1,720,959 research outputs found
Efeito da aplicação de extrato de erva-mate (llex paraguariensis) assistido por ultrassom na estabilidade oxidativa de linguiça suína
No full textThe antioxidant properties of yerba mate has long been known and studied, the main reason is regarding its many therapeutic principles. Its phenolics content, main source of antioxidant agents, can also be applied in the industry for retarding the unwanted biochemical changes in the shelf-life of food. Therefore, this work is shown as an opportunity to demonstrate the potential of yerba mate extracts applied to pork sausages, a product which has as main limiting of its shelf-life expectancy the lipid oxidation. To obtain the extract was applied a factorial design by adding axial points, seeking for the best conditions of ultrasound extraction for increased antioxidant activity in response to free radical scavenging activity determined by DPPH and ABTS. The variables studied were temperature (22, 30, 50, 70 and 78 °C) and time (6, 10, 20, 30 and 34 min.). In the conditions of this study, the temperature was the only variable that showed, with 95% confidence level, positive influences significantly, both linear and quadratic, in the antioxidant activity of the yerba mate extracts. Thus, the following conditions were chosen in order to obtain the yerba mate extract: ultrasound bath for 10 minutes at 60 ° C. Then the extract was applied in fresh pork sausage in different concentrations of sodium erythorbate (0, 0.01 and 0.02%) and yerba mate extract (0, 0.03 and 0.06%). Accordingly, the yerba mate extract showed an improved ability to inhibit the oxidation of pork sausage when applied above 0.06% and lower concentrations of sodium erythorbate concentrations of 0.01% combined, in this study conditions. The consumer acceptance in the sensorial analysis was verified between two sausage formulations, both with the same concentration of sodium erythorbate, however just one of them was added yerba mate extract (0.03%). The test showed no significant difference between the assessment of color, flavor and global score, with acceptance levels above 70% for those attributes.A propriedade antioxidante da erva-mate há tempos é conhecida e estudada como principal razão de muitos dos seus princípios terapêuticos. Seus compostos fenólicos, principais agentes antioxidantes, podem ser aplicados também na indústria para retardar as alterações bioquímicas prejudiciais ao shelf life dos alimentos. Assim, justifica-se este trabalho como uma oportunidade de demonstrar o potencial de extratos de erva-mate aplicados a embutidos cárneos, alimentos que possuem como principal limitante da sua vida de prateleira as oxidações lipídicas. Para obtenção dos extratos foi aplicado um planejamento fatorial tipo estrela, visando as melhores condições de extração por ultrassom para uma maior atividade antioxidante em resposta aos testes de captura de radicais livres ABTS e DPPH. As variáveis testadas foram temperatura (22, 30, 50, 70 e 78°C) e tempo (6, 10, 20, 30 e 34 min.). Nas condições deste estudo, a temperatura foi a única variável que demonstrou, com nível de confiança de 95%, influencia significativa positiva, tanto linear quanto quadrática, na atividade antioxidante dos extratos de erva-mate. Desta forma, optou-se pelas seguintes condições para obtenção de um extrato de erva mate: banho de ultrassom por 10 minutos a 60°C. Em seguida, o extrato foi aplicado em linguiça suína frescal variando as concentrações de eritorbato de sódio (0, 0,01 e 0,02%) e extrato de erva-mate (0, 0,03 e 0,06%). Nestas condições, o extrato de erva-mate demonstrou uma melhor capacidade de inibir a oxidação da linguiça suína quando aplicado em concentrações acima de 0,06% combinado com concentrações de eritorbato de sódio menores que 0,01%, nas condições deste estudo. Uma análise sensorial de aceitação foi aplicado entre duas formulações de linguiça, ambos com a mesma concentração de eritorbato de sódio, porém a um deles foi adicionado 0,03% de extrato de erva-mate. O teste demonstrou que não há diferença significativa entre a avaliação dos tributos cor, sabor e Nota Global dos provadores, com níveis de aceitação acima de 70% para estes atributos
