acids. It was noted an increase in the amounts of total saturated fatty acids from 43.36% (control) to 43.60% (palm oil with essential oil after 11 frying cycles at the concentration of 100ug.g-1). This fact proves that during the frying process, there is an increase in the rate of formation of saturated fatty acids. However, the addition of oregano essential oil did not provide significant change in the fatty acids of palm oil used in frying process of potato chips. The addition of oregano essential oil in a concentration of 100 ug./mL-1 until the third frying cycle showed a reduction effect of trans fatty acid formation. Although, during 11 frying cycles it was not noticed the essential oil effect under trans fatty acid formation. It can be suggested that this factor may be correlated to the frying time, which may not have been sufficient for significant formation of saturated and trans compounds.

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Extreme abiotic factors, such drought combined with heat waves and/or high UVB radiation are predicted to become more frequent in the future. The impact on plant production of these challenges on multipurpose Moringa oleifera L. remains unclear. A susceptibility of this species may lead to increase poverty in endangered regions. M. oleifera is a woody species native from sub-Himalaya regions under high climate stress pressure. The interest on this species is emerging due to its several medicinal properties and its nutritional value. Agropharmaceutical industry is interest in this species too. To understand the impact of increased climate factors, young (2 months old) plants of this species were exposed to water deficit (WD) and UVB (alone or combined). WD and WD+UVB imposition consists of unwater for 4 days. After 1 day withholding water, UVB and WD+UVB were irradiated with 26.3 kJ m-2 distributed per 3 days. Immediately after treatment exposition (1 day) and after 10 days, plant water status, growth, carbon metabolism and oxidative stress were measured. Overall no significant differences were observed in WD, regarding the parameters analysed, except on gas exchanges, MDA and phenols. The plants exposed to UVB showed, in general, more severe effects, as higher pigment content, MDA and membrane permeability, while no changes were observed in the total antioxidant activity. Plants exposed to UVB+WD, despite changes observed, the impact was lower than the one observed in UVB exposed plants, meaning that a protective/adaptive mechanism was developed in the plants under combined stressors. On the other hand, in all treatments the net CO2 assimilation rate decreased. Results suggest that M. oleifera has some tolerance to WD and UVB, and that develops mechanism of adaptation to these two types of stress that often arise in combination under a climate change scenario.

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A contaminação fúngica acarreta alterações na qualidade nutricional e no valor econômico de produtos alimentícios podendo causar danos patológicos em plantas, animais e humanos. A identificação da atividade antioxidante, antifúngica e antimicotoxinas, em extratos de microalgas com propriedade de inibir a multiplicação de fungos e subseqüente produção de micotoxinas abre a perspectiva de empregar substâncias mais eficientes e com maior ação específica contra estes microorganismos. Entre os compostos com propriedades inibidoras de radicais livres, de crescimento fúngico e produção de micotoxinas, destacam-se os compostos fenólicos, que podem inibir a atividade metabólica microbiana, dificultando a atividade de enzimas. Neste estudo foram avaliados o poder de inibição de multiplicação fúngica de Rhizopus oryzae e Aspergillus flavus pelos extratos fenólicos de Chlorella sp. e Spirulina platensis, bem como sua atividade antioxidante, e a atividade antimicotoxinas da última microalga contra Aspergillus flavus. O conteúdo de fenóis totais foi em média 1000 µgfenóis/g Spirulina platensis e 600 µgfenóis/g Chlorella sp., sendo que o acido gálico e o cafeíco foram identificados como compostos majoritários na Spirulina platensis. As determinações de glicosamina (parede celular) e ergosterol (membrana celular) mostraram-se bons indicativos do desenvolvimento microbiano permitindo uma boa estimativa da inibição dele. O extrato fenólico de Spirulina platensis apresentou capacidade de inibir cerca de 50% a formação da parede e da membrana celular para ambos os fungos estudados e de 100% a produção de aflatoxina B1 até o 10º dia de cultivo do Aspergillus flavus. Além disso, o extrato metanólico de Spirulina platensis inativou 53,5% o DPPH reativo, limitou o escurecimento enzimático ocasionado pela peroxidase em 55% e inibiu a peroxidação lipídica em 46% após 14 dias de armazenamento sob luz. Estes resultados mostram que a ação antifúngica, antimicotoxinas e antioxidante está naturalmente presente em alguns tecidos microbianos e que encontrar a forma de extraí-los e aplicá-los como conservantes alimentícios é muito promissor para substituição aos antifúngicos e outros conservantes químicos.

