941 resultados para Yeast extract


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This paper aimed to assess the tocopherol content and evaluate the fatty acid profile in soybean oil supplemented with salvia extract during heating, so as to verify the isolated and synergistic effect of natural and synthetic antioxidants. In order to obtain the extract, the lyophilized and crushed salvia was subjected to extraction by ethyl alcohol for 30 min, with a 1:20 salvia:ethyl alcohol ratio, under continuous agitation. Afterwards, the mixture was filtered and the supernatant was subjected to the rotary evaporator at 40 °C. Later the control treatments, ES (3000 mg kg-1 salvia extract), TBHQ (50 mg kg-1), and mixture (ES+50 mg kg-1 TBHQ) were prepared and subjected to 180 °C for 20 h. Samples were taken in time intervals 0, 10, and 20 h and analysed in terms of tocopherol content and fatty acid profile. Regarding the tocopherol and fatty acid profile analysis, it was found that the extract proved efficient in oil protection, when added isolated to soybean oil subjected to thermo oxidation. According to the results, salvia extract is a viable alternative that might be applied in industrialized processing of oils as natural antioxidant.

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The aim of this study was to evaluate the effects of yeast cell wall extract (YCW) in dry diet on the fecal microbiota, concentration of short-chain fatty acids (SCFA) and on the odor reduction of cats feces. We used 20 animals of both sexes, randomly assigned to four treatments and five repetitions totaling 20 experimental units: 1) dry commercial diet (control); 2) control + 0.2%, 3) control + 0.4%, and 4) control + 0.6% of YCW in dry matter. Enterobacteriaceae and lactic acid bacteria, fecal concentration of acetic, propionic and butyric acids, ammonia nitrogen and sensory panel were performed. There were no significant differences (p> 0.05) for bacterial counts and the concentration of SCFA and ammonia, but in sensory panel a reduction in the odor of feces could be noted with the use of 0.2% of YCW. We concluded that the addition of up to 0.6% YCW had no effect on the microbiology and the concentration of fatty acids, but there is potential for its use as an additive because of the improvement in the odor of feces. However, further studies are needed to understand the mechanisms of action and the effects of prebiotics for domestic cats.

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Tissue engineering has been defined as an interdisciplinary field that applies the principles of engineering and life sciences for the development of biological substitutes to restore, maintain or improve tissue function. This area is always looking for new classes of degradable biopolymers that are biocompatible and whose activities are controllable and specific, more likely to be used as cell scaffolds, or in vitro tissue reconstruction. In this paper, we developed a novel bionanocomposite with homogeneous porous distribution and prospective natural antimicrobial properties by electrospinning technique using Stryphodedron barbatimao extract (Barbatimão). SEM images showed equally distribution of nanofibres. DSC and TGA showed higher thermal properties and change crystallinity of the developed bionanocomposite mainly because these structural modification. © 2012 Elsevier B.V.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Purpose: The purpose of this paper is to evaluate the antioxidant activity of ginger ethanol extract in soybean oil under thermoxidation. Design/methodology/approach: A total of four treatments were used: soybean oil free of synthetic antioxidants, soybean oil containing 2,500 mg/kg of ginger extract, soybean oil containing 50 mg/kg of TBHQ, soybean oil containing the mixture of natural extract, and TBHQ in the before-cited concentration. The treatments were discontinuously submitted to plates heated at 180°C, for 20 hours. Samples were removed in the times of 0, 4, 8, 12, 16 and 20 hours of heating and they were analyzed as to their oxidative stability, total polar compounds, peroxide and conjugated diene values. Findings: The results showed the efficiency of the ginger extract in protecting the oil against lipid oxidation. It could be concluded that ginger extract might be indicated as an additive that acts against lipid oxidation and, consequently, increases shelf life of food. Practical implications: These studies may prove to be beneficial to the exploitation of natural antioxidant sources for the preservation and/or extension of raw and processed food shelf life. Therefore, they could also be applied in the area of pharmaceuticals for the protection of human life. Originality/value: This study offers information on the use of natural antioxidants as an alternative to the use of synthetic antioxidants, which might be considered toxic. © Emerald Group Publishing Limited.