Isolamento e identificação de bactérias láticas com potencial proteolítico a partir de sourdough produzidas em Londrina, Paraná, Brasil
Get PDFWheat flour is one of the most common causes of food allergies, mainly because of the presence of gluten. The growing number of individuals with some sensitivity or pathology related to wheat proteins and scarcity of therapies for treatment (as simply adopting a gluten-free diet can be complex) demonstrate the need for alternative treatments. The present study aimed to isolate and identify lactic acid bacteria (LAB) from long-fermented bread dough (sourdough), with the potential to hydrolyze allergenic wheat proteins. Three different dough samples were collected from sourdough production establishments in Londrina, PR, USA. The breads were prepared in a laboratory. As positive controls, two formulations were prepared using only biological yeast containing lyophilized Saccharomyces cerevisiae. The fermentation process was monitored based using pH and acidity values, and the amount of gluten after fermentation was determined using the gravimetric method. LAB isolated from sourdough were inoculated into a medium containing gluten as the sole nitrogen source to evaluate the hydrolysis potential of wheat protein. Microorganisms were identified using biochemical and genotypic tests, genomic amplification using polymerase chain reaction and subsequent sequencing of the 16S region of ribosomal RNA. Seven LAB isolates were identified, including Lactiplantibacillus plantarum and Companilactobacillus crustorum. Compared with traditional fermentation, sourdough shows significant changes in pH and acidity during fermentation. There was a significant reduction in dry gluten (19.90%) (w/w) at the end of sourdough fermentation compared with that of traditional dough (S. cerevisiae). Although sourdough does not completely eliminate gluten, it can reduce the amount of gluten and improve the digestibility of wheat-based products. Further studies could be intersting to assess their impact on allergenicity in individuals sensitive to wheat proteins.A farinha de trigo é uma das causadoras mais comuns de alergia alimentar e isto se deve principalmente à presença do glúten. O crescente número de indivíduos portadores de alguma sensibilidade às proteínas do trigo, aliado à escassez de terapias para tratamento, já que a simples adoção de uma dieta isenta de glúten pode ser complexa, demonstra a necessidade de que alternativas sejam buscadas. O presente estudo teve por objetivo isolar e identificar bactérias láticas (BAL) em massas de pães de fermentação natural prolongada (sourdough), com potencial de hidrolisar as proteínas alergênicas do trigo. Três massas diferentes foram coletadas em estabelecimentos produtores de sourdough na região de Londrina - PR, Brasil. Em seguida, os pães foram reproduzidos em laboratório. Como controle positivo, foram produzidas duas formulações utilizando apenas fermento biológico comercial liofilizado contendo Saccharomyces cerevisiae. O processo fermentativo foi acompanhado por medidas de pH e acidez, e a quantidade de glúten após as fermentações foi determinada pelo método gravimétrico. As BAL isoladas a partir das sourdough foram inoculadas em meio contendo glúten como única fonte de nitrogênio, para avaliação do potencial de hidrólise da proteína do trigo. A identificação dos microrganismos foi realizada por testes bioquímicos e genotípicos por amplificação genômica através da técnica de Reação em Cadeia da Polimerase (PCR) e posterior sequenciamento da região 16S do DNA ribossomal. No total, foram obtidos sete isolados de BAL que foram identificados como Lactiplantibacillus plantarum e Companilactobacillus crustorum. Em comparação a fermentação tradicional, as sourdough apresentaram alteração significativa de pH e acidez durante a fermentação, além de redução significativa de 19,90% (m/m) de glúten seco quando comparados às massas tradicionais (S. cerevisiae). Embora o sourdough não elimine completamente o glúten, ele pode reduzir sua quantidade e melhorar a digestibilidade de produtos à base de trigo. No entanto, são necessários estudos adicionais para avaliar seu impacto na alergenicidade em indivíduos com sensibilidade às proteínas do trigo
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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