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Untreated effluents that reach surface water affect the aquatic life and humans. This study aimed to evaluate the wastewater s toxicity (municipal, industrial and shrimp pond effluents) released in the Estuarine Complex of Jundiaí- Potengi, Natal/RN, through chronic quantitative e qualitative toxicity tests using the test organism Mysidopsis Juniae, CRUSTACEA, MYSIDACEA (Silva, 1979). For this, a new methodology for viewing chronic effects on organisms of M. juniae was used (only renewal), based on another existing methodology to another testorganism very similar to M. Juniae, the M. Bahia (daily renewal).Toxicity tests 7 days duration were used for detecting effects on the survival and fecundity in M. juniae. Lethal Concentration 50% (LC50%) was determined by the Trimmed Spearman-Karber; Inhibition Concentration 50% (IC50%) in fecundity was determined by Linear Interpolation. ANOVA (One Way) tests (p = 0.05) were used to determinate the No Observed Effect Concentration (NOEC) and Low Observed Effect Concentration (LOEC). Effluents flows were measured and the toxic load of the effluents was estimated. Multivariate analysis - Principal Component Analysis (PCA) and Correspondence Analysis (CA) - identified the physic-chemical parameters better explain the patterns of toxicity found in survival and fecundity of M. juniae. We verified the feasibility of applying the only renewal system in chronic tests with M. Juniae. Most efluentes proved toxic on the survival and fecundity of M. Juniae, except for some shrimp pond effluents. The most toxic effluent was ETE Lagoa Aerada (LC50, 6.24%; IC50, 4.82%), ETE Quintas (LC50, 5.85%), Giselda Trigueiro Hospital (LC50, 2.05%), CLAN (LC50, 2.14%) and COTEMINAS (LC50, IC50 and 38.51%, 6.94%). The greatest toxic load was originated from ETE inefficient high flow effluents, textile effluents and CLAN. The organic load was related to the toxic effects of wastewater and hospital effluents in survival of M. Juniae, as well as heavy metals, total residual chlorine and phenols. In industrial effluents was found relationship between toxicity and organic load, phenols, oils and greases and benzene. The effects on fertility were related, in turn, with chlorine and heavy metals. Toxicity tests using other organisms of different trophic levels, as well as analysis of sediment toxicity are recommended to confirm the patterns found with M. Juniae. However, the results indicate the necessity for implementation and improvement of sewage treatment systems affluent to the Potengi s estuary

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The consumer interest in healthy foods with high amounts of antioxidants is one of the important factors for reducing the risk of disease and it has encouraged researchers and industry to develop innovative and functional products and ingredients. To that end, the objective of this research was to study the bioactive compounds present in the acai pulp, blueberry and goji berry samples, as well as the phenolic compounds form of extraction using the response surface methodology (RSM), antioxidant and antimicrobial activity of it, identification and quantification of compounds by high-performance liquid chromatography (HPLC) and, at the end, the development of petit suisse cheeses added with freeze-dried extracts of the samples. A 2³ factorial design was used to analyze the solvent effect (ethanol and water), time (30 and 60 min) and temperature (30 °C and 60 °C) on the extraction and determination of total phenolic compounds (TPC) and antioxidant activity (AA). The variables time and temperature had a positive effect on the antioxidant activity (AA) in their highest levels with 60 min and 60 °C respectively. The ethanol solvent 80 % is more efficient in TPC extraction with AA in all arrays. The identification of phenolic compounds performed by HPLC revealed the presence of catechin, epicatechin, rutin, myricetin, chlorogenic acid, coumaric acid and ferulic acid. Regarding the AA the acai pulp showed higher activity in vitro when extracted by 60 °C for 60 min, but none of the three extracts analyzed under these conditions showed antibacterial activity against Staphylococcus aureus and Salmonella bongori in the concentrations tested (95.00 to 2.34 mg/mL. For petit suisse cheeses added with phenolic extract of the samples, the sample containing goji berry achieved greater sensory acceptance among judges (75.67%), second only to the commercial sample used for comparison with 91.56 % of acceptance. In relation to the storage time, the oxidation was evaluated by the level of thiobarbituric acid reactive substances and color analysis. Both analysis were satisfactory, making the extracts addition an alternative to preserve the product properties and give it a high content of bioactive and nutritive compounds.

