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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Isolamento dos constituintes do Tegumento da Castanha de Caj? (TCC) e avalia??o do seu potencial como antioxidante natural / Isolation of the constituents of cashew nut integument (CNI) and evaluation of its potential as a natural antioxidant

Oliveira, Nat?lia de Freitas 25 April 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-27T20:56:01Z No. of bitstreams: 1 NataliaDeFreitasOliveira_TESE.pdf: 17307152 bytes, checksum: 67b914f696cbef8db6c64e30f9b3221b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-27T21:01:53Z (GMT) No. of bitstreams: 1 NataliaDeFreitasOliveira_TESE.pdf: 17307152 bytes, checksum: 67b914f696cbef8db6c64e30f9b3221b (MD5) / Made available in DSpace on 2017-04-27T21:01:53Z (GMT). No. of bitstreams: 1 NataliaDeFreitasOliveira_TESE.pdf: 17307152 bytes, checksum: 67b914f696cbef8db6c64e30f9b3221b (MD5) Previous issue date: 2016-04-25 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / O caj? (Anacardium occidentale L.) ? uma das principais fontes de renda dos produtores rurais da regi?o Nordeste do Brasil. A castanha de caj? ? constitu?da por tr?s partes: casca, am?ndoa e uma pel?cula marrom conhecida como tegumento (TCC). ?leos vegetais brutos possuem diferentes constituintes que s?o indesej?veis ao produto final, uma vez que podem ocasionar a oxida??o no ?leo. Fatores como a degrada??o oxidativa s?o de extrema import?ncia para o aumento do tempo de estocagem de ?leos e gorduras. Neste trabalho procurou-se isolar os diferentes tipos de metab?litos secund?rios do tegumento; elaborar e otimizar uma metodologia para o refino dos ?leos de canola e girassol; e avaliar o potencial antioxidante do extrato do tegumento da castanha de caj? na estabilidade oxidativa (EO) de ?leos vegetais. A abordagem fitoqu?mica demonstrou que o tegumento ? rico em diversos metab?litos, como os alcal?ides, sais de am?nio e os compostos fen?licos (taninos). Os ?leos foram analisados em quatro grupos de amostras: industrial, bruto, degomado e neutralizado. Os ?leos neutralizados de canola e girassol apresentaram acidez livre (IA) abaixo dos ?leos industrializados, bem como os ?ndices de iodo (II) e per?xido (IP). Atrav?s dos resultados obtidos, verificou-se que o processo de refino adotado resultou em um produto com padr?o semelhante ao ?leo industrializado e dentro das normas. O teste de oxida??o acelerada, Schaal Oven Test, e as an?lises IA, IP, absortividade espec?fiva (AE) em 232 e 270nm, dienos (DC) e trienos conjugados (TC), e EO em PetroOxy foram realizados, observando-se que as adi??es de antioxidantes naturais nos ?leos vegetais asseguraram a estabilidade oxidativa ap?s o envelhecimento acelerado em estufa. Evidenciou-se, tamb?m, que o ?leo de canola foi mais est?vel e resistente a longos per?odos de estocagem. O uso dos extratos metan?licos de tegumento (MDF) forneceu melhores resultados de IA, IP, DC em rela??o ao controle e ao antioxidante sint?tico BHA. O per?odo de indu??o avaliado pelo PetroOxy foi aumentado com a adi??o dos antioxidantes naturais do TCC, demonstrando que sua a??o antioxidante em ?leos vegetais o torna um potencial composto bioativo natural. / The cashew (Anacardium occidentale L.) is one of the main sources of income for farmers in the Northeast region of Brazil. The cashew nut is composed of thee main parts: peel, almond, and a brown film known as integument (CNI). Crude vegetable oils have different constituents which are undesirable in the end product, causing oil oxidation. Factors such as oxidative degradation are extremely important to increase the shelf life of oils and fats. This research was developed aiming to: identify and isolate different types of secondary metabolites from the integument; develop and optimize a methodology for refining canola and sunflower oils; and evaluate the antioxidant potential of the integument extract in oxidative stability (OS) of vegetable oils. The phytochemical approach showed that the integument is rich in various metabolites such as alkaloids, ammonium salts, phenolic compounds (tannins). The oils were analyzed in four groups of samples: industrial oil, crude oil, degummed oil, and neutralized oil. The values of acidity contente (AV) obtained for the canola and sunflower neutralized oils were lower than the ones for industrial oils, as well as for iodine index (II) and peroxide index (PV). The results showed that the adopted refining process resulted in na oil with similar properties of the industrial one and in accordance with Brazilian standards. The accelerated oxidation test, Schaal Oven Test, and the AV, PV, especific absorty (EA) analysis, at 232 and 270nm, and OS (PetroOxy) were performed and it was observed that the addition of the natural antioxidants in vegetable oils ensured oxidative stability after accelerated aging in stove. It is also evident that the canola oil is more stable and resistant to long periods of storage. The use of integument methanolic extracts (IME) provided better results for AV, PV, DC in relation to the control and the synthetic antioxidante (BHA). The induction period measured by PetrOxy was increased with the addition of natural antioxidants from CNI, demonstrating that this product presents antioxidant action for vegetable oils, allowing it?s use as a natural bioactive compound.

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