765 resultados para Licopeno - Antioxidantes


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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The biodiesel is defined as the mono-alkyl ester derived from long-chain fatty acids, from renewable sources such as vegetable oils or animal fat, whose use is associated with the replacement of fossil fuels in diesel engine cycle. The biodiesel is susceptible to oxidation when exposed to air and this process of oxidation affects the quality of fuel, mainly due to long periods of storage. Because of this, the oxidation stability has been the focus of numerous researches since it directly affects the producers, distributors and users of fuel. One of the possibilities to increase the resistance of biodiesel is the autoxidation treatment with inhibitors of oxidation. The antioxidants can be used as potential inhibitors of the effects of oxidation on the kinematic viscosity and the index of acidity of biodiesel, thereby increasing oxidative stability. This work aims to examine the efficiency of antioxidants, α-tocopherol and butylated hydroxy-toluene (BHT), added the biodiesel content of remembrance through Pressurized-Differential Scanning Calorimetry (P-DSC), Thermogravimetry (TG) and Petrology. The results showed that the use of antioxidant BHT, at the concentration of 2000ppm, increased resistance to oxidation of the biodiesel and oxidative induction time (OIT), which is a better result as antioxidant than the α-tocopherol. With the thermogravimetric analysis, it was observed that the biodiesel presented an initial decomposition temperature of lower tendency than that of oil, demonstrating to be more volatile, bearing great similarity to the diesel and being characterized as an alternative fuel. The rheological analysis indicated that each sample of biodiesel behaved as a Newtonian fluid

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This work aims to study the effects of adding antioxidants, such as, α- tocopherol and BHT on the thermal and oxidative stability of biodiesel from cottonseed (B100). The Biodiesel was obtained through the methylical and ethylical routes. The main physical and chemical properties of cotton seed oil and the B100 were determined and characterized by FTIR and GC. The study of the efficiency of antioxidants, mentioned above, in concentrations of 200, 500, 1000, 1500, 2000ppm, to thermal and oxidative stability, was achieved by Thermogravimetry (TG), Differential Thermal Analysis (DTA), Differential Scanning Calorimetry (DSC), Differential Scanning Calorimetry - Hi-Pressure (P-DSC) and Rancimat. The Biodiesel obtained are within the specifications laid down by Resolution of ANP No7/2008. The results of TG curves show that the addition of both antioxidants, even in the lowest concentration, increases the thermal stability of Biodieseis. Through the DTA and DSC it was possible to study the physical and chemical transitions occurred in the process of volatilization and decomposition of the material under study. The initial time (OT) and temperature (Tp) of oxidation were determined through the P-DSC curve and they showed that the α-tocopherol has a pro-oxidant behavior for some high concentrations. The BHT showed better results than the α-tocopherol, with regard to the resistance to oxidation

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Lipid oxidation is certainly one of the most important alterations that affect both oils or fats and foods that contain them. It is responsible for the development of unpleasant taste and smell in foods, making them unsuitable for consuming. The use of antioxidants permits a longer useful life of these products. This work presents a bibliographic review of research carried out in order to evaluate the antioxidant activity of natural or synthetic substances used in the conservation of food lipid. Among such substances, the following antioxidants are highlighted: butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroquinone (TBHQ), propyl gallate (PG), tocopherols, phenolic acids and isolated compounds from rosemary and oregano.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Sessenta e nove acessos de Psidium, coletados em seis estados brasileiros, foram analisados para dois métodos não hierárquicos de agrupamento e por componentes principais (CP), visando orientar programas de melhoramento. Foram analisadas as variáveis ácido ascórbico, β-caroteno, licopeno, fenóis totais, flavonóides totais, atividade antioxidante, acidez titulável, sólidos solúveis, açúcares solúveis totais, teor de umidade, diâmetro lateral e transversal do fruto, peso da polpa e das sementes/fruto, número e produção de frutos/planta. Foram observados agrupamentos específicos para os acessos de araçazeiros no método de Tocher e do k-means e na dispersão tridimensional dos quatro CPs. Os acessos de araçazeiros foram separados dos de goiabeira. Não foi observado nenhum agrupamento específico por estado de coleta, indicando a inexistência de barreiras na propagação dos acessos de goiabeira. As análises sugerem a prospecção de maior número de amostras de germoplasma num menor número de regiões, bem como acessos divergentes com alto teor de compostos nutricionais.

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The present study evaluated the effect of the use of natural antioxidants in different spent hens processed meat, the physical-chemical and sensory characteristics of product were analyzed. The experiment was conducted at the Technology Laboratory of Animal Products, Department of Technology - FCAV/Unesp - Campus of Jaboticabal. Forty-five laying hens with approximately 80 weeks of age were used, distributed in a completely randomized experimental design in a 4x4 factorial arrangement, 4 condiment types (control, rosemary, clove and oregano, and the last three natural antioxidants) and 4 storage times (0; 3; 6 and 9 days at 4°C), with sixteen treatments and tree repetitions. It were evaluated the characteristics of humidity, pH, color, cooking loss, shear force, TBARS number and sensory analyze. The averages were obtained by Tukey test 5% of significance. The results showed an interaction between the storage time and condiments types in all analyzed parameters. It was concluded that oregano use decreased the processed meat oxidation, also pleased the judges in sensory analysis. The lowest notes in sensory analysis were obtained with the treatment that contained clove.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Alimentos e Nutrição - FCFAR