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Trinitrotoluene in the purification step (TNT) produced in industries, are carried out two washes at the end of the process. The first wash is done with vaporized water, which originates from the first effluent called yellow water, then the second washing with the use of sodium sulfite is performed (Na2SO3), generating a second effluent red water. This study aimed to study the individual effects, as well as the association of heterogeneous photocatalysis using TiO2 and biological treatment in air lift reactor using activated sludge (bacterial biomass) for the remediation of wastewater contaminated with nitroaromatic compounds in order to reduce toxicity and adjust the legal parameters according to regulatory agencies for disposal in waterways. The photocatalytic treatment was conducted by factorial design obtaining the best reaction conditions (pH 6.5 and concentration of TiO2 0.1 gL-1), with best results obtained at 360 minutes of reaction, reducing the absorbance 97.00%, 94.20% of the chemical oxygen demand (COD), 67.70% of total phenols, as well as a total reduction of observed peaks and assigned to nitroaromatic compounds by high-performance liquid chromatography. In the biological treatment, there was a 53.40% reduction in absorbance at 275 nm 10.00% 36.00% COD and total phenols in a short time (3 days), while for extended periods (48 days) there was an antagonistic influence on the results so that was the elevation of these parameters (COD and total phenols) instead of reducing. Chromatographic analysis confirmed the effectiveness of the biological degradation by reducing the peaks corresponding to compounds DNT and TNT. The Association of photocatalytic and biological treatments decreased results in the order of 91.10% absorbance, 70.26% of total phenols and 88.87% of COD. While the combination of biological and photocatalytic treatments generated relatively lower efficiencies, with 77.30% of absorbance reduction, 62.10% reduction of total phenols and a decrease of 87.00% of COD. In general, when comparing the chemical and biological processes in isolation, the photocatalytic treatment showed the best results. However, comparing the results of isolation and established associations, the association biological x photocatalysis showed more promising results in the treatment of red water effluent.

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The southern region of Brazil, especially the states of Parana and Santa Catarina stand out for growing grapes and apples for fresh consumption and in order to add value to these products, process the material for the production of wine, juices and jellies . As a result large quantities of by-products, such as peels, seeds and pulp are produced becoming environmental problems. Studies reuse of these by-products have attracted interest because they have shown a high biological potential, due to the presence of high levels of phenolic compounds, which are associated with a lower incidence of disease caused by oxidative stress, due to its antioxidant, antiinflammatory and antibacterial properties. Currently, few studies are presented on the phenolic composition and biological potential of waste grape variety Bordô (Vitis labrusca) and apple (Malus domestica) Gala variety, cultivated in southern Brazil. Within this context, the objectives of this study were: compare the efficiency of solidliquid and liquid-liquid extraction, perform the optimization and validation of analytical methodology by HPLC-DAD for the separation, identification and quantification of multiclass phenolic compounds, evaluate the activity antioxidant by sequestering methods of free radical 2,2-diphenyl-1 picrilhidrazina (DPPH) and 2,2-azino-bis (3- ethyl-benzthiazoline-6-sulphonic acid) (ABTS) solution, reduction of Fe3+ in Fe2+ method (FRAP), ORAC, RP-HPLC-ABTS online, Rancimat and determination of total phenolics three agro-industrial byproducts, pomace and stems grape Bordô produced in Paraná Southwest region and Gala apple pomace coming from the Santa Catarina West. Optimization and validation of chromatographic method showed satisfactory quality parameters for the compounds of interest and the solidliquid extraction was more efficient in extracting phenolic evaluated. The three byproducts evaluated showed significant levels of phenolic compounds when analyzed by HPLC, especially flavonoids, catechin and epicatechin besides that showed significant antioxidant capacity. The grape stems extract had the highest sequestration capacity of DPPH and ABTS radical and reduced iron, and high content of phenolic compounds. The apple pomace extract showed the best response to the Rancimat method, which indicates a high potential to protect the oil from lipid oxidation, was no significant difference when compared to synthetic antioxidant TBHQ. The results of this study showed that the agro-industrial coproducts analyzed are rich in phenolic compounds of high antioxidant capacity and therefore must be better explored by the food and pharmaceutical industries.

