EQA - Escola de Química e Alimentos
URI permanente desta comunidadehttps://rihomolog.furg.br/handle/1/1610
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22 resultados
Resultados da Pesquisa
- ItemBiodegradação de deoxinivalenol por aspergillus oryzae e rhizopus sp.: um estudo bioquímico de degradação e toxicidade(2008) Buffon, Jaqueline Garda; Furlong, Eliana BadialeA contaminação aleatória de alimentos por micotoxinas afeta as condições de sanidade das dietas de humanos e animais. Dentre as toxinas fúngicas, deoxinivalenol (DON) se destaca pela freqüente contaminação de produtos agrícolas e alimentos e pela sua resistência a degradação pelo emprego de métodos tradicionais de processamento, o que motiva políticas de controle e a busca por técnicas de descontaminação. A descontaminação biológica empregando processsos fermentativos tem sido apontada como uma alternativa promissora, pois permite degradar micotoxinas através do sistema enzimático microbiano e melhorar características funcionais e sensoriais de matérias-primas e insumos alimentícios. Este trabalho teve por objetivo estudar condições e mecanismos de biodegradação de deoxinivalenol empregando Aspergillus oryzae e Rhizopus sp. em sistemas fermentativos submersos. Para tanto, foi necessário adequar metodologia para reação de derivação na determinação cromatográfica de DON; estudar o potencial e condições de degradação via fermentação submersa por Aspergillus oryzae e Rhizopus sp.; e avaliar a atividade de oxidoredutases e a citotoxicidade dos extratos fementados. A otimização da metodologia estabeleceu a melhor condição para a reação de derivação com 200 µL de anidrido trifluoroacético e 18 mg de bicarbonato de sódio, durante 6 minutos a 74 °C na faixa entre 7 e 21 µg de DON. A quantificação de DON residual no meio fermentado mostrou que as espécies fúngicas Rhizopus sp. e Aspergillus oryzae possuem a capacidade de degradar DON demonstrando índices médios de 87,4 e 62,4% respectivamente, principalmente quando o meio submerso foi água estéril e fermentação realizada durante 48 horas. A velocidade máxima de degradação neste intervalo foi de 10,8 e 12,4 ppb/h, observando também um aumento na atividade específica da enzima peroxidase. Os extratos dos fermentados com A. oryzae e Rhizopus sp. apresentaram efeito de inibição de proliferação celular (IC50) quando concentrados 10 vezes em 48 e 72 horas respectivamente. Os meios fermentados com Rhizopus sp. apresentaram menor efeito (1,5 vezes) quando comparado com Aspergillus oryzae.
- ItemEndoglucanase and total cellulase from newly isolated Rhizopus oryzae and Trichoderma reesei: production, characterization, and thermal stability(2014) Kupski, Larine; Pagnussatt, Fernanda Arnhold; Buffon, Jaqueline Garda; Furlong, Eliana BadialeA multienzymatic complex production was evaluated, as well as endoglucanase and total cellulase characterization, during solid-state fermentation of rice industry wastes with Rhizopus oryzae CCT 7560 (newly isolated microorganism) and Trichoderma reesei QM 9414 (control). R. oryzae produced enzymes with higher activity at 15 h of fermentation (5.1 and 2.3 U g−1 to endoglucanase and total cellulase), while T. reesei produced them at 55 h (15.3 and 2.8 U g−1 to endoglucanase and total cellulase). The optimum temperature for total cellulase and endoglucanase was 60 °C. For Trichoderma and Rhizopus, the optimum pH was 5.0 and 6.0 for total cellulase and 6.0 and 5.0 for endoglucanase, respectively. The enzymes produced by Rhizopus presented higher stability at the temperature range evaluated (25–100 °C); the endoglucanase KM value was 20 times lower than the one found for Trichoderma. The characterization of the cellulolytic enzymes from the fungal species native of rice husk revealed that they can be more efficient than the genetically modified enzymes when rice husk and rice bran are used as substrates.
