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Bousted, Mary. "A socio-political analysis of the personal growth ideology of English teaching." Thesis, University of York, 1999. http://etheses.whiterose.ac.uk/10867/.
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Hilson, Patricia F., and n/a. "From oracy to literacy via writing : a Montessori approach for the pre-school." University of Canberra. Education, 1987. http://erl.canberra.edu.au./public/adt-AUC20060724.131835.
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Traditionally, children's formal introduction to print has occurred when
they enter primary school around five years of age. The progress of this
literacy development typically has been from the child's spoken language
into reading. In this approach writing emerges out of reading experience.
Montessori's theory suggests that children can come to literacy via
writing, specifically via the sounds of the alphabet. Her approach rests on
the view that the alphabet can represent the sounds of spoken language.
Given the sounds/symbols to write the child can learn to map spoken
language to print. As children explore the print system in writing they will
build up knowledge and understanding sufficient to support easy access to
reading.
According to Montessori the pre-school years offer an optimal time for
this development to occur. She maintains that where literacy acquisition
emerges out of spoken language via writing into reading the potential for
creative written expression may be more available to the child than where
the progression is first into reading. In this latter approach the thoughts
and conventions of other writers (reading) may limit the child's
expression.
Theoretical issues regarding young children's capacities to learn as well as
issues surrounding the writing/reading precedence are discussed.
To examine the process from children's spoken language into writing, a
series of naturalistic observations were carried out in three Montessori
classes. Children's progress from oracy to literacy and the learning
environments which facilitated this process are documented and discussed.
In presenting the children's learning environments an informal exposition of
Montessori's approach to language learning at the pre-school level is given.
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Olbers, Jenny. "The use of oracy skills when teaching English to Swedish speaking primary school pupils." Thesis, Luleå tekniska universitet, Institutionen för hälsa, lärande och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-82965.
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This study aims to understand in what way focused verbal exercises improve pupils’ overall expressive understanding of English together with their use of extramural English. The study took into consideration and demonstrated that learning and acquisition of an additional language appears to happen both consciously and subconsciously. The tasks carried out in this study strengthened pupils’ abilities and confidence for oracy in the classroom in conjunction with being modelled by their English teacher. This was achieved through short verbal exercises, with a focus on sentence structure. The study concluded that most pupils improved their oracy skills because of their progressive use of full sentences when answering questions and in other oral contexts. The persistent undertaking of striving towards completing sentences showed that they required a greater active use of English. Pupils understood to resource their latent vocabulary and comprehension. Moreover, the pupils achieved improved confidence in demonstrating an understanding to structure their speech.
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Axelsson, Erik. "”Vad kaotiskt allt skulle vara utan samtal.” : En fenomenografisk studie över elevers uppfattning om samtal." Thesis, Södertörns högskola, Lärarutbildningen, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-33429.
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The aim of this study is to examine what perception grade 2 students has of dialogue when focusing on the Swedish language. The study is supported by phenomenography, which focuses on the students’ own conclusions surrounding the importance of dialogue. The survey is also supported by a metacognitive perspective. To achieve the aim, the following three questions has been formulated: What perceptions do students in grade 2 have concerning dialogue? In what way does the students’ perceptions of dialogue differ? Do the students perceive dialogue as something of value? In summary, the results of this study are that in each student group it is agreed upon that dialogues are important but a majority of the students finds it difficult to keep up a dialogue. Therefore, it is important that teachers get all the help they need to be able to work with oracy, i.e. the ability to use oral tools such as speaking and listening. For them to succeed Mercer (2017) urges that oracy, as a tool, receives much more attention in schools.
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Scanlan, Mary. "My story in a box: linking home and school to explore identity, creative writing and oracy." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492566.
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My research took a socio- cultural perspective on literacy learning, which sought to discover ways in which knowledge and exchange of the different practices found in the domains of home and school might be utilised to benefit pupils. It was based within a collaborative action research framework (Elliott, 1991) in which I worked as a teacher researcher in partnership with class teachers and parents. I focussed on literacy in Key Stage 1. Pupils were asked to take home a shoebox and select artefacts to inspire their creative writing in school and parents were asked to discuss these choices with their child.
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McCormack, Brittany. "The Development of Oracy in Students with English as an Additional Language or Dialect Through Music." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/370572.
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This research investigates the potential of a music intervention to develop musicality and oracy in primary school aged students with English is an additional language or dialect (EAL/D). The research inquired: 1) what is the effect of a music intervention on the musicality of students with EAL/D; and 2) what is the effect of a music intervention on the level of oracy (verbal fluency, prosody and pronunciation) of students with EAL/D.
Music and speech are both auditory forms of communication, and neuroscientific research indicates that there are common processing mechanisms between them (Moreno, 2009; Patel, 2008). As a result, past research has continued to draw upon music and music pedagogy to explore its ability to develop other cognitive domains. The prevalence of music and its similarities to particular oracy skills further encouraged the use of music to investigate its potential to develop the verbal fluency, prosody, and pronunciation for students with EAL/D.
Australia’s immigration rates have continued to increase, in which 20% to 25% of school students have English as an additional language or dialect (Commonwealth of Australia, 2016a; Hammond, 2014). The Australian Curriculum, Assessment and Reporting Authority ([ACARA], 2014b) notes that students with EAL/D are seen to struggle with aspects of oracy, and are expected to meaningfully communicate in spoken English for a variety of social and academic purposes. Although Australian teachers have access to a variety of curriculum documents, these documents do not outline specific strategies for teachers of students with EAL/D to assist in the development of their verbal fluency, prosody and pronunciation. Therefore, this research attempted to do so through the implementation of an eight-week music intervention that drew upon the principles of audiation from Gordon’s Music Learning Theory (The Gordon Institute for Music Learning [GIML], 2017a). The principles of audiation from Gordon’s Music Learning theory were used in this intervention due to the focus on pitch and rhythm. This focus would allow students to develop tonal and rhythmic vocabularies, and thus assist in their ability to audiate, or to hear sounds in their heads.
The implementation of this music intervention reflected the pragmatic nature of this research as it aimed to investigate music’s potential to develop three specific oracy skills for students with EAL/D: verbal fluency, prosody, and pronunciation. A single-subject experimental design (SSED) methodology was employed as it allowed the individual reporting of student participant results. Results from qualitative and quantitative data indicated that all students demonstrated improvements in their level of musicality after their participation in the music intervention to varying degrees. All participants were noted as having increased levels of pronunciation, but only five of the six participants improved their level of prosody post-intervention. No significant improvements could be reported for students’ verbal fluency. Results indicated there is the potential for this music intervention to develop prosody and pronunciation for students with EAL/D. Although these positive results were obtained, further research is needed over an extended period of time to investigate the full extent of music’s influence on these skills and additional areas within other cognitive domains.
Additional results from semi-structured interviews and observations indicated all students demonstrated an increase in their confidence, motivation and engagement, and that the music intervention facilitated the development of relationships between peers and staff. Previous research found that music is an engaging tool that alleviates the anxiety associated with language learning (Ara, 2009; Fonseca-Mora, Toscano-Fuentes, & Wermke, 2011). It can be suggested that potential correlations exist between confidence, motivation and engagement and the development of their prosody and pronunciation, as it encouraged students to take risks and experiment with their verbal communication in the English language, in turn influencing the facilitation of relationships. Further research into this area would be needed, however, to confirm or refute these suggested correlations.
Results from this research revealed there is potential for this music intervention to develop specific oracy skills for students with EAL/D, particularly prosody and pronunciation. This research may assist primary school teachers in developing specific strategies to target and develop verbal fluency, prosody, and pronunciation for students with EAL/D. Additionally, this research adds to the growing body of knowledge around the benefits of music developing skills in other cognitive domains.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School Educ & Professional St
Arts, Education and Law
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Beaumont, Natasha. "Multimodal language and learning: Drama as EAL/D pedagogy in the early primary classroom." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/22696.
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This paper is a qualitative exploration of the experiences of three English as an additional language or dialect (EAL/D) Year 1 students and their classroom teacher. The study interprets their engagement in socio-dramatic roleplay as a form of oral and written literacy instruction. Analysis centres around the body language and classroom conversations of participants, as well as the pedagogic strategies implemented. The methodologies used are hermeneutic phenomenology and narrative interpretation. Human personalities are impossible to represent using purely quantitative means. Stories, however, are able to vividly depict complex psychosocial environments. Classrooms are such an environment, as full of relationships and feelings as they are of concepts and curriculum. Hence, in presenting a case for drama as a highly engaging language enrichment pedagogy, this study has been inspired and informed by the work of Van Manen (2016a, 2016b) and Polkinghorne (1988), both significant contributors to the field of human experience. This investigation builds upon a growing body of research demonstrating that drama-rich strategies and techniques are a classroom innovation that can improve student engagement and learning outcomes. Drama encourages vocal expressiveness and creative language use. It also allows young students to use their innate physicality to create and access multimodal meaning. Multimodality is becoming increasingly valued in the fields of second language learning and social equity. Finding different ways of representing knowledge to help support increasingly diverse student populations is now an acknowledged best practice. Drama utilises body language as an alternative mode of communication, one that EAL/D students are able to adopt as easily as their mainstream language peers.
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Mannion, James. "Metacognition, self-regulation, oracy : a mixed methods case study of a complex, whole-school 'Learning to Learn' intervention." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/289131.
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This doctoral thesis presents the findings of a mixed methods case study of Learning Skills, a new approach to Learning to Learn that was developed and implemented at a secondary school in the south of England between 2010 and 2014, and evaluated using data collected between 2009 and 2017. Learning to Learn is a field of educational theory and practice that aims to help young people get better at learning by focusing on the processes of learning (the how as well as the what), and by enabling them to take ownership over aspects of their own learning through activities such as goal setting, self-monitoring and structured reflection. The field has developed significantly throughout the last 40 years, with a number of approaches having been implemented on a large scale in the UK. Research into metacognition and self-regulation suggests that Learning to Learn programmes should help boost academic attainment. To date however, large-scale evaluations have found mixed results, with no clear impact on academic attainment. Using an intervention design used widely in medicine and other fields, Learning Skills reconceptualises Learning to Learn as a 'complex intervention' comprised of multiple areas of evidence-informed practice. The rationale for complex interventions is that the marginal gains emerging from any individual avenue of practice stack up and interact to yield a larger effect size overall. The Learning Skills programme, which started as a year seven taught course and developed into a whole-school approach to teaching and learning, focuses centrally on three key concepts: metacognition, self-regulation and oracy. This evaluation of Learning Skills incorporates eight strands of data collection and analysis over an eight-year period, using the previous year group at the same school as a control group. These include baseline measures; attitude to learning scores; psychometric questionnaires; a language of learning evaluation; reflective learning journals; student interviews; teacher interviews; and student attainment across all subjects in years nine and 11. The primary outcome analysis - student attainment across all subject areas at three and five years - found that Learning Skills cohort one achieved significantly higher grades than the control cohort, with accelerated gains among young people from economically disadvantaged backgrounds. Secondary data analysis incorporating a range of qualitative and quantitative methods indicates a causal relationship between Learning Skills and academic attainment. As well as evaluating the impact of a new and promising approach to Learning to Learn, this study generates new knowledge about the implementation and evaluation of complex interventions in education.
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Perez-Adamson, Clara. "Does an oracy intervention affect the way that teachers cope with students who challenge or worry them in some way?" Thesis, University of Essex, 2018. http://repository.essex.ac.uk/22932/.
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The Voice 21: Improving oracy intervention funded by the Education Endowment Foundation (EEF) was focused upon improving the quality of classroom dialogue at the Y7 level. It has four key elements: (i) an oracy curriculum, which includes dedicated oracy lessons and strategies for building oracy in regular school lessons; (ii) a training package for school staff; (iii) strategies to build a whole-school oracy culture, including building oracy into assemblies and parents’ evenings, and (iv) an oracy assessment tool, which helps teachers to identify specific speaking and listening skills. Past research focussed upon oracy has established that oracy can lead to school age students achieving substantially improved skills in maths, science, and reasoning. This study attempts to develop an understanding of how vulnerable students were thought about and engaged with in a school that had recently completed the EEF intervention. Five teachers were interviewed and asked about their experiences of working with students perceived as challenging or worrying before and after the intervention, and about the possible impact of the intervention on relationships among students and teachers in the school. A social constructivist epistemological position was adopted and a grounded theory methodology was used. Teachers reported that students developed skills in listening and relating to other students, which contributed to improved relations among students. Teachers also reflected that the intervention offered them the space to develop more trusting and close relationships with students. Oracy was described as serving students who were challenging or worrying by helping teachers to identify students with language difficulties, by giving students who attracted negative attention opportunities to participate positively in school and by offering students who were otherwise socially vulnerable tools to present their ideas, and a platform from which to influence the school culture.
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Keyser, Dorothy. "Oracy, Literacy and the Music of Adam De La Halle: The Evidence of the Manuscript Paris, BibliothèQue Nationale f.fr. 25566." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc332454/.
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This study examines the thirteenth century Artesian trouvère Adam de la Halle in the manuscript Paris, Bibliothèque Nationale f.fr 25566 as it pertains to the oral/literate model for explaining characteristics of musical traditions. The fortuitous collaboration of a single scribe with a single composer on a musical collection encompassing a cross-section of thirteenth-century styles and idioms make this repertoire uniquely appropriate to a comparison of musical oracy and literacy.
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Crerand, Mary E. Lavin. "From first language literacy to second language oracy to second language literacy : the act of writing in a foreign language context." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1239369687.
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Malherbe, Neil. "A critical analysis of the importance of oracy in the classroom, with particular reference to secondary schools in the Cape Education Department." Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1003355.
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In the past thirty years, oracy has received prominence as a means to enhance teaching styles and assist with learning. Much of what has been written in this field has been by those interested in a 'language across the curriculum' approach, such as Barnes (1969) who developed the terms 'exploratory talk' and 'final draft talk'. The linguist, M.A.K. Halliday {1989} and others have suggested that the teacher's approach should be to encourage what he terms 'heuristic talk' i.e. relatively unstructured exploratory language used by the pupils in talking towards an understanding of a concept. It is more evident in certain school subjects that pupils may have difficulty in understanding abstract or complex concepts. In this regard, English, mathematics and physical science were selected for the purpose of this study, as each has its own metalanguage, specific to that subject. It is presumed that some pupils may find difficulty in these subjects because of the subject-specific language inherent in each. This work explores whether a programme of increased oracy alleviates some of these problems and it makes recommendations for the implementation of such a programme. The period involved for the purpose of this study was five weeks, during which teachers of three selected classes presented lessons in such a way that oral work was stressed. At the completion of this programme, a test was written for comparison with past experiences. Pupils answered a comprehensive questionnaire and staff involved were interviewed; the results of this feedback, in conjunction with what has been written by others in this field, forms the basis for this work. The primary recommendation emerging from this and other studies is that a shift away from a teacher-/ and textbook-dominated approach is necessary. Pupils need to contextualise knowledge in their own terms. One important way of accomplishing this is by affording them theopportunity to interact orally with each other and with the teacher.
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Lilliehöök, David, and Hampus Söderberg. "Säg vad du menar och mena vad du säger! : En diskursanalytisk studie av svenska grundskolans nationella prov, läroplan och kommentarmaterial för årskurs 4-6." Thesis, Södertörns högskola, Lärarutbildningen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-31648.
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The aim of this study was to identify discourses about oracy and the spoken language, how these discourses were constructed as well as investigating how these discourses compared to those about writing and written language. Through the use of a social-constructivist approach, we have analysed central documents in the Swedish school system and deconstructed these to uncover implicit meanings bound to them. The materials analysed include a standardised test taken by pupils in the 6th grade along with an excerpt from the Swedish curriculum, containing the aim of Swedish as a school subject, as well as a complimentary material provided for clarifying purposes. We’ve fragmented these documents to identify discourse-indicating variables and their possible function in constructing discourse. In this study we have identified small-scale discourses which we believe to be contributing to the present view on oracy as well as an implicit undermining of its legitimacy, something which we haven’t found any signs of in texts associated with written-language education.This undermining presents itself as language which is hard to decipher, which may be perceived as leading to the expressed uncertainty amongst Swedish teachers and a vertigo linked to these forms of educating. Conclusions drawn from this study point toward a favouring of written activities in the texts, reasons for which we believe could be historical and/or social in nature.
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Söderberg, Hampus. ""Vad det hela faller på är flera saker..." : En diskursanalytisk studie utifrån mellanstadielärares utsagor om muntlighetsundervisningen i den svenska skolans svenskämne." Thesis, Södertörns högskola, Lärarutbildningen, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-33409.
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The aim of this study is to better understand how oracy education is viewed by a selection of active intermediate-school teachers in the school-subject Swedish. Oracy in the intermediate-school level of education is a subject which is rarely researched and this study thus seeks to broaden the base of knowledge available to future studies. Data was gathered through internet-based interview questions sent to respondents from a selection of Swedish schools as well as teacher students. This was then analysed through a discourse-analytic method. Through the use of this method, common themes were identified within many of the respondents’ answers which in turn pointed to some discourses about oracy. What I found was that common topics circled around the pupils and the classroom climate, Oracy in education and time in both a resource- and fairness perspective. These made up for three main discourses in the material: A preparatory-activities discourse concerning how the pupils are to be prepared for oracy education. This was separated into two discussions about: (1) the maturity of the pupils and (2) teaching proper preparation strategies. A benefits discourse centring on how the student benefit from oracy education. The respondents’ statements point towards there being two benefits of oracy education: (1) its role in providing a well-rounded education and (2) it acting towards their own personal maturity as speakers. A resource discourse which addresses the time-aspect of a teacher’s practice. Two main parts of this discourse focused on: (1) how teachers save time by taking notes during oral examination forms and (2) The problems with fairness faced when time constraints force an oral exam to be split into more than one period.