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O rápido crescimento da procura e na produção de Physalis está associado às suas características nutracêuticas e medicinais, por estarem associadas ao bemestar e à saúde. O reconhecimento e o conceito da qualidade dos frutos é cada vezmais importante, abrangendo a aparência do produto, o aroma, a textura e o valor nutricional. Com a realização deste trabalho pretendeu-se avaliar as propriedades físicoquímicas das bagas de physalis, bem como os conteúdos em compostos bioativos com potenciais benefícios para a saúde humana. Neste trabalho foi avaliada uma variedade de physalis (Physalis peruviana L.), sendo os frutos provenientes de uma exploração localizada na região Norte-Centro de Portugal. Foram realizadas análises físicas às 'physalis' frescas, tendo sido determinados o calibre, a cor e a textura. Na análise química, realizaram-se as determinações, da humidade, da fibra bruta, dos açúcares totais e redutores, da acidez total titulável, do teor de sólidos solúveis totais, do ácido ascórbico, dos carotenóides, dos compostos fenólicos totais, dos orto-difenóis e dos flavonóides. Foi ainda determinada a atividade antioxidante pelos métodos ABTS e DPPH e os extratos submetidos a condições simulantes do trato digestivo. As physalis em estudo apresentaram, em média um diâmetro de 1,69 cm e uma massa de 2,77 g. Relativamente à cor, as bagas apresentaram-se claras, (L*=65,72), e com uma tendência para a cor vermelha (a*=16,69), e uma forte intensidade amarela (b*=58,11). No que diz respeito à textura, a firmeza foi de 2,40 N e a elasticidade foi de 2,94 mm. Quanto à caracterização química foram encontrados os seguintes resultados: 83,02% de água, 4,61% de fibra, 8,79% de açúcares totais, 1,25% de acidez total, expressa em ácido cítrico. A amostra continha ainda 5,95 μg/g de carotenoides 26,7 mg de ácido ascórbico por 100 g. Os valores de fenóis totais (42,74 e 59,95 mg EAG/100 g) e de atividade antioxidante determinada pelo método DPPH (7,73 e 9,61 μmol TE/g), e pelo método ABTS (12,28 e 13,71 μmol TE/g) variam de acordo com as condições de extração. Verificou-se ainda uma correlação forte entre os dois métodos. No que diz respeito às condições in vitro de simulação das condições do trato digestivo, verificou-se um decréscimo ao longo do trato digestivo tanto no teor em compostos fenólicos bem como na atividade antioxidante. Em termos globais houve uma retenção de 43% dos compostos fenólicos totais e 26% da atividade antioxidante.

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The aim of the present study was to investigate the effect of different production and conservation factors on some properties of blueberries. Among the production factors considered were cultivar (Duke, Bluecrop and Ozarkblue) and production mode (organic or conventional). Regarding the conservation factors were evaluated temperature (ambient or refrigeration) and storage time (0, 7 and 14 days). The properties under study belong to three categories: physical properties (color and texture); chemical properties (moisture content, sugars and acidity) and phenolic and antioxidant properties (total phenols, anthocyanins, tannins, ABTS antioxidant activity, DPPH antioxidant activity). The results revealed that moisture content was only influenced by cultivar and that both acidity and sugar contents varied according to the production mode used. Also it was evidenced that the antioxidant activity was not statistically different between cultivars, production modes or conservation conditions. Regarding the phenolic compounds, the tannins were significantly higher for the blueberries produced in organic agriculture. Regarding color significant differences were also encountered and the most intense blue was found in blueberries from cv. Duke, produced in organic farming and stored under refrigeration. Textural attributes were also very significantly influenced by all factors at study: cultivar, production mode and conservation, and the berries from cv. Duke stored under refrigeration showed the highest firmness.

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Laccases (LCs) are multicopper oxidases that find application as versatile biocatalysts for the green bioremediation of environmental pollutants and xenobiotics. In this study we elucidate the degrading activity of Lac2 pure enzyme form Pleurotus pulmonarius towards aflatoxin B1 (AFB1) and M1 (AFM1). LC enzyme was purified using three chromatographic steps and identified as Lac2 through zymogram and LC-MS/MS. The degradation assays were performed in vitro at 25 °C for 72 h in buffer solution. AFB1 degradation by Lac2 direct oxidation was 23%. Toxin degradation was also investigated in the presence of three redox mediators, (2,2′-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]) (ABTS) and two naturally-occurring phenols, acetosyringone (AS) and syringaldehyde (SA). The direct effect of the enzyme and the mediated action of Lac2 with redox mediators univocally proved the correlation between Lac2 activity and aflatoxins degradation. The degradation of AFB1 was enhanced by the addition of all mediators at 10 mM, with AS being the most effective (90% of degradation). AFM1 was completely degraded by Lac2 with all mediators at 10 mM. The novelty of this study relies on the identification of a pure enzyme as capable of degrading AFB1 and, for the first time, AFM1, and on the evidence that the mechanism of an effective degradation occurs via the mediation of natural phenolic compounds. These results opened new perspective for Lac2 application in the food and feed supply chains as a biotransforming agent of AFB1 and AFM1.