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Extracellular xylanase and β-xylosidase production by a Penicillium janczewskii strain were investigated in liquid cultures with xylan from oat spelts under different physical and chemical conditions. The selected conditions for optimized production of xylanase and β-xylosidase were 7 days, pH 6.5, at 30 °C and 8 days, pH 5.0, at 25 °C, respectively. The xylanase exhibited optimal activity in pH 5.0 at 50 °C and the β- xylosidase in pH 4.0 at 75 °C. The xylanase was more stable at pH 6.0 to 9.5, while the β-xylosidase remained stable at pH ranging from 1.6 to 5.5. The xylanase half-life (T50) at 40, 50, and 60 °C was 183, 15, and 3 min, respectively. β-xylosidase half-life was 144, 8, and 4 min at 50, 65, and 75 °C, respectively. When applied to the biobleaching of Eucalyptus kraft pulp, xylanase dosages of 2 and 4 U/g dried pulp reduced, respectively, kappa number by 3.0 and 3.3 units after 1 h treatment, demonstrating that the use of P. janczewskii xylanases in this process is quite promising. The pulp viscosity was not altered, confirming the absence of cellulolytic enzymes in the fungal extract.

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The crude ethanolic extract from aerial parts of Pothomorphe umbellata L. (Piperaceae) and fractions obtained by partitions sequentially among water-methanol, methylene chloride, and ethyl acetate, as well as the major constituent, 4-nerolidylcatechol, were, respectively, evaluated and evidenced for antioxidant and cytotoxic effects through fluorometric microplate and microculture tetrazolium assays in HL-60 cells. The crude ethanolic extract demonstrated the preeminent antioxidant activity (IC50 = 1.2 μg/mL) against exogenous cytoplasmic reactive oxygen species, followed by the water-methanolic (IC50 = 4.5 μg/mL), methylene chloride (IC 50 = 5.9 g/mL), ethyl acetate (IC50 = 8.0 g/mL), 4-nerolidylcatechol (IC50 = 8.6 g/mL), and the sterol fractions (IC50 > 12.5 μg/mL). Vitamin C, the positive control used in this assay, presented IC50 value equivalent to 1.7 μg/mL. 4-Nerolidylcatechol (IC50 = 0.4 μg/mL) and methylene chloride fraction (IC50 = 2.3 μg/mL) presented considerable cytotoxicity probably because of the presence of an o-quinone, an auto-oxidation by product of the catechol. Polar compounds, present in the ethanol extract, appear to increase the solubility and stability of the major active constituent, acting synergistically with 4-nerolidylcatechol, improving its pharmacokinetic parameters and increasing significantly its antioxidant activity which, in turn, suggests that the aqueous-ethanolic extract, used in folklore medicine, is safe and effective. © 2013 Andrey P. Lopes et al.

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The incidence of opportunistic fungal infections has increased in recent decades due to the growing proportion of immunocompromised patients in our society. Candida krusei has been described as a causative agent of disseminated fungal infections in susceptible patients. Although its prevalence remains low among yeast infections (2-5%), its intrinsic resistance to fluconazole makes this yeast important from epidemiologic aspects. Non mammalian organisms are feasible models to study fungal virulence and drug efficacy. In this work we have used the lepidopteran Galleria mellonella and the nematode Caenorhabditis elegans as models to assess antifungal efficacy during infection by C. krusei. This yeast killed G. mellonella at 25, 30 and 37°C and reduced haemocytic density. Infected larvae melanized in a dose-dependent manner. Fluconazole did not protect against C. krusei infection, in contrast to amphotericin B, voriconazole or caspofungin. However, the doses of these antifungals required to obtain larvae protection were always higher during C. krusei infection than during C. albicans infection. Similar results were found in the model host C. elegans. Our work demonstrates that non mammalian models are useful tools to investigate in vivo antifungal efficacy and virulence of C. krusei. © 2013 Scorzoni et al.