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Smith, Andrew John Alexander. "Microphysical modelling of aerosols in the ORAC retrieval." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:127ca383-e4bf-44f4-8915-badca16c5016.
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This thesis describes an investigation of, and improvements to, the microphysical modelling of aerosols in the Oxford-Rutherford Appleton Laboratory Aerosol and Clouds retrieval (ORAC), which is used to obtain aerosol properties from measurements by the Advanced Along Track Scanning Radiometer (AATSR). Modelling decisions determine the light scattering properties of the aerosol classes which in turn alter the retrieved aerosol properties: aerosol optical depth, and effective radius. The maritime, mineral dust, urban, and biomass burning aerosol classes were first investigated, and then improvements implemented. Major additions to the scheme include the ability to model non-spherical dust as spheroids, soot as fractal aggregates, and to coat spherical particles with an extra layer of differing refractive index (whose thickness can be modified by ambient relative humidity where necessary). Output from aerosol retrievals containing these new models is presented. Modelling of marine aerosol was found to be adequate, but an improvement in the relative humidity assumptions led to an average 5 % increase in aerosol optical depth (AOD). Modelling of mineral dust aerosols has been dramatically altered by the addition of non-spherical dust and hygroscopic particles, leading to increases in measured AOD of over 100 % during dust events, compared to the previous model. Measurement of biomass burning aerosol has been tested with an `ageing' aerosol scheme, leading to increases in over-land measured AOD of 0.14 (~50 % increase). With such significant changes in AOD, representation of aerosol light scattering properties is seen to be important factor in the accuracy of the ORAC scheme. Finally, a method of optimising the placement of detectors in an aerosol measurement device is presented.
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Silva, Filipe André Nascimento. "Avaliação antioxidante de 3,5-dimetil isoxazol, pirazóis e tiazóis utilizando o método ORAC (capacidade de absorção de radicais oxigênio)." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-27052011-111106/.
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Os radicais livres são espécies químicas que reagem rapidamente com diversos compostos e alvos celulares, por possuírem tempo de meia vida muito curto e serem espécies altamente instáveis. A formação destes compostos constitui uma ação contínua e fisiológica, cumprindo funções biológicas essenciais as quais ocorrem pela perda ou adição de um único elétron a um composto não radicalar. Estas reações podem ocorrer em processos bioquímicos do sistema imune ou químicos, causando prejuízo às células através da destruição de componentes, como proteínas, lipídios, açúcares e nucleotídeos. Sabe-se que existem compostos que são efetivos contra tais espécies, prevenindo os danos provocados pelo estresse oxidativo. O objetivo deste trabalho foi estudar compostos heterocíclicos que possuam nitrogênio em sua estrutura (azóis), que figuram na literatura como moléculas exemplares de compostos de aplicação farmacológica de amplo espectro. Dentre estes compostos foram analisados os derivados de pirazóis (26 compostos), tiazóis (7 compostos) e 1 isoxazol (3,5-dimetilisoxazol). Estes 34 compostos foram avaliados pela metodologia ORAC (Capacidade de Absorção de Radicais Oxigênio) a fim de determinar e/ou de avaliar seu potencial antioxidante. A escolha do método ORAC se deu pelo fato das moléculas estudadas apresentarem características hidrofílicas e lipofílicas, além de ser um método validado pela literatura, disponível e de ampla aplicação. O método ORAC avalia a capacidade antioxidante da amostra, medindo sua habilidade de proteger a fluoresceína (FL) da oxidação pelo AAPH no meio reacional. O AAPH é um gerador de radicais livres que a 37°C retira hidrogênio do meio, promovendo a redução da fluorescência da fluoresceína em λ medido pelo tempo. Seis compostos apresentaram atividade antioxidante de boa à moderada: 3,5-dimetil-1H-pirazol (2.382 µmol eq.Trolox/g); 3-fenil-5-(4-fluorfenil)-1-tiocarbamoil-4,5-diidro-1H-pirazol (6.354 µmol eq.Trolox/g); 3-fenil-5-(2-metoxifenil)-1-tiocarbamoil-4,5-diidro-1H-pirazol (8.739 µmol eq.Trolox/g); 5-(2,4-diclorofenil)-3-fenil-1-tiocarbamoil-4,5-diidro-1H-pirazol (6.022,226 µmol eq.Trolox/g); 2-[5-(4-metoxifenil)-3-fenil-4,5-diidro-1H-pirazol-1-il]-4-feniltiazol (3.135 µmol eq.Trolox/g); e finalmente 2-[5-(3-nitrofenil)-3-fenil-4,5-diidro-1H-pirazol-1-il]-4-feniltiazol (2.700 µmol eq.Trolox/g). Os experimentos com o método ORAC para os azóis estudados apresentaram reprodutibilidade na execução experimental e demonstraram ser uma alternativa viável para estudos de moléculas sintéticas de potencial antioxidante.Free radicals are chemical species that react rapidly with various compounds and target cells, as they have a very short half life and are highly unstable. The formation of these compounds consists of a continuous, physiological action, which includes essential biological functions and occurs through the loss or addition of a single electron to a non-radical compound. These reactions may occur in biochemical processes of the immune system, or by chemical reactions, causing damage to the cells through the destruction of components such as proteins, lipids, sugars and nucleotides. It is known that compounds exist which are effective against these species, preventing damage caused by oxidative stress. The object of this work was to study heterocyclic compounds that have nitrogen in their structure (azoles), which appear in the literature as exemplary molecules of compounds with a wide spectrum of pharmacological applications. Of these compounds, derivatives of pyrazoles (26 compounds), thiazoles (7 compounds) and 1 isoxazole (3,5-dimethylisoxazole) were analyzed. These 34 compounds were evaluated by the ORAC (Oxygen Radicals Absorption Capacity) in order to determine and/or evaluate its antioxidant potential. The choice of ORAC method is based on the fact that the molecules studied have hydrophilic and lipophilic characteristics, as well as a method validated by the literature, which is available and widely used. The ORAC method evaluates the antioxidant capacity of the sample, measuring its ability to protect the fluorescence (FL) of the oxidation by the AAPH in the reaction medium. AAPH is a generator of free radicals which, at 37°C, removes hydrogen from the medium, promoting the reduction of fluorescence from fluorescein in λ measured by time. Six compounds present good to moderate antioxidant activity: 3,5-dimethyl-1H-pyrazole (2.382 µmol eq.Trolox/g); 3-phenyl-5-(4-fluorphenyl)-1-thiocarbamoyl-4,5-dihydro-1H-pyrazole (6.354 µmol eq.Trolox/g); 3-phenyl-5-(2-methoxyphenyl)-1-thiocarbamoyl-4,5-dihydro-1H-pyrazole (8.739 µmol eq.Trolox/g); 5-(2,4-diclorophenyl)-3-phenyl-1-thiocarbamoyl-4,5-dihydro-1H-pyrazole (6.022,226 µmol eq.Trolox/g); 2-[5-(4-methoxyphenyl)-3-phenyl-4,5-dihydro-1H-pyrazole-1-il]-4-phenylthiazole (3.135 µmol eq.Trolox/g); and finally, 2-[5-(3-nitrophenyl)-3-phenyl-4,5-dihydro-1H-pyrazole-1-il]- 4-phenylthiazole (2.700 µmol eq.Trolox/g). Experiments with the ORAC method for the azoles studied present reproducibility in the experimental execution, and have proven to be a viable alternative for studies of synthetic molecules with antioxidant potential.
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Pereira, Gustavo Araujo 1991. "Estudo dos parâmetros de extração de compostos fenólicos e avaliação da atividade antioxidante in vitro da banana (Musa sp.)." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254206.
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Orientador: Gláucia Maria PastoreDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O objetivo do presente trabalho foi estudar a influência dos parâmetros de extração sólido-liquido e de enzimas fenoloxidases (peroxidase) na recuperação de compostos fenólicos a partir do pó da casca de banana liofilizada (CBL), bem como quantificar o conteúdo de compostos fenólicos totais (FT), flavonoides totais (CF) e a atividade antioxidante da CBL e do pó da polpa de banana liofilizada (PBL). A banana utilizada foi da variedade Prata no estágio 6 de maturação (casca totalmente amarela). Primeiramente, o estudo foi iniciado com a seleção dos parâmetros de extração (temperatura, agitação, solvente e relação sólido-líquido) por meio de um Delineamento Fracionado 24-1 e, em seguida, o método de Superfície de Resposta foi empregado para otimizar os principais fatores do processo de extração (relação sólido-líquido e solvente). A casca da banana apresentou elevada atividade da enzima peroxidase (POD), o que provocou a oxidação dos compostos fenólicos e a redução da capacidade antioxidante do extrato. As melhores condições para a extração de compostos fenólicos a partir da casca de banana foram: relação sólido-solvente de 2,5 g/100 mL (1:40), solvente etanol 54% (v/v etanol:água) e homogeneização com auxílio de Ultra Turrax por 30s a 11.000 rpm. O conteúdo de FT obtido com esse sistema de extração foi de 2,44 g EAG/100 g CBL. A casca de banana apresentou conteúdo de FT (2,44 g EAG/100 g CBL), CF (2,32 g EC/100 g CBL) e atividade antioxidante mensurada pelos métodos de DPPH (380,84 ?mol EQT/g CBL; IC50 = 71,74 ?g/mL), TEAC (325,84 ?mol EQT/g CBL) e ORACFL (ORAC Total = 994,33 ?mol EQT/g CBL) maiores do que a polpa de banana (FT = 0,25 g EAG/100 g PBL; CF = 0,21 g EC/100g PBL; DPPHIC50 = 690,97 ?g/mL; TEAC = 11,05 ?mol EQT/g PBL; ORAC Total = 80,16 ?mol EQT/g PBL). A banana é uma das frutas mais produzidas no mundo, e devido ao seu elevado consumo e abundância pode ser considerada uma importante fonte de compostos antioxidantes. Finalmente, por meio deste estudo foi possível verificar que a polpa e a casca de banana apresentam compostos fenólicos antioxidantes. Mais estudos devem ser realizados para verificar a influência do consumo desse
Abstract: The objective of the present work was to study the influence of solid-liquid extraction parameters and phenoloxidases enzymes in the recovery of phenolic compounds from freeze-dried banana peel powder (BPP), as well as to quantify the total phenolic content (TPC), flavonoid content (FC) and antioxidant activity of BPP and freeze-dried banana pulp powder (BPU). The banana Prata variety was utilized in 6th stage of ripening (fully yellow peel). First of all, the study started with the selection of the extraction parameters (temperature, agitation, solvent and solid-liquid ration) through factionary design (24-1). Subsequently, the Response Surface Methodology (RSM) was employed to optimize the main parameters of the extraction process (solid-liquid ration and solvent). The banana peel showed high peroxidase activity (POD), which led the oxidation of phenolic compounds and the decrease of antioxidant activity of the extract. The best conditions for the extraction of phenolic compound from BPP were solid-liquid ration of 2.5 g/100 mL (1:40), solvent ethanol 54% (v/v ethanol:water) and homogenization using Politron at 11.000 rpm for 30 s. The total phenolic content obtained whit this extraction system was 2.44 g GAE/100 g BPP. The banana peel showed TPC (2.44 g GAE/100 g BPP), FC (2.32 g CE/100 g BPP), and antioxidant activity measured by DPPH (380.84 ?mol TE/g BPP; IC50 = 71.74 ?g/mL), TEAC (325.84 ?mol TE/g BPP) and ORACFL (ORAC Total = 994.33 ?mol TE/g BPP) methods higher than banana pulp (TPC = 0.25 g GAE/100 g BPU; FC = 0.21 g CE/100 g BPU; DPPHIC50 = 690.97 ?g/mL; TEAC = 11.05 ?mol TE/g BPU; ORAC Total = 80.16 ?mol TE/g BPU). The banana is one of the most produced and consumed fruit in the entire world and can be considered as an important source of natural antioxidants. In this sense, this study was to possible found that banana pulp and peel have phenolic compounds with antioxidants properties. More studies should be performed to verify the relationship between banana consumption and human health. Furthermore, research addressing the use of the banana peel by food and pharmaceutical and medical industries. fruto tropical na saúde do corpo humano e também pesquisas abordando o uso da casca na indústria de alimentos e no desenvolvimento de novos produtos
Mestrado
Ciência de Alimentos
Mestre em Ciência de Alimentos
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Calomeni, Andressa do Valle. "Utilização de película de amendoim para produção de pigmento natural em pó: estudo do efeito do processo de atomização na estabilidade, propriedades antioxidante e antimicrobiana do material." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-03022016-162446/.
Full textAbstract:
A película do amendoim apresenta coloração vermelha intensa e é rica em compostos fenólicos, todavia o extrato líquido é instável e de difícil comercialização. Os objetivos deste trabalho foram extrair os pigmentos da película do amendoim, estudar o processo de secagem por atomização deste extrato, caracterizar os pós obtidos, bem como sua propriedade antioxidante, antimicrobiana e estabilidade durante o armazenamento, sempre comparando com o controle. Quanto a caracterização do extrato líquido foi analisado fenólicos totais, pH, umidade, cinzas, proteínas, lipídeos, açúcares, aflatoxina e acidez. Os extratos foram então misturados com agente carreador nas concentrações de 10, 20 e 30%, estes foram atomizados em spray dryer com temperaturas do ar de entrada de 130, 150 e 170ºC. Para obtenção da amostra controle, parte do extrato foi liofilizado sem a presença de agente carreador. Os pós obtidos foram caracterizados quanto à umidade, atividade de água, higroscopicidade, morfologia, tamanho das partículas, cor, teor de fenólicos totais, solubilidade, estabilidade, propriedade antimicrobiana e antioxidante pelos métodos: ORAC, DPPH e HPLC-ABTS on line. Na caracterização do extrato líquido foram obtidos os seguintes resultados: 0,24% de proteína, 2,31% de açúcares, 0,09% de cinzas, 1,41% de lipídeos, 0,91% de acidez titulável, 42,88 mg de ác. gálico eq./g de extrato (fenólicos totais), pH de 5,30, 90,93% de umidade e 1,81 ng aflatoxina/mL extrato (aflatoxina). Na caracterização dos pós, a umidade foi menor para pós secos a 170ºC e para concentração de 10% de maltodextrina e foi sempre menor que o controle. A higroscopicidade foi menor quanto maior a concentração de maltodextrina, pois esta tem baixa higroscopicidade. Temperaturas mais altas geraram pós mais higroscópicos, pois esses tinham menor umidade. Com relação à solubilidade, os valores variaram de 85,60 a 91,91%, obtendo-se maiores valores para pós com maiores concentrações de maltodextrina, pois esta apresenta elevados valores de solubilidade. O controle apresentou solubilidade mais baixa de 77,62%. Já os parâmetros de cor tiveram influência apenas da concentração de maltodextrina, sendo que as amostras com menor concentração apresentaram cor mais acentuada, o que era de se esperar visto que a maltodextrina apresenta coloração branca. Portanto, o controle sempre apresentou a coloração mais intensa frente aos pós atomizados. A temperatura de 170ºC originou pós de superfícies mais lisas, apresentando assim melhor escoamento. Com o estudo de estabilidade, verificou-se que as amostras atomizadas tiveram menor perda de cor em relação à liofilizada, e as amostras com maior concentração de maltodextrina (30%) preservaram melhor os fenólicos totais, destacando-se a temperatura de 150 ºC. Em relação à atividade antioxidante, o tratamento T5 se destacou frente aos outros, apresentando o melhor valor de atividade antioxidante por todos os métodos estudados. O extrato da película de amendoim em pó também apresentou atividade antimicrobiana contra as bactérias Gram-positivas Staphylococcus aureus e Listeria monocytogenes, apresentando ainda capacidade bactericida para Staphylococcus aureus. Frente a esse estudo, tem-se na película de amendoim um potencial aditivo natural, podendo ser utilizado como pigmento em pó que apresenta excelente estabilidade, baixa higroscopicidade e alta solubilidade; além de apresentar atividades biológicas como capacidade antioxidante e antimicrobiana.The peanut skin presents intense red color and is rich in phenolic compounds, however the liquid extract is unstable and difficult to commercialize. The aim of this project was to extract the pigments of peanut skin, study the process of spray drying this extract, characterize the powders as well as its antioxidant properties, antimicrobial properties and storage stability, when compared to the control. The extract was characterized measuring the phenolic compounds, pH, moisture, ash, protein, lipids, sugars, aflatoxin and acidity. The extracts were then mixed with the carrier agent at concentrations of 10, 20 and 30%, these were atomized in a spray dryer at inlet air temperatures of 130, 150 and 170 º C. To obtain a control sample, part of the extract was freeze-dried without the presence of maltodextrin. The powders were characterized for moisture, water activity, hygroscopicity, morphology, particle size, color, total phenolic content, solubility, stability, antimicrobial and antioxidant properties by the methods: ORAC, DPPH and ABTS HPLC-online. In the analysis of the liquid extract, the following results were obtained: 0.24% protein, 2.31% sugar, 0.09% ash, 1.41% lipid, 0.91% titratable acidity, 42.88 mg of Galic acid eq. / g extract (phenolic), pH of 5.30, 90.93% moisture and 1.81 ng aflatoxin / mL extract (aflatoxin). In the analysis of the powders, moisture was lower for powders dried at 170ºC and with 10% maltodextrin concentration and was always lower than the control. The hygroscopicity is lower as higher the concentration of maltodextrin, since the last has low hygroscopicity. Higher temperatures generated more hygroscopic powders, because they reduced moisture. In concern to solubility, the values ranged from 85.60 to 91.91%; higher values were obtained for powders with higher concentrations of maltodextrin, since it has high solubility values. The control showed lower solubility of 77.62%. The color parameters were influenced only by the concentration of maltodextrin; the samples with lower concentrations showed more pronounced color, what was to be expected since maltodextrin is white. Therefore, controls have always presented with more intense color than the atomized powders. The temperature of 170 ºC originated powders with smoother surfaces, thus resulting in better flow. In the evaluation of stability, it was found that the atomized sample suffered lower color loss compared to the freeze dried sample, and samples with higher concentrations of maltodextrin (30%) had better preservation of total phenolics, especially at a temperature of 150ºC. In concern to antioxidant activity, the T5 treatment stood out compared to the others, showing the best values of antioxidant activity in all methods studied. The extract of peanut skin in powder also showed antimicrobial activity against Gram-positive bacteria Staphylococcus aureus and Listeria monocytogenes, with bactericidal properties against Staphylococcus aureus. This study clearly showed that peanut skin is a potential natural additive product and may be used as a powdered pigment which has excellent stability, low hygroscopicity and high solubility, besides having biological activities, such as antioxidant and antimicrobial capabilities.
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Infante, Juliana. "Composição fenólica e atividade antioxidante de polpa, casca, semente e folha de espécies frutíferas nativas do Brasil." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11141/tde-19122013-165106/.
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O Brasil possui uma imensa diversidade biológica, na qual muitos compostos bioativos podem ser encontrados e utilizados em beneficio à sociedade. No entanto, processos de degradação do ambiente e introdução de espécies exóticas têm contribuído ao conhecimento e uso limitadosde muitas plantas nativas, sendopequena a quantidade de estudos sobre sua composição química e potencial biológico. A prevenção de doenças crônicas constantemente vem sendo associada à atividade antioxidante de metabólitos secundários dos vegetais, principalmente os fenólicos. Assim, o objetivo deste trabalho foi avaliar a atividade antioxidante e composição fenólica de cinco espécies frutíferas nativas do Brasil (G. brasiliensis, E. leitonii, E. involucrata, E. brasiliensis e E. myrcianthes). Os métodos capacidade de redução do Folin-Ciocalteau, autoxidação do sistema ?-caroteno/ácido linoleico, capacidade de absorção de radicais oxigênio (ORAC), sequestro dos radicais livres DPPH e ânion superóxido foram aplicados na determinação da atividade antioxidante dos extratos etanólicos de folha, casca, semente e polpa das espécies selecionadas. As amostras demonstraram significativa atividade antioxidante e, em alguns casos, superior as frutas comumente consumidas pela população brasileira. Em geral, folhas apresentaram as maiores atividades, mas o destaque foi a semente de E. leitonii que exibiu os melhores resultados em quatro dos cinco métodos utilizados: 120,67 mg AG.g-1 na redução do reagente Folin; 7,08 Gmol Trolox.g-1 no ?-caroteno; EC50 de 0,26 mg.mL-1 e 0,07 mg.mL-1 no sequestro do ânion superóxido e DPPH, respectivamente; 514,75 Gmol Trolox.g-1 no ORAC para o qual a folha de E. involucrata obteve o maior valor (1393,3 Gmol Trolox.g-1). Os extratos das espécies nativas também demonstram efeito antioxidante contra radicais de relevância biológica, como peroxila e superóxido. Por meio de CG-EM e CLAE acoplado a arranjo de fotodiodos, os principais compostos fenólicos encontrados nos extratos vegetais foram catequina, epicatequina e ácido gálico. Este trabalho demonstrou o grande potencial antioxidante das frutíferas nativas brasileiras, evidenciando assim possível efeito positivo em sistemas biológicos.Brazil has a great biodiversity, in which many bioactive compounds can be found and used to benefit the society. However, environmental degradation processes and introduction of exotic species have contributed to limited use and knowledge of many native plants, reflecting in few studies about chemical composition and biological potential. The prevention of chronic diseases has been constantly associated with the antioxidant activity of plants secondary metabolites, mainly the phenolics. The objective of this study was to evaluate the antioxidant activity and the phenolic composition of five Brazilian native fruitful species (G. brasiliensis, E. leitonii, E. involucrata, E. brasiliensis e E. myrcianthes). The methods of Folin-Ciocalteau reducing capacity, co-oxidation of ?-carotene/linoleic acid system, oxygen radical absorbance capacity (ORAC), DPPH and superoxide free radical scavenging were used to determine the antioxidant activity of ethanolic extracts of leaf, peel, seed and pulp of the selected species. The samples showed significant antioxidant activity and, in some cases, it was superior to fruits commonly consumed by Brazilian population. In general, leaves presented the highest activities, but the seed of E. Leitonii stood out exhibiting the best results in four of the five methods: 120.67 mg GA.g-1 in the Folin reducing; 7.08 Gmol Trolox.g-1 in the ?-carotene; EC50 of 0.26 mg.mL-1 and 0.07 mg.mL-1 in the superoxide and DPPH scavenging, respectively; 514.75 Gmol Trolox.g-1 in the ORAC, for which the E. Involucrata leaf had the highest value (1393.3 GmolTrolox.g-1). The extracts of native species also demonstrate antioxidant effect against radicals of biological relevance, such as peroxyl and superoxide. By GC-MS and HPLC coupled to a photodiode array, the major phenolic compounds found in the plant extracts were catechin, epicatechin and gallic acid. In this study, Brazilian native fruitful presented high antioxidant potential, showing a possible positive effect on biological systems.
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Gupta, Elera Gaytri Devi. "Effect of Antioxidants and Oxidative Stress on Different Cancer Cell Types." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3227.
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Vaccinium cyanococcus, most commonly known as blueberry, is a fruit native to North America that is known for its unique taste and high antioxidant content. The skin, seed and juice of both organically and conventionally grown blueberry extract were analyzed for antioxidant content using both the Hydrophilic and Lipophilic Oxygen Radical Absorbance Capacity (ORAC) assays. Results from the Hydrophilic ORAC test showed that conventionally grown blue berries had a higher antioxidant capacity across all samples, while the Lipophilic ORAC assay showed that the antioxidant concentration of organically cultivated blueberry juice was highest, but conventionally grown blueberry seed and skin extract showed higher antioxidant content. The vitamin C content of both conventional and organic blueberries were analyzed using High Performance Liquid Chromatography (HPLC), where the organic blueberries showed a higher vitamin C concentration. In general, both organic and conventional blueberries are rich in antioxidants, and therefore, possess potential health benefits that require further study.
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Pazinatto, Caroline. "Avaliação in vitro da capacidade antioxidante de grãos de amaranto (Amatanthus Cruentus)." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256393.
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Orientador: Flavia Maria NettoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O amaranto se destaca por seu perfil protéico, rico em aminoácidos essenciais e pela presença de outros compostos tais como: fibras, esqualeno, tocoferóis, tocotrienóis e compostos fenólicos, que lhe confere propriedades especiais, incluindo propriedade antioxidante. A fácil adaptação da planta a diferentes condições climáticas, juntamente com as suas qualidades nutricionais e funcionais, aumentam o interesse em introduzir a cultura do amaranto no Brasil. Apesar de bem caracterizado quimicamente e de apresentar compostos com potencial fisiológico, poucos estudos foram realizados para avaliar o potencial do grão de amaranto como alimento funcional. O presente trabalho tem como objetivo avaliar a capacidade antioxidante dos diferentes produtos obtidos a partir do grão integral de amaranto (Amaranthus cruentus). Após a moagem e o desengorduramento dos grãos para a obtenção da farinha desengordurada, diferentes processos, incluindo a hidrólise com Alcalase, foram utilizados na produção dos diversos produtos de amaranto que foram posteriormente digeridos in vitro com as enzimas pepsina e pancreatina. Os efeitos dos processos e da digestão in vitro das frações protéicas, e o efeito dos compostos fenólicos totais na capacidade antioxidante, em extrato aquoso e metanólico, foram avaliados utilizando o ensaio da capacidade seqüestradora de radicais DPPH e o ensaio de ORAC. O teor de fenóis totais apresentou elevada correlação com a capacidade antioxidante quando avaliada no extrato metanólico. Entretanto, a correlação foi menor quando avaliada no extrato aquoso, sugerindo que os compostos hidrossolúveis podem interferir nas avaliações. A hidrólise com Alcalase elevou significativamente o potencial antioxidante das amostras, de 2 a 4 vezes a capacidade seqüestradora de radicais DPPH e de 13 a 15 vezes os valores de ORAC. A digestão in vitro aumentou a capacidade antioxidante medida por ambos os ensaios (até 7 vezes para a capacidade seqüestradora de radicais DPPH e 12 para o valor de ORAC), especialmente para o concentrado protéico e seus hidrolisados. O elevado teor de fenóis totais liberados e o aumento da capacidade antioxidante dos produtos de amaranto após a digestão in vitro sugerem que o mesmo ocorre após a digestão fisiológica. Os resultados sugerem que a inclusão de produtos de amaranto na dieta, especialmente concentrado protéico e seus hidrolisados, pode promover benefícios à saúde
Abstract: Amaranth is well known for its protein profile, rich in essential amino acids and the presence of other compounds such as fiber, squalen, tocols (tocopherols and tocotrienols) and phenolic compounds that are responsible for its special properties, including antioxidant capacity. The easy adaptation of the plant to different climate conditions, together with its nutritional qualities and functional properties, increase the interest to introduce the culture of amaranth in Brazil. Despite being well characterized chemically and exhibiting compounds with physiological potential, few studies have been conducted to evaluate the potential of amaranth grain, as a functional food. This study aims to evaluate the antioxidant capacity of different products obtained from amaranth grain (Amaranthus cruentus). After milling and defatting the grain to obtain deffated amaranth flour, different processes, including Alcalase hydrolysis, were used to produce a variety of products that were digested in vitro with pepsin and pancreatin. The effects of the processes and of the digestion in vitro of the protein fractions, and the effect of the total content of phenolic compounds on the antioxidant capability in aqueous and methanolic extracts were evaluated using scavenging capacity of DPPH radical and ORAC assays. Total phenolic compounds content showed high correlation with the antioxidant capacity, when evaluated in methanolic extract. However, the correlation was lower when using the aqueous extract, suggesting that water soluble compounds may interfere in these evaluations. Hydrolysis with Alcalase increased significantly the antioxidant potencial, from 2 to 5 times the scavenging DPPH capacity and 13 to 15 the ORAC values. In vitro digestion increased the antioxidant capacity measured by both assays (up to 7 times for scavenging DPPH capacity and 12 times for ORAC assays), especially for protein concentrate and its hydrolysates. The high content of phenolic compounds released and the increase in antioxidant capacity after in vitro digestion of the amaranth products suggests that the same occurs after the physiological digestion. These results suggest that the inclusion of these products, especially concentrate and its hydrolysates, in the diet should promote health benefits
Mestrado
Nutrição Experimental e Aplicada à Tecnologia de Alimentos
Mestre em Alimentos e Nutrição
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Hosseini-Beheshti, Elham. "Characterization of antioxidant activities from fruits rich in delphinidin or malvidin anthocyanins." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/912.
Full textAbstract:
Anthocyanins have been shown to possess specific antioxidant capacities, which
may provide an underlying protective effect against many chronic diseases . Although the
antioxidant capacity of anthocyanins has been well established, less is known about the
extent to which specific anthocyanin composition affects total antioxidant capacity . The
aim of the present study was to compare the antioxidant capacity of two different soft
fruits, blackcurrant and grape, which have distinctly different anthocyanin profiles.
The anthocyanin profiles of grape and blackcurrant were characterized by
HPLC/MS coupled with a diode array detector. Results showed that blackcurrant
contained four predominant anthocyanins, cyanidin 3-glucoside, delphinidin 3-glucoside,
cyanidin 3-rutinoside, and delphinidin 3-rutinoside . In contrast, malvidin 3-glucoside,
delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and peonidin 3-
glucoside were the major anthocyanins found in grape . The concentration of individual
anthocyanins in all berries was quantified with HPLC/UV using cyanidin 3-glucoside as
an external standard . Finally, results showed a greater (p<0.05) antioxidant capacity of
blackcurrant compared to grape. The total antioxidant capacity of crude extracts from
each was measured by Oxygen Radical Absorbance Capacity (ORAC) and ABTS assays.
Anthocyanin antioxidant capacity index (AACI), derived from the product of
antioxidant (ORAC) activity for each of major anthocyanin present in blackcurrant and
grape, was also used to determine whether the antioxidant capacity of crude anthocyanin
fractions represents either the sum total anthocyanin content or, alternatively, a synergy
between different anthocyanins components . Our results indicated that a plausible
potential synergy between anthocyanin components in regards to ORAC antioxidant
capacity existed in blackcurrant and grape semi-purified anthocyanin extracts.
Furthermore, it could be concluded that both total anthocyanin content as well as
the composition of individual anthocyanins in soft fruits is important to assess total
antioxidant capacity of different berry sources .
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Oracz, Joanna [Verfasser], Stefan [Akademischer Betreuer] Hell, Stefan [Gutachter] Hell, and Tim [Gutachter] Salditt. "Coordinate-targeted optical nanoscopy: molecular photobleaching and imaging of heterostructured nanowires / Joanna Oracz ; Gutachter: Stefan Hell, Tim Salditt ; Betreuer: Stefan Hell." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1172071942/34.
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Leite, Alice Vieira. "Avaliação da composição e da capacidade antioxidante "in vivo" e "in vitro"de antocianinas da casca de jabuticaba (Myrciaria jaboticaba (Vell.) Berg) liofilizada em ratos Wistar." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255063.
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Orientador: Mário Roberto Maróstica JúniorDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O objetivo do presente estudo foi avaliar a produção de casca de jabuticaba em pó, sua composição de antocianinas e efeito antioxidante em animais de laboratório. Muitas frutas tropicais são ricas em antocianinas e existem poucos dados disponíveis sobre a caracterização e quantificação destas antocianinas. A identificação e quantificação de antocianinas de casca de jabuticaba liofilizada foram realizadas por HPLC-PDA e HPLC-ESI-MS/MS e revelaram a presença de dois compostos, delfinidina-3-glicosídeo e cianidina-3- glicosídeo (635,3 e 1964 mg/100 de peso seco), respectivamente. Para as análises do potencial antioxidante foram utilizados os ensaios de ORAC, DPPH e ABTS. Para estes ensaios foram encontrados os seguintes valores, respectivamente, 25514,25±3037,24 YMTEAC.g-1, 45,38 Yg.ml-1, 9457,74±54,29 YMTEAC.g-1. Foram quantificados também os fenólicos totais por Folin-Ciocalteau, e encontrado 556,28±20,37 gGAEb.kg-1 .Neste estudo, a casca de jabuticaba liofilizada mostrou uma grande capacidade antioxidante comprovada por todos os métodos antioxidantes analisados, pela quantidade de compostos fenólicos encontrada e principalmente pela concentração de cianidina-3-glicosídeo e delfinidina-3- glicosídeo. Diante dos dados descritos acima, o efeito antioxidante da ingestão de pó casca de jabuticaba liofilizada no plasma de ratos foi investigado em dois experimentos. No primeiro foi realizado um teste de cinética de absorção, no qual trinta e cinco ratos machos, divididos em 5 grupos, receberam por gavagem 7 mg de antocianinas/ 100 g de peso. A coleta de sangue foi realizada nos tempos 0, 30, 60 e 120 minutos. O potencial antioxidante foi quantificado no plasma por ORAC e TEAC. Neste experimento não ocorreu diferença significativa no potencial antioxidante plasmático quando comparados os diversos tempos. No segundo experimento, 40 ratos machos foram divididos em 4 grupos que consumiram, respectivamente, 0, 1, 2 e 4% de pó de casca de jabuticaba liofilizada acrescido a dieta. Foi observado um aumento no potencial antioxidante plasmático (1.7 vezes pelo método de TEAC e 1.3 vezes por ORAC), porém a concentração de 4% não apresentou efeito antioxidante. A partir dos resultados do potencial antioxidante in vivo, e diante do fato de que a ingestão de uma dieta rica em antioxidantes e com pouca quantidade de gorduras pode reduzir o risco de obesidade e resistência à insulina, investigou-se o efeito da casca de jabuticaba liofilizada sobre as concentrações plasmáticas de glicose, frações lipídicas, aspartato aminotransferase e alanina aminotrasferase em ratos Wistar machos adultos. Os animais foram distribuídos nos seguintes grupos: G0, o grupo controle e G1, G2 e G4, os grupos que receberam 1, 2 e 4%, respectivamente, do pó de casca de jabuticaba liofilizada adicionado à dieta AIN-93M. A suplementação reduziu as concentrações de glicose nos grupos G1 e G2, porém no grupo G3 esse efeito não foi encontrado. O colesterol total sofreu redução para os animais tratados com 1% de cascas de jabuticabas em relação ao grupo controle, mas os animais tratados com 2 e 4% de cascas de jabuticabas sofreram aumento no colesterol total e da fração LDL-colesterol, porém, o valor para colesterol total apresenta-se dentro da faixa normal para ratos Wistar. Os triacilgliceróis e a fração HDL-colesterol não sofreram alterações significativas. Os resultados indicam um possível benefício da suplementação da casca de jabuticaba na redução da glicemia plasmática, dos níveis de LDL e colesterol total e a possível existência de uma dose recomendada
Abstract: The objective of this study was to evaluate the antioxidant effects of anthocyanin and the antioxidant effects of peel jabuticaba powder in laboratory animals. Many tropical fruits are rich in anthocyanins, but there are few data available on the characterization and quantification of these anthocyanins. The identification and quantification of anthocyanins from bark jabuticaba was performed by HPLC-PDA and LC-ESI-MS/MS Q-TOF. The analysis revealed the presence of two compounds, delphinidin-3-glucoside and cyanidin-3-glucoside (635, 3 and 1964 mg/100 dry weight, respectively). ORAC, DPPH and ABTS methods were used for antioxidant analysis and the results were, 25514,24±3037,24 µMTEAC.g-1, 45.38 Yg.ml-1, 9457,74±54,29 µMTEAC.g-1, respectively. The total phenolics (Folin-Ciocalteau method) revealed that the jabuticaba powder contained 556,28±20,37 gGAEb.kg-1. In this study, freezedried peel jabuticaba showed great antioxidant proven by all methods antioxidants tested. The effects of the ingestion of jabuticaba peel in the antioxidant capacity of plasma of rats was investigated in two 'in vivo¿ experiments. In the first test, the absorption kinetics were evaluated. The male rats were divided into 5 groups received, by gavage, 7 mg anthocyanins / 100 g of body weight. Blood collection was performed at 0, 30, 60 and 120 minutes. The antioxidant potential was quantified in plasma by ORAC and TEAC. In this experiment there was no significant difference in plasma antioxidant potential when comparing the different times. In the second experiment, 40 rats were divided into 4 groups that consumed, respectively, 0, 1, 2 and 4% powdered peel jabuticaba lyophilized plus diet. We observed an increase in plasma antioxidant potential (1.7 times by the method of TEAC and ORAC by 1.3 4 times), but the concentration of 4% had no antioxidant effect. We investigated the effect of freeze-dried peel jabuticaba on plasma glucose, lipid fractions, aminotransferase and aspartate aminotransferase alanian in adult male Wistar rats. The animals assigned to groups G0, the control group, G1, G2 and G4 groups receiving 1, 2 and 4%, respectively, of freeze-dried peel jabuticaba added to the AIN-93M diet. Supplementation reduced the concentration of glucose in G1 and G2, but in G4 this effect was not found. Total cholesterol was reduced in animals treated with 1% bark jabuticabas in the control group, but animals treated with 2 and 4% experienced an increase in total cholesterol and LDL cholesterol, but the value for cholesterol total amount is within the normal range for rats. Triglycerides and HDL-cholesterol did not change significantly. The results indicate the possible benefit of supplementing with bark jabuticaba in reducing plasma glucose, LDL cholesterol and total cholesterol and the possible existence of a dose
Mestrado
Nutrição Experimental e Aplicada à Tecnologia de Alimentos
Mestre em Alimentos e Nutrição
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Furuhagen, Sara. "Application and interpretation of biomarkers in ecotoxicology - from molecular to individual level responses." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-120161.
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The use of biomarkers is considered a promising alternative, or complement, to traditional ecotoxicological assays. Toxic effects are often initially manifested at the molecular or biochemical level, biomarkers are therefore used as sensitive indicators of toxic exposure. Ideally, biomarkers would also indicate reduced fitness and possible later effects at the individual or population levels. However, implementing biomarkers in ecotoxicology is challenging and few biomarkers have an established connection to reduced individual fitness. The aim of this thesis was to increase the value and improve the interpretation of biomarker responses in ecotoxicological studies by examining the impact of confounding factors and the relationship between oxidative biomarkers and reproductive effects in crustaceans. The sensitivity of biomarkers was confirmed in paper I as toxic effects of pharmaceuticals with conserved drug target orthologs were observed at the molecular and biochemical levels both earlier and at lower concentrations than effects on mortality and reproduction. No toxic effects were observed for the pharmaceutical without identified drug target orthologs, thus stressing the importance of considering toxic mechanisms and being aware of the most likely target when evaluating toxic effects also in non-target species. Many xenobiotics and environmental stressors interfere with oxidative processes, making oxidative biomarkers interesting to study in ecotoxicology and stress ecology. Still, feeding rate was identified as a confounding factor for antioxidant capacity (assayed as oxygen radical absorbance capacity, ORAC) and lipid peroxidation in ecotoxicological studies (paper II). However, ORAC normalized to protein was independent of altered feeding rates, hence it can be applied as a suitable exposure biomarker without considering alterations and effects of feeding rate. The connection between reproduction and oxidative stress is dual, as reproduction both can be inhibited by oxidative stress and induce pro-oxidative processes. Further, a positive association was found between ORAC and the occurrence of embryo aberrations in the benthic amphipod Monoporeia affinis (paper III). An association between antioxidant defense and reproduction was also observed for Daphnia magna (paper IV). Threshold values for identification of exposed individuals and prediction of possible later reproductive effects were established for ORAC. This thesis has contributed to diminishing some of the knowledge gaps limiting the use of oxidative biomarkers in ecotoxicology, by contributing to increased understanding of how oxidative biomarkers relate to important life-traits. Moreover, ORAC has been identified as a suitable biomarker of not only exposure, but also reproductive effects. Future research should continue to establish connections between biomarker responses and effects at higher levels, and focus on providing defined threshold values to enable predictions about later effects.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
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Livingston, Justin Ryan. "The Antioxidant and DNA Repair Capacities of Resveratrol, Piceatannol, and Pterostilbene." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5525.
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Lifestyle diseases represent a large burden on developed societies and account for much morbidity worldwide. Research has shown that eating a diet rich in fruit and vegetables helps to ameliorate and prevent some of these diseases. Antioxidants found in fruits and vegetables may provide a substantial benefit in reducing disease incidence. This thesis examines the antioxidant properties of resveratrol, piceatannol, and pterostilbene, and the ability of Burkitt's Lymphoma (Raji) cells to uptake these three antioxidants. It also studies the effect of the antioxidants in protecting against DNA damage and their role in DNA repair following oxygen radical exposure in Raji cells. The Oxygen Radical Absorbance Capacity (ORAC) assay was used to measure overall antioxidant contribution as well as the ability of Raji cells to uptake antioxidant following exposure to 2,2’-Azobis(2-methyl-propionamide) dihydrochloride (AAPH). The single cell gel electrophoresis (Comet) assay was used to assess DNA damage and DNA repair rates of cells. Results showed that Raji cells, following oxygen radical exposure, significantly uptake pterostilbene (p < 0.0001), but not piceatannol or resveratrol. Piceatannol provided protection against hydrogen peroxide induced DNA damage, but pterostilbene and resveratrol increased DNA damage following hydrogen peroxide treatment. None of the compounds showed any effect on DNA repair. Overall, this study indicates there is merit for further research into the bioactive roles, including antioxidant capacity, of all three compounds. Such research may provide evidence for the more widespread use of these and other food based compounds for preventing lifestyle diseases.
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Hunt, Spencer Philip. "Whole-Genome Assembly of Atriplex hortensis L. Using OxfordNanopore Technology with Chromatin-Contact Mapping." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8580.
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Atriplex hortensis (2n = 2x = 18, 1C genome size ~1.1 gigabases), also known as garden orach, is a highly nutritious, broadleaf annual of the Amaranthaceae-Chenopodiaceae family that has spread from its native Eurasia to other temperate and subtropical environments worldwide. Atriplex is a highly complex and polyphyletic genus of generally halophytic and/or xerophytic plants, some of which have been used as food sources for humans and animals alike. Although there is some literature describing the taxonomy and ecology of orach, there is a lack of genetic and genomic data that would otherwise help elucidate the genetic variation, phylogenetic position, and future potential of this species. Here, we report the assembly of the first highquality, chromosome-scale reference genome for orach cv. ‘Golden’. Sequence data was produced using Oxford Nanopore’s MinION sequencing technology in conjunction with Illumina short-reads and chromatin-contact mapping. Genome assembly was accomplished using the high-noise, single-molecule sequencing assembler, Canu. The genome is enriched for highly repetitive DNA (68%). The Canu assembly combined with the Hi-C chromatin-proximity data yielded a final assembly containing 1,325 scaffolds with a contig N50 of 98.9 Mb and with 94.7% of the assembly represented in the nine largest, chromosome-scale scaffolds. Sixty-eight percent of the genome was classified as highly repetitive DNA, with the most common repetitive elements being Gypsy and Copia-like LTRs. The annotation was completed using MAKER which identified 31,010 gene models and 2,555 tRNA genes. Completeness of the genome was assessed using the Benchmarking Universal Single Copy Orthologs (BUSCO) platform, which quantifies functional gene content using a large core set of highly conserved orthologous genes (COGs). Of the 1,375 plant-specific COGs in the Embryophyta database, 1,330 (96.7%) were identified in the Atriplex assembly. We also report the results of a resequencing panel consisting of 21 accessions which illustrates a high degree of genetic similarity among cultivars and wild material from various locations in North America and Europe. These genome resources provide vital information to better understand orach and facilitate future study and comparison.
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Andreae, Mary Christine. "Value of Raisins for Reduction of Oxidative Stress, Endothelial Dysfunction, and Inflammation in Obesity." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34102.
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This study investigated the effects of daily consumption of Thompson seedless raisins on markers of inflammation, oxidative stress and endothelial activation in response to an acute high-fat meal in obese individuals. Seventeen overweight men and women consumed raisins or placebo (264 kcal/d) for 14 d in a randomized cross-over design while following a low-flavonoid, weight-maintenance diet. Four high-fat (53% fat) meals were consumed with the respective treatment pre and post interventions. Measures at fasting, and 2, 3 and 4 hours postprandial included markers of oxidative stress (urinary 8-isoPGF2α; serum Oxygen Radical Absorbance Capacity, ORAC), inflammation (serum C-reactive protein, CRP; interleukin-6, IL-6), endothelial function (serum soluble intercellular adhesion molecule-1, sICAM-1; soluble vascular adhesion molecule-1, sVCAM-1), and metabolic measures (free fatty acids (FFA), triacylglycerol (TAC), glucose, insulin). Urinary 8-isoPGF2α decreased 22% and ORAC increased 3% pre to post interventions combined. Postprandial metabolic responses differed by gender, males surpassed females for several measures: FFA, triacylglycerol, glucose, and sVCAM-1. Neither the meals nor treatment with raisins had any noteworthy influence on fasted measures of inflammation or endothelial dysfunction. Acute high fat meal consumption did not result in evidence of inflammation or oxidative stress in these relatively healthy, overweight individuals. Providing all food in regular pattern reduced measures of oxidative stress. Gender influenced metabolic responses to meals; males had a greater postprandial response in metabolic measures than females.Master of Science
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Arraki, Kamel. "Les stilbénoïdes chez les Cypéracées : isolation, identification et étude de leurs activités biologiques : identification et dosage des stilbènes dans des vins Tunisiens." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0481/document.
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Les stilbènes sont des composés phénoliques issus du métabolisme secondairevégétal, dont la distribution au sein du règne végétal est limitée aux espèces qui ont acquis aucours de l’évolution la capacité à synthétiser ces molécules. Leurs impacts et leurs activitésbiologiques tels que les effets neuroprotecteurs, anticancérigènes, antioxydants ont déjàconcerné plusieurs sujets d’étude. C’est dans ce contexte que l’objectif de notre travail a prisnaissance. Dans un premier temps, nous avons isolé et identifié ces molécules chez quelquesespèces de la famille des Cypéracées. Cette étude phytochimique a été réalisée en utilisant unensemble de stratégies analytiques et préparatives faisant appel à la CLHP analytique etpréparative et la CPC (Chromatographie de Partage Centrifuge) pour l’obtention desmolécules pures et à la LC-Masse et la RMN pour l’identification des composées isolés. Dansun second temps, nous avons étudié les activités biologiques in vitro de ces produits telles queles activités antioxydantes par trois méthodes (ORAC, DPPH et MCA) et l’effet de cesstilbènes sur la cytotoxicité neuronale induite par le peptide β-amyloïde avec des cellulesPC12. Nous avons isolé une nouvelle molécule, le carexinol A, pour la première fois, qui amontré une forte activité anti-amyloïde. La dernière partie de cette thèse fait état de l’analyseet du dosage des stilbènes dans des vins tunisiens dont le vin Sidi Zahia qui a donné lesmeilleurs résultatsStilbenes are phenolic compounds of plant secondary metabolism, whosedistribution within the plant kingdom is limited to species that have acquired during theevolution the ability to synthesize these molecules. Their impacts and their biologicalactivities such as neuroprotective, anticarcinogenic, antioxidant effects have already touchedseveral topics. It is in this context that the purpose of our work arose. First, we have isolatedand identified these molecules in some species of the sedge family. Phytochemical studieswere performed using a set of analytical and preparative strategies by means of analytical andpreparative HPLC and CPC (Centrifugal Partition Chromatography) for obtaining puremolecules and LC-Mass and NMR for identification of compound isolated. In a second step,we investigated the in vitro biological properties of these products such as antioxidantactivities by three methods (ORAC, DPPH and MCA) and their effect on neuronalcytotoxicity induced by β-amyloid peptide with PC12 cells. We isolated a new molecule, forthe first time, carexinol A, that showed strong anti-amyloid activity. The last part of this thesisrefers to the analysis and determination of stilbenes in Tunisian wines including Sidi Zahiawine that gave the best results
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Massaretto, Isabel Louro. "Características químicas e nutricionais de arroz-preto, vermelho e selvagem e comparação por análise estatística multivariada." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-04062014-152239/.
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O arroz (Oryza sativa L.) é consumido predominantemente na forma polida, porém há uma tendência na procura por grãos integrais não pigmentados e pigmentados, como o preto e o vermelho, e também pelo arroz selvagem, que pertence ao gênero Zizania. Além da composição nutricional e propriedades sensoriais distintas, os tipos pigmentados possuem compostos bioativos, que atribuem cor aos grãos e que têm sido relacionados a efeitos benéficos à saúde. Contudo, uma comparação em termos nutricionais e de bioativos entre esses grãos ainda inexiste. Este projeto visou comparar a composição química, incluindo os compostos fenólicos totais (CFT), os polifenóis majoritários e a capacidade antioxidante de três amostras de arroz-preto produzido no Estado de São Paulo, duas de arroz-preto produzido no Estado do Rio Grande do Sul e 11 de arroz-preto produzido no Estado de Santa Catarina, 9 de arroz-vermelho, produzido nos estados mencionados e, 6 amostras de arroz selvagem, importadas do Canadá e comercializadas em São Paulo; todas as amostras foram produzidas e/ou comercializadas no período de 2009 a 2011. A comparação das variáveis foi feita pelo uso de análise estatística uni- e multivariada. Fez parte do escopo do projeto avaliar o efeito do cozimento sobre a estabilidade dos CFT e a atividade antioxidante. Também foi conduzida uma comparação preliminar dos teores de fitoquímicos lipossolúveis, γ-orizanol, tocoferóis e tocotrienóis, entre 7 amostras de arroz-preto e 4 de arroz-vermelho, todas da safra de 2013. Com base nas análises químicas e na análise estatística multivariada, foi possível agrupar os vários tipos de arroz em quatro grupos, significativamente diferentes entre si: arroz selvagem, arroz-preto de grãos longos, arroz-preto de grãos médios e arroz-vermelho. O grupo que mais se diferenciou dos demais foi o arroz selvagem, por apresentar os maiores teores proteicos (12,9 g/100g) e de ácido α-linolênico (0,12 g/100g) e os menores teores de lipídeos (0,9 g/100g), de compostos fenólicos e atividade antioxidante, entre os grupos estudados. Outro grupo com características distintas foi o arroz-preto de grãos longos que se destacou principalmente pelo elevado teor de compostos fenólicos, representados pelas antocianinas, e elevada atividade antioxidante. A cianidina-3-O-glicosídeo foi identificada por CLAE-DAD-MS/MS, como sendo a antocianina majoritária. Os teores de proteínas e de lipídeos, da ordem de 9,8 e 3,6 g/100g, respectivamente, foram maiores do que dos outros dois grupos estudados. O arroz-preto de grãos médios e o vermelho foram similares em termos de composição de nutrientes e CFT. Os teores proteicos em ambos os grupos foi, em média, de 8,8 g/100g. Porém, enquanto no arroz-preto predominam antocianinas, a coloração do arroz-vermelho é conferida por proantocianidinas, com diferenças na sua atividade antioxidante. O arroz-preto de grãos médios apresentou atividade antioxidante mais do que o dobro do arroz-vermelho, no entanto próxima ao do arroz-preto de grãos longos. Este resultado indica que o elevado teor de antocianinas, independente do formato do grão, é responsável pela alta capacidade antioxidante no arroz-preto. A análise multivariada demonstrou que o formato do grão é determinante na diferenciação dos dois grupos de arroz-preto em termos de composição de nutrientes, como proteínas e lipídeos, mas não de fitoquímicos e de atividade antioxidante. O método ORAC foi mais apropriado para avaliar a atividade antioxidante do arroz-preto, por ser mais sensível à presença de antocianinas do que o método de DPPH·. Nos outros dois grupos, vermelho e selvagem o método de DPPH· também pode ser utilizado. O cozimento do arroz provocou perda significativa nos teores de CFT e na atividade antioxidante do arroz-preto e vermelho. No arroz-preto, a perda de CFT foi de 26%, em média, enquanto a perda das antocianinas foi de 50%. A explicação pode ser que durante o cozimento uma parte das antocianinas seja convertida em ácido protocatecóico, que é dosado como CFT. No arroz-vermelho, a redução de CFT foi de 60%, possivelmente devido a uma insolubilização de parte das proantocianidinas. No arroz selvagem, o cozimento não causou perdas significativas. A capacidade antioxidante dos vários grupos de arroz após o cozimento depende do método empregado, sendo fortemente correlacionada com os teores de CFT remanescentes. Assim, o arroz-preto, mesmo depois de cozido, apresentou a maior capacidade antioxidante, seguido do arroz-vermelho e do selvagem. Numa avaliação inicial, os teores dos fitoquímicos lipossolúveis, γ-orizanol e homólogos da vitamina E, foram semelhantes em arroz-preto e vermelho, indicando que independem da coloração do pericarpo.Rice (Oryza sativa L.) is mostly consumed in its milled form; however there is an increasing demand for whole non-pigmented and pigmented rice, such as black, red, and wild rice, which the latter belongs to the genus Zizania. Pigmented rice has particular nutritional composition and sensory characteristics, and in addition high amounts of phenolic compounds, which not only confer color but also has been linked to beneficial effects on human health. To date, little is known about the nutritional and bioactive contents of these grains. The aim of this study was to compare the chemical composition, including the total phenolic compounds (TPC), the majoritarian polyphenols and the antioxidant radical efficiency of the following accessions: three black rice from the state of São Paulo, two black rice from the state of Rio Grande do Sul, eleven black rice genotypes from Santa Catarina state, nine red rice from those states and six wild rice, imported from Canada and marketed in São Paulo. All samples were cultivated and/or marketed from 2009 to 2011. Data were evaluated by uni- and multivariate statistical analysis. The effect of cooking on the stability of TPC and antioxidant capacity was also evaluated. In addition, a preliminary comparison of γ- oryzanol, tocopherols and tocotrienols was carried out between two groups: seven black rice and four red rice samples, all of them cultivated in 2013. Based on chemical results and multivariate statistical analysis it was possible to cluster the various types of rice in four groups, significantly different among themselves: wild rice, black long grain rice, black medium grain rice, and red rice. Wild rice was the most dissimilar group due to its highest contents of protein (12.9 g/100g) and α-linolenic acid (0.12 g/100g), and the lowest amounts of lipids (0.9 g/100g), TPC, and antioxidant capacity. Black long grain rice was characterized mainly by its high contents of TPC, especially anthocyanins and by its elevated antioxidant capacity. Cyanidin-3-O-glycoside was identified by HPLC-DAD-MS/MS as being the main anthocyanin. The protein and lipid mean contents in these groups were respectively, 9.8 and 3.6 g/100g and were higher than the amounts in the other next two types of rice. The black medium grain rice and red rice were similar in terms of nutrient composition and TPC. The average amount of protein in both groups was about 8.8 g/100g. However, in black rice prevails anthocyanins, while in red rice coloration is provided by proanthocyanidins, which results in differences in antioxidant activity. Medium and long black grain rice showed a 2-fold higher antioxidant activity than red rice. These findings indicate that the high content of anthocyanins, independent of the grain shape, is responsible for the high antioxidant capacity in black rice. The multivariate analysis demonstrated that the grain shape is fundamental to differentiate black rice in terms of nutrient composition, like protein and lipids, but not in relation to amounts of phytochemicals and antioxidant capacity. ORAC was more suitable than DPPH· methodology to evaluate the antioxidant activity of black rice, due to its high correlation to anthocyanin contents. Conversely, DPPH· can be a consistent method to evaluate antioxidant capacity of red and wild rice. Cooking resulted in significant loss on TPC contents and on the antioxidant capacity of black and red rice. In black rice, 26% of TPC was reduced on average, while the loss of anthocyanins was 50%. The reason may be that during cooking, part of the anthocyanins is converted into protocatechuic acid, which is quantified as TPC. The reduction in TPC in red rice was 60%, possibly due to a partial insolubilization of proanthocyanidins. In wild rice, cooking caused no significant loss of TPC. The antioxidant capacity of different types of cooked rice was dependent on the method used, being strongly correlated with the remaining levels of TPC. Thus, black rice even after cooking showed the highest antioxidant capacity, followed by red and wild rice. From a preliminary evaluation, the contents of lipophilic phytochemicals, γ-orizanol and vitamin E homologues were similar in black and red rice, which indicates that the contents of these compounds are not dependent of the pericarp color.
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Aikman, Matthew Andrew. "Exercise and DNA damage and repair in middle aged men / Andrew Aikman." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1490.
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Garrett, Andrew Robert. "Antioxidants in Cancer Research and Prevention: Assay Comparison, Structure-Function Analysis, and Food Product Analysis." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2735.
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Recent epidemiological studies have suggested that the development and progression of several chronic diseases may be initiated or augmented by oxidative stress. Reactive oxygen species and reactive nitrogen species react readily with and can damage nucleic acids, proteins, and lipids. While biological systems are equipped antioxidant defenses to cope with oxidative stress, oxidative damage may still occur when oxidative stress overwhelms antioxidant defenses. This damage, if left unchecked, may lead to a variety of degenerative diseases, including heart disease, Alzheimer's Disease, Parkinson's Disease and cancer. Several assays have been designed to describe the antioxidant activity of various phytochemicals, vitamins, and other compounds. The ORAC and TOSC assays have emerged as industry standards for measuring antioxidant activity due to their high reliability and sensitivity. Until recently, however, little has been done to assess the relative correlation between these two assays. Furthermore, no assay has been developed to measure changes in antioxidant activities of cells in response to oxidative stress. The current work investigates the correlation between measured antioxidant activities of samples in the both the ORAC and TOSC assays. Recent antioxidant research also focuses on relating chemical structure to antioxidant activity. Previous research in this area has included a broad range of chemical groups, but no study has attempted to formulate a structure-function framework that has applicability to compounds of any group. The current work uses amino acids as a simplest-case model for studying the relationships between chemical structure and antioxidant activity. One particular area of emerging research has centered around comparing organic and conventionally grown food products. The impetus of these investigations lies in claims made by organic supporting groups that these food products are generally more beneficial than their conventional counterparts. Despite the rapid rise in popularity of organic foods, there remains a dearth of research investigating these claims. The current work compares the antioxidant activities of organic and conventionally grown blueberries and apples.
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Scheffler, Thomas. "Privacy enforcement with data owner-defined policies." Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6793/.
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This thesis proposes a privacy protection framework for the controlled distribution and use of personal private data. The framework is based on the idea that privacy policies can be set directly by the data owner and can be automatically enforced against the data user.
Data privacy continues to be a very important topic, as our dependency on electronic communication maintains its current growth, and private data is shared between multiple devices, users and locations. The growing amount and the ubiquitous availability of personal private data increases the likelihood of data misuse.
Early privacy protection techniques, such as anonymous email and payment systems have focused on data avoidance and anonymous use of services. They did not take into account that data sharing cannot be avoided when people participate in electronic communication scenarios that involve social interactions. This leads to a situation where data is shared widely and uncontrollably and in most cases the data owner has no control over further distribution and use of personal private data.
Previous efforts to integrate privacy awareness into data processing workflows have focused on the extension of existing access control frameworks with privacy aware functions or have analysed specific individual problems such as the expressiveness of policy languages. So far, very few implementations of integrated privacy protection mechanisms exist and can be studied to prove their effectiveness for privacy protection. Second level issues that stem from practical application of the implemented mechanisms, such as usability, life-time data management and changes in trustworthiness have received very little attention so far, mainly because they require actual implementations to be studied.
Most existing privacy protection schemes silently assume that it is the privilege of the data user to define the contract under which personal private data is released. Such an approach simplifies policy management and policy enforcement for the data user, but leaves the data owner with a binary decision to submit or withhold his or her personal data based on the provided policy.
We wanted to empower the data owner to express his or her privacy preferences through privacy policies that follow the so-called Owner-Retained Access Control (ORAC) model. ORAC has been proposed by McCollum, et al. as an alternate access control mechanism that leaves the authority over access decisions by the originator of the data.
The data owner is given control over the release policy for his or her personal data, and he or she can set permissions or restrictions according to individually perceived trust values. Such a policy needs to be expressed in a coherent way and must allow the deterministic policy evaluation by different entities.
The privacy policy also needs to be communicated from the data owner to the data user, so that it can be enforced. Data and policy are stored together as a Protected Data Object that follows the Sticky Policy paradigm as defined by Mont, et al. and others.
We developed a unique policy combination approach that takes usability aspects for the creation and maintenance of policies into consideration. Our privacy policy consists of three parts: A Default Policy provides basic privacy protection if no specific rules have been entered by the data owner. An Owner Policy part allows the customisation of the default policy by the data owner. And a so-called Safety Policy guarantees that the data owner cannot specify disadvantageous policies, which, for example, exclude him or her from further access to the private data. The combined evaluation of these three policy-parts yields the necessary access decision.
The automatic enforcement of privacy policies in our protection framework is supported by a reference monitor implementation. We started our work with the development of a client-side protection mechanism that allows the enforcement of data-use restrictions after private data has been released to the data user. The client-side enforcement component for data-use policies is based on a modified Java Security Framework. Privacy policies are translated into corresponding Java permissions that can be automatically enforced by the Java Security Manager.
When we later extended our work to implement server-side protection mechanisms, we found several drawbacks for the privacy enforcement through the Java Security Framework. We solved this problem by extending our reference monitor design to use Aspect-Oriented Programming (AOP) and the Java Reflection API to intercept data accesses in existing applications and provide a way to enforce data owner-defined privacy policies for business applications.Im Rahmen der Dissertation wurde ein Framework für die Durchsetzung von Richtlinien zum Schutz privater Daten geschaffen, welches darauf setzt, dass diese Richtlinien oder Policies direkt von den Eigentümern der Daten erstellt werden und automatisiert durchsetzbar sind. Der Schutz privater Daten ist ein sehr wichtiges Thema im Bereich der elektronischen Kommunikation, welches durch die fortschreitende Gerätevernetzung und die Verfügbarkeit und Nutzung privater Daten in Onlinediensten noch an Bedeutung gewinnt. In der Vergangenheit wurden verschiedene Techniken für den Schutz privater Daten entwickelt: so genannte Privacy Enhancing Technologies. Viele dieser Technologien arbeiten nach dem Prinzip der Datensparsamkeit und der Anonymisierung und stehen damit der modernen Netznutzung in Sozialen Medien entgegen. Das führt zu der Situation, dass private Daten umfassend verteilt und genutzt werden, ohne dass der Datenbesitzer gezielte Kontrolle über die Verteilung und Nutzung seiner privaten Daten ausüben kann. Existierende richtlinienbasiert Datenschutztechniken gehen in der Regel davon aus, dass der Nutzer und nicht der Eigentümer der Daten die Richtlinien für den Umgang mit privaten Daten vorgibt. Dieser Ansatz vereinfacht das Management und die Durchsetzung der Zugriffsbeschränkungen für den Datennutzer, lässt dem Datenbesitzer aber nur die Alternative den Richtlinien des Datennutzers zuzustimmen, oder keine Daten weiterzugeben. Es war daher unser Ansatz die Interessen des Datenbesitzers durch die Möglichkeit der Formulierung eigener Richtlinien zu stärken. Das dabei verwendete Modell zur Zugriffskontrolle wird auch als Owner-Retained Access Control (ORAC) bezeichnet und wurde 1990 von McCollum u.a. formuliert. Das Grundprinzip dieses Modells besteht darin, dass die Autorität über Zugriffsentscheidungen stets beim Urheber der Daten verbleibt. Aus diesem Ansatz ergeben sich zwei Herausforderungen. Zum einen muss der Besitzer der Daten, der Data Owner, in die Lage versetzt werden, aussagekräftige und korrekte Richtlinien für den Umgang mit seinen Daten formulieren zu können. Da es sich dabei um normale Computernutzer handelt, muss davon ausgegangen werden, dass diese Personen auch Fehler bei der Richtlinienerstellung machen. Wir haben dieses Problem dadurch gelöst, dass wir die Datenschutzrichtlinien in drei separate Bereiche mit unterschiedlicher Priorität aufteilen. Der Bereich mit der niedrigsten Priorität definiert grundlegende Schutzeigenschaften. Der Dateneigentümer kann diese Eigenschaften durch eigene Regeln mittlerer Priorität überschrieben. Darüber hinaus sorgt ein Bereich mit Sicherheitsrichtlinien hoher Priorität dafür, dass bestimmte Zugriffsrechte immer gewahrt bleiben. Die zweite Herausforderung besteht in der gezielten Kommunikation der Richtlinien und deren Durchsetzung gegenüber dem Datennutzer (auch als Data User bezeichnet). Um die Richtlinien dem Datennutzer bekannt zu machen, verwenden wir so genannte Sticky Policies. Das bedeutet, dass wir die Richtlinien über eine geeignete Kodierung an die zu schützenden Daten anhängen, so dass jederzeit darauf Bezug genommen werden kann und auch bei der Verteilung der Daten die Datenschutzanforderungen der Besitzer erhalten bleiben. Für die Durchsetzung der Richtlinien auf dem System des Datennutzers haben wir zwei verschiedene Ansätze entwickelt. Wir haben einen so genannten Reference Monitor entwickelt, welcher jeglichen Zugriff auf die privaten Daten kontrolliert und anhand der in der Sticky Policy gespeicherten Regeln entscheidet, ob der Datennutzer den Zugriff auf diese Daten erhält oder nicht. Dieser Reference Monitor wurde zum einen als Client-seitigen Lösung implementiert, die auf dem Sicherheitskonzept der Programmiersprache Java aufsetzt. Zum anderen wurde auch eine Lösung für Server entwickelt, welche mit Hilfe der Aspekt-orientierten Programmierung den Zugriff auf bestimmte Methoden eines Programms kontrollieren kann. In dem Client-seitigen Referenzmonitor werden Privacy Policies in Java Permissions übersetzt und automatisiert durch den Java Security Manager gegenüber beliebigen Applikationen durchgesetzt. Da dieser Ansatz beim Zugriff auf Daten mit anderer Privacy Policy den Neustart der Applikation erfordert, wurde für den Server-seitigen Referenzmonitor ein anderer Ansatz gewählt. Mit Hilfe der Java Reflection API und Methoden der Aspektorientierten Programmierung gelang es Datenzugriffe in existierenden Applikationen abzufangen und erst nach Prüfung der Datenschutzrichtlinie den Zugriff zuzulassen oder zu verbieten. Beide Lösungen wurden auf ihre Leistungsfähigkeit getestet und stellen eine Erweiterung der bisher bekannten Techniken zum Schutz privater Daten dar.
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Chung, Hyun. "Characterization of antioxidant activities of soybeans and assessment of their bioaccessibility after in vitro digestion." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/29638.
Full textAbstract:
Nine Virginia soybeans grown in a single location were compared for their antioxidant properties and isoflavone profiles. The extracts were evaluated for their total phenolic contents (TPC), Oxygen Radical Absorbance Capacity (ORAC), and DPPHâ ¢ radical scavenging activities. In order to evaluate efficient preparation methods for soybean antioxidants, three Virginia-grown soybeans were extracted using different extraction strategies. The extraction techniques included soxhlet extraction, conventional solvent extraction, and ultrasonic-assisted extraction (UAE) with 5 different common solvent systems including 50% and 80% aqueous acetone, 50 and 70% aqueous ethanol, and 80% aqueous methanol. The TPC in the soybean extracts and isoflavone compositions were significantly different among cultivars. Malonylgenistin was the major isoflavone in all soybean seeds, accounting for 75-83% of the total measured isoflavones. The V01-4937 variety had the highest total isoflavone and malonylgenistin contents, followed by V03-5794. The antioxidant activities of the soybean extracts were also significantly different. Overall, the V01-4937 soybean was the variety that stood out from the other tested Virginia soybeans because it had the highest TPC, ORAC value, and isoflavone contents as well as the second highest DPPHâ ¢ scavenging activity. Ultrasonic treatment improved the extraction of soybean phenolics by more than 50% compared to solvent alone. The UAE with 50% aqueous acetone was the most efficient for extraction of phenolic compounds in the soybean seeds. The conventional and UAE with 70% aqueous ethanol extracts had the highest ORAC values, while the soxhlet methanol extracts had the highest DPPHâ ¢ radical scavenging activities. Our results suggest that different extraction technologies have a remarkable effect on soybean antioxidant estimation and the UAE is more appropriate for soybean phenolic extraction because it is less time and solvent consuming than the conventional solvent and soxhlet extractions. The V01-4937 soybean with the highest TPC was evaluated for its antioxidant activity and isoflavone contents in an in vitro digestive system. After gastrointestinal digestion, soybean extracts contained higher TPC and ORAC values than cooked soybean (before digestion) but they were relatively low in DPPHâ ¢ radical scavenging capacity. The glucosides, daidzin, genistin, and malonylgenistin showed stability during simulated digestion with 83.3 %, 59.4 %, and 10.7 % recovery, respectively. Aglycones, including daidzein and genistein, were recovered at 37 % and 73.7 %, respectively, after in vitro digestion. In this study, daidzin was the most stable and bioaccessible isoflavone determined using the in vitro digestive system. Among the aglycones, genistein was more stable and bioaccessible than daidzein after digestion. In conclusion, soybean antioxidant activities were different among cultivars and efficient extraction for TPC was found using UAE with 50% aqueous acetone. Furthermore, antioxidant activities were stable during digestion and genistein, within aglycones tested, was the most stable and bioaccessible compound following in vitro digestion. This information may provide manufacturers or researchers information required to develop food or nutraceutical products processed for better bioaccessibility of soybean bioactive components.Ph. D.
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Cacchi, Mattia. "Qualita di nuove accessioni di fragola (fragaria x ananassa) in funzione del tipo di materiale di propagazione: Aspetti analitici e sensoriali." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7877/.
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La ricerca è stata svolta presso il Consiglio per la Ricerca e la Sperimentazione in Agricoltura - Unità di Ricerca per la Frutticoltura di Forlì (CRA-FRF) ed ha riguardato lo studio delle caratteristiche qualitative e di alcuni composti bioattivi dei frutti di 10 diverse accessioni varietali di fragola (6 varietà: Alba, Nora, Garda, Jonica, Brilla, Pircinque; 4 selezioni in avanzata fase di studio ottenute nell’ambito dei programmi di breeding pubblico-privati condotti e coordinati dal CRA-FRF: CE 51, CE 56, VR 177.2, VR 4) coltivate per un biennio nello stesso ambiente (cesenate). Sono state considerate due differenti tipologie di piante: frigoconservata (tipologia tradizionale) e fresca “cima radicata” (tipologia innovativa che si sta sempre più affermando presso i produttori).
L’obiettivo principale di questa tesi è finalizzato alla caratterizzazione qualitativa e nutrizionale dei frutti raccolti dalle due tipologie di pianta. L’interesse di monitorare l’effetto di questa innovativa tecnica di coltivazione deriva dalla sua sempre maggiore affermazione in quanto consente una significativa riduzione dei costi di produzione. Lo studio delle 10 accessioni di fragola (tra cui quelle che attualmente stanno dominando lo standard varietale del Nord Italia) può permettere di aggiungere informazioni importanti sulla loro caratterizzazione qualitativa, in particolare sulle caratteristiche sensoriali mediante un approccio quantitativo descrittivo. Infine, la ripetizione dello studio per due annate differenti può consentire di valutare l’influenza del fattore “anno” sui caratteri studiati.
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Chase, Jennifer Leigh. "Utah Red Raspberry Jam: The Effects of Formulation, Heating, and Time on Color, Flavor, Texture, and Antioxidant Capacity." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4278.
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The amount and type of antioxidants present in raspberries is dependent upon cultivar, ripeness, and growing conditions. Previous research on raspberry jam has reported some color, antioxidant, and flavor loss after processing and storage, though it is unknown to what extent similar changes will occur in raspberries grown in Utah. Sugar concentration and heating temperature as well as storage time were evaluated in an effort to maximize color retention, flavor, antioxidant content, shelf life, and consumer acceptance of Utah-grown raspberry jam. Four types of jams were processed in two batches each: low-sugar (40-42 Brix) and typical sugar (65-68 Brix) at 85 and 95 C, from two separate farms in Utah. Oxygen Radical Absorbance Capacity (ORAC), total anthocyanin content (TAC), color, headspace, Brix, pH, consistency, and water activity were measured in fresh jam, and after one and three months of typical storage (dark, room temperature) to evaluate changes after storage. A sensory analysis compared three-month stored jam to fresh jam made from the same berry crop. ORAC significantly declined in all jams during storage. Fresh low-sugar jam was found to contain higher ORAC values than high-sugar jam after processing and after three months of storage. All jams retained their initial anthocyanins over the first month and significantly lost an average of 28.8% anthocyanins between months 1 and 3 of storage. Color loss was found to be less pronounced than anthocyanin degradation, though nearly all jams maintained initial L*, C*, and h* values over the first month then significantly decreased by the third month of storage. When comparing fresh and three-month jam, significant sensory differences were found in color, overall acceptability, flavor, and texture. All parameters scored higher for freshly-made jam, though three-month stored jam was still found to be acceptable to consumers. In summary, after three months of storage, significant nutrient quantity and sensory quality remains in Utah raspberry jam, despite significant declines in several assays and significant differences between treatments.
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Silva, Fernanda Guimarães Drummond e. 1983. "Atividade antioxidante de produtos proteicos de linhaça (Linum usitatissimum L.)." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256383.
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Orientador: Flavia Maria NettoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-19T21:19:52Z (GMT). No. of bitstreams: 1 Silva_FernandaGuimaraesDrummonde_M.pdf: 1363127 bytes, checksum: 68b1a97c95798f4425019ee900814160 (MD5) Previous issue date: 2012
Resumo: Existem evidências numerosas sobre o papel dos radicais livres em uma série de condições patológicas, incluindo envelhecimento, câncer, esclerose múltipla, doenças cardiovasculares. Hidrolisados protéicos de diferentes fontes têm sido estudados por seu potencial antioxidante. A atuação antioxidante da proteína, na maioria das vezes, encontra-se limitada devido à conformação espacial, que concentra resíduos capazes de neutralizar radicais livres no interior da molécula, dificultando o acesso das espécies reativas aos centros nucleofílicos. A hidrólise da proteína contribui para aumentar a exposição desses resíduos de aminoácidos, aumentando sua atuação como antioxidante. Compostos fenólicos podem estar presentes em hidrolisados proteicos de origem vegetal, devido a sua associação com as proteínas. Métodos in vitro que simulam as condições do trato gastrointestinal permitem estudar como a digestão pode interferir na atividade antioxidante de peptídeos e compostos fenólicos. O presente trabalho tem como objetivos obter hidrolisados proteicos com capacidade antioxidante a partir da farinha de linhaça e avaliar o efeito da digestão in vitro pode interferir nessa atividade. A farinha de linhaça marrom foi desengordurada, obtendo-se a farinha de linhaça marrom desengordurada (FLMD). O concentrado proteico de linhaça (CPL) foi obtido a partir da FLMD por extração alcalina e precipitação no ponto isoelétrico seguida de neutralização. Para obtenção dos hidrolisados proteicos (HPL), a partir do CPL, com Alcalase, foi realizado um delineamento composto central rotacional (DCCR) 2². As variáveis independentes foram pH que variou entre 7,5 a 9,5 e relação enzima: substrato (E:S) que variou de 1:150 a 1:30. As variáveis dependentes foram grau de hidrólise (GH), teor de substâncias redutoras do reagente de Folin-Ciocalteau e atividade antioxidante, determinada por FRAP e ORAC. Teor de substâncias redutoras e atividade antioxidante foram avaliados a partir dos extratos aquosos e metanólico (metanol 70%). Os hidrolisados de maior atividade antioxidante, a FLMD e o CPL foram submetidos à digestão in vitro, simulando as condições da digestão gastrintestinal. As amostras antes e após a digestão in vitro foram caracterizadas por eletroforese em sistema SDS-PAGE Tricina e por cromatografia liquida de alta eficiência de fase reversa (HPLC- RP). O teor de substâncias redutoras e da atividade antioxidante das amostras FLMD, CPL e HPL foram avaliados antes e após a digestão in vitro. As condições ótimas para obtenção de HPL de maior GH (21,0%) são pH entre 7,5 e 8,0 e E:S entre 1:60 e 1:30, indicando que a faixa de pH ótimo da enzima e a alta E:S favorecem maior hidrólise do CPL. Para obtenção de HPL com maior teor de substâncias redutoras para os extratos aquoso (24 mg EAG/ g HPL) e metanólico (20 mg EAG/ g HPL) as condições ótimas são pH ~ 8,5 /E:S 1:30. Este resultado parece estar relacionado à liberação de compostos fenólicos ligados a proteína e também de peptídeos durante a hidrólise. Açúcares e aminoácidos aromáticos presentes no hidrolisado podem interferir na reação e superestimar o teor de fenóis dos HPL. A maior atividade antioxidante determinada pelo método de FRAP para o extrato aquoso (42 mg SF/ g HPL) se dá nas condições de pH ~ 9,5/E:S ~1:150 e para o extrato metanólico (40 mg SF/ g HPL) pH entre 8,5 e 9,0/E:S entre 1:90 a 1:150. Para o método de ORAC, as condições ótimas para maior atividade antioxidante no extrato aquoso (300 µmol TE/ g HPL) são pH entre 7,5 a 9,5/E:S ~ 1:30 ou ~1:150 e para o extrato metanólico (330 µmol TE/ g HPL) são pH ~ 8,5/E:S entre 1:150 e 1:30. Os hidrolisados de maior atividade antioxidante foram os obtidos em pH 8,5/E:S 1:90, e em pH 9,2/E:S 1:133 denominados HPL 0 e HPL 3, respectivamente. Para a FLMD, CPL e os hidrolisados, após a digestão in vitro, observou-se que o teor de substâncias redutoras totais aumentou (9 a 20 vezes) para todas as amostras. O teor de substâncias redutoras do CPL (~24 mg EAG/ g amostra), em ambos os extratos, após a digestão in vitro se igualou ao teor dos hidrolisados (~23 mg EAG/ g amostra). Este resultado sugere que tanto a hidrólise com Alcalase quanto o processo digestório liberam compostos redutores, dentre eles fenólicos da proteína de linhaça. A atividade antioxidante dos extratos de FLMD e CPL, determinada por FRAP, também aumentou (de 3 a 10 vezes) após a digestão, mas não se igualou à atividade antioxidante dos hidrolisados (48 mg SF/g amostra). No entanto, o CPL apresentou atividade antioxidante determinada por ORAC semelhante à dos hidrolisados no extrato aquoso (~420,24 µmol TE/ g amostra) e 10 % maior que o encontrado para os hidrolisados (~365 µmol TE/ g amostra) no extrato metanólico. Após a digestão in vitro, os hidrolisados apresentaram a maior atividade antioxidante medida por FRAP (50 mg SF/ g amostra), e o CPL, a maior atividade determinada pelo método de ORAC (~430 µmol TE/ g amostra). Estes resultados sugerem o processo digestório é tão ou mais eficiente que a Alcalase em liberar os compostos com atividade redutora no CPL. Uma vez que a metodologia de determinação da atividade antioxidante por ORAC tem maior proximidade com o mecanismo de oxirredução que ocorre in vivo, esses resultados sugerem o uso do CPL como melhor produto protéico da linhaça com maior potencial antioxidante para a formulação de nutracêuticos e alimentos funcionais
Abstract: There are several evidences which indicate the role of free radicals on a series of pathological conditions, including aging, cancer, multiple sclerosis and cardiovascular disease. Hydrolysates from different sources have been studied because of their antioxidant potential. The antioxidant activity of the protein, in most cases, is limited due to their conformation, which concentrates residues capable of neutralize free radicals in the molecule¿s core, hampering the access of the reactive species to nucleophilic sites. The protein hydrolysis contributes to increasing the exposure of these amino acid residues, increasing their role as antioxidants. Phenolic compounds may also be present in vegetable protein hydrolysates because of their association with proteins. In vitro methods that simulate the conditions of the gastrointestinal digestion are an important way to evaluate how the digestion affects the antioxidant activity of phenolic compounds and peptides. This study aims at obtaining hydrolysates with antioxidant capacity from defatted flaxseed flour and evaluate the effect of the in vitro digestion on this activity. The brown flaxseed flour was defatted, resulting in the brown defatted flaxseed meal (BDFM). The flaxseed protein concentrate (FPC) was obtained from the BDFM by alkaline extraction and precipitation at the isoelectric point followed by neutralization. To obtain the flaxseed protein hydrolysates (FPL), using FPC and Alcalase, a central composite rotational design (DCCR) was performed. The independent variables were pH ranging from 7.5 to 9.5 and enzyme: substrate ratio (E: S) that ranged from 1:150 to 1:30. The dependent variables were the degree of hydrolysis (DH), total phenolic content and antioxidant activity, determined by FRAP and ORAC. Phenolic and antioxidant activity were evaluated from the aqueous and methanol (70% methanol). The hydrolysates with the highest antioxidant activity, the CPL FLMD were submitted to the in vitro digestion. The samples obtained before and after the in vitro digestion were characterized by electrophoresis SDS-PAGE- tricine and HPLC. The total phenolic content and antioxidant activity of FLMD, CPL and HPL were evaluated before and after in vitro digestion. The optimum conditions to obtain HPL with the highest GDH (21.0%) are pH (7.5-8) and E:S ratio (1:60-1:30), which indicates that the Alcalase optimum pH and highest E:S ratio collaborates to highest hydrolysis of CPL. To obtain HPL with higher content of Folin-Ciocalteau reducing compounds content in aqueous (EAG 24 mg / g HPL) and methanol (20 mg EAG / g HPL) extracts, the optimum conditions were pH ~ 8.5 / E: S 1:30. This result seems to be related to the release of phenolic compounds bound to protein and also of peptides during hydrolysis. The highest antioxidant activity determined by the FRAP method in the aqueous extract (42 mg SF / g HPL) occurs under pH ~ 9.5 / E: S ~ 1:150 and the methanol extract (40 mg SF / g HPL) pH 8.5-9.0 / E: S 1:90-1:150. For the ORAC method, optimum conditions for increased antioxidant activity in aqueous extract (300 µmol TE / g HPL) are pH 7.5-9.5 / E: S ~ 1:30 or 1:150 and the methanol extract (330 µmol TE / g HPL) are pH ~ 8.5 / E: S 1:30-1:150. The hydrolysates with the highest antioxidant activities were obtained at pH 8.5 / E: S 1:90, and at pH 9.2 / E: S 1:133 denominated HPL ) and HPL 3, respectively. For FLMD, CPL and hydrolysates, after in vitro digestion, the content increased (9-20 times) for all samples. The Folin-Ciocalteau reducing capacity of the CPL (EAG ~ 24 mg / g sample) in both extracts after in vitro digestion equaled the content of hydrolysates (EAG ~ 23 mg / g sample). This result suggests that both hydrolysis with Alcalase and the digestion process are able to release phenolic compounds from the flaxseed products. The antioxidant activity of extracts of FLMD, CPL determined by FRAP, also increased (from 3 to 10 times) after digestion, but did not reached the antioxidant activity of hydrolysates (48 mg SF / g sample). However, when the activity was determined by ORAC, the FPC showed value similar to the hydrolysates, measured on the aqueous extract (~ 420.24 µmol TE / g sample) and 10% higher than on the methanol extract (~ 365 µmol TE / g sample). After in vitro digestion, hydrolysates showed the highest antioxidant activity measured by FRAP (SF 50 mg / g sample), and the FPC, the highest activity determined by ORAC method (~ 430 micromol TE / g sample). These results suggest that digestive process are equally or more effective than Alcalase in releasing peptides and phenolic compounds present in the FPC. Since the methodology for determining the antioxidant activity by ORAC utilizes a biologically relevant radical source, these results suggest the use of FPC as the best protein product of flaxseed with potential antioxidant in the formulation of nutraceuticals and functional foods
Mestrado
Nutrição Experimental e Aplicada à Tecnologia de Alimentos
Mestre em Alimentos e Nutrição
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Ibarra, Sixto Alvin. "OBTENTION AND CHARACTERIZATION OF ROSEMARY AND ASH TREE SEED EXTRACTS AND STUDY OF THEIR PREVENTIVE EFFECTS ON METABOLIC DISORDERS." Doctoral thesis, Universitat Politècnica de València, 2011. http://hdl.handle.net/10251/10795.
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La prevalencia de los trastornos metabólicos está creciendo a nivel mundial. Botánicos, como el romero (Rosmarinus officinalis L.) y las semillas de fresno (Fraxinus excelsior L.), pueden ser una alternativa para mejorar estos trastornos. El objetivo de esta tesis doctoral fue generar extractos industriales de las partes comestibles de estas plantas, identificar sus compuestos por HPLC, HPLC-MS y RMN, y determinar su eficacia y seguridad. Se desarrollaron tres extractos de romero - estandarizados al 20% de ácido carnósico, 20% de ácido rosmarínico, y 40% de ácido ursólico. El extracto rico en ácido ursólico mostró la menor capacidad antioxidante en modelos ORAC y FRAP in vitro, mientras que los otros dos extractos tuvieron capacidades más elevadas. Sin embargo, el extracto rico en ácido carnósico (RE) fue superior en la inhibición de la oxidación de LDL ex vivo, y fue el único seleccionado para estudios posteriores. Se desarrolló un extracto de semilla de fresno (FE) de acuerdo a su uso tradicional en Marruecos, siendo identificados salidrosido y 9 glucósidos secoiridoides, dos de ellos fueron descubiertos por primera vez: Excelside A y Excelside B. En estudios in vitro, RE y FE activaron receptores nucleares que regulan la homeostasis de la glucosa y la energía, y actuaron sobre mecanismos contra la obesidad y la dislipidemia - RE activa PPAR? e inhibe la lipasa pancreática, y FE estimula PPAR? y evita la diferenciación de preadipocitos. La eficacia de ambos extractos para el control de trastornos metabólicos fue confirmada en ratones C57BL/6J administrados con una dieta baja en grasa, una dieta alta en grasa, o una dieta alta en grasa más 0.5% RE (HFD.RE) o 0.5% FE (FED) durante 16 semanas. HFD.RE limitó el aumento del peso corporal y grasa en el epidídimo en un 69% (P<0.01) y 79% (P<0.001), respectivamente. HFD.RE también redujo la glucemia (72%, P<0.01) y los niveles de colesterol (68%, P<0.001). FED redujo la glucemia (76.52%, P<0.001), insulinemia (53.43%, P<Ibarra, SA. (2011). OBTENTION AND CHARACTERIZATION OF ROSEMARY AND ASH TREE SEED EXTRACTS AND STUDY OF THEIR PREVENTIVE EFFECTS ON METABOLIC DISORDERS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10795
Palancia
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Pretorius, Corlea. "Antioxidant properties of Lippia javanica (Burm.f.) Spreng. / C. Pretorius." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4726.
Full textAbstract:
The evolution of aerobic metabolic processes unavoidably led to the production of reactive
oxygen species (ROS). ROS have the ability to cause harmful oxidative damage to
biomolecules. Increased ROS generation and subsequent oxidative stress have been
associated with aging and neurodegenerative disorders such as Parkinson’s and Alzheimer’s
diseases as a result of the extreme sensitivity of the central nervous system to damage from
ROS. Antioxidant defence systems have co–evolved with aerobic metabolic processes to
counteract oxidative damage inflicted by ROS. The impact of neurodegenerative disorders
on society is increasing rapidly as the life expectancy of the global population increases. In
this day and age, a much younger group of the population is also experiencing
neurodegenerative symptoms as a result of the harmful effect of the human
immunodeficiency virus (HIV) on the central nervous system.
Plants are an invaluable source of medicinal compounds. The use of plants for their healing
properties is rooted in ancient times. The aim of this study was to select from twenty one
plants, the plant with the most promising antioxidant activity and to determine whether
extracts of this plant could act as free radical scavengers, comparing the results to Trolox, a
known free radical scavenger. The next step was to isolate and characterize a compound
from an extract exhibiting promising antioxidant activity. Bioassay–guided fractionation was
followed to achieve this.
During screening trials, twenty one plants, namely Berula erecta, Heteromorpha
arborescens, Tarchonanthus camphoratus, Vernonia oligocephala, Gymnosporia buxifolia,
Acacia karroo, Elephantorrhiza elephantina, Erythrina zeyheri, Leonotis leonurus,
Plectranthus ecklonii, P. rehmanii, P. venteri, Salvia auretia, S. runcinata, Solenostemon
latifolius, S. rotundifolius, Plumbago auriculata, Clematis brachiata, Vangueria infausta,
Physalis peruviana and Lippia javanica were selected from literature, based on reported
antioxidant activity within the plant families, for screening of their antioxidant activity. One
hundred and ten extracts were prepared from the leaves, using Soxhlet extraction and the
solvents petroleum ether (PE), dichloromethane (DCM), ethyl acetate (EtOAc) and ethanol
(EtOH), consecutively.
The focus during initial screening trials was on chemistry–based assays. The oxygen radical
absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays were
employed for the primary screening of the one hundred and ten leaf extracts. The ORAC
assay was used to determine whether the plant extracts were able to scavenge peroxyl
radicals and the FRAP assay was used to determine the reducing abilities of the extracts.
Quantification of the peroxyl radical scavenging activity by the ORAC assay revealed that
activity was observed for most of the extracts, with the ethyl acetate and ethanol extracts of
L. javanica exhibiting the most promising activity. This pattern of activity was also found with the reducing capacity evaluated by the FRAP assay in which the EtOAc and EtOH extracts of
L. javanica also exhibited the most promising activity.
L. javanica was selected for further study by screening for biological activity, employing the
nitro–blue tetrazolium (NBT) assay and thiobarbituric acid reactive substances (TBARS)
assay. Using a cyanide model to induce neurotoxic effects in rat brain homogenate, the
neuroprotective properties of the extracts of L. javanica leaves were examined using the NBT
assay and compared to that of Trolox. The NBT assay determines the level of superoxide
anions. All the extracts of L. javanica significantly reduced superoxide anion generation at all
concentrations used. The petroleum ether and ethyl acetate extracts, at all concentrations,
reduced superoxide anion generation to values lower than that of the control, suggesting that
these extracts may be able to attenuate normal free radical processes in the brain. The
petroleum ether extract exhibited the most promising activity at a concentration of 1.25 and
2.5 mg/ml and also exhibited similar results as the ethyl acetate extract at a lower
concentration than the ethyl acetate extract (2.5 mg/ml compared to 5 mg/ml).
A toxin–solution consisting of hydrogen peroxide (H2O2), iron(III)chloride (FeCl3) and ascorbic
acid was used to induce lipid peroxidation and the ability of the extracts of the leaves of
L. javanica to attenuate lipid peroxidation was investigated in rat brain homogenate and
compared to that of Trolox. All of the extracts of L. javanica significantly attenuated toxininduced
lipid peroxidation at all concentrations used. All of the extracts were also able to
significantly attenuate toxin–induced lipid peroxidation to values lower than that of the control.
These results suggest that all of the extracts of L. javanica possess the ability to attenuate
not only toxin–induced lipid peroxidation, but also lipid peroxidation that occurs during normal
processes in the brain.
The petroleum ether extract was subjected to bioassay–guided fractionation using column
and thin–layer chromatography and the NBT and TBARS assays. Fraction DD1 was
investigated by means of nuclear magnetic resonance, infrared and mass spectrometry. The
exact structure of fraction DD1 was not elucidated.
Considering all the results, it is clear that L. javanica shows great potential as a medicinal
plant with antioxidant activity and may therefore be beneficial in diminishing the destructive
oxidative effects inflicted by free radicals. There are however still many compounds to be
isolated from L. javanica.
Key words: Verbenaceae, Lippia javanica, antioxidant, neurodegeneration, oxygen radical
absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP), nitro–blue
tetrazolium assay (NBT), thiobarbituric acid reactive substances assay (TBARS).Thesis (M.Sc. (Pharmaceutical Chemistry))--North-West University, Potchefstroom Campus, 2011.
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Matrose, Albertina Neliswa. "Evaluation of the antioxidant and anti-diabesity potential of cyclopia maculata using in vitro non-cell based screening models." Thesis, University of the Western Cape, 2014. http://hdl.handle.net/11394/4262.
Full textAbstract:
Masters of ScienceThe aim of this study was therefore to evaluate the antioxidant and anti-diabesity potential of a hot water extract of C. maculata in non-cell based assays and correlate the activities with phenolic composition. Total antioxidant capacity (TAC) was assessed in terms of free radical scavenging and iron reducing ability. The DPPH, ABTS, ORAC and FRAP assays were employed. Anti-diabesity potential was assessed in terms of the inhibition of the digestive enzymes, α-glucosidase and pancreatic lipase
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Techer, Sophie. "Criblage d’activités biologiques de plantes endémiques ou indigènes de La Réunion - Recherche de molécules antivirales ciblant le virus du chikungunya." Thesis, La Réunion, 2013. http://www.theses.fr/2013LARE0014/document.
Full textAbstract:
Ce travail de thèse s'attache à identifier des plantes et/ou molécules à activités cytotoxique, antioxydante, anti-inflammatoire et antivirale ciblant le virus du chikungunya (CHIKV) dans le but de trouver des alternatives thérapeutiques vis-à-vis du stress oxydatif et de l'inflammation, mécanismes impliqués dans les maladies chroniques non transmissibles (diabète, obésité…), et de la maladie du chikungunya, maladie vectorielle réémergente. La première partie de ces travaux présente les résultats obtenus lors d'un criblage d'activités biologiques réalisé sur une sélection de dix-huit plantes endémiques et indigènes de La Réunion. Les activités ciblées ont été les activités cytotoxiques sur une lignée cellulaire humaine (cellules THP-1), les activités antioxydantes évaluées par un test in cellulo d'hémolyse et par quatre tests chimiques (TEAC/DPPH/FRAP/ORAC) ainsi qu'une évaluation de la teneur en composés phénoliques (test FOLIN) et les activités anti-inflammatoires testées sur des macrophages murins (cellules RAW-BlueTM). Les résultats obtenus ont permis de mettre, plus particulièrement, en évidence les activités de différents extraits : cytotoxique pour Carissa spinarum, antioxydantes pour Agarista buxifolia et Dryopteris wallichiana et anti-inflammatoire pour Stillingia lineata et Indigofera ammoxylum. La deuxième partie du travail est consacrée à l'étude phytochimique d'une espèce indigène de La Réunion, Stillingia lineata, choisie en raison des résultats obtenus lors de ce criblage biologique préliminaire et de ceux du programme Phytochik. Un fractionnement bioguidé par un test antiviral, réalisé sur des cellules Vero (cellules rénales de singe vert Cercopithecus aethiops) contaminées par le CHIKV, a conduit à l'isolement de trois macrocycles diterpéniques rares de type tonantzitlolone dont l'un présente une structure non caractérisée jusque-là, et d'un pimarane de structure nouvelle. La 4'-acétoxytonantzitlolone a été identifiée comme molécule candidate contre le CHIKV (CE50 = 7 μM). Des relations structure-activité ont pu être définies ; la présence d'un groupement oxygéné sur la chaîne latérale des tonantzitlolones semble jouer un rôle important sur la réponse antivirale de ces squelettes diterpéniquesThe aims of this PhD work were to identify plants and/or molecules with cytotoxic, antioxidant, anti-inflammatory or antiviral (chikungunya virus , CHIKV) activities in order to find therapeutic alternatives towards oxidative stress and inflammation, mechanisms involved in chronic noncommunicable diseases (diabetes, obesity ...), and chikungunya disease, reemerging vector-borne disease. The first part of this work presents the results obtained from a biological screening carried out on a selection of eighteen endemic and indigenous plants of La Réunion. The targeted activities were cytotoxicity on a human cell line (THP-1), antioxidant activities evaluated using an in cellulo hemolysis assay and four chemical tests (TEAC / DPPH / FRAP / ORAC) together with an evaluation of the content of phenolic compounds (FOLIN test) and anti-inflammatory activity tested in murine macrophages (RAW cells-BlueTM). The results allowed to highlight activities of different extracts in particular : cytotoxic for Carissa spinarum, antioxidant for Dryopteris wallichiana and Agarista buxifolia and anti-inflammatory for Stillingia lineata and Indigofera ammoxylum.The second part of this work is devoted to the phytochemical study of Stillingia lineata, an indigenous species of La Réunion chosen because of the results obtained in this preliminary biological screening and those carried out in Phytochik programme. Bioassay-guided fractionation performed on Vero cells (green monkey kidney cells Cercopithecus aethiops) infected with CHIKV led to the isolation of three rare macrocycle-type diterpenes called tonantzitlolone and a new pimarane. The 4'-acetoxytonantzitlolone was identified as a candidate molecule against CHIKV (EC50 = 7 μM). Structure-activity relationships have been defined, the presence of an oxygenated group on the side chain of tonantzitlolones seems to play an important role in the antiviral response of the diterpene skeleton
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Waldron, Sarah Winona. "Children's responses to culturally relevant oracy practices." Thesis, 2014. http://hdl.handle.net/1828/5667.
Full textAbstract:
The purpose of this qualitative action research was to explore how early primary children respond to the implementation of culturally relevant oracy practices in an inclusive classroom. This study, which took place over five months in an inner city school in Western Canada, focused on children’s oracy skills following four events facilitated by an Aboriginal Elder. Data consisted of an oral assessment, transcriptions of the four events, artefacts created by the students, photographs, and the teacher’s research journal. Data analysis consisted of a comparative assessment of the student’s oral language skills and a content and discourse analysis of the transcriptions. Data analysis revealed that children respond favourably to culturally responsive oracy practices, that they are able to meet the B.C. Ministry of Education prescribed learning outcomes, and such practices adhere to the Aboriginal Enhancement Agreement (2005).Graduate
0727
0524
winona.waldron@shaw.ca
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Tichapondwa, Stanslaus Modesto. "The effects of a course in classroom text and discourse on oracy in high school classrooms." Thesis, 2008. http://hdl.handle.net/10500/2015.
Full textAbstract:
The study investigates the potential of teacher talk in enhancing learner capacity to negotiate learning, premised on a view of classroom interaction as guided construction of knowledge. It examines the extent to which levels of oracy - essentially, awareness of the language of instruction, and the ability to use it more effectively - can be raised by exposing teachers to an in-service distance education language-based course. The main research questions are:
a. What are the effects of the course in classroom text and discourse on oracy in the high school classroom?
b. How can the quality of classroom discourse be assessed in a relatively systematic and objective manner?
With regard to the second question, an analytical framework was developed that defined three key constructs in terms of discourse acts, namely teacher dominance, teacher effectiveness and learner initiative, and these constructs formed the basis of the three hypotheses. Patterns of interaction in English, mathematics and geography classes during the first year of high school in Harare, Zimbabwe (main study) and Zomba, Malawi (supplementary study) were analysed. The Zimbabwe study used a pretest-posttest control group design, with six teachers in the experimental group and three as controls, while the Malawi study used a posttest-only control group design with three teachers in each group. The experimental groups took part in an intervention programme known as the Litraid Project, a course on classroom text and discourse. The findings, interpreted both quantitatively and qualitatively, showed that after intervention the experimental group teachers dominated classrooms less and used discourse input more consciously and effectively. Similarly, their learners showed improved ability to negotiate learning, as reflected in their heightened levels of initiative and discourse output, both in class and group discussion. Hence the conclusion that classroom praxis, specifically in English second language situations, benefits from a conscious enhancement of oracy, leading to more effective teaching and learning.Linguistics
D.Litt. et Phil. (Linguistics)
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Wang, Jhih-Jheng, and 王至正. "Measurement of Antioxidant Capacity of Horticultural Crops Using Oxygen Radical Absorbance Capacity (ORAC) Assay." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/66084342143435244719.
Full textAbstract:
碩士國立臺灣大學
園藝學研究所
94
Abstract Oxygen radical absorbance capacity (ORAC) assay is regarded as the recommended method for representing the total hydrophilic antioxidant capacity in fruits and vegetables. This method measures the decay of fluorescence as the fluorescent probe is oxidized by the peroxy radicals generated from AAPH (2,2-Azobis(2-amidinopropane) dihydrochloride). At present, there are two fluorescent probes being used in the ORAC assay, the β-phycoerythrin (β-PE), an fluorescent algae protein; and fluorescein (FL), an organic fluorescent molecule. The object of this paper is to compare the fluorescence stability, influence of solvent on free radical reaction, and the responses of different antioxidants in the ORAC assay by using these two probes. Results showed that under excitation irradiation, FL remained stable during the assay period, while β-PE lost its fluorescence intensity with time. Using phosphate buffer or methanol as solvent did not influence the fluorescence change of the free radical reaction, but using acetone or ethanol as solvent would affect the reaction. Both β-PE and FL probes have shown linear correlation at the concentration range of 0~10 μΜ for the water-soluble vitamin E analog trolox. Similar linearity and sensitivity were obtained with other antioxidants, including glutathione, ascorbic acid, sodium ascorbate, uric acid, rutin, catechin and catechol. The relative antioxidant capacity (with respect to trolox) of various antioxidants were further compared, the antioxidant value of glutathione obtained with β-PE was similar to that of FL. For ascorbic acid, Sodium ascorbate and uric acid, the antioxidant values obtained with β-PE was higher than that of the FL. While for phenolic compounds including rutin, catechin and catechol, the antioxidant values obtained with β-PE was lower than that of FL. These results indicated that interactions between free radicals, antioxidants and fluorescence probes were different among various antioxidants. Since the relative antioxidant capacity of all the phenolic compounds was much higher than trolox in both assays, it is a good indication that phenolic compounds possess high antioxidation capacity against peroxy radicals. The total oxyradical scavenging capacity (TOSC) assay is another method for total hydrophilic antioxidant capacity, which is based on the oxidation of α-keto-γ-methylthiobutyric acid by 2,2’-azobis-amidino -propane (ABAP) with the evolution of ethylene as the quantifiable end product. Linear correlations were observed between TOSC antioxidant capacity and concentration of various antioxidants. The antioxidants being tested include trolox, ascorbic acid, glutathione, rutin, catechin and catechol. The antioxidant capacity of ascorbic acid and glutathione were similar to the ORACFL assay, and antioxidant capacity of all the phenolics, rutin, catechin and catechol are lower than that of the ORACFL assay. Fourteen horticulture crops were analyzed for their antioxidant capacity by both the TOSC assay and the ORACFL assay. The results of ORACFL and TOSC assay had rather poor correlation, indicating the difficulty of comparing results of two different assays. When using mixtures of two or more antioxidant standards, both ORACFL and TOSC assays gave linear regression curve between measured and calculated values, but the ORACFL had better correlation coefficients. Based on the accuracy and reliability of the assay methods, the ORAC assay was considered the better method to be chosen. In the last part, the antioxidant capacity of 24 vegetables and 5 fruits grown in Taiwan was measured by the ORACFL assay. The total hydrophilic antioxidant capacity of all the fruits and vegetables analyzed ranged between 2.08 ± 1.11 to 58.19 ± 1.48 μmole Trolox equiv./g. Among them, ‘Taiwan’ cutting lettuce, ‘Kaiya’, ‘C×Y cross’ and ‘Siashan’ cabbages all had relative high amount of antioxidant capacity, that is, higher than 40 μmole Trolox equiv./g. There are significant differences in antioxidant capacity among cultivars of the same crop, and there are differences among vegetables grown in different locations and by different growers. But there were no difference between vegetables grown by the same grower at the same location but harvested at different time. It is concluded that in addition to the differences among cultivars, antioxidant capacity of crops may be influenced by environmental factors as well as cultivation styles.
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Cheng, Yu-Hsuan, and 鄭又瑄. "Measurement of Antioxidant Capacity of Vegetables Using Oxygen Radical Absorbance Capacity（ORAC）and Folin-Ciocalteu Reagent Reducing Capacity（FCR）Assay." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/55207036073793414144.
Full textAbstract:
碩士國立臺灣大學
園藝學研究所
99
Fruits and vegetables are rich in compounds that possess antioxidative capacity, such as carotenoids, flavonoids and phenolics, and these compounds act as the major source of antixidants in our daily diet. A number of methods, that were based on different principles, had been developed to determine the antioxidant capacity in our food. In this research, two of the major methods for antioxidant capacity assay: the Oxygen radical absorbance capacity assay（ORAC）and the Folin-Ciocalteo reagent reducing capacity assay（FCR）were studied in detail. First, standard assay procedures were established for these two assays and the relative antioxidant capacity of ten phytochemicals representing antioxidants commonly found in vegetables were obtained and the differences between these two assays were compared. Then, the most effective way of extracting antioxidant components from vegetable tissue was studied and the antioxidant capacities of sixteen vegetables sold in local market were assayed and the correlation between the antioxidant capacity and the antioxidant compounds were further analyzed. The ORAC assay utilizes Fluorescein as the fluorescent probe, its optimum excitation and emission wavelengths were 490 nm and 510 nm respectively. During the assay, the sample and the probe were mixed first and incubated at 37℃for 5 min in darkness, then the free radical generating compound AAPH was added to initiate the reaction. The changes in fluorescence with time were monitored with a spectro- fluorometer until the fluorescence dropped to less than 1% of the initial value. The area under the fluorescence curve（AUC）was then used to calculate the antioxidant capacity of the sample. The ORAC assay system was not affected by the presence of 5% methanol or 2% acetone; however, the decline of fluorescence was strongly interfered by the presence of 0.5% ethanol in the system. Ten phytochemicals commonly found in vegetables, including ascorbic acid, chlorogenic acid, gallic acid, catechin, luteolin, myricetin, rutin, kaempferol, apigenin, and quecertin were assayed by the ORAC method and all of them gave good linear correlations between concentration and AUC, indicating the validity of the ORAC assay. Based on the curves of fluorescence decline obtained from these ten compounds, three types of pattern could be distinguished, probably representing different mode of antioxidation reaction by these compounds. The FCR assay utilize the Folin-Ciocalteu reagent as reactant, it undergo oxidation reaction with phenolics or other compounds having reducing capacities under alkaline condition. Both gallic acid and Trolox gave good linear correlations by the FCR assay, indicating the method was suitable for antioxidant assay. By using Trolox as the mutual reference compound, the ten phytochemicals were assayed by three antioxidant capacity assays: the FCR, the ORAC and the DPPH assay; and the resulting relative antioxidant capacities were compared for consistency. The ORAC assay was found to be able to react with different types of antioxidant, and the results were highly representative of the antioxidant capacity of the system. The FCR assay showed preference for water soluble compounds, but also gave comparable results with the ORAC assay. The DPPH assay was less consistent with the other two assays and was less responsive to compounds with higher antioxidant capacity. Onion powders extracted with methanol containing 1.2 N HCl at 90℃for two hours gave the highest antioxidant capacity by all three assay methods. This extraction condition was used to obtain extracts from 16 vegetables commonly found in local market, and they were assayed for antioxidant capacity by the ORAC, the FCR and the DPPH assay. In the DPPH assay, over 95% free radical scavenging capacity was obtained for all vegetable samples, suggesting the inability of this assay in distinguishing the antioxidant capacities among different vegetables. On the other hand, both the FCR and the ORAC assay gave different results for different vegetables. Vegetables that showed the highest antioxidant capacity were okra, sweetpotato leaf and Chinese parsley by the FCR assay; and sweetpotato, Chinese parsley and leaf lettuce by the ORAC assay. The absolute antioxdant capacity were between 300~1500 μmol TE･g-1，by the FCR assay and between 100~800 μmol TE･g-1 by the ORAC assay. Statistical analyses were carried out with data from the results of antioxidant capacity assay of 16 vegetables and the contents of ascorbic acid and 6 individual flavonoids. The result showed that there was a significant correlation, r=0.77, between the ORAC assay and the FCR assay, indicating the consistency of these two assays in measuring the antioxidant capacity of the sample. The correlation coefficient between ascorbic acid content and the ORAC assay and the FCR assay were 0.73 and 0.62 respectively, indicating the dominant role of ascorbic acid played in the antioxidant capacity of vegetables. The relationship between antioxidant capacity and antioxidant compounds were further analyzed with multiple linear regression. The best multiple linear regression equation for the ORAC assay showed that ascorbic acid was the major component, and the best multiple linear regression equation for the FCR assay showed that ascorbic acid, quecertin and apigenin were the important factors. The result also showed that ascorbic acid was involved in the antioxidant capacity in all 16 vegetable studied. Results of this study indicated that both the ORAC assay and the FCR assay could distinguish the antioxidant capacity of different vegetable correctly and therefore were considered as the recommended method for antioxidant capacity assay for horticultural products in the future.
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Harrington, Whitney Leigh. "The Effects of Roasting Time and Temperature on the Antioxidant Capacity of Cocoa Beans from Dominican Republic, Ecuador, Haiti, Indonesia, and Ivory Coast." 2011. http://trace.tennessee.edu/utk_gradthes/976.
Full textAbstract:
Roasting is an important processing step for developing cocoa flavor, color, and aroma. Cocoa beans contain polyphenolic compounds, which can be desirable antioxidants. Oxygen Radical Absorbance Capacity (ORAC) values can be used as an indicator of health benefits of antioxidants in foods. ORAC values measure total antioxidant capacity of different foods by measuring antioxidant scavenging activity against peroxyl radical induced by 2,2’-azobis (2-amidinopropane) dihydrochloride (AAPH). This measurement of total antioxidant capacity gives a complete assessment during which the inhibition time and inhibition degree are measured as the reaction comes to a completion. ORAC values were determined as Trolox Equivalents (TE). Cocoa beans were also measured for antioxidants using Total Phenolics assay and DPPH assay and measured as gallic acid equivalents (GAE). Cocoa beans from the Ivory Coast were roasted at varying times (10-40 minutes) and temperatures (100ºC -190ºC). It was determined that cocoa beans from the Ivory Coast, roasted at 130ºC for 30 minutes resulted in an ORAC value of 522,789 μmol (micromoles) TE/g, GAE value of 2.46 mg/L as determined by Total Phenolics, and GAE value of 1.48 mg/L as determined by DPPH assay. The analyzed values tended to decrease at the highest temperatures and times of roasting. Cocoa beans from different countries were roasted at 130ºC for 30 minutes and antioxidants were analyzed. It was determined that Dominican Republic and Ecuador had the highest TE values (487,913 and 463958 μmol (micromoles) TE/g respectively). GAE differed and Total Phenolic assay found Haiti had the highest GAE (3.26 mg/L) and DPPH assay found Ivory Coast and Dominican Republic had the highest (0.623 and 0.610 mg/L respectively). If an acceptable flavor, color, and aroma of cocoa can be developed at a roasting temperature closer to 130ºC than to 160ºC, then a greater antioxidant content should occur in dry cocoa powder.
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Ranamukhaarachchi, Sahan. "Production and fractionation of antioxidant peptides from soy protein isolate using sequential membrane ultrafiltration and nanofiltration." Thesis, 2012. http://hdl.handle.net/10012/6620.
Full textAbstract:
Antioxidants are molecules capable of stabilizing and preventing oxidation. Certain peptides, protein hydrolysates, have shown antioxidant capacities, which are obtained once liberated from the native protein structure. Soy protein isolates (SPI) were enzymatically hydrolyzed by pepsin and pancreatin mixtures. The soy protein hydrolysates (SPH) were fractionated with sequential ultrafiltration (UF) and nanofiltration (NF) membrane steps. Heat pre-treatment of SPI at 95 degrees celsius (C) for 5 min prior to enzymatic hydrolysis was investigated for its effect on peptide distribution and antioxidant capacity. SPH were subjected to UF with a 10 kDa molecular weight cut off (MWCO) polysulfone membrane. UF permeate fractions (lower molecular weight than 10 kDa) were fractionated by NF with a thin film composite membrane (2.5 kDa MWCO) at pH 4 and 8. Similar peptide content and antioxidant capacity (α=0.05) were obtained in control and pre-heated SPH when comparing the respective UF and NF permeate and retentate fractions produced. FCR antioxidant capacities of the SPH fractions were significantly lower than their ORAC antioxidant capacities, and the distribution among the UF and NF fractions was generally different. Most UF and NF fractions displayed higher antioxidant capacities when compared to the crude SPI hydrolysates, showing the importance of molecular weight on antioxidant capacity of peptides. The permeate fractions produced by NF at pH 8 displayed the highest antioxidant capacity, expressed in terms of Trolox equivalents (TE) per total solids (TS): 5562 μmol TE/g TS for control SPH, and 5187 μmol TE/g TS for pre-heated SPH. Due to the improvement in antioxidant capacity of peptides by NF at pH 8, the potential for NF as a viable industrial fractionation process was demonstrated.
Principal component analysis (PCA) of fluorescence excitation-emission matrix (EEM) data for UF and NF peptide fractions, followed by multi-linear regression analysis, was assessed for its potential to monitor and identify the contributions to ORAC and FCR, two in vitro antioxidant capacity assays, of SPH during membrane fractionation. Two statistically significant principal components (PCs) were obtained for UF and NF peptide fractions. Multi-linear regression models (MLRM) were developed to estimate their fluorescence and PCA-captured ORAC (ORAC-FPCA) and FCR (FCR-FPCA) antioxidant capacities. The ORAC-FPCA and FCR-FPCA antioxidant capacities for NF samples displayed strong, linear relationships at different pH conditions (R-squared>0.99). Such relationships are believed to reflect the individual and relative combined contributions of tryptophan and tyrosine residues present in the SPH fractions to ORAC and FCR antioxidant capacities. Therefore, the proposed method provides a tool for the assessment of fundamental parameters of antioxidant capacities captured by ORAC and FCR assays.
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Hambira, Chipo. "Proanthocyanidins, anthocyanins and phenolic acids in food barleys of diverse origin." 2010. http://hdl.handle.net/1993/3841.
Full textAbstract:
Phytochemicals found in grains complement those found in fruits and vegetables. These phytochemicals, though minor compounds, contribute to the antioxidant properties which are related to the health benefits associated with the consumption of whole grain. In this thesis project, nine barley genotypes of diverse origin namely CI2230 from Nepal, CI1248 from Israel, 3 Peruvian genotypes; Peru 3, Peru 16 and Peru 35, Hokuto Hadaka from Japan, EX116; a cross between Moroccan and Canadian genotype, EX83; a cross between two Canadian genotypes and EX127; a cross between Canadian and German genotypes were studied. The genotypes were categorized based on appearance into purple, black and yellow grains. Phenolic acids and flavonoids were identified and quantified in these diverse genotypes using HPLC-ESI-MS analysis. The main classes of dietary flavonoids studied in the barleys were anthocyanins and flavan-3-ols. Phenolic acids were identified and quantified (p-coumaric, ferulic, sinapic, caffeic, vanillic). Three ferulic acid dehydrodimers (8-0-4â DFA, 8-5â benzofuran form and 5-5â DFA) were also identified. The most abundant dimeric flavan-3-ols were procyanidins B3 and prodelphinidin B3. The monomeric unit, (+)-catechin, was the most abundant while catechin glucoside (m/z 451) was also identified. Among the Peruvian genotypes, Peru 16 and Peru 35 exhibited relatively high levels of total PA content. Total phenolic content and antioxidant activities of methanolic, acetone and alkali hydrolyzed extracts of the nine barley genotypes was determined by the Folin- Ciocalteau assay, DPPH radical scavenging assay and oxygen radical absorbance capacity (ORAC assay).The acetone extract exhibited the highest antioxidant capacity using all the methods of analysis. Furthermore, dark colored grains were found to exhibit higher contents of phenolic compounds. The phenolic acids, PAs and anthocyanins identified and quantified had significant contribution to the overall antioxidant capacity of the barley whole grain. Four hull-less genotypes namely CI2230, EX127, CI1248 and Peru 35 were further partially sprouted to establish the effects of sprouting on phenolic acid composition. Partial sprouting was observed to significantly increase the soluble conjugated phenolic acids. The barley genotypes studied were found to contain different quantities of phytochemicals and had high proanthocyanidin content thereby rendering them as alternative sources of antioxidants. Barley sprouts present a possible novel food ingredient with improved properties such as phenolic acid composition and other benefits such as easier incorporation into food products under development.
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Eversley, Tiffany C. "Le potentiel antioxydant de l’alimentation tel qu'estimé par le score ORAC : une comparaison des apports des personnes âgées avec démence du type Alzheimer avec ceux des témoins sans problèmes cognitifs." Thèse, 2012. http://hdl.handle.net/1866/8489.
Full textAbstract:
Le stress oxydatif et la formation des radicaux libres sont impliqués dans plusieurs mécanismes de la mort neuronale qui caractérisent la maladie d'Alzheimer. Les antioxydants sont reconnus comme une source de protection contre le stress oxydatif et peuvent avoir un effet protecteur sur le développement de la maladie d’Alzheimer. Cette étude visait à évaluer le potentiel antioxydant, par le biais du score « oxygen radical absorbance capacity » (ORAC), de l’alimentation habituelle de personnes âgées atteintes de la maladie d’Alzheimer en comparaison avec des témoins appariés pour l’âge sans problèmes cognitifs. L’hypothèse stipulait que les patients atteints de la maladie d’Alzheimer ont une alimentation dont le potentiel antioxydant est inférieur à celui des témoins sans problèmes cognitifs. L’étude a consisté en des analyses secondaires de données provenant de l’étude « Nutrition-Mémoire » (NMS), durant laquelle quarante-deux patients avec une démence du type Alzheimer (DTA) probable et leurs aidants étaient suivis pendant une période de dix-huit mois. Pour la présente étude, les données provenaient de trois jours de collecte alimentaire, ont été colligées au début (T0) de l’étude NMS, selon la méthode « Multiple-Pass ». Le potentiel antioxydant de l’alimentation a été déterminé à l’aide de la description des aliments énumérés dans la base de données des valeurs ORAC de l’USDA. Les résultats de l’étude ont montré que les patients avaient une alimentation dont le potentiel antioxydant était inférieur à celui des témoins (13784,07 ± 7372,70 μmol TE/100g contre 23220,54 ± 10862,55 μmol TE/100g, patients et témoins, respectivement; p<0,0001). Les analyses de régression hiérarchique pas à pas montraient que l’IMC, l’éducation, et le groupe (patients, témoins) étaient des facteurs influençant le score ORAC total. La consommation des aliments riches en antioxydants est un comportement préventif à faible risque qui pourrait bénéficier des individus susceptibles de développer la maladie d'Alzheimer.Oxidative stress and the formation of free radicals are involved in several mechanisms of neuronal death that are characteristic of Alzheimer's disease. Antioxidants are known to help defend against oxidative stress and may protect against the development of Alzheimer's disease. This study aims to evaluate the antioxidant potential, using the “oxygen radical absorbance capacity” (ORAC) score of the diet of older adults people with Alzheimer's disease compared with cognitively-intact age-matched controls. It was hypothesized that the antioxidant potential of the diet of elderly people with Alzheimer's disease will be lower than that of controls without cognitive problems. The current study is a secondary analysis of data obtained from the "Nutrition-Memory study" (NMS). The NMS study recruited forty-two patients with probable Alzheimer’s disease, and their caregivers, and followed them over a period of eighteen months. The current study focuses on three days of dietary data collection, compiled at the beginning (T0) of the NMS study. The antioxidant potential of the diet was determined using the list of ORAC scores highlighted in the USDA database for the oxygen radical absorbance capacity of selected foods. Our results showed that the diet of patients (13784.07 ± 7372.70 μmol TE/100g) had a lower antioxidant potential than that of controls (± 23220.54 10862.55 μmol TE/100g). Moreover, BMI, education and group-status were factors that influenced the total ORAC score. Eating foods rich in antioxidants is a low risk preventative behaviour that could benefit individuals susceptible to developing Alzheimer’s disease.
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Duro, Lia Susana Lourenço Simões. "Métodos para a determinação do potencial antioxidante dos frutos." Master's thesis, 2016. http://hdl.handle.net/10451/34615.
Full textAbstract:
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2016As polpas e os extratos de frutos têm sido identificados como fontes potenciais de grande atividade antioxidante. Tendo em conta que o stress oxidativo foi descrito como estando envolvido em patologias degenerativas, tais como o cancro, Parkinson, Alzheimer, doenças cardiovasculares e doenças autoimunes, atualmente efetuam-se diversos estudos, a fim de verificar e comprovar a atividade antioxidante de frutos e de outros alimentos na prevenção dessas doenças. Para avaliar a atividade antioxidante dos frutos, podem ser utilizados, individualmente ou em conjunto, diversos métodos. Neste contexto, apresenta-se uma revisão dos métodos mais utilizados na avaliação do potencial antioxidante dos frutos, nomeadamente por remoção de um radical peroxil (ORAC, Oxygen Radical Absorbance Capacity e TRAP, Total Reactive Antioxidant Potential), pela capacidade de redução de um metal (FRAP, Ferric Reducing Antioxidant Power e CUPRAC, Cupric ion Reducing Antioxidant Capacity), pela capacidade de remoção de um radical orgânico (ABTS, método do ácido 2,2'-azino-bis-3-etilbenzotiazolina-6-sulfónico e DPPH, método do 2,2-difenil-1-picril-hidrazil) e pela quantificação de produtos formados durante a oxidação de lípidos (TBARS, Thiobarbituric Acid Reactive Substances, oxidação das lipoproteínas de baixa densidade (LDL, Low Density Lipoprotein) e co-oxidação do β-caroteno). Apresentam-se também as vantagens e as desvantagens de cada um dos métodos.
Fruit pulp and fruit extracts have been identified as potential great sources of antioxidant activity. Although oxidative stress has been previously described as being involved in degenerative diseases such as cancer, Parkinson's, Alzheimer's, cardiovascular diseases and autoimmune diseases, there are currently several studies being performed in order to verify and confirm the antioxidant activity of fruits and other foods for the prevention of these diseases. Several methods may be used, individually or together, to evaluate the antioxidant activity in fruits. In this report, the author comprehensively reviews the literature regarding the methods used in the evaluation of the fruit antioxidant potential, namely by removal of a peroxyl radical (ORAC, Oxygen Radical Absorbance Capacity and TRAP, Total Reactive Antioxidant Potential), by the capacity of reduction of a metal (FRAP, Ferric Reducing Antioxidant Power and CUPRAC, Cupric ion Reducing Antioxidant Capacity), by the ability to remove an organic radical (ABTS, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid method and DPPH, 2,2- diphenyl-1-picril – hydrazyl method) and by the quantification of the products formed during the oxidation of lipids (TBARS, Thiobarbituric Acid Reactive Substances, LDL oxidation and Co-oxidation of β-carotene). The author also presents advantages and disadvantages of each method.