- ItemDeoxynivalenol and nivalenol in commercial wheat grain related to Fusarium head blight epidemics in southern Brazil(2012) Del Ponte, Emerson Medeiros; Buffon, Jaqueline Garda; Furlong, Eliana BadialeA three-year (2006–2008) survey on commercial wheat grain was conducted aimed at quantifying the intensity of Fusarium head blight epidemics related to kernel quality and levels of deoxynivalenol (DON) and nivalenol (NIV). Grain samples, obtained from 38 municipalities throughout the state of Rio Grande do Sul, Brazil, were assessed visually for Fusarium-damaged kernels (FDK) and chemically using liquid chromatography–mass spectrometry (LC–MS/MS). Overall FDK mean levels were 15.5%, not differing among the years. Co-contamination was predominant (59/66) across samples and overall mean levels of DON and NIV were 540 and 337 lg/kg, respectively. When the levels of both mycotoxins were added together (DON + NIV), a higher correlation with FDK was found (R = 0.36, P < 0.01), compared to single toxin data. For the first time, the presence of NIV in levels comparable to DON is reported from a multi-year regional epidemiological survey in the country which should be of concern to the small grains industry.
- ItemAplicação de carboxipeptidase obtida de Rhizopus na degradação de ocratoxina A(2013) Kupski, Larine; Alves, Chiara Leal; Buffon, Jaqueline Garda; Furlong, Eliana BadialeMicotoxinas são metabólitos secundários produzidos por fungos filamentosos em diferentes etapas da cadeia produtiva de alimentos. Entre micotoxinas, ocratoxina A (OTA) é de grande importância, e apresenta efeitos carcinogênicos, nefrotóxicos e teratogênicos. Estes efeitos vêm motivando o desenvolvimento de métodos capazes de diminuir esta contaminação aos níveis permitidos pela legislação. Os métodos biológicos envolvendo o uso de enzimas e microorganismos para degradação da OTA tem se destacado, em função da especificidade reacional e das condições brandas para a detoxificação. Neste trabalho foram estabelecidas condições de extração de carboxipeptidase A a partir de biomassa fermentada por Rhizopus oryzae para empregá-la na degradação de OTA, tendo pancreatina como controle. A metodologia padronizada para extração enzimática consistiu em agitação ultrassônica durante 30 minutos numa potencia fixa de 150 W e 40kHz. O extrato enzimático do microorganismo apresentou uma capacidade de degradação de 19,4%, que ocasionou uma degradação 49% superior a ação da pancreatina. Este resultado confirma a vantagem da utilização de enzimas microbianas em detrimento as de origem vegetal inclusive para processos de biodegradação micotoxicologica.
- ItemActivity of rice bran proteic extracts against Fusarium graminearum(2013) Pagnussatt, Fernanda Arnhold; Bretanha, Cristiana Costa; Meza, Silvia Leticia Rivero; Buffon, Jaqueline Garda; Furlong, Eliana BadialeThe application of natural antifungal substances is motivated by the need for alternatives to existing methods that are not always applicable, efficient, or that do not pose risk to consumers or the environment. Furthermore, studies on the behaviour of toxigenic species in the presence of natural fungicides have enabled their safe application in the food chain. This study aimed to identify the fraction of the rice grain with greater inhibitory activity of amylase and related to its antifungal and antimycotoxigenic potential against Fusarium graminearum CQ 244 biomass. The greatest inhibitory effect was observed in extracts of bran, which inhibited by 90% the fungal amylase activity. The primary fractionation of the rice bran extract was more efficient when ethanolic extracts was precipitated by acetone, resulting in a specific inhibition estimated at 20 μg min-1mg protein1, PF 45 and recovery 61%. The rice bran protein extracts showed fungistatic activity against F. graminearum, with MIC50 of 419 μg ml-1 and 168 mg ml-1 estimated from glucosamine and amylase inhibition, respectively, which cause 63% biomass inhibition and 40% of the nivalenol (NIV) production.
- ItemEffect of Deoxynivalenol and T-2 Toxin in Malt Amylase Activity(2010) Buffon, Jaqueline Garda; Baraj, Edlira; Furlong, Eliana BadialeThe objective of this work was to evaluate the effect of DON and T-2 toxin levels on the malt amylase activity. The malt was contaminated in accordance with central composite design experiment with DON and T-2 toxin levels until 1000 ng/g. The activities of the enzymes were evaluated by Bernfeld method. The increase in T-2 toxin concentration inhibited the a-amylase activity. However, the increase of both toxins concentration caused inverse effect. The interaction between toxins indicated synergetic effect on the b-amylase activity. An increased activity occurred when the toxins contamination levels in malt were higher (1000ng/g malt). The trichothecenes interfered with the performance of aminolitic enzymes in the stage of malting, resulting in a significant model for enzymatic activity of b-amylase.
- ItemPropriedade das frações proteicas de cultivares de arroz, aveia e trigo(2011) Pagnussatt, Fernanda Arnhold; Buffon, Jaqueline Garda; Gutkoski, Luiz Carlos; Furlong, Eliana BadialeOs cereais são fontes de inibidores enzimáticos que agem sobre a α-amilase, que alteram a disponibilidade do amido e podem representar uma ferramenta útil para a resistência dos vegetais ao ataque de agentes patogênicos. Neste estudo foram analisadas as características físico-químicas e da fração proteica de aveia, arroz e trigo, cultivados no Rio Grande do Sul, com o objetivo de correlacioná-las, posteriormente, com a presença de inibidores enzimáticos e resistência à contaminação fúngica. As amostras de grãos de aveia, trigo e arroz foram caracterizadas físico-quimicamente e avaliadas quanto à digestibilidade proteica in vitro, solubilidade em sistema aquoso e atividade enzimática de hidrolases. A aveia apresentou maior teor lipídico e proteico e a cultivar UPFA 20 Teixeirinha demonstrou a menor digestibilidade em função do teor de fibras. O maior conteúdo de glutelina foi detectado no arroz cultivar BR 424, acompanhado pelo maior teor de proteína bruta e digestibilidade. As variedades de trigo apresentaram maior atividade de α-amilase e β-amilase, o que sugere que esse cereal é mais susceptível à degradação fúngica quando comparado com arroz e aveia, em vista da maior disponibilidade de açúcares. A atividade inibidora de amilases dos extratos proteicos dos cereais foi maior nos cultivares de aveia.
- ItemExtraction of fungal amylase inhibitors from cereal using response surface methodology(2011) Pagnussatt, Fernanda Arnhold; Bretanha, Cristiana Costa; Buffon, Jaqueline Garda; Furlong, Eliana BadialeThis study involved the application of response surface methodology to recover amylase-inhibiting protein fractions from oats, rice and wheat, in order to promote strategic procedures to reduce the risk of fungal contamination. The parameters studied were ethanol concentration, agitation time and type of grain using fractional factorial design 33-1. Fungal amylase (Fungamyl®) inhibition was used as the response. The results showed that in oats and wheat, optimum recovery of protein extracts capable of inhibiting Fungamyl® activity was achieved using 70% ethanol for 12 hours’ agitation, whereas for rice, the best condition was obtained with 95% ethanol and 7 hours’ agitation. It was shown that statistical treatment to combine process variables and enzyme activity measurement can be adopted for the selection and subsequent purification of enzyme inhibitors with antifungal activity.
- ItemApplication of protein-phenolic based coating on tomatoes (Lycopersicum esculentum)(2012) Cipolatti, Eliane Pereira; Kupski, Larine; Rocha, Meritaine da; Oliveira, Melissa dos Santos; Buffon, Jaqueline Garda; Furlong, Eliana BadialeThe aim of this study was to investigate the use of protein-phenolic based coating made from fermented rice bran on cherry tomatoes (Lycopersicum esculentum). Tests were performed with glycerol 3% (v/v), glycerol with protein-phenolic rice bran extract (5%), glycerol with protein-phenolic extract after 96 hours of fermentation (5%), and a control (without coating). The coated cherry tomatoes were kept at room temperature for 28 days. Mass loss, pH and acidity, total soluble solids, and carotenoids were determined every 96 hours. The coating made from the biomass extract reduced the carotenoid and acidity levels in the fruits studied by 17 and 21.1%, respectively, compared to the control. The coating proved an efficient barrier to water vapor with mass loss of 57% less than the control suggesting that it can be used as an alternative for vegetable tissue conservation.
- ItemAnálises quali e quantitativas de micotoxinas em águas da cadeia produtiva do arroz por CCD e CCDAE(2012) Leite, Clarice Caldeira; Buffon, Jaqueline Garda; Fagundes, Carlos Alberto Alves; Furlong, Eliana BadialeThis study validated a simple and applied method for determining mycotoxins aflatoxin B1, aflatoxin B2, ochratoxin A, zearalenone and deoxynivalenol, in water from the rice production chain. Five solvent combinations for extraction were tested, with quantification performed by TLC/HPTLC and confirmation by LC-MS/MS. Mycotoxins in water from field and rice industries were evaluated. Mycotoxin recovery levels were around 90%. Two samples from rice parboiling waste were contaminated (deoxynivalenol/aflatoxin B1, 110/9 ng mL-1; and deoxynivalenol, 100 ng mL-1). Zearalenone, deoxynivalenol and ochratoxin A (36, 30 and 28%) were carried to soaking water during parboiling.
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