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Since the beginning of propolis research, several groups have studied its antibacterial, antifungal, and antiviral properties. However, most of these studies have only employed propolis ethanolic extract (PEE) leading to little knowledge about the biological activities of propolis water extract (PWE). Based on this, in a previous study, we demonstrated the anti-inflammatory and immunomodulatory activities of PWE. In order to better understand the equilibrium between effectiveness and toxicity, which is essential for a new medicine, the characteristics of PWE were analyzed. We developed and validated an RP-HPLC method to chemically characterize PWE and PEE and evaluated the in vitro antioxidant/antimicrobial activity for both extracts and the safety of PWE via determining genotoxic potential using in vitro and in vivo mammalian micronucleus assays. We have concluded that the proposed analytical methodology was reliable, and both extracts showed similar chemical composition. The extracts presented antioxidant and antimicrobial effects, while PWE demonstrated higher antioxidant activity and more efficacious for the most of the microorganisms tested than PEE. Finally, PWE was shown to be safe using micronucleus assays. © 2013 Bruno Alves Rocha et al.

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Some of the Piper species have been applied for the treatment of several diseases (anti-oxidant, antimicrobial, anti-inflammatory, and analgesic), considering multiple applications used in traditional medicine of different countries. About these, the present study evaluated some biological activities of Piper cubeba, as writhing test induced by acetic acid, ear edema induced by croton oil and paw edema induced by carrageenan were used by evaluated the analgesic and anti-inflammatory activities of crude hydroalcoholic extract (PCE) and its fractions of different polarities of P. cubeba L. seeds. The lethal dose (LD50) and the effective dose (ED50) were evaluated too. Both the PCE and dichloromethane fraction showed decrease values of edema and abdominal constrictions. The results obtained in this study confirm the low toxicity and analgesic and anti-inflammatory activities of PCE from P. cubeba seeds, justifying its use in folk medicine. Copyright © 2013, Phcog.Net, Published by Reed Elsevier India Pvt. Ltd. All rights reserved.

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The purpose of this work was to determine the levels of protein and the amino acid distribution in the cell mass of yeast strains (Saccharomyces sensu stricto) originated from Brazilian bioethanol industries. The protein was analyzed with the Kjeldahl method and the amino acids, by using high-performance liquid chromatography (HPLC). The percentages of the protein found ranged from 39 to 49%. The results show that in spite of some variation in numbers between the different yeast strains, all of them presented an amino acid profile similar to the one in the literature for S. cerevisae. The amino acids that have occurred in the largest amounts were: aspartic, glutamic acids and lysine, and those in the lowest amounts were: cysteine and methionine. Although the characteristics of the feedstock used and the process conditions are determinant of the protein values obtained in dry mass, this work elucidates that the intrinsic properties of the yeast strain influence these values.

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Although many Brazilian sugar mills initiate the fermentation process by inoculating selected commercial Saccharomyces cerevisiae strains, the unsterile conditions of the industrial sugar cane ethanol fermentation process permit the constant entry of native yeast strains. Certain of those native strains are better adapted and tend to predominate over the initial strain, which may cause problems during fermentation. In the industrial fermentation process, yeast cells are often exposed to stressful environmental conditions, including prolonged cell recycling, ethanol toxicity and osmotic, oxidative or temperature stress. Little is known about these S. cerevisiae strains, although recent studies have demonstrated that heterogeneous genome architecture is exhibited by some selected well-adapted Brazilian indigenous yeast strains that display high performance in bioethanol fermentation. In this study, 11 microsatellite markers were used to assess the genetic diversity and population structure of the native autochthonous S. cerevisiae strains in various Brazilian sugar mills. The resulting multilocus data were used to build a similarity-based phenetic tree and to perform a Bayesian population structure analysis. The tree revealed the presence of great genetic diversity among the strains, which were arranged according to the place of origin and the collection year. The population structure analysis revealed genotypic differences among populations; in certain populations, these genotypic differences are combined to yield notably genotypically diverse individuals. The high yeast diversity observed among native S. cerevisiae strains provides new insights on the use of autochthonous high-fitness strains with industrial characteristics as starter cultures at bioethanol plants. © 2013 John Wiley & Sons, Ltd.

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The possible benefits of some bioactive flavones and xanthones present in plants of the genus Syngonanthus prompted us to screen them for estrogenic activity. However, scientific research has shown that such substances may have undesirable properties, such as mutagenicity, carcinogenicity and toxicity, which restrict their use as therapeutic agents. Hence, the aim of this study was to assess the estrogenicity and mutagenic and antimutagenic properties. We used recombinant yeast assay (RYA), with the strain BY4741 of Saccharomyces cerevisiae, and Ames test, with strains TA100, TA98, TA97a and TA102 of Salmonella typhimirium, to evaluate estrogenicity, mutagenicity and antimutagenicity of methanolic extracts of Syngonanthus dealbatus (S.d.), Syngonanthus macrolepsis (S.m.), Syngonanthus nitens (S.n.) and Syngonanthus suberosus (S.s.), and of 9 compounds isolated from them (1 = luteolin, 2 = mix of A-1,3,6-trihydroxy-2-methoxyxanthone and B-1,3,6-trihydroxy-2,5- dimethoxyxanthone, 3 = 1,5,7-trihydroxy-3,6-dimethoxyxanthone, 4 = 1,3,6,8-tetrahydroxy-2,5-dimethoxyxanthone, 5 = 1,3,6,8-tetrahydroxy-5- methoxyxanthone, 6 = 7-methoxyluteolin-8-C-β-glucopyranoside, 7 = 7-methoxyluteolin-6-C-β-glucopyranoside, 8 = 7,3′-dimethoxyluteolin- 6-C-β-glucopyranoside and 9 = 6-hydroxyluteolin). The results indicated the estrogenic potential of the S. nitens methanol extract and four of its isolated xanthones, which exhibited, respectively, 14.74 ± 1.63 nM; 19.54 ± 6.61; 7.20 ± 0.37; 6.71 ± 1.02 e 10.01 ± 4.26 nM of estradiol-equivalents (EEQ). None of the extracts or isolated compounds showed mutagenicity in any of the test strains and all of them showed antimutagenic potential, in particular preventing mutations caused by aflatoxin B1 (AFB1) and benzo[a]pyrene (B[a]P). The results show that the xanthones, only isolated from the methanol extract of S. nitens capitula, probably were the responsible for its estrogenic activity and could be useful as phytoestrogens, providing a new opportunity to develop hormonal agents. In addition, flavones and xanthones could also be used as a new antimutagenic agent. Since, the mutagens are involved in the initiation and promotion of several human diseases, including cancer, the significance of novel bioactive phytocompounds in counteracting these pro-mutagenic and carcinogenic effects is now gaining credence. © 2013 Elsevier Inc. All rights reserved.

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Saccharomyces and non-Saccharomyces yeast species from a winery located in Brazil were identified by ribosomal gene-sequencing analysis. A total of 130 yeast strains were isolated from grape surfaces and musts during alcoholic fermentation from Isabel, Bordeaux, and Cabernet Sauvignon varieties. Samples were submitted to PCR-RFLP analysis and genomic sequencing. Thirteen species were identified: Candida quercitrusa, Candida stellata, Cryptococcus flavescens, Cryptococcus laurentii, Hanseniaspora uvarum, Issatchenkia occidentalis, Issatchenkia orientalis, Issatchenkia terricola, Pichia kluyveri, Pichia guilliermondii, Pichia sp., Saccharomyces cerevisiae, and Sporidiobolus pararoseus. A sequential substitution of species during the different stages of fermentation, with a dominance of non-Saccharomyces yeasts at the beginning, and a successive replacement of species by S. cerevisiae strains at the final steps were observed. This is the first report about the yeast distribution present throughout the alcoholic fermentation in a Brazilian winery, providing supportive information for future studies on their contribution to wine quality. © 2013 Springer Science+Business